Associations of Age at Diagnosis and Duration of Diabetes With Morbidity and Mortality Among Older Adults

Key Points Question Is age at diabetes diagnosis associated with the risk of distal outcomes among adults 50 years and older? Findings This cohort study of 36 060 adults 50 years and older used data from a national longitudinal health survey and found that diabetes diagnosed at 50 to 59 years of age was significantly associated with elevated risks of incident heart disease, stroke, disability, cognitive impairment, and mortality. However, the associations between diabetes and all outcomes decreased as age at diabetes diagnosis increased, even when accounting for diabetes duration. Meaning Differences in the association of diabetes with negative health outcomes support differential diabetes management across age-at-diagnosis groups.

• Adjudication Level One: If the respondent disputed the prior wave record but now replies that he has the disease, we adjudicated his response as "Yes". If the respondent disputed the prior wave record and replies that he does not now have the disease, we examined his prior wave responses for evidence of having the disease. If evidence was present, we adjudicated his response as "Yes"; if evidence was not present, we adjudicated his response as "No".
• Adjudication Level Two: For "Don't know" and "Refuse to answer" responses, we examined the respondent's prior wave responses for evidence of having the disease. If evidence was present, we adjudicated his response as "Yes"; if evidence was not present, we adjudicated his response as "No".
• Adjudication Level Three: For a "No" response in the current wave being preceded by a "Yes" response in the prior wave, we examined the respondent's prior wave responses for evidence of having the disease. If evidence was present, we adjudicated his response as "Yes"; if evidence was not present, we adjudicated his response as "No".
• Adjudication Level Four: When a "Yes" response in the current wave was followed by a dispute of this "Yes" response in the succeeding wave, we examined the respondent's current wave responses for evidence of having the disease. If evidence was present, we adjudicated his response as "Yes"; if evidence was not present, we adjudicated his response as "No".
Adjudication Levels 1 through 4 are conservative correctives, based on the logic of and the phrasing within the HRS questionnaires themselves. (Fisher, Faul, Weir, et al., 2005) Levels 1 through 4 address inconsistencies in chronic disease reporting by respondents between adjacent waves (that the respondent participated in). To restate, Levels 1 through 4 draw on evidence from the same wave or the immediately preceding wave." For the present study, the evidence for diabetes includes (1) the self-reported answer "Yes" to at least one of the following questions and/or (2) A1c measurement ≥6.5.
• In order to treat or control your diabetes, are you now taking medication that you swallow?
• Are you now using insulin shots or a pump? eFigure 1. The Cumulative Incidence Curves of All-Cause Mortality for Each Diabetes Age-at-Diagnosis Group and Its Matched-Control Group The starting point of the follow up years is the year of diabetes diagnosis for diabetes and the matched calendar year for the matched controls (MCs). Therefore, the time scale of the cumulative incidence curve is the duration of diabetes for diabetes patients and matched aging for MCs.
The Events/N (%) denotes the number of events of each outcome by the total number of participants, who are outcome free at diabetes diagnosis or matched calendar year, (percentage) in either diabetes or matched controls (MCs) stratified by three diabetes age-of-diagnosis groups. The total Ns are the same between the diabetes and MCs as they were designed by 1-1 propensity score matching. The hazard ratios (95% confident interval) between diabetes and MCs are estimated for each outcome and each age-of-diagnosis group incorporating respondent-level weights at the year of matching. For participants who had 0 or missing weights at the year of matching, the average sample weights across all year were used. Participants who had 0 or missing weights throughout were removed in the Cox models. The p-value column presents the pvalues testing the corresponding HR of diabetes to the null hypothesis (HR=1). The interaction p-value column presents the p-value comparing the HR of diabetes of the corresponding age of diagnosis group to the HR of diabetes in the reference age of diagnosis group 50-59.
The figures are separately for A) insulin non-user and oral medication non-user; B) insulin user; C) insulin non-user and oral medication user. The Events/N (%) denotes the number of events of each outcome by the total number of participants, who are outcome free at diabetes diagnosis or matched calendar year, (percentage) in either diabetes or matched controls (MCs) stratified by three diabetes age-of-diagnosis groups. The total Ns are the same between the diabetes and MCs as they were designed by 1-1 propensity score matching. The hazard ratios (95% confident interval) between diabetes and MCs are estimated for each outcome and each age-of-diagnosis group. The p-value column presents the p-values testing the corresponding HR of diabetes to the null hypothesis (HR=1). The interaction p-value column presents the p-value comparing the HR of diabetes of the corresponding age of diagnosis group to the HR of diabetes in the reference age of diagnosis group 50-59.