Adherence to and persistence with antidiabetic medications and associations with clinical and economic outcomes in people with type 2 diabetes mellitus: A systematic literature review

Abstract

We designed a systematic literature review to identify available evidence on adherence to and persistence with antidiabetic medication in people with type 2 diabetes (T2D). Electronic screening and congress searches identified real-world noninterventional studies (published between 2010 and October 2020) reporting estimates of adherence to and persistence with antidiabetic medication in adults with T2D, and associations with glycaemic control, microvascular and/or macrovascular complications, hospitalizations and healthcare costs. Ninety-two relevant studies were identified, the majority of which were retrospective and reported US data. The proportions of patients considered adherent (median [range] 51.2% [9.4%-84.3%]) or persistent (median [range] 47.7% [16.9%-94.0%]) varied widely across studies. Multiple studies reported an association between greater adherence/persistence and greater reductions in glycated haemoglobin levels. Better adherence/persistence was associated with fewer microvascular and/or macrovascular outcomes, although there was little consistency across studies in terms of which outcomes were improved. More adherent and more persistent patients were typically less likely to be hospitalized or to have emergency department visits/admissions and spent fewer days in hospital annually than less adherent/persistent patients. Greater adherence and persistence were generally associated with lower hospitalization costs, higher pharmacy costs and lower or budget-neutral total healthcare costs compared with lower adherence/persistence. In conclusion, better adherence and persistence in people with T2D is associated with lower rates of microvascular and/or macrovascular outcomes and inpatient hospitalization, and lower or budget-neutral total healthcare expenditure. Education and treatment strategies to address suboptimal adherence and persistence are needed to improve clinical and economic outcomes.

Keywords: GLP-1RAs; adherence; healthcare costs; insulin; oral antidiabetic medications; persistence; resource utilization; type 2 diabetes.

FIGURE 1

Change in HbA1c level from baseline by A, adherence to and B, persistence with antidiabetic medication in studies reporting this outcome. Bars with an asterisk indicate statistically significant results for adherent/persistent versus nonadherent/nonpersistent patients (P < 0.05). Min et al and Reynolds et al did not report P values for adherent versus nonadherent patients. Eliasson et al and Melzer‐Cohen et al did not report P values for persistent versus nonpersistent patients. For adherence, studies were included if they reported change in HbA1c (follow‐up times varied, as indicated for each study); for persistence, studies were included if they reported change in HbA1c over 6, 12 or 24 months. ^aData shown are means, except for Min et al which are median. HbA1c, glycated haemoglobin

FIGURE 2

Healthcare costs by A, adherence to and B, persistence with antidiabetic medication in selected relevant studies. Bars with an asterisk indicate statistically significant results for adherent/persistent versus nonadherent/nonpersistent patients (P < 0.05). Buysman et al, Gentil et al and Hansen et al did not report P values for adherent versus nonadherent patients. Kalirai et al and Lin et al did not report P values for persistent versus nonpersistent patients. ^aData from the subset of patients with depression/anxiety. ^bData from the subset of patients without depression/anxiety. ^cData from the first year of treatment. ^dData from the second year of treatment. CAD, Canadian dollar; ED, emergency department; FU, follow‐up; NR, not reported; USD, United States dollars