Epidemiology of heart failure in rural Chhattisgarh, India

INTRODUCTION

Cardiovascular diseases (CVDs) are the leading cause of death and disability in India resulting in an estimated 14.1% of disability-adjusted life years.¹ CVDs, including heart failure (HF), are leading causes of death and disability in both urban and rural India.² Estimates suggest a HF prevalence of 1.3 million to 22.7 million, with an annual incidence of 0.5–1.8 million in India.^3,4

In urban areas and high-income states, ischaemic heart disease (IHD) is the leading cause of HF.⁵ However, this may not be representative of rural areas. In low- and middle-income countries (LMICs), the portion of HF attributable to IHD in rural areas is less than 1%, but in urban areas can be as high as 18%.⁶ In rural settings, rheumatic heart disease (RHD), non-ischaemic cardiomyopathies, congenital anomalies, and right heart failure (RHF) are larger contributors to HF burden rather than traditional risk factors such as atherosclerosis.^6,7

We describe the characteristics of patients hospitalized for HF in a secondary care hospital in Chhattisgarh in rural central India. The hospital serves primarily indigenous populations and other traditionally deprived social groups. We report HF categories, prevalence of traditional CVD risk factors, and characteristics of HF based on caste as a proxy for structural violence.⁸

METHODS

RESULTS

Of 101 patients identified in the initial screening, 88 were admitted with HF during the study period. Fifty-five patients (62.9%) were women and the mean age was 42.1 years (Table I). The largest social category in our cohort was ST, followed by SC and OBC. The mean BMI at admission was 17.9 kg/m², and over half our patients were underweight.

Tobacco use was more common in men than women, as was hypertension. One in 5 patients had prior pulmonary tuberculosis, while only 7% of patients had diabetes. The median duration of symptoms at presentation was 90 days for men and 30 days for women.

We were able to categorize HF type in 87 patients (Table II). Cardiomyopathy was the most common HF category, followed by RHD and isolated RHF. Of the 32 patients with cardiomyopathy, 5 had coexistent RHD, 5 had peripartum cardiomyopathy, 3 had suspected alcoholic cardiomyopathy, and 2 had suspected myocarditis. Detailed echocardiographic parameters for each category of HF are shown in Supplementary Table II.

In patients with isolated RHF, prior tuberculosis was strongly associated with developing isolated RHF (OR 4.74; Table III). Tobacco use was also associated with a six-fold higher odds of RHF.

DISCUSSION

We studied the epidemiology of HF and clinical outcomes of patients from socially vulnerable communities in rural Chhattisgarh and Madhya Pradesh. Although rural India is also diverse, our study shows that a rural population faces specific risk factors that lead to different aetiologies of HF than in urban India. Patients in our cohort were young and predominantly women. The categories of HF were primarily cardiomyopathy, RHD and RHF. The prevalence of traditional cardiovascular risk factors was low.

Our study is unique in its focus on a rural impoverished population. People living in severe poverty are under-represented in prior studies of HF in India. The Trivandrum Heart Failure Registry (THFR) studied 1205 patients from 13 urban and 5 rural hospitals in Kerala. However, patients from rural hospitals comprised <10% of the cohort analysed¹¹ and the prevalence of poverty in rural Kerala (12%) is far less than that in rural Chhattisgarh (55%) or Madhya Pradesh (42%).¹² The INDUS study surveyed over 10 000 people in a rural community setting for HF, but only 12 patients were identified by symptoms.¹³

The risk factors for HF in our cohort are similar to those in other rural low-income countries such as Rwanda and Haiti,⁶ while different from studies in urban India. HF patients in our study were much younger (42 years) than those in urban India (53–61 years old).^11,14–17 Patients in our study had a lower prevalence of traditional cardiovascular risk factors including diabetes (7% v. 46%–66%), hypertension (11% v. 34%–58%), and tobacco consumption (11% v. 38%–42%) compared with earlier Indian studies.^11,14,15,17 While a majority of patients in other studies were overweight or obese,^15,17 50% of our patients with HF were underweight. Furthermore, the SC and ST groups had the lowest prevalence of diabetes, hypertension, tobacco use and obesity, reflecting an inverse association between the degree of poverty and traditional risk factors for CVD.

While IHD is the leading (40%–72%) cause of HF in studies from urban India and high-income countries,^{3,4,11,14,16,18,19} it may be a minority cause among the 69% of Indians who live in rural areas. In our cohort, cardiomyopathy was the most common category of HF, but only 7 patients had features of possible ischaemic cardiomyopathy including regional wall motion abnormalities or prior history of myocardial infarction.

RHD was a common cause of HF in about one-third of our cohort. The reported percentage of HF in India attributable to RHD varies greatly (3.5%–52%) with most studies reporting less than our study,^{3,4,11,13,14,18} again highlighting the heterogeneity of India and the importance of studies focused on rural populations.

A fair proportion of patients had isolated RHF. Although described in other LMICs as developing secondary to chronic obstructive pulmonary disease (COPD), TB and indoor air pollution,^7,20 RHF has not been described in HF studies from India.^11,15,19 Consistent with prior studies, both smoking and TB were associated with RHF in our study. Post-mortem studies show that between 3.7% and 46% of patients with pulmonary TB develop RHF.²¹ However, RHF is a late manifestation of untreated pulmonary disease, taking an average of 16 years to develop.²² We suspect that studies from urban India did not report TB as an important aetiology of RHF, because patients from these settings do not face the same social and structural barriers to care as rural India.