Diabetes Has Lethal Consequences in Asia

Veronica Hackethal, MD

April 19, 2019

Asian individuals with diabetes have substantially increased risk for all-cause and cause-specific death, according to a study published online today in JAMA Network Open.

The study is the largest of its kind to date to evaluate all-cause and cause-specific mortality related to diabetes across a wide range of Asian countries, the authors note.

"Patients diagnosed with type 2 diabetes are at a substantially elevated risk of premature death. It is important to maintain optimal glycemic control to reduce risk of complications and eventually risk of death," senior author Wei Zheng, PhD, of Vanderbilt University, Nashville, Tennessee, told Medscape Medical News via email.

The current diabetes epidemic has hit Asian countries hard. Over 230 million people in Asia now suffer from diabetes. That represents about 55% of the world's diabetic population, making Asia home to the largest number of people with diabetes in the world. Increasing rates of obesity and adoption of a Westernized lifestyle may be contributing to the epidemic in these countries, according to the authors.

To see how diabetes is affecting mortality in the region, first author Jae Jeong Yang, PhD, from Vanderbilt University, and colleagues pooled results from 22 prospective cohort studies conducted in Asia between 1963 and 2006. Included studies had a follow-up of at least 3 years and were participating in the Asia Cohort Consortium, a collaborative group that is studying the links between genetics, environment, and human disease.

The analysis included 1,002,551 Asian individuals from mainland China, Japan, South Korea, Singapore, Taiwan, India, and Bangladesh. Slightly more than half (51.7%; n = 518,537) of participants were women. At baseline, 3.6% of women and 4.8% of men self-reported that they had been diagnosed with diabetes by a physician. The median age of the participants was 54 years.

During a median follow-up of 12.6 years, 148,868 study participants died.

Results indicated that individuals with diabetes had 1.89 times increased relative risk for all-cause mortality compared to those without diabetes (hazard ratio [HR], 1.89; 95% confidence interval [CI], 1.74 – 2.04), after adjusting for age, sex, smoking, education, marital status, rural vs urban residence, obesity, and year of birth.

Regarding relative risk for death from specific medical conditions, the authors found that the highest relative risk was for death from diabetes itself (HR, 22.8; 95% CI, 18.5 – 28.1).

In descending order, the following conditions also conferred increased relative risk for death: renal disease (HR, 3.08; 95% CI, 2.50 – 3.78); coronary heart disease (HR, 2.57; 95% CI, 2.19 – 3.02); tuberculosis (HR, 2.28; 95% CI, 1.41 – 3.69); liver disorder (HR, 2.24; 95% CI, 1.87 – 2.68); and ischemic stroke (HR, 2.15; 95% CI, 1.85 – 2.51).

Compared with adults who do not have diabetes, women had higher relative risk for diabetes-related death than men (HR, 2.09 vs 1.74; P for interaction < .001). Risk for cardiovascular disease (CVD) and renal disease were particularly high among women with diabetes compared with men (CVD: HR, 2.30 vs 1.82; P < .001; renal disease: HR, 3.44 vs 2.85; P = .01).

Relative risk for all-cause death among adults with diabetes vs those without was highest among people aged 30 to 49 years (HR, 2.43) and decreased with increasing age (50 to 59 years: HR, 2.06; 60 to 69 years: HR, 1.87; aged 70 or older: HR, 1.51; P for interaction < .001).

Sensitivity analyses that excluded participants with a history of CVD or cancer (except nonmelanoma skin cancer) yielded similar results.

Compared with Westernized countries, the relative risks for diabetes-related mortality in this study are "exceptionally high," according to the authors. They note that in general, studies in Western countries have reported 15% to 90% increased relative risk for all-cause mortality in individuals with diabetes compared to those without diabetes.

"We found that diabetes is associated with a much higher risk of premature death in our study compared with that reported by previous studies conducted in Western countries. It is likely that these differences are partially due to less optimal care for diabetes, particularly in less well-developed countries," Zheng said in an email.

Lack of access to healthcare and medication, as well as insufficient diabetes education, may contribute to inadequate glycemic control and worse diabetes outcomes, according to the authors.

The findings in women may also reflect lower quality of care in women compared to men, they add.

Asians' susceptibilities to factors that contribute to diabetes-related death may differ from those of Westerners. Compared with people of European ancestry, Asians have increased likelihood of dying from renal disease, increased susceptibility to insulin resistance, and higher rates of hypertension, hyperlipidemia, and visceral fat. Asians also tend to develop diabetes at younger ages and at lower body mass index levels, the authors note.

"Our findings suggest the urgent need for developing diabetes management programs that are tailored to Asian populations and the subsequent strong implementation of these programs in Asia," the authors conclude.

The authors mentioned several potential limitations. The study lacked information on diabetes type. However, the analysis excluded people younger than 30 years, and only 0.2% of participants were diagnosed before age 20. Therefore, most study participants likely had type 2 diabetes. Also, most studies took place in East Asia, and there were limited data on South Asian populations, though sensitivity analyses suggested no single study or country drove results.

The authors have disclosed no relevant financial relationships.

JAMA Netw Open. Published online April 19, 2019. Full text

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