All-cause and cause-specific mortality in older people with and without diabetes in Norwegian home care services: a nationwide registry study.

backgroundAs the number of older people living at home increases, the role of home care services (HCS) becomes more important. Diabetes is associated with premature mortality and is common among older people in HCS, yet mortality patterns among HCS recipients are not well known. This study aimed to estimate all-cause and cause-specific mortality risk in persons with pharmacologically treated diabetes receiving HCS compared to other HCS recipients and explore whether mortality risk differed between diabetes treatment subgroups.

methodsThis nationwide registry study merged data from the Norwegian Information System for the Nursing and Care Sector with data from the Norwegian Prescription Database, the Norwegian Patient Registry, and the Cause of Death Registry (CDR). The study population included recipients of HCS (aged 65-90 years at baseline) in Norway between 2009 and 2014. Individuals were classified as having pharmacologically treated diabetes (hereafter referred to as diabetes) (≥ 1 prescription of glucose-lowering drugs (GLD) in the current half year or the year before), or not having diabetes. Those with diabetes were further sub-classified into "non-insulin GLD only", "insulin and non-insulin GLD", or "insulin only". Time of death and the underlying cause of death were retrieved from CDR. The study population, diabetes status, covariates, and all-cause mortality were updated each half-year. Mortality risk was compared between groups using Cox proportional hazards regression, with age as time scale, and reported as hazard ratio (HR) with 95% CIs.

resultsWomen in the "insulin only" group had a higher risk of all-cause mortality (HR 1.18 (CI 1.11-1.25)) than women without diabetes, while in the "non-insulin GLD only" and "insulin and non-insulin GLD" subgroups, both women and men with diabetes had lower mortality risks than those without diabetes. Overall, persons with diabetes had a higher risk of cardiovascular mortality (HR 1.23 (CI 1.19-1.28)) compared to persons without diabetes, and a lower risk of dying from cancer (HR 0.68 (CI 0.66-0.70)) and respiratory disease (HR 0.67 (CI 0.62-0.72)).

conclusionMortality risk varied by diabetes status and treatment subgroups. Most diabetes subgroups had lower all-cause mortality risk than those without diabetes, except for women using "insulin only", underscoring the need for individualized HCS.