Mortality due to diabetes come down in high income countries 

New Delhi: A recent study entitled ‘Contrasting Associations Between Diabetes and Cardiovascular Mortality Rates in Low-, Middle-, and High-Income Countries: Cohort Study Data from 143,567 Individuals in 21 Countries in the PURE Study’, was recently published online in Diabetes Care. This project, called the Prospective Urban Rural Epidemiology (PURE) studyis coordinated by the Population Health Research Institute (PHRI), Hamilton Health Sciences and McMaster University, Canada. PURE includes data from 21 countries which include high-income countries[HIC (Canada, Saudi Arabia, Sweden and United Arab Emirates)], middle-income countries[MIC (Argentina, Brazil, Chile, China, Colombia, Iran, Malaysia, Palestine, Philippines, Poland, South Africa and Turkey)], and low-income countries[LIC (Bangladesh, India, Pakistan, Tanzania and Zimbabwe)] (all countries listed in alphabetical order).

What are the salient features of this study?
•    The Prospective Urban Rural Epidemiological (PURE) is a multicenter, population-based prospective cohort study that enrolled 143,567 adults aged 35 to 70 years from 631 urban and rural communities in 21 countries [16,286 from high income countries (HIC), 94,385 from middle income countries (MIC) and 32,896 from low income countries (LIC)] with a mean follow-up of 9 years.
•    We report for the first time, on differences the incidence of cardiovascular disease and mortality rates in individuals with and without diabetes residing in these 21 high, middle and low-income countries.
What are the novel findings from this study?
•    The study shows that the overall cardiovascular disease rates remain higher in those with diabetes across all regions. However, among those with diabetes, all-cause and cardiovascular mortality were strikingly higher among those with diabetes in LIC, compared to MIC and HIC. 
•    Thus the corresponding rates of all-cause mortality were 13.8 in LIC, 7.2 in MIC and 4.2 inHIC (per 1,000 person years of followup), while those of cardiovascular mortality were 5.7 in LIC, 2.2 in MIC and 1.0 in HIC (per 1,000 person years of followup).
•    When the analysis was performed by categorizing countries based on wealth index, within the LIC, the mortality was higher in those with lowest wealth index compared to the upper two tertiles of wealth, whereas such a clear pattern with the wealth index was not observed in the MIC and HIC.
•    The increased CV mortality in those with diabetes in LIC remained unchanged even after accounting for behavioral risk factors (such as, physical activity level and smoking) and treatments (those on blood pressure lowering drugs, cholesterol lowering drugs, glucose lowering agents and aspirin), whereas in MIC and HIC, there is some reduction of the risk, suggesting that treatment levels remain suboptimal in LIC.

What is the significance of this study?
•    Our results underscore the urgent need to improve access to quality diagnostic and therapeutic health care in those with diabetes in LIC especially in the poorer strata of these countries, so that the excess mortality rates could be reduced.

Dr.R.M.Anjana, the Managing Director of Dr.Mohan’s Diabetes Specialities Centre and Vice President of Madras Diabetes Research Foundation and the first author of the study said, “We report that the all-cause and cardiovascular mortality were markedly higher among those with diabetes in LIC compared to MIC and HIC. These differences between could be related to differences in access to health care systems in HIC, MIC and LIC. We report here on the low use of antidiabetic, antihypertensive and lipid lowering drugs in LIC compared to MIC and HIC even among those with CVD and diabetes. Thus, there is an urgent need to ensure access, and adherence to, CVD risk lowering medications if the mortality rates in LIC and MIC have to improve to the levels currently seen in HIC.”

Dr.V.Mohan, Chairman of Dr.Mohan’s Diabetes Specialities Centre and President of Madras Diabetes Research Foundation said “In this study, we also observed that in the LIC countries which includes India, , the highest mortality rates were observed among individuals in the lowest tertile of personal wealth. The probable reason why there was no clear correlation between mortality rates and wealth index among the HIC and MIC could be that there is a more equitable distribution of healthcare in those countries due to availability of social security systems, insurance and other facilities, whereas in the LIC, there is absence of universal health insurance systems and social support mechanisms”.

Dr Salim Yusuf,  Principal Investigator of the PURE Study from PHRI , Hamilton, Canada and senior author of the study adds “ The findings of this study are very significant as they provide new data on the all cause and cardiovascular mortality rates in people with and without diabetes from regions of the world  belonging to different socio economic levels.  The study points to the urgent need for  provision of quality care through a universal health care package and improved access to quality health care systems if mortality rates due to CVD are to be decreased in LIC, particularly among those with diabetes and those belonging to  the poorer strata of society”