The place of DPP-4 inhibitors in the treatment algorithm of diabetes type 2: a systematic review of cost-effectiveness studies

Objective: To conduct a systematic review of cost-effectiveness, cost-utility, and cost-benefit studies of DPP-4 inhibitors for diabetes treatment versus other antidiabetics. Methods: Three investigators searched the CRD York, Tufts CEA Registry, and MEDLINE databases through 2015. We reviewed all potentially relevant titles and abstracts, and screened full-text articles, according to inclusion criteria. We established a quality score for each study based on a 35-item list. Results: A total of 295 studies were identified, of which 20 were included. The average quality score was 0.720 on a 0–1 scale. All studies were performed in high- and middle-income countries, using a 3rd-party payer perspective and randomized clinical trials to measure effectiveness. Sitagliptin, saxagliptin and vildagliptin had an ICER below 25,000 €/QALY, as second-line and as add-ons to metformin, in comparison to sulfonylureas. When compared with sitagliptin, liraglutide (GLP-1 receptor agonist) had an ICER of up to 22,724 €/QALY for the 1.2-mg dosage, and up to 32,869 €/QALY for the 1.8-mg dosage. Insulin glargine was dominant when compared with sitagliptin. Conclusions: According to the WHO threshold applied to the country and year of each study, DPP-4 inhibitors were highly cost-effective as second-line, as add-ons to metformin, in comparison with sulfonylureas. More recent therapies (GLP-1 receptor agonists and insulin glargine) were highly cost-effective in comparison to DPP-4 inhibitors. These results were obtained, however, on the basis of a limited number of studies, relying on the same few clinical trials, and financed by manufacturers. Further independent research is needed to confirm these findings.