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Overview of the systematic review process

Systematic review and meta-analysis

Source & acknowledgement

https://www.terripigott.com/meta-analysis https://mason.gmu.edu/~dwilsonb/ma.html https://www.campbellcollaboration.org/research-resources/training-courses.html https://handbook-5-1.cochrane.org/ https://www.youtube.com/user/Biostat100 https://www.youtube.com/user/collaborationtube https://www.meta-analysis.com/pages/videotutorials.php?cart=BWJJ3522355

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Overview of the systematic review process

  1. 1. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Systematic Reviews – An overview Dr. S. A. Rizwan M.D., Public Health Specialist & Lecturer, Saudi Board of Preventive Medicine – Riyadh, Ministry of Health, KSA 24.11.2019
  2. 2. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Overview of the course 24.11.2019
  3. 3. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Resources • Book: Practical Meta-analysis (Lipsey and Wilson) • Cochrane Handbook https://handbook-5-1.cochrane.org/ (Ch 7,8,16) • Campbell Collaboration https://www.campbellcollaboration.org/ • Online YT course: https://www.youtube.com/watch?v=pP7_VBrG_TY&list=PL- h5cI5Bkvt0J-O0kq_9J9_aksWFPgR7s • And accompanying book https://indd.adobe.com/view/5fc8f9a0- bf1e-49d3-bf5f-a40bfe5409e0 24.11.2019
  4. 4. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Overview of steps in SRMA • Introduction • Steps in systematic review • Data extraction • Quality assessment • Analysis and interpretation • Report writing • Publishing • Challenges 24.11.2019
  5. 5. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Where do we stand? 24.11.2019
  6. 6. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Purpose / objective Why do I need to know about systematic reviews? 24.11.2019
  7. 7. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Because it is highest level of evidence 24.11.2019
  8. 8. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Just a formality 24.11.2019
  9. 9. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course To truly understand research in context 24.11.2019
  10. 10. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course To practice ethically 24.11.2019
  11. 11. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course To sound more knowledgeable 24.11.2019
  12. 12. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course To make yourself less gullible Oh Really!! 24.11.2019
  13. 13. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Because it is part of the knowledge translation 24.11.2019
  14. 14. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Steps in systematic review • Team formation • Topic selection • Protocol and registration • Search strategy • Selection of studies • Data extraction • Quality assessment • Meta-analysis and interpretation • Report writing 24.11.2019
  15. 15. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Form a team 24.11.2019
  16. 16. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Brain storm ideas 24.11.2019
  17. 17. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Select one of the best ideas 24.11.2019
  18. 18. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Choosing a topic • Where there is still no concrete evidence for one argument – dilemma • Novel • Interesting • Feasible • Enough literature is around • Global, regional or national • Make sure there isn’t one already existing 24.11.2019
  19. 19. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Don’t reinvent the wheel • Check first in: • PubMed • Google Scholar • PROSPERO • Cochrane Library • Campbell Collaboration Reviews 24.11.2019
  20. 20. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Types of research questions 24.11.2019
  21. 21. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Examples of research questions 24.11.2019
  22. 22. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course What study design to look for in different situations 24.11.2019
  23. 23. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Example of a clinical research question 24.11.2019
  24. 24. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Example of an epidemiology research question 24.11.2019
  25. 25. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Write the protocol and register 24.11.2019
  26. 26. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Develop and apply search strategy Topical herbal interventions for gingivitis 24.11.2019
  27. 27. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Select the relevant studies 24.11.2019
  28. 28. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Try to make out if it makes any sense 24.11.2019
  29. 29. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Put the sense into words 24.11.2019
  30. 30. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Also, mention why it may not make any sense to some 24.11.2019
  31. 31. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Disseminate & update 24.11.2019
  32. 32. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course So far… • Deciding the topic and formulating the research question • Prepare the protocol • Search strategy • Selection of studies • So moving on… 24.11.2019
  33. 33. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Data extraction • What • How • Who • Where 24.11.2019
  34. 34. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Extract the data and enter it 24.11.2019
  35. 35. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course What to extract? For analysis • Study ID • Location, year • Study design • Sample size • PICO (TS) • Confounders adjusted • Effect size (95% CI) • Subgroup results • Other relevant For quality assessment • Risk of bias • Selection (Allocation concealment, Sequence, Randomization) • Blinding • Measurement bias • Attrition • Reporting • Sample size adequacy • Representativeness 24.11.2019
  36. 36. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course How to extract? • Read the article completely, not only the relevant sections • Adhere to predefined criteria and codes • Be diligent and avoid errors • If doubtful, mark and discuss with others • If deriving your own effect size, mention it • Keep a track of assumptions 24.11.2019
  37. 37. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Concentrate on the outcome • Each outcome has 5 elements • Domain (caries) • Specific measurement (DMFT) • Specific metrics (change from baseline) • Methods of aggregation (mean, percent) • Time point (at 6 months) 24.11.2019
  38. 38. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Effect size • This is how we are going to express the result of the study • Examples • Prevalence, mean • Odds ratio, relative risk, hazard ratio • Risk difference, mean difference • Diagnostic test measures • Others 24.11.2019
  39. 39. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Who should extract? 24.11.2019
  40. 40. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course How to store? • Codified or in simple text • Must be amenable to checking of double entry • Confidential 24.11.2019
  41. 41. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Examples: prevalence studies 24.11.2019
  42. 42. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Examples: case-control/cohort studies Study ID Year Location Study design Sample size Age Cohort/case/ controls recruitment Exposure Outcome Confounder Comparison OR men OR women OR total Gupta PC, 2005 (8) 1991 - 2000 India, Mumbai Cohort Cohort size=99570 ≥35 All individuals aged >=35 years on the appropriate electoral list were approached by investigators for an interview. Self- reported smoking, chewing, mixed habits Deaths through household interviews. Age, education Exclusive tobacco chewer vs. no habit of tobacco 1.40 (0.95 - 2.06) 1.57 (1.16 - 2.13) 1.50 (1.18 - 1.90) Gajalaksh mi V, 2015a (10) 1995 - 2001 India Case- control Cases=8994 controls=711 37 >25 case, >35 control Deaths were obtained from records in the Village Administrative Offices Proxy- reported for cases, self- reported for controls Verbal autopsy for cause of death Restricted to non- smoking non- alcoholic, adjusted for age and education Exclusive chewer vs. no habit of tobacco & alcohol 1.50 (1.00 - 2.30) 1.70 (1.40 - 2.10) 1.66 (1.38 - 1.99) 24.11.2019
  43. 43. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Examples: RCT 24.11.2019
  44. 44. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Examples: RCT 24.11.2019
  45. 45. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Examples: RCT (in Cochrane) 24.11.2019
  46. 46. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Examples: RCT (in Cochrane) 24.11.2019
  47. 47. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Examples: case reports 24.11.2019
  48. 48. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Examples: case series 24.11.2019
  49. 49. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Examples: animal studies 24.11.2019
  50. 50. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Quality assessment • Reporting guidelines • Critical appraisal • Grading 24.11.2019
  51. 51. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course The dish is only as good as the ingredients we put into making it 24.11.2019
  52. 52. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course RCT Clinical trials, community trials, drug trials, diagnostic trials 24.11.2019
  53. 53. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Reporting guidelines • Whether details are mentioned or not? (intentional or unintentional?) 24.11.2019
  54. 54. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Cochrane ROB tool (6 domains) 24.11.2019
  55. 55. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Example for Cochrane ROB tool 24.11.2019
  56. 56. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Graphing ROB in RCTs • Low ROB • High ROB • Unclear ROB 24.11.2019
  57. 57. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Graphing ROB across studies 24.11.2019
  58. 58. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course ROB summary within and across studies 24.11.2019
  59. 59. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Non-Cochrane tool 24.11.2019
  60. 60. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Observational studies Case control, cohort, cross-sectional studies 24.11.2019
  61. 61. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Reporting guidelines 24.11.2019
  62. 62. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Critical appraisals A Cochrane Risk Of Bias Assessment Tool: for Non-Randomized Studies of Interventions (ACROBAT-NRSI) 24.11.2019
  63. 63. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course ACROBAT-NRSI (7 domains) 24.11.2019
  64. 64. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Example of ACROBAT NRSI tool 24.11.2019
  65. 65. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Graphing ROB 24.11.2019
  66. 66. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course ROB summary 24.11.2019
  67. 67. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Example of ROB non-Cochrane: prevalence studies 24.11.2019
  68. 68. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Observational studies Case series, case reports 24.11.2019
  69. 69. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Reporting guidelines 24.11.2019
  70. 70. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Critical appraisal For case reports For case series 24.11.2019
  71. 71. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Explanation of CEBM tool for case report 24.11.2019
  72. 72. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Explanation of Carey et al tool for case series (8 domains) Domain Yes No Unclear Clearly Defined Question What is it about the natural history of the disease that the author wants to address? Health care utilization? Return to work? Functional status? Well-Described Study Population Case definition, Specific clinical and/or radiologic criteria Are the criteria used clinical? Radiographic? Have they been used before? Is a reference included?, involve explicit inclusion and exclusion criteria, stage of disease or illness, standard descriptive information should include age, gender, socioeconomic status, The number of patients evaluated should be described. How many years did it take to arrive at the sample size? Follow-up of the patients should be consistent, with description of why patients were lost to follow-up, refused the study intervention Well-Described Intervention clear description of the procedure or treatment, sufficiently clear that another center could replicate, cointerventions should be described in reasonable detail 24.11.2019
  73. 73. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Explanation of Carey et al tool for case series (contd.) Domain Yes No Unclear Use of Validated Outcome Measures How was improvement detected in the case series? Individual assessing the patient’s outcome should ideally be masked to the specific intervention Length of observation and the intervals between clinical observations should be standardized and of sufficient duration to be clinically meaningful, some justification as to the duration of follow-up should be provided Appropriate Statistical Analyses statistical tests yielding P values or confidence intervals are not needed and in most cases are inappropriate. However, some types of analyses may be useful, esp. when addressing a lack of improvement, use of historical controls is often misleading. In case of pre-post analysis, tests for paired data should be used. authors sometimes assess many clinical and biologic variables and seize on one or two that demonstrate an improvement. Any statistical testing should address the fact that multiple comparisons are made 24.11.2019
  74. 74. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Explanation of Carey et al tool for case series (contd.) Domain Yes No Unclear Well-Described Results adequacy of follow-up should be described Number of patients who are lost to follow-up, number of patients who switch to another provider or pursue other treatment choices, and number of patients who die from other causes Discussion/Conclusions Supported by the Data conclusion should be supported by the data limitations (and there are always limitations) should be made explicit. If the investigator thinks that the procedure or treatment is ready for a randomized trial, he or she should say so and possibly describe what that trial might look like Funding/Sponsorship potential conflict of interest should be fully disclosed at the time of submission. 24.11.2019
  75. 75. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Example of Carey et al tool for case series 24.11.2019
  76. 76. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Animal studies 24.11.2019
  77. 77. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Reporting guidelines 24.11.2019
  78. 78. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Critical appraisal SYRCLE tool 24.11.2019
  79. 79. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course SYstematic Review Centre for Laboratory animal Experimentation tool 24.11.2019
  80. 80. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Example: SYRCLE tool 24.11.2019
  81. 81. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Explanation of O’ Connor et al tool 24.11.2019
  82. 82. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Example of O’ Connor et al tool 24.11.2019
  83. 83. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Other tools 24.11.2019
  84. 84. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Graphing ROB across studies 24.11.2019
  85. 85. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Analysis and interpretation 24.11.2019
  86. 86. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Two sides Qualitative Quantitative 24.11.2019
  87. 87. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course In other words… 24.11.2019
  88. 88. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Qualitative synthesis 24.11.2019
  89. 89. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course It is like describing a marriage function by observing the people attending 24.11.2019
  90. 90. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Need for qualitative synthesis • To develop and convey a deeper understanding of how an intervention might be working (or not) • Patterns in a body of evidence, yielding a deeper understanding and helping readers to interpret the findings of the quantitative synthesis • Relevance to real-world clinical settings 24.11.2019
  91. 91. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Items to describe • Clinical and methodological characteristics of included studies, including their size, inclusion/exclusion of important subgroups, timelines, etc. • Strengths and limitations of included studies • How flaws in the design or execution of the studies could bias the results (make your reasoning clear) • Relationships between study characteristics and their reported findings • Relevance of individual studies to populations, comparisons, co- interventions, settings, and outcomes or measures of interest 24.11.2019
  92. 92. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Since you are mainly focusing on qualitative synthesis… • Describe the results under different sections to make it easy • Included studies • Excluded studies 24.11.2019
  93. 93. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Characteristics of trial design • Two studies were cluster randomised at the level of the school (Saied-Moallemi 2009; Worthington 2001); with the remaining two trials randomised at the level of the individual (Petrecca 1994; Zanin 2007). One study was conducted in South America (Brazil) Zanin 2007, two in Europe, Petrecca 1994 in Italy and Worthington 2001 in the UK and one in Asia, Saied-Moallemi 2009 in Tehran. • Sample size: In total 2302 children participated in the four studies, of these 1529 children were subject to behavioural interventions and 773 children acted as controls. Sample sizes ranged from 30 (Zanin 2007) to over 400 per group (Petrecca 1994). For a more detailed breakdown of sample size per study please refer to the Characteristics of included studies tables. Two studies reported that power calculations were conducted to inform the sample size (Saied-Moallemi 2009; Zanin 2007), the remaining two studies did not report how the sample size was arrived at. • Of the included studies, two did not state the source of trial funding, the study by Saied-Moallemi 2009 was supported by the Iran Centre for Dental Research and the other study by the National Sugar Bureau (Worthington 2001). 24.11.2019
  94. 94. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Characteristics of the participants • 4 to 7 year olds (baseline) One study was conducted with children aged 4 to 7 years (Zanin 2007). The intervention reported by Zanin 2007, taught an age- appropriate modified toothbrushing technique to the children. This was done through instruction and demonstration. The tech- nique took into account the limited motor control of children at this age and aimed to improve the children’s plaque removal abil- ity. Supervised brushing sessions took place every 3 months. In addition, the intervention involved educational elements which covered dental hygiene and consumption of cariogenic food and drink. • 8 to 12 year olds (baseline) Two studies were conducted with children aged 8 to 12 years (Saied-Moallemi 2009; Worthington 2001). They were both de- livered and monitored by dental professionals, with one involv- ing teachers alongside dental professionals (Saied-Moallemi 2009). Both linked the school programme to the home with varying levels of parental involvement. 24.11.2019
  95. 95. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Characteristics of the interventions In all cases, interventions took the form of educational programmes, broken down into a series of classroom-based lessons. Lessons were designed to fit into the UK national curriculum in one study (Worthington 2001). Details of the design of the interventions of the remaining studies were not reported. All interventions included toothbrushing instruction and skill lessons and information on the use of fluoride toothpaste. Supervised tooth- brushing practice sessions with the children were carried out in two of the interventions (Worthington 2001; Zanin 2007). Although all interventions included dietary elements (as per inclusion cri- teria), the strength of this component varied across the interven- tions. Information around dietary effects was provided through group discussion (Worthington 2001) or lessons (Zanin 2007), or via instruction (Petrecca 1994) and in one study was provided only through leaflets or worksheets (Saied-Moallemi 2009). In all studies, it appeared that the dietary elements came secondary to dental hygiene in terms of the strength of delivery. General dental health information and more detailed information around the behaviour health link was included in all interventions. Interventions were delivered by specifically trained dental nurses (Worthington 2001) and by school health counsellors and teachers (Saied- Moallemi 2009). For the remaining studies, it is unclear who delivered the interventions. Disclosing tablets were used as part of the interventions in one study as part of a classroom activity (Worthington 2001). Structures for transition of the intervention into the home were absent in two of the studies (Petrecca 1994; Zanin 2007). Saied-Moallemi 2009 described one intervention arm that pro- vided parents with leaflets and materials (e.g. brushing charts and worksheets) used in the school with the aim of getting the parents to replicate the intervention at home (these children did not receive an intervention in school). The remaining intervention arm in this study included a combination of home and school elements, each intended to reinforce the other. One study encouraged a link to the home with the provision of oral health related home work tasks (along the same theme as the work in schools) lasting around 1 hour. Parents or grandparents were required to complete these with the children (Worthington 2001). 24.11.2019
  96. 96. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Characteristics of the interventions In three of the studies, control groups were non-intervention controls; no preventive treatment or instruction was provided (Petrecca 1994; Saied-Moallemi 2009; Worthington 2001). How- ever in one of these studies half the control schools became active at 4 months (Worthington 2001). In the remaining study (Zanin 2007) treatment, including fillings and extractions, was provided as well as an annual supervised toothbrushing session. Of the included trials, two did not report that pilot work had been carried out prior to the development of the intervention (Saied- Moallemi 2009; Zanin 2007). One study conducted pilot work on a population previously examined by the authors (Petrecca 1994) and the remaining study piloted the intervention with children and teachers to test measures, delivery and materials prior to the RCT (Worthington 2001). In the included studies post-intervention outcome measures were reported at 3 months (Saied-Moallemi 2009), 6 months (Zanin 2007) and 1 year after the intervention (Petrecca 1994). Worthington 2001 employed a cross-over design and as such re- ported post-intervention outcome measures at 4 months within phase one and after 3 months for phase two. Only one of the included studies reported having an additional follow-up time point (Petrecca 1994). 24.11.2019
  97. 97. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Excluded studies • Studies not included in this review (and the reason for exclusion) can be found in the Characteristics of excluded studies table. • The most common reason for exclusion was study design. Studies were also excluded where behavioural interventions were provided along side clinical interventions such as sealants or varnish making it impossible to determine the effect of the behavioural intervention alone. Additionally, a substantial number of studies were excluded on the basis that the intervention did not contain the two key components described in the inclusion criteria (oral hygiene and diet) for this review. Most commonly, interventions tended to be based around oral hygiene only. 24.11.2019
  98. 98. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Risk of bias in included studies 24.11.2019
  99. 99. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Interventions and outcomes 24.11.2019
  100. 100. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Incomplete outcome data 24.11.2019
  101. 101. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course A concise overall version Briefly, most of them were population based cohort studies, which was the most appropriate study design for determining the hazard of dying due to SLT exposure. Most of studies documented the cause of death either by linking with national registers or by conducting verbal autopsy during house-to-house visits. In most studies, the cause of death was codified according to ICD. Almost all the studies were carried out in India, USA and Sweden but no eligible study could be retrieved from African (AFR), Eastern Mediterranean (EMR) and Western Pacific (WPR) regions. Almost all the cohort studies included young to middle aged participants (mostly ≥15 years) at entry and most European and American studies analysed the risk for men only, probably because of the low prevalence of SLT use among women. 24.11.2019
  102. 102. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course A concise overall version (Contd.) Except for two case-control studies, the sample size in all the cohort studies ran into tens of thousands of participants indicating adequate internal validity to make valid estimates of mortality ratio, especially for rare outcomes such as cancer. In most studies, the OR was calculated for a comparison between the exclusive SLT user and non-tobacco user, which represented the best possible scenario to delineate the independent effect of SLT. Each study was unique in its handling of confounders and a variety of factors such as age, race, residence, wealth, education, occupation, body mass index, smoking, drinking, exercise, diet and others were considered. As far as the quality of studies is concerned, it has to be borne in mind that the studies included here were observational epidemiological studies and bear the inherent biases associated with such designs.(Web table 3) But nonetheless these were the only study designs capable of delineating the association between SLT use and mortality outcomes within the ethical framework, which does not allow for randomization of individuals to a known carcinogen. 24.11.2019
  103. 103. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Quantitative synthesis 24.11.2019
  104. 104. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course It is like answering to the mindset of a husband… ‫ﻛ‬‫م‬‫ا‬‫ﻟ‬‫ﺛ‬‫ﻣ‬‫ن‬ ? ‫ﻛ‬‫م‬‫ھ‬‫و‬‫ﺟ‬‫ﻣ‬‫ﯾ‬‫ل‬ ? 24.11.2019
  105. 105. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Software names Free • RevMan • R • Meta-analysis add-In for Microsoft Excel • Meta-Essentials • Open Meta-Analyst • Forest plot viewer Paid • Stata • Comprehensive meta-analysis • Stats direct • SAS • SPSS (macros from D. Wilson) http://commfaculty.fullerton.edu/jreinard/meta-analysis_programs.htm 24.11.2019
  106. 106. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Software • Learn one that best suits you and your objective • Use a combination 24.11.2019
  107. 107. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Preparing the data for analysis • Study ID • Year • Moderators • Quality variables • Effect sizes and their respective columns 24.11.2019
  108. 108. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Types of analyses • Main or primary analysis • Secondary analysis • Subgroup analysis • Sensitivity analysis • Meta-regression • Publication bias analysis 24.11.2019
  109. 109. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Points to remember • Double check all estimates and analysis • Make sure that the results are in line with existing knowledge • Try to explain abnormalities 24.11.2019
  110. 110. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Writing it up 24.11.2019
  111. 111. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Guidelines/ Checklists 24.11.2019
  112. 112. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Short and crisp but with all the details 24.11.2019
  113. 113. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Plan for a web appendix in advance 24.11.2019
  114. 114. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Critical details should be present in the main script • Complete methodology • Assumptions • Main results with subgroups • Main tables • Flow charts & forest plots • Research in context • Limitation and biases 24.11.2019
  115. 115. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Abstract • Depends on journal • Background • Objectives • Search methods • Selection criteria • Data collection and analysis • Results • Conclusions 24.11.2019
  116. 116. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Research in context • What was already known on this topic? • What this study adds? • Implications of all available evidence 24.11.2019
  117. 117. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Example of research in context 24.11.2019
  118. 118. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Background/ Introduction 24.11.2019
  119. 119. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Methods 24.11.2019
  120. 120. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Methods (contd.) 24.11.2019
  121. 121. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Results 24.11.2019
  122. 122. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Tables • Panels: selection criteria, assumptions • Compulsory • Selected study characteristics • Primary analysis • Depending on study • Secondary analysis • Sensitivity analysis • Meta-regression 24.11.2019
  123. 123. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Figures • Compulsory • Flowchart of study selection • Forest plot for primary analysis (if appropriate) • Publication bias: funnel plot (if appropriate) • Others • Maps • Forest plot for sub groups 24.11.2019
  124. 124. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Discussion 24.11.2019
  125. 125. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Web appendix • Detailed methods • Detailed description of individual studies • Search strategy, keywords used • Removed studies and reasons for removal • Critical appraisal checklist of studies • Maps • Forest plots of subgroups, funnel plots • Assumptions • References • Other analysis 24.11.2019
  126. 126. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Give team members to write different sections and finally streamline 24.11.2019
  127. 127. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Run through at least 3 drafts 24.11.2019
  128. 128. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Get it reviewed by your friends 24.11.2019
  129. 129. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Qualities of good manuscript • Set the premise in an intriguing and scientific manner, generating interest in the reader • Transfer the flow of your thought in a clear and non-confusing manner • Use simple words and stick to the reporting format • Keep main points in paper and shift all ancillary details to supplementary sections • Get it reviewed by experts in the field 24.11.2019
  130. 130. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Write for the target journal • Most journals will not reject a very well conducted systematic review paper • Increasing chances of publication in good journals • Global relevance • Clinical practice changing • Exhaustive literature review • High quality of methodology and analysis 24.11.2019
  131. 131. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course List of possible journals for submission Journal Impact factor Journal Impact factor Lancet 45 AJE 5 BMJ 17 AJPH 4.5 PLOS medicine 15 AJPM 4.5 JNCI 12 Addiction 4 Lancet GH 10 JECH 3.5 IJE 9 NTR 3 Annual review PH 8 BMC public health 2.2 Epidemiology review 8 IJMR 2 BMC medicine 7 Tobacco control 6 Epidemiology 6 WHO bulletin 5 24.11.2019
  132. 132. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Be prepared for rejection • Be ready to answer reviewers 24.11.2019
  133. 133. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Popularize your work • Social media • Facebook • Twitter • Academia • ResearchGate • Local press 24.11.2019
  134. 134. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Repeat!!! Or Take rest!!! Depending on your experience 24.11.2019
  135. 135. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Challenges in doing SRMA • Seems a daunting task • Seems difficult to understand • Consumes time • Lack of guidance • Many unforeseen obstacles 24.11.2019
  136. 136. Saudi Board of Preventive Medicine, Riyadh Ministry of Health, KSA Lecture 01/10 Dr. S. A. Rizwan, M.D.Demystifying statistics series: Meta-analysis course Thank you Kindly email your queries to sarizwan1986@outlook.com 24.11.2019

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