Distribution of 10-Year and Lifetime Predicted Risk for Cardiovascular Disease in the Indian Sentinel Surveillance Study Population (Cross-Sectional Survey Results)
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View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by PubMed Central Open Access Research Distribution of 10-year and lifetime predicted risk for cardiovascular disease in the Indian Sentinel Surveillance Study population (cross-sectional survey results) Panniyammakal Jeemon,1,2,3 Dorairaj Prabhakaran,1,3,4 Mark D Huffman,1,5 Lakshmy Ramakrishnan,6 Shifalika Goenka,1 K R Thankappan,7 V Mohan,8 Prashant P Joshi,9 B V M Mohan,10 F Ahmed,11 Meera Ramanathan,12 R Ahuja,13 Vivek Chaturvedi,14 Donald M Lloyd-Jones,5 K Srinath Reddy,3 on behalf of the Sentinel Surveillance in Industrial Populations Study Group To cite: Jeemon P, ABSTRACT ARTICLE SUMMARY Prabhakaran D, Huffman MD, Introduction: Cardiovascular disease (CVD) et al . Distribution of 10-year prevention guidelines recommend lifetime risk and lifetime predicted risk for Article focus stratification for primary prevention of CVD, but no - cardiovascular disease in the Lifetime risk of cardiovascular disease (CVD) in Indian Sentinel Surveillance such risk stratification has been performed in India to the Indian population. Study population date. - Gender differences in lifetime risk of CVD. (cross-sectional survey Methods: The authors estimated short-term and - Educational status and lifetime risk of CVD. results). BMJ Open 2011;1: lifetime predicted CVD risk among 10 054 disease-free, e000068. doi:10.1136/ adult Indians in the 20e69-year age group who Key messages bmjopen-2011-000068 participated in a nationwide risk factor surveillance - Nearly half of individuals with a low short-term study. The study population was then stratified into predicted risk had a high predicted lifetime risk < Prepublication history for high short-term ($10% 10-year risk or diabetes), low for CVD. this paper is available online. short-term (<10%)/high lifetime and low short-term/ - The proportion of individuals with all optimal risk To view these files please factors was 15%. visit the journal online (http:// low lifetime CVD risk groups. - A significantly lower proportion of individuals in bmjopen.bmj.com). Results: The mean age (SD) of the study population (men¼63%) was 40.8610.9 years. High short-term the lowest educational class had all optimal risk Received 25 January 2011 risk for coronary heart disease was prevalent in more factors compared with individuals in the higher Accepted 25 March 2011 than one-fifth of the population (23.5%, 95% CI 22.7 educational class. - to 24.4). Nearly half of individuals with low short-term Approximately one in two men and three in four This final article is available predicted risk (48.2%, 95% CI 47.1 to 49.3) had a high women from working families in India had low for use under the terms of predicted lifetime risk for CVD. While the proportion of short-term predicted risk for CVD. the Creative Commons Attribution Non-Commercial individuals with all optimal risk factors was 15.3% Strengths and limitations of this study 2.0 Licence; see (95% CI 14.6% to 16.0%), it was 20.6% (95% CI - These are the first estimates to combine short- http://bmjopen.bmj.com 18.7% to 22.6%) and 8.8% (95% CI 7.7% to 10.5%) in term and lifetime predicted risks for CVD in India. the highest and lowest educational groups, - Our simple cardiovascular-risk-factor counting respectively. strategy provides a good way of identifying Conclusion: Approximately one in two men and three individuals at high and low lifetime risk for CVD, in four women in India had low short-term predicted but the lifetime CVD risk prediction model has risks for CVD in this national study, based on not been validated or calibrated in India. aggregate risk factor burden. However, two in three men and one in two women had high lifetime predicted 1 risks for CVD, highlighting a key limitation of nearly one-third of all deaths. Coronary heart short-term risk stratification. disease (CHD) deaths, a major contributor to CVD deaths in India, rose from 1.17 million in 1990 to 1.59 million in 2000 and are further For numbered affiliations see projected to rise to 2.03 million in 2010.2 Risk end of article. stratification and identification of individuals Correspondence to INTRODUCTION with a high risk for CHD who could poten- Dr Dorairaj Prabhakaran; Cardiovascular disease (CVD) is the leading tially benefit from intensive primary preven- [email protected] cause of death in India, contributing to tion efforts are critically important in Jeemon P, Prabhakaran D, Huffman MD, et al. BMJ Open 2011;1:e000068. doi:10.1136/bmjopen-2011-000068 1 Lifetime CVD risk stratification in the Indian population reducing the burden of CVD in India. Short-term CHD and their family members) by stratified random risk assessment and stratification tools have been widely subsampling for biochemical analysis. The study is used for risk stratification among asymptomatic individ- approved by ethic committee/institutional review boards e uals who are clinically free of CHD.3 11 However, of all participating academic institutes, and written a significant proportion of CHD events occur among informed consent was obtained from all participants. A individuals with a relatively low short-term (10 year) total of 19 973 (11 898 men) individuals consented to predicted CHD risk,12 as many of them become high-risk participate in the questionnaire survey and 10 543 indi- across the lifespan. Lifetime CVD risk estimation, which viduals for the biochemical analysis in the age group of measures the cumulative risk of developing the disease 20e69 years. Individuals with a past history of CHD, during the remainder of an individual’s lifespan, may missing values for age, systolic blood pressure (SBP), provide a more appropriate assessment on future CVD total cholesterol (TC), HDL cholesterol (HDL-c), risk than short-term (typically 10 year) risk estimates, plasma glucose (PG), antihypertensive treatment history especially in younger individuals in whom short-term and tobacco use were excluded from the analysis. The risks are low. Therefore, various guidelines now recom- final database included 10 054 individuals. mend stepwise stratification of asymptomatic and disease- Socio-demographics, lifestyle habits, medications and free individuals into high short-term, low short-term/ medical history (including the Rose angina question- high lifetime and low short-term/low lifetime CHD risk naire) were assessed using a structured questionnaire groups for targeting primary prevention strategies in all administered by trained study staff. Standard procedures e eligible individuals.13 16 and equipments were used to measure body weight and Short-term CHD risk prediction models discriminate height. Blood pressure was measured using automated reasonably well across ethnic groups17 but need to be BP monitoring equipment (Omron MX3, Bannockburn, recalibrated based on the differences in age- and sex- Illinois, USA). Two measurements were taken at least specific disease incidence rates of the population in 5 min apart before collecting the blood samples and question. Since Indians have been shown to have averaged. Study participants were instructed in advance a higher risk factor burden at younger ages compared not to consume any drinks and tobacco at least 1 h with Western populations,18 risk prediction models before attending the screening clinic. A fasting blood developed in Western countries may underestimate sample was also collected (minimum 8 h fasting) for short-term CHD risk. Short-term risk prediction models, biochemical analysis of PG and serum lipids. The central such as the Framingham Risk Score, have been recali- coordinating laboratory reanalysed 10% of the brated for Indian emigrants to the UK in the ETHRISK biochemical samples and reported less than 5% coeffi- calculator19 and to a small rural population in India.20 cient of variation between the central coordinating However, no lifetime risk models have been available for laboratory results and the individual laboratory results. Indians living in India. We report here the estimates of lifetime CVD risk Risk factor definitions among disease-free, adult Indians who participated in Current tobacco use was defined as the use of any form of a nationwide risk factor surveillance study in industrial tobacco products (smoking and smokeless form) in the settings, using a previously published short-term and previous 30 days. Obesity was defined as a body mass $ 2 lifetime risk algorithm based on traditional CVD risk index (BMI) of 30 kg/m . Diabetes was defined as $ 23 factors (age, sex, total and high-density lipoprotein either a fasting PG value of 126 mg/dl or on medi- cholesterol, tobacco, blood pressure, antihypertensive cation for diabetes. CHD was defined as physician- treatment, and diabetes).13 21 confirmed myocardial infarction or unstable angina or symptoms suggestive of CHD from the Rose angina METHODS questionnaire. Low high-density cholesterol (HDL-c) was Study participants defined as an HDL-c of <40 mg/dl for men or <50 mg/dl We identified eligible individuals from the Sentinel for women.13 Surveillance study in the Indian industrial Population (SSIP) database. The details of the SSIP study have been Short-term and lifetime risk stratification described previously.22 Briefly, 10 medium-to-large The 10-year short-term predicted risk for CHD events industries (defined as industries employing 1500e5000 (myocardial infarction or coronary death) was estimated people) were selected from different sites spread across for all participants using the Adult Treatment Panel III India, from both public and private sectors, based on (ATP III) risk-assessment tool.13 17 A high short-term their willingness to participate in the study and prox- predicted risk was defined as a 10-year predicted risk for imity to an academic medical institution. All employees a hard CHD event (death, myocardial infarction) of and their family members between the ages of 20 and $10% or diagnosed diabetes.24 Among individuals with 69 years were eligible to be included in the survey.