Income may factor into mortality risk among adults with type 2 diabetes

Key takeaways:

• Increased risks for mortality based on low income were greatest among adults under the age of 40 years.
• Factors contributing to this may include lower treatment adherence and less frequent health care visits.

Low income corresponded with a higher risk for death among individuals with type 2 diabetes, a South Korean-based cohort analysis published in JAMA Network Open suggested.

Adults aged younger than 40 years showed the strongest association between mortality risk and income, according to study investigators.

“[Income] is an important socioeconomic indicator that has effects on personal health,” Ji Yoon Kim, MD, from the Korea University College of Medicine, and colleagues wrote. “Low income is associated with a high risk of poor glycemic control, complications and poor regulation of cardiovascular risk factors.”

Previous research has identified income-based disparities among those with diabetes, but differences in health outcomes based on socioeconomic status between younger and older adults with type 2 diabetes “have not been extensively studied,” the researchers wrote.

In the study, Kim and colleagues examined a cohort of 1,240,780 adults — of whom 604,975 had a type 2 diabetes diagnosis — to determine the risks for all-cause mortality, cancer-related mortality and cardiovascular-related mortality based on income status across three age groups.

The investigators reported adjusted ORs for all-cause mortality of 1.47 (95% CI, 1.44-1.5) among adults with type 2 diabetes and low income, 1.79 (95% CI, 1.75-1.83) among those with type 2 diabetes and middle income and 2.03 (95% CI, 1.99-2.08) for those with type 2 diabetes and high income.

Researchers found a greater risk for all-cause mortality in adults with low income and type 2 diabetes aged 20 to 39 years (adjusted HR = 2.88; 95% CI, 2.25-3.69), 40 to 59 years (aHR = 1.9; 95% CI, 1.81-2) and 60 to 79 years (aHR = 1.26; 95% CI, 1.23-1.29) vs. those with high income.

They also reported an increased risk for cardiovascular mortality among adults with type 2 diabetes and low income aged 20 to 39 years (aHR = 2.66; 95% CI, 1.3-5.42) and 60 to 79 years (aHR = 1.32; 95% CI, 1.25-1.39) compared with adults with high income.

Kim and colleagues further noted aHRs for cancer mortality of 1.46 (95% CI, 0.92-2.33) in those with low income and aged 20 to 39 years and 1.19 (95% CI, 1.14-1.24) in those with low income and aged 60 to 79 years vs. those with high income.

Further analysis showed similar mortality risks among men and women.

The researchers acknowledged some study limitations. For example, the possibility of residual confounders, and potential lack of general applicability to other countries because the entire sample was composed of South Koreans.

“Given South Korea’s high level of medical accessibility, other countries lacking such conditions might exhibit more serious disparities,” they wrote.

Kim and colleagues also highlighted various factors that could have contributed to the higher mortality risk in younger adults, such as lower diabetes treatment adherence, less frequent health care checkups and differences in treatment following the occurrence of atherosclerotic CVD.

Ultimately, “more efforts at the social and national level should be made to reduce the disparities in health outcomes according to socioeconomic status among young adults with type 2 diabetes,” they concluded.