Socioeconomic gradients in CVD and risk factors

Our previous research identified empirically that, with the exception of smoking,8 CVD risk factors including obesity, diabetes, hypercholesterolaemia and hypertension show a marked gradient where the prevalence of risk factors and proportion of CVD mortality9 increase with corresponding increases in SES.4 SES gradients of similar magnitude and direction are found in the paper by Khetan and colleagues6 for CVD risk factors and control of these risk factors presumably through greater access to treatment and follow-up support among higher SES groups. Among the lowest SES group, 45% of participants had one or more CVD risk factors indicating a widespread prevalence of risk factors across the study population. Although Goyal and colleagues did not directly assess SES–risk factor associations, the increase in CVD risk factors over the study period is likely to be in part related to demographic changes in the community and improvements in the SES profile in the later survey. Many studies with SES–risk factor associations in India have been published since our original review, which has been updated as new evidence becomes available. The current database contains 114 studies and more than 900 SES–CVD and risk factor associations, covering over two times the number of studies and two and a half times the number of association as the initial review. A preliminary analysis of these data indicated that 80% of SES associations with diabetes and obesity were positive compared with 60% of associations between SES and hypertension and hypercholesterolaemia and roughly half of the SES–CVD associations. These findings indicate that although the SES gradients for risk factors are relatively stable, more studies have reported inverse gradients or null associations and the direction of association with CVD is less consistent. Although study quality was not assessed, the majority are cross-sectional and were limited to local or regional coverage and may not be representative of the whole of India.

Although determining the point at which social gradients in CVD and risk factors in India may ‘crossover’ to reflect the direction of SES associations observed in high-income countries remains an important epidemiological question, efforts need to be made to address the growing burden of CVD and risk factors across all segments of Indian society. To do so equitably, however, requires several considerations. First, resource allocation for prevention and treatment of CVD should be proportion to the burden within states or districts and by urban and rural areas. In many rural areas, the population continues to be faced with a substantial burden of communicable diseases and maternal–child under nutrition.10 Continuing efforts are required to ensure progress on improving the social circumstances and conditions in these areas while also promoting improvements in health behaviours such as smoking and poor diet that can improve the CVD risk factor profile. Second, there is an urgent need for national surveillance and monitoring of CVD and risk factors in India to appropriately prepare for any large shifts in the distribution of risk factors and disease. Khetan and colleagues present one possible model for such a surveillance system using community health workers for risk factor screening, education, follow-up and for reaching lower SES groups. Further research is needed on how to scale up such a model and whether integration is possible with existing national systems such as the Sample Registration System or Annual Health Survey. Large cross-sectional surveys such as the National Family Health Survey and District Level Health Survey are also extremely useful in quantifying the burden of disease but challenging to undertake and require commitment and resources to conduct repeat surveys at regular intervals. Finally, as the burden of CVD and risk factors increase, health systems need to develop appropriate mechanisms to ensure equal access to detection, treatment, including access to health workers and medications, and adequate control of CVD and risk factors across SES group. Data from Khetan et al 6 and elsewhere11 12 suggest that inequity in treatment and control of risk factors remains high in India. India has experienced tremendous economic growth in recent decades, but improvements have been remarkably uneven and concentrated among a small minority.13 There is a risk that healthcare resources could follow a similar trajectory amid the target of universal health coverage.