The document discusses strategies for assessing global disease burden, including the Global Burden of Disease study established by WHO. It examines hypertension specifically, defining it and discussing its prevalence, risk factors, and relationship to cardiovascular outcomes. Hypertension is a leading cause of mortality and disability worldwide according to DALYs. Family history, lifestyle factors like diet and exercise, and conditions like obesity influence hypertension risk.

1. Strategies for
assessment of global
disease burden
Dr. Nagula Praveen

2.  WHO was founded in 1948.
 GBD study – Global Burden of Diseases study (1997)
 Standardized approach to the epidemiological assessment of medical conditions
and risk factors.
 The main categories are
 1. communicable, maternal, neonatal, and nutritional diseases
 2. non- communicable diseases
 3. injuries
 Risk factors associated with these conditions under the main categories are
 A. Environmental risks
 B. Behavioural risks
 C. Metabolic risks

3. Dis Mod - MR
• Can be used to estimate age- , sex-, and country –
specific prevalence from heterogenous and often sparse
data sets.
• Burden associated with each condition is measured as
disability – adjusted life years (DALYs)

4. DALYs
• Combine information regarding premature death (years of
life lost, YLLs) as well as disability caused by the condition
(years lived with disability, YLDs)
• One DALY corresponds to one lost year of health and is
calculated as YLL plus YLD.
• YLDs- multiplying the estimated number of incident cases
by the average duration of the disease and a disability
weight factor (range 0-1 where 0 is total health and 1 is
total disability)

5. Epidemiology and global
burden of hypertension

6. Introduction
• In 2015, exposure to high systolic blood pressure (BP)
accounted for 10.7 million deaths (33.2% of deaths
attributed to all risk factors)
• Nearly 212 DALYs or 20.9 % of DALYs from all risk
factors.
• It is a leading cause of outpatient visits and a major cause
of hospitalization for stroke, chronic kidney disease, heart
failure and other CVDs.

7. • In adults, BP levels for defining hypertension are chosen
based on their relation to cardiovascular morbidity and
mortality.
• In children, the definition of hypertension is arbitrarily
based on the normal distribution of BP in healthy children
and not on BP partition values associated with any
cardiovascular morbidity and mortality.

8. Hypertension
• Chronic elevation of average systolic BP at 140mm Hg or
higher and/or diastolic BP at 90 mmHg or higher.
SBP DBP
Hypertension ≥ 140 mm Hg ≥ 90 mm Hg
High normal 130-139 mm Hg 85-89 mm Hg
normal 120 -129 mm Hg 80-89 mm Hg
ideal <120 mm Hg < 80 mm Hg
Hypertension
( not for ≥ 16 years)
SBP, DBP at 95 percentile for sex, age and height, when
measured on atleast three separate occasions
High normal BP >90 < 95 percentile
Grade I 95 -99 + 5 mm Hg
Grade II > 99 + 5 mm Hg

9. Primary, secondary and resistant
hypertension
• No specific cause can be identified on physical
examination and routine laboratory evaluation.
• Specific etiology of hypertension idenitified
• 5-10% in adults
• Children and adolescentes 85%
• Resistant hypertension – more than target range with
patient using three medications (including diuretic)

10. White coat hypertension
• Average BPs in the doctors office are routinely in the
hypertension range while home BP measurements or 24
hour ambulatory BP measurements show normotension.
• Masked hypertension or white coat normotension
• 23% for SBP , 24% for DBP
• 40% in some studies
• Selenta and colleagues – coined the term

11. WHO STEP wise approach to
surveillance
• Age standardized prevalence of hypertension was 33.2%.
• Prevalence is highest in Africa in the range of 30% for all adults
combined
• Lowest in America at 18%.
• Adverse intrauterine environment and low birth weight
contribute to high BP in children.
• 2.6% increase in risk of high SBP in overweight children
compared with non-overweight children.
• Sedentary lifestyle and physical inactivity were risk factors
• Boys more than girls affected.

12. • Three out of four adults – family history of hypertension
• Half of children – family history of hypertension
• Association is even greater when both parents have
hypertension.
•

13. • Risk of CVD doubles for each increment of 30 m mHg of
SBP or 10mm Hg DBP.
• 40-9 years – increment in BP is associated with two fold
difference in the stroke death rate, and ischaemic heart
disease and from other vascular causes.
• Lower BP does not confer protection against CVD
• >57% of all myocardial infarctions and nearly half of all
strokes occur in persons with BP in the normal range.

14. • Rapsomaniki et al
• 5.2 year median follow up
• Association with high systolic BP were strongest for
intracerebral hemorrhage, sub arachnoid hemorrhage and
stable angina
• Weakest for abdominal aortic aneurysm