Age at Diagnosis of Diabetes Associated With Different Adverse Outcomes

Patients with diabetes who were diagnosed at a young age had a greater risk for heart disease, stroke, disability, cognitive impairment, and all-cause mortality, according to a study published in JAMA Network Open.

Diabetes is most prevalent in older adults, an expanding segment of the population of the United States. Older adults and middle-aged adults are treated similarly for diabetes, but it is unclear if this is the best course of action, as it’s possible the 2 age groups need to be treated differently due to differing adverse events. This study aimed to investigate 5 outcomes (heart disease, stroke, disability, cognitive impairment, and all-cause mortality) and compare their prevalence across age groups.

The analysis used the data from the 1995 to 2018 waves of the Health and Retirement Study (HRS). The respondents were from 6 HRS cohorts, including adults who lived in a community and those who were in nursing facilities. Respondents who self-reported incident diabetes with a diagnosis when they were aged 50 years or older were included whereas respondents who never reported diabetes acted as controls. Respondents were excluded if they had missing age data, were younger than 50 years, missing self-reported diabetes information, reported diabetes at the baseline HRS interview, had 1 of the outcomes before their diagnosis of diabetes, or had missing data for that outcome.

The analysis included 36,034 respondents, of which 7739 had self-reported incident diabetes. There were 1866 respondents who had a diagnosis at 50 to 59 years, 2834 at 60 to 69 years, and 3039 at 70 years or older. There were 4267 (55.1%) women in this cohort and the mean (SD) age of the population was 67.42 (9.88) years, with a mean follow-up of 20 (IQR, 8-26) years.

Respondents aged 70 years and older at diagnosis were more likely to be male (45.5% vs 38.6%), non-Hispanic White (73.7% vs 49.9%), not married (47.1% vs 26.3%), and have less educational attainment (less than 12 years, 28.5% vs 39.7%) and wealth (less than $40,000, 75.2% vs 52.6%) compared with the group aged 50 to 59 at diagnosis.

Adults who were older at diagnosis also had a lower median body mass index (27.4 [IQR, 24.3-30.9] vs 31.3 [IQR, 27.4-35.9]), less smoking (6.4% vs 19.9%), and a higher prevalence of comorbid conditions (heart disease, 44.4% vs 20.7%; disability, 8.8% vs 1.9%) compared with those aged 50 to 59 years at diagnosis.

The incident rate ratio (IRR) of heart disease between each diabetes group and their matched control group decreased as the age at diagnosis of diabetes increased. The IRRs were 1.69 (95% CI, 1.42-2.02) for those aged 50 to 59 years, 1.24 (95% CI, 1.08-1.41) for those aged 60 to 69 years, and 1.16 (95% CI, 1.00-1.35) for those aged 70 years and older at the time of diagnosis.

Respondents who were diagnosed with diabetes aged 50 to 59 years had a higher incidence of stroke (IRR, 1.70; 95% CI, 1.34-2.15), disability (IRR, 2.03; 95% CI, 1.55-2.66), and mortality (IRR, 1.43; 95% CI, 1.24-1.65) compared with their matched controls. Respondents who were diagnosed with diabetes aged 60 to 69 years had a significantly higher incidence of stroke (IRR, 1.39; 95% CI, 1.15-1.67) and disability (IRR, 1.29; 95% CI, 1.07-1.55) compared to their matched control, although the IRR was lower than for those aged 50 to 59 years at the time of diagnosis.

Diabetes was also associated with an elevated risk of heart disease (HR, 1.66; 95% CI, 1.40-1.96), stroke (HR, 1.64; 95% CI, 1.30-2.07), disability (HR, 2.08; 95% CI, 1.59-2.72), cognitive impairment (HR, 1.30; 95% CI, 1.05-1.61), and mortality (HR, 1.49; 95% CI, 1.29-1.71) for those who were diagnosed with diabetes aged 50 to 59 years compared with their matched control. Diabetes was only associated with elevated mortality (HR, 1.08; 95% CI, 1.01-1.17) for those aged 70 years and older when diagnosed.

There were some limitations to this study. Measurement errors could not be ruled out due to the self-reporting of diabetes in the respondents. Self-reported diabetes also could distinguish between the 2 types of diabetes. Matched controls may be subjected to ascertainment bias because of the shorter follow-up for reporting diabetes. The impact of prediabetes was not explored in this study.

The researchers concluded that the association of diabetes with incident distal outcomes varied by the age of diagnosis, with those younger at time of diagnosis more susceptible to adverse outcomes when compared with those who are diagnosed at a later age.

Reference

Cigolle CT, Blaum CS, Lyu C, Ha J, Kabeto M, Zhong J. Associations of age at diagnosis and duration of diabetes with morbidity and mortality among older adults. JAMA Netw Open. 2022;5(9):e2232766. doi:10.1001/jamanetworkopen.2022.32766.