New Delhi: Known Covid comorbidities are not expected to have a large impact on the mortality rates in India, compared to a higher income country like England, a new study has found.
The study was conducted to understand how known Covid-19 health risk factors affect mortality rates and the age distribution of mortality in a lower-middle-income country like India, and identify which health conditions drive the differences in a high-income country like England.
“Known Covid-19 health risk factors are not expected to have a large effect on mortality or its age distribution in India relative to England. The high share of Covid-19 deaths from people under age 60 in low and middle income countries (LMICs) remains unexplained,” the study noted.
Published on 16 December in BMJ journal, the study was conducted by researchers from Dartmouth College, Stanford University, and Johns Hopkins University, among others.
The study said high uncontrolled diabetes and respiratory disease make Covid mortality worse in India, but low rates of other illnesses, especially obesity, make up the difference in the UK.
The study found “83.7 per sent of Indian adults are below the age of 60, compared with 69.9 per cent of English adults”.
“Indians have substantially lower rates of obesity and cancer (4.4 per cent and 0.3 per cent in India compared with 27.9 per cent and 2.8 per cent in England), but higher rates of uncontrolled diabetes, kidney disease and chronic liver disease (8.9 per cent, 9.7 per cent and 5.3 per cent in India compared with 2.1 per cent, 5.6 per cent and 2.6 per cent in England,” it said.
Diabetes in India is “overwhelmingly uncontrolled”, said the study. In contrast, three-quarters of all diabetes cases in England are controlled. The report explained that the sum of both controlled and uncontrolled hypertension cases is also higher in India at young ages (40-49 years), but lower at higher ages (70–79 years). England, however, has higher obesity rates at all ages.
“Comorbidities were associated with a 6.26% lower risk of mortality in India compared with England,” the study noted.
Differences in health conditions between India and England have almost no effect on Covid mortality, indicating that the higher share of deaths in younger populations in India comes from the demographic distribution alone, the study said.
“We found that comorbidities identified as key risk factors in high-income countries are not associated with higher expected mortality in India relative to England, in aggregate or among the young,” the study stated.
“This suggests that understanding the other factors that may explain the differential mortality among the young observed in lower income contexts, such as different patterns of infection, under-resourced health systems or comorbidities unique to LMICs, should be a priority for further research,” it added.
The study used three kinds of data — the relative risk of Covid-19 mortality associated with gender, age and each health condition, the age-specific prevalence of each health condition in England and India, and the age and gender distributions for the two countries.
Data was obtained from district-level household survey and the Annual Health Survey in India, and aggregate data were obtained from the Health Survey for England and the Global Burden of Disease, Risk Factors and Injuries Studies.
This was a modelling study, which means it is an analytical methodology that accounts for events over time and across populations, based on data drawn from primary or secondary sources and in the context of healthcare evaluation.
At the time when the study was conducted, India had the second highest number of cumulative Covid-19 infections in the world and one of the highest growth rates in infections.
Citing absence of data on factors leading to Covid-related mortality as the only limitation, the study said, “The key limitation of this study is that there are virtually no data on the Covid-19 mortality risks associated with health conditions that are more common in LMICs than in high-income countries, such as protein calorie malnutrition, micronutrient deficiency and HIV/AIDS.”
It added: “If these conditions make individuals more susceptible to severe infections, then population health may indeed exacerbate the severity of Covid-19 in LMICs.”