Contribution of sudden cardiac death to total mortality in India - a population based study

Abstract

Introduction: Epidemiology of sudden cardiac death (SCD) in India is understudied.

Methods: We assessed proportion of SCD among total mortality in a population in Southern India using a staged, questionnaire-based kindred-wide approach. Detailed questionnaires (DQs) were completed by medical trainees from 8 medical colleges. Preliminary questionnaires evaluated total deaths in the kindred of a respondent. Deaths due to obvious non-cardiac causes were excluded. DQs were completed for the remaining deaths and categorized using a three-member adjudication system.

Results: A total population of 22,724 was evaluated by 478 respondents, (278 M and 200 F). Out of a total of 2185 deaths, 1691 (77.4%) were recallable. A total of 173 (10.3%; 128 M and 45 F; mean age - 60.8 ± 14 years) deaths were adjudicated as SCD. Of these, 82 (47.3%) were ≤ 60 years of age. Prior MI, LV dysfunction and prior aborted SCD were found in 33.5%, 22.5% and 5.7% respectively. Coronary artery disease (CAD) was observed in 66 (38%) and acute myocardial infarction documented in 30 (17%). At least 1 of 3 CAD risk factors - hypertension, diabetes, or smoking was observed in 80.6%. Proportion of subjects with at least one risk factor for CAD were similar in the age groups above and below 50 years (67.6% vs. 81.7%, p=0.065).

Conclusions: SCD contributed to 10.3% of overall mortality in this population from Southern India. On an average, SCD cases were 5-8 years younger compared to populations reported in the western hemisphere, with a high prevalence of major risk factors for CAD.