Diabetes mellitus increases risk of adverse drug reactions and death in hospitalised older people: the SENATOR trial

Purpose: Adverse drug reactions (ADRs) are a major cause of morbidity and mortality, especially in older people. Older people with diabetes mellitus may be at especially high risk of ADRs but this risk has not been well studied. This study aimed to compare severity and type of ADRs in hospitalised, multimorbid older people with and without diabetes and secondly to assess the impact of ADRs on mortality, rehospitalisation and length of stay.Methods: Participants in the SENATOR (Software Engine for the Assessment and optimization of drug and non-drug Therapy in Older peRsons) trial were assessed for 12 common and 'other' prevalent and incident adverse drug reactions using a blinded end-point adjudication process. Descriptive analyses, logistic regression and mediation analyses were undertaken.Results: Of 1537 people in the SENATOR trial, 540 (35.1%) had diabetes mellitus (mean age 77.4 +/- 7.3 years, 58.5% male). In the total population, 773 prevalent and 828 incident ADRs were reported. Both prevalent and incident symptomatic hypoglycaemia and incident acute kidney injury (AKI) were significantly more common in people with diabetes (p < 0.05). Patients with diabetes had higher all-cause mortality at 12 weeks than those without (9.1% vs 6.3%, p = 0.04). Mediation analysis revealed that mortality was significantly higher (OR = 1.43, Sobel test p = 0.048) in people with diabetes and ADRs causing AKI.Conclusions: Older multimorbid people with diabetes presenting to hospital with acute illness have significantly more ADRs than those without, and a significantly higher mortality that is mediated by medication-associated AKI and poorer renal function.