TYPE 1 DIABETES, END STAGE RENAL DISEASE, AND RISK OF DEMENTIA

Abstract

Due to advances in care, individuals with type 1 diabetes (T1) are now commonly living to old age, however their risk and protective factors for dementia have not been evaluated. End stage renal disease (ESRD) is a serious microvascular complication of T1 that involves functional and structural changes of the kidney. Studies in the general population suggest associations between renal function and cognition, yet it is unknown if ESRD is a risk factor for dementia in T1 diabetes. Dynamic cohort study (1996–2015) of T1 Kaiser Permanente Northern California members >50 years old. 3,742 patients with T1 diabetes (79% White, 4% Asian, 5% Black, 6% Hispanic, 4% Other, and 3% missing). Electronic medical records were used to capture ESRD, birth year, sex, race, hypertension, stroke, hyperlipidemia, and glycosylated hemoglobin (HbA1c), and dementia diagnoses (ICD-9 331.0, 290.0–290.4, 294.1x, 294.2x, and 294.8) from primary care, neurology, memory clinics, and psychiatry. We specified Cox proportional hazard models (age as time scale) to evaluate the association between ESRD and dementia, adjusted for demographics and baseline medical risk factors. Participants were censored at dementia diagnosis, death, gap in health plan membership, or end of study. At entry, the mean age was 56.1 (range:50.0–96.5) and 7% of members had ESRD. 9.9% of patients with ESRD and 4.7% of patients without ESRD developed dementia during follow-up (mean follow-up=6.2 years). Patients with ESRD were more likely to have comorbid hypertension, hyperlipidemia, and stroke (all p-values<0.001). Patients with ESRD, compared to without, had over a 3-fold risk of dementia, adjusted for age (adjusted hazard ratio (aHR)=3.62; 95% Confidence Interval (CI): 2.17–6.02). Further adjusting for demographics, ESRD was associated with 182% elevated risk (95% CI: 1.67–4.75). Additional adjustment of hypertension, hyperlipidemia, stroke, and HbA1c did not attenuate the association; ESRD was associated with more than double the risk of dementia (aHR=2.36; 95% CI: 1.37–4.06).