This document discusses clinical prediction rules (CPRs), which are decision tools used by clinicians to predict outcomes. It covers the development, validation, and functions of CPRs. Specifically, it outlines 8 standards for developing a CPR, including clearly defining outcomes and predictors, ensuring reliability of predictors, having an adequate sample size, and accurately measuring a CPR's performance. An example CPR for ankle fractures is used to illustrate the development process. The document emphasizes the importance of prospectively validating CPRs in new populations before implementation, to assess their accuracy outside the initial study.
Clinical prediction rule in spinal painNityal Kumar
This lecture is on spinal pain and the clinical methods used in treating the pain. Clinical prediction rules is a research method done systematically describing when to use which method of treatment approach
Evidence based practice (EBP) in physiotherapy Saurab Sharma
This presentation is the classroom lecture for undergraduate physiotherapy students whom I teach at Kathmandu University School of Medical Sciences in Nepal. This is an introductory lecture. Students carry on with steps of EBP in the years to come during the student life and use it for their presentations and clinical learning placement.
Other students too may benefit. I highly encourage other students, especially in some parts of India where EBP is not taught, and is reserved for Master's degree program. I completely disagree with this concept, as EBP is the pillar of a responsible physiotherapy practice. Early it starts, better it is.
Neurophysiological Facilitation of Respiration is a treatment technique used for respiratory care of patients with unconscious or non-alert, and ventilated, and also with a neurological condition
NPF is the use of external proprioceptive and tactile stimuli that produce reflex respiratory movement responses and that increase the rate and depth of breathing
Clinical prediction rule in spinal painNityal Kumar
This lecture is on spinal pain and the clinical methods used in treating the pain. Clinical prediction rules is a research method done systematically describing when to use which method of treatment approach
Evidence based practice (EBP) in physiotherapy Saurab Sharma
This presentation is the classroom lecture for undergraduate physiotherapy students whom I teach at Kathmandu University School of Medical Sciences in Nepal. This is an introductory lecture. Students carry on with steps of EBP in the years to come during the student life and use it for their presentations and clinical learning placement.
Other students too may benefit. I highly encourage other students, especially in some parts of India where EBP is not taught, and is reserved for Master's degree program. I completely disagree with this concept, as EBP is the pillar of a responsible physiotherapy practice. Early it starts, better it is.
Neurophysiological Facilitation of Respiration is a treatment technique used for respiratory care of patients with unconscious or non-alert, and ventilated, and also with a neurological condition
NPF is the use of external proprioceptive and tactile stimuli that produce reflex respiratory movement responses and that increase the rate and depth of breathing
Clinical reasoning is one of the pillars for good physiotherapy practice. It is an integral component of evidence based practice. It is a thought process that develops over time in a clinician. The first step is to start thinking of a clinical problem.
The lecture is delivered to first year physiotherapy students at Kathmandu University School of Medical Sciences, Nepal. The students will continue with case discussion using similar model proposed by Mark Jones and Darren Rivett in his book. Further real cases and the cases in Mark Jones will be discussed in the subsequent classes over the Bachelor of Physiotherapy course.
Clinical research is quite vital in the field of physiotherapy. Physiotherapists depends on information from researches to enhance the knowledge they have already gained through their university education and with continuous education courses.
Various types of muscle imbalance occurs in human body due to either articular, fascial or neural causes. as described by Janda this slide show elaborates on the same aspect and also differentiates two schools of thoughts on muscle imbalance, its assessment and treatment in the view of physiotherapy.
A highly structured, goal-oriented, individualized intervention program designed to return the employee to work. Our Work Hardening programs are multidisciplinary in nature and utilize real or simulated work activities designed to restore physical, behavioral and vocational functions.
Corrective exercises in the treatment of scoliosisNikos Karavidas
Physiotherapeutic Scoliosis Specific Exercises (PSSE) can be used as an exclusive treatment for mild scoliosis and in combination with bracing for greater curves. There are 3 RCT's and 1 Systematic review with meta-analysis, which prove the effectiveness of the PSSE (Level of Evidence I)
Knee joint anatomy, biomechanics, pathomechanics and assessmentRadhika Chintamani
the knee complex complete anatomy, biomechanics, pathomechanics and its physical assessment in one single slideshow.a brief table given for easy understanding of what special test to be performed in which condition along with evidences of each special test.
small correction in slide number: 10
during flexion of tibia over femur in OKC; tibia glides and rolls posteriorly
during extension of tibia over femur in OKC: tibia glides and rolls anteriorly
The 6-minute walk test (6MWT) is an easy to perform and practical test that has been used in the assessment of patients with a variety of cardiopulmonary diseases including pulmonary arterial hypertension (PAH). It simply measures the distance that a patient can walk on a flat, hard surface in a period of 6 minutes.
Clinical reasoning is one of the pillars for good physiotherapy practice. It is an integral component of evidence based practice. It is a thought process that develops over time in a clinician. The first step is to start thinking of a clinical problem.
The lecture is delivered to first year physiotherapy students at Kathmandu University School of Medical Sciences, Nepal. The students will continue with case discussion using similar model proposed by Mark Jones and Darren Rivett in his book. Further real cases and the cases in Mark Jones will be discussed in the subsequent classes over the Bachelor of Physiotherapy course.
Clinical research is quite vital in the field of physiotherapy. Physiotherapists depends on information from researches to enhance the knowledge they have already gained through their university education and with continuous education courses.
Various types of muscle imbalance occurs in human body due to either articular, fascial or neural causes. as described by Janda this slide show elaborates on the same aspect and also differentiates two schools of thoughts on muscle imbalance, its assessment and treatment in the view of physiotherapy.
A highly structured, goal-oriented, individualized intervention program designed to return the employee to work. Our Work Hardening programs are multidisciplinary in nature and utilize real or simulated work activities designed to restore physical, behavioral and vocational functions.
Corrective exercises in the treatment of scoliosisNikos Karavidas
Physiotherapeutic Scoliosis Specific Exercises (PSSE) can be used as an exclusive treatment for mild scoliosis and in combination with bracing for greater curves. There are 3 RCT's and 1 Systematic review with meta-analysis, which prove the effectiveness of the PSSE (Level of Evidence I)
Knee joint anatomy, biomechanics, pathomechanics and assessmentRadhika Chintamani
the knee complex complete anatomy, biomechanics, pathomechanics and its physical assessment in one single slideshow.a brief table given for easy understanding of what special test to be performed in which condition along with evidences of each special test.
small correction in slide number: 10
during flexion of tibia over femur in OKC; tibia glides and rolls posteriorly
during extension of tibia over femur in OKC: tibia glides and rolls anteriorly
The 6-minute walk test (6MWT) is an easy to perform and practical test that has been used in the assessment of patients with a variety of cardiopulmonary diseases including pulmonary arterial hypertension (PAH). It simply measures the distance that a patient can walk on a flat, hard surface in a period of 6 minutes.
Discover the most common reasons why people everyday experience foot and ankle pain, and what can be done to prevent and treat the problem. This informative slideshow was created by Advanced Podiatry of Tampa, Florida.
Common foot and ankle injuries and diseasesCATHY WILLIAMS
At RNV Podiatry, Dr. Rachel N. Verville provides you with the best treatment for your foot and ankle problems in Plano, Frisco, and Dallas, Texas.
http://www.rnvpodiatry.com/arthritic-foot-ankle-plano-texas.html
Common Foot and Ankle Injuries: You Don’t Have to Suffer!Summit Health
Join us for a lecture on common foot and ankle injuries, diseases, and conditions, including skin lesions/soft tissue masses, fungal nails, plantar fasciitis, bursitis, hammertoes, bunions, tendonitis, ankle sprains, and arthritis. In addition to discussing causes, the lecture will focus on treatments that can help you get back on your feet!
JOURNAL CLUB ON CORONALLY ADVANCED FLAP vs THE POUCH TECHNIQUE COMBINED WITH ...Shilpa Shiv
CORONALLY ADVANCED FLAP vs THE POUCH TECHNIQUE COMBINED WITH A CONNECTIVE TISSUE GRAFT TO TREAT MILLER'S CLASS I GINGIVAL RECESSION, JCP 2014;41(4):387-395.
Clinical trials: quo vadis in the age of covid?Stephen Senn
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Big Data Meets Biomedicine: Opportunities & ChallengesJen-Hsiang Chuang
There has been a dramatic increase in the number of publications using big data for biomedical applications in recent years. Although biomedical data with heterogeneous and unstructured data sources are increasing rapidly, it is expected that investments in big data applications in biomedicine have the potential to improve disease management from diagnosis to prevention to personalized medicine.
Health Information Technology for Disease Surveillance & Response: H7N9 as ...Jen-Hsiang Chuang
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New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
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Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
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CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
micro teaching on communication m.sc nursing.pdfAnurag Sharma
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Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
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Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
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2. Clinical Prediction Rules (CPRs)
• Synonym: clinical decision rules
• Definition: decision-making tools for
clinicians including 3 or more variables
– Provide the probability of an outcome
– Suggest a diagnostic or therapeutic course of
action
Laupacis A, et al. Clinical prediction rules. JAMA 1997;277:488-494. 2
3. Clinical Prediction Rules Vs.
Clinical Practice Guidelines
• Clinical prediction rules
– Derived from original research involving many
patients and mathematical analysis
• Clinical practice guidelines
– Consensus among experts
– GOBSAT (Good Old Boys Sat At Table)
(Miller J, et al. Lancet 2000;355:82-3)
– But can include CPRs
3
4. Functions of CPRs
• CPRs help clinicians cope with uncertainty
and improve efficiency
– Cope with uncertainty
• Community-acquired pneumonia (Fine MJ,
et al. NEJM 1997;336:243-250)
– Improve efficiency
• Ottawa Ankle Rules for the use of
radiography (Stiell IG, et al. Ann Emerg
Med 1992;21:384-90)
Stiell IG, et al. Annals Emergency Med 1999;33:437-47. 4
5. Prototype of a CPR for
Predicting Death
Predictor variables Score
Age > 75 yr 6
Severe pain 10
Emergency 5
Total points 0-21
Interpretation of the score
High risk: > 6 points (30% deaths) -> aggressive Tx
Low risk: ≤ 6 points (3% deaths) -> conservative Tx
Wasson JH, et al. Clinical prediction rules. NEJM 1985;313:793-9. 5
6. Three Stages in the
Evaluation of a CPR
1. Development of a CPR
2. Prospective validation of a CPR
3. Impact analysis of a CPR
McGinn TG, et al. Users’ guide to the medical literature. JAMA 2000;284:79-84. 6
7. So What?
• Q: “Give me the reasons why I need to stay
here to listen your presentation?”
• A: a medical informatician may play two
roles
– Reader role
– Developer role
7
9. Checklist of Standards for
Development of a CPR
1. Definition of outcome
2. Definition of predictor variables
3. Reliability of predictor variables
4. Selection of subjects
5. Sample size
6. Mathematical techniques
7. Sensibility of CPR
8. Accuracy
Stiell IG, et al. Annals Emergency Med 1999;33:437-47. 9
10. 1. Definition of Outcome
• Clearly defined and clinically important
– Explicit criteria for diagnosis
– Biologic better than behavioral outcome
• Blind assessment of outcome
– More important for a “soft” outcome
– Less important for a “hard” outcome
10
11. 2. Definition of Predictor Variables
• Clearly defined
– Best: collected prospectively, specifically
– Less good: collected prospectively as part of
another study
– Worst: collected from retrospective review of
records
• Blind assessment of predictor variables
11
12. 3. Reliability of Predictor Variables
• Only reliable variables be included
– Intraobserver reliability
– Interobserver reliability
• Measurement of reliability
– Dichotomous or nominal data: κ
– Ordinal data: weighted κ
– Continuous data: intraclass correlation
coefficient
http://www.dmi.columbia.edu/homepages/chuangj/kappa/
12
13. 4. Selection of Subjects
• Patient characteristics stated
– Inclusion and exclusion criteria
– Method of selection
– Clinical and demographic characteristics
• Study site described
– Type of institution (primary, secondary,
tertiary)
– Setting (clinic, ER, hospital ward)
– Teaching or non-teaching
13
14. 5. Sample Size
• Overfitting problem
– Too few outcome events per predictor variable
• Appropriate sample size
– Rule of thumb: at least 10 outcome events per
independent variable
– e.g., 3 findings to predict death => at least 30
patients died
14
15. 6. Mathematical Techniques
• Mathematical methods adequately described and justified
– Multivariate analysis
• Logistic regression
• Discriminant analysis
– Machine learning
• Recursive partitioning (including decision tree
learning)
• Neural networks
– Survival analysis (survival data only)
• Cox's Proportional Hazard Model
15
16. Multivariate Analysis
• General model
• Logistic regression
– Where P is probability of outcome; G is log odds of
outcome
• Discriminant analysis
– Compute cutoff (C)
– Assign patient to class 1 if G < C; otherwise assign
patient to class 2
nn xbxbxbbG ++++= 22110
P
P
G
−
=
1
ln
16
17. Logistic Regression Vs.
Discriminant Analysis
• Logistic regression is much more popular than
discriminant analysis (Concato et, al. 1993)
– Logistic regression
• Binary outcome
• Estimate individual risk and odds ratios
– Discriminant analysis
• Categorical outcome
• Optimal performance requires many predictor
variables as continuous data
• Famous application: diagnosis alcoholism
17
18. Recursive Partitioning
• Principle
– Build an empirical tree diagram by repetitively
splitting patient population into smaller and
smaller categories
Yes No
4
5Employed
2
1
Yes
3
No
Age>30
18
19. Recursive Partitioning Vs.
Multivariate Analysis
• Recursive partitioning provides a simpler
classification rule
• Recursive partitioning may identify
nonlinear relationships with outcome event
• Recursive partitioning need greater sample
size
• Logistic regression can estimate individual
risk and odds ratios
Cook EF, et al. J Chron Dis 1984;37:721-31. 19
20. Cross SS, et al. Introduction to neural network. Lancet 1995;346:1075-9.
Neural Networks
20
21. Clinical Applications of
Neural Networks
• Diagnosis
– AMI, Appendicitis, back pain, dementia, STD
• Imaging
– Radiographs, PET, NMR, perfusion scans
• Analysis of wave forms
– ECGs, EEGs
• Outcome prediction
– Recovery from surgery, cancer, liver transplantation
• Identification of pathological specimens
• Genomics
Baxt WG. Application of ANN to clinical medicine. Lancet 1995;346:1135-8.
21
22. Kattan MW, et al. ANN for medical classification decisions. Arch Pathol Lab Med 1995;119:672-7.
Advantages of Neural Networks
•Multiple partitioning
•Nonlinear partitioning
22
23. Disadvantages of Neural
Networks
• Slow to train
• “Black-boxes”
Kattan MW, et al. ANN for medical classification decisions. Arch Pathol Lab Med 1995;119:672-7.23
24. 7. Sensibility of CPR
• “Sensibility”
– clinically reasonable, easy to use, course of action
described
– judgment
• Clinically reasonable
– Content validity
• Easy to use
– Length of time needed to apply
– Simplicity of interpretation
• Course of action described
24
25. 8. Accuracy of CPR
• Rationale
• Measurement of accuracy
– 2x2 table with sensitivity, specificity, with
respective 95% CIs
– Receiver operator characteristic (ROC) curves
• Statistical validation
– Cross-validation: Training set vs. test set
Wasson JH, et al. Clinical prediction rules. NEJM 1985;313:793-9. 25
26. Classification
Performance of a CPR
Predicted
Outcome
Actual Outcome
Disease No Disease
Disease 74 244
No Disease 0 247
Sensitivity (95% CI): 1.0 (0.95-1.0)
Specificity (95% CI): 0.50 (0.46-0.55)
Stiell IG, et al. Implementation of the Ottawa Ankle Rules. JAMA 1994;271:827-32. 26
27. Kuo HS, Chuang JH, Tang GJ, et al. Chin Med J (Taipei) 1999;62:673-681.
27
28. Example: Development of a CPR
Ottawa Ankle Rules
Stiell IG, et al. Ann Emerg Med 1992;21:384-90
28
30. The Need for an Ankle Rule
• Blunt ankle trauma
– One of the most common injuries in ER
– Less than 15% of patients have fractures
– Physicians used to order radiography for all
ankle injury patients
– 85% negative for fracture
– $500 M annually in North America
– No widely accepted guideline
Stiell IG, et al. Implementation of the Ottawa Ankle Rules. JAMA 1994;271:827-32. 30
31. Study Design
• Objective
– Develop CPR with 100% sensitivity
• Design
– Prospective survey of ED patients over 5 months
• Patient population:
– Setting: Two university hospital EDs in Ottawa
– Inclusion: All acute blunt injuries of ankle
– Exclusion: < 18 y/o, pregnant, referral, etc
• Data collection
– 32 clinical variables collected by 21 trained physicians
before radiography
– 100 patients examined by a 2nd
physician 31
32. Study Design (Cont.)
• Measurements of outcomes
– Radiography interpreted by a radiologist blinded to the
contents of data collection sheets
• No fracture or insignificant fracture
• Clinically significant fracture
• Data analysis
– Variables found to be both strongly associated with a
significant fracture (P < 0.05) and reliable (κ > 0.6)
were analyzed by logistic regression and recursive
partitioning
32
33. Results
• 70 (10.2%) significant malleolar fractures in
689 ankle injury patients
• Univariate analysis: 17 variables were
significantly associated with fractures
• 9 non-reliable variables were further
eliminated
• Logistic regression: Sen: 1.0, Spe: .29
• Recursive partitioning: Sen: 1.0, Spe: .40
33
34. 689
561128
70#
39#
Yes No
31#
67
Yes
12# 494
No
19#
21118#
Yes
283
No
1#
35 248
0#
NoYes
1#
441
High Risk 248 Low Risk
A
B
C
D
LEGEND
# Fracture
A Unable to bear weight
immediately and in ED
B Age 55 or greater
C Bone tenderness B4 or B5
D Bone tenderness B8 or B9
Recursive Partitioning of 689 Cases
34
36. Problems of CPRs With
Statistical Validation Only
• Many statistically derived rules fail to
perform well when tested in a new
population
– Overfitting or instability in the original derived
model
– Differences in prevalence of disease
– Differences in severity of cases
– Differences in how the CPR is applied
Stiell IG, et al. Annals Emergency Med 1999;33:437-47. 36
37. Prospective Validation of a CPR
• Validation
– Its repeated application leads to the same
results
• Types of validation
– Narrow validation: application of rule in a
similar setting and population
– Broad validation: application of rule in multiple
clinical settings with varying prevalence and
outcomes of disease
McGinn TG, et al. Users’ guide to the medical literature. JAMA 2000;284:79-84. 37
38. Development of a Clinical
Prediction Rule
McGinn TG, et al. Users’ guide to the medical literature. JAMA 2000;284:79-84. 38
39. Methodological Standards for
Validation of a CPR
• Unbiased, wide spectrum patient population
• Blinded assessment of outcomes and
predictor variables
• Careful follow-up of predicted normal
patients
• Training for correctly applying rules
McGinn TG, et al. Users’ guide to the medical literature. JAMA 2000;284:79-84. 39
40. Results of Validation Studies of
Ottawa Ankle Rules
Markert RJ, et al. Am J Emerg Med 1998;16:564-7.
Country
(Year)
# of
Subjects
Sensitivity
(%)
Specificity
(%)
CA (1993) 1032 100 39
US (1994) 71 100 19
NZ (1994) 350 93 11
US (1994) 631 100 19
US (1995) 422 95 16
40
42. Reasons for No Impact
of an Accurate CPR
• Clinician’s intuition may be as good as the
CPR
• Calculations involved may be cumbersome
• Practical barriers to acting on the results of
CPR
– Medical liability risk
– Patient demand factor
McGinn TG, et al. Users’ guide to the medical literature. JAMA 2000;284:79-84. 42
43. Methodological Standards for
Impact Analysis of a CPR
• Study design
– Cluster-based randomized control trial
– Before-after study
• Effect on use
– e.g., ordering of radiography
• Accuracy of rule
• Acceptability of physicians & patients
Stiell IG, et al. Annals Emergency Med 1999;33:437-47. 43
44. Impact Analysis of Ottawa
Ankle Rules in France
• Randomized 5 EDs to use or not use CPR
• 2 in intervention group (906 patients)
– Meeting, pocket cards, posters, and data collection
forms
• 3 in usual care group (1005 patients)
– data collection forms only
• Results: (unit of analysis was physician)
– ordering of radiography: I: 79%; C: 99% (P=.03)
– I: 3/112 missed fractures (incomplete data forms: 2,
rule interpretation error by physician: 1)
Auleley GR, et al. JAMA 1997;277:1935-9. 44
45. Summary
• Development of an effective prediction rule
is a long, rigorous, and expensive process
• Properly developed and validated prediction
rules can influence clinical practice
45
46. Performance Evaluation
• Discrimination
– Ability of a prediction model to separate those
who experience events from those who do not
– Area under a ROC curve (c statistic)
• Calibration
– Measures how closely predicted outcomes
agree with actual outcomes
– Hosmer-Lemeshow goodness-of-fit test
46