Absolute cardiovascular risk scores and medication use in rural India: a cross-sectional study

Objectives: We compared the performance of laboratory-based cardiovascular risk prediction tools in a low-income and middle-income country setting, and estimated the use of antihypertensive and lipid-lowering medications in those deemed at high risk of a cardiovascular event.

Design: A cross-sectional study.

Setting: The study population comprised adult residents (aged ≥18 years) of the Rishi Valley region located in Chittoor District, south-western Andhra Pradesh, India.

Participants: 7935 participants were surveyed between 2012 and 2015. We computed the 10-year cardiovascular risk and undertook pair-to-pair analyses between various risk tools used to predict a fatal or non-fatal cardiovascular event (Framingham Risk Score (FRS), World Health Organization Risk Score (WHO-RS) and Australian Risk Score (ARS)), or a fatal cardiovascular event (Systematic COronary Risk Evaluation (SCORE-high and SCORE-low)). Concordance was assessed by ordinary least-products (OLP) regression (for risk score) and quadratic weighted kappa (κ_w, for risk category).

Results: Of participants aged 35-74 years, 3.5% had prior cardiovascular disease. The relationships between risk scores were quasi-linear with good agreement between the FRS and ARS (OLP slope=0.96, κ_w=0.89). However, the WHO-RS underestimated cardiovascular risk compared with all other tools. Twenty per cent of participants had ≥20% risk of an event using the ARS; 5% greater than the FRS and nearly threefold greater than the WHO-RS. Similarly, 16% of participants had a risk score ≥5% using SCORE-high which was 6% greater than for SCORE-low. Overall, absolute cardiovascular risk increased with age and was greater in men than women. Only 9%-12% of those deemed 'high risk' were taking lipid-lowering or antihypertensive medication.

Conclusions: Cardiovascular risk prediction tools perform disparately in this setting of disadvantage. Few deemed at high risk were receiving the recommended treatment.