Hospitalization in adults aged 75 years and older with type 2 diabetes: the role of kidney impairment and glycemic control

Abstract

Older adults aged ≥ 75 years with type 2 diabetes (T2D) experience high healthcare utilization, yet evidence on treatment patterns and outcomes in this age group is limited. To assess associations between glycemic control, kidney function, and hospitalization among individuals aged ≥ 75 years with T2D. Individuals aged ≥ 75 years with T2D were identified in 2018 using data from a population‑based healthcare database covering all levels of care in Region Halland. Healthcare utilization, including hospital admissions, hospital days, primary care encounters and mortality, was evaluated during 2019. Inclusion required at least one measurement of glycated hemoglobin (HbA1c) and estimated glomerular filtration rate (eGFR). Kidney function was classified by eGFR ≥ 60; 30–59; <30 mL/min/1.73 m², and HbA1c as < 52, 52–70, or > 70 mmol/mol. Associations with hospital days were analyzed using Poisson regression adjusted for demographic, clinical, and treatment variables. The cohort comprised 1,446 individuals (49% women); 88 patients (6%) died during follow‑up. HbA1c was < 52 mmol/mol in 43%, 52–70 mmol/mol in 45%, and > 70 mmol/mol in 12%. CKD was common, with 56% classified as stage 3 and 10% as stage 4–5. Hospital days were higher among individuals with CKD stage 4–5 (RR 1.93, 95% CI:1.71–2.17) and HbA1c > 70 mmol/mol (RR 1.44, 95% CI:1.28–1.61). Primary care encounters were frequent (physician visits: 4.6 [SD 3.7]; nurse visits: 9.0 [SD 9.3]) and associated with CKD but not with glucose dysregulation. Insulin use was associated with more hospital days, whereas metformin and incretin‑based therapy were associated with fewer. In adults aged ≥ 75 years with T2D, hospitalization burden was substantial and was associated with advanced CKD and poor glycemic control, while primary care encounters were frequent. These findings demonstrate an association between kidney function, glycemic status, and healthcare utilization in older adults with T2D. In individuals aged ≥75 years with type 2 diabetes, hospitalization was driven primarily by advanced chronic kidney disease and multimorbidity rather than glycemic control alone. Higher HbA1c levels were independently associated with more hospital days, but with smaller effects than severe renal disease. Older individuals with type 2 diabetes required both frequent primary care contacts and substantial hospital care, highlighting the complexity of multimorbidity in advanced age. Insulin treatment was associated with increased hospital days in this older cohort, whereas metformin and incretin-based therapies were associated with fewer hospital days.