What are the consequences of over and undertreatment of type 2 diabetes mellitus in a frail population? A systematic review

Abstract Aims This review aims to identify the evidence base for the consequences of over and undertreatment of type 2 diabetes mellitus in a frail population. Method In this systematic review, we searched MEDLINE, Embase, PubMed, CINAHL and the Cochrane Library for studies from January 2001 to 15th August 2022. We included a variety of study types that assessed and reported frailty including patients ≥18 years old. Studies included those that reported the prevalence of over or undertreatment of diabetes mellitus in a frail population and those examining outcomes related to glucose control in frail older people living with diabetes. Data were extracted using a bespoke extraction table using a narrative synthesis approach. Results A total of 4114 articles were identified with 112 meeting inclusion criteria. These included 15,130 participants across the 11 studies with sample sizes ranging from 101 to 11,140. Several areas were identified in the included studies where under or overtreatment of diabetes impacted outcomes for patients. These included hospital admissions, readmissions, length of stay, falls, mortality, cognitive impairment and cardiovascular disease outcomes. Conclusion The results showed that there was a high heterogeneity of outcomes between the studies and that many examined small numbers of participants. In this review, both over and undertreatment were shown to increase adverse outcomes in frail older people. Further research around optimal glycaemic control for frail older people living with diabetes is required with the aim to identify ideal target ranges and produce practical clinical guidelines to promote attainment of these.