Cardiovascular disease a top killer of Southeast Asian diabetics
Cardiovascular diseases, renal diseases and infections account for majority of the deaths in diabetic Southeast Asians, for which diabetic kidney disease (DKD) is an independent risk factor, according to a recent Singapore study.
Linking medical records from regional hospitals with the Singapore Death Registry Database, researchers identified 2,061 patients (mean age, 57.5±12.1 years; 59.9 percent male) with type 2 diabetes mellitus (T2DM) whose pertinent clinical and biochemical information were obtained. Specific causes of death were identified from the death certificates.
Participants were stratified according to ethnicity. Majority were Chinese (n=1,302; mean age, 58.3±12.5 years; 62.3 percent male), followed by Malays (n=403; mean age, 56.9±11.0 years; 55.5 percent male) and Indians (n=356; mean age, 55.0±11.0 years; 56.7 percent male). The mean duration of diabetes in the overall sample was 11.4±8.7 years and was significantly protracted in Malays (9.8±7.7 years). [Asia Pac J Public Health 2019;doi:10.1177/1010539519849317]
There were 365 deaths reported over a mean follow-up of 5.5±2.9 years and 10,909 patient-years. The resulting crude mortality rate was 33.5 events per 1,000 patient-years. Malays were significantly more likely to die of any cause than their Chinese counterparts.
In terms of specific causes, majority of the deaths were due to cardiovascular disease (44 percent; n=158). This was followed by infections (n=62; 17 percent), renal diseases (n=60; 17 percent), cancer (14 percent; n=49) and other causes (8 percent; n=28). Five mortality events had unknown causes and were excluded from further analysis.
Malays continued to be at a significantly higher risk of death attributable to cardiovascular diseases (hazard ratio [HR], 2.09; 95 percent CI, 1.42–3.10; p<0.001), renal diseases (HR, 2.60; 1.36–4.94; p=0.004) and cancer (HR, 2.68; 1.23–5.84; p=0.01) relative to Chinese participants. Except for cancer, the cause-specific mortality risks in Malays were attenuated after controlling for baseline renal function.
After accounting for covariates, baseline estimated glomerular filtration rate (eGFR) emerged as a significant factor for deaths from cardiovascular (HR, 0.99; 0.98–0.99; p<0.001) and renal (HR, 0.95; 0.93–0.96; p<0.001) diseases. No such effect was observed for deaths from infections and cancers.
Moreover, urinary albumin-creatinine ratio was also significantly correlated with mortality from cardiovascular diseases (HR, 1.30; 1.18–1.43; p<0.001), renal diseases (HR, 1.31; 1.10–1.57; p=0.003) and infections (HR, 1.38; 1.17–1.62; p<0.001). Glycated haemoglobin (HbA1c), in comparison, was significantly associated with all specific causes of death.
“HbA1c was independently associated with all the specific causes of mortality, while presence of [DKD] was associated with higher risks of mortality caused by CVD, renal disease and infection,” researchers said.
“DKD has two roles in mortality risk in our T2DM cohort. One, DKD may progress to end-stage renal failure and directly result in premature mortality. Two, DKD is an established driver of CVD mortality,” they explained. [Nat Rev Nephrol 2016;12:73-81]
Glycaemic control has also been shown to be an important factor for mortality, with an extensive literature linking HbA1c to cardiovascular and renal disease mortality, researchers added. [N Engl J Med 2015;373:1720-1723;; PLoS Med 2010;7:e1000236]
Overall, the present findings underline the importance of preventing and treating DKD, as well as of improving glycaemic control, “to mitigate burden of premature mortality in patients with T2DM,” researchers said.