The Efficacy of Adding Pioglitazone to Insulin Therapy in Type 2 Diabetes: A Systematic Review and Meta-analysis

The significant increase of type 2 diabetes and its complications in individuals requires developing new approaches to control this disease. The present study aimed to evaluate the efficacy of pioglitazone and insulin combination therapy, compared to insulin therapy in patients with type 2 diabetes.

Medline, Cochrane Library, and Embase were searched for Randomized Controlled Trials (RCTs) comparing pioglitazone in combination with any insulin-containing regimen and the same insulin regimen alone in patients with type 2 diabetes. Hand searching was conducted in journals, congresses, and RCT registration databases related to diabetes. There were no restrictions on the language and publication year of articles. RCTs were evaluated based on the inclusion and exclusion criteria; the quality of studies was evaluated using the Jadad and the Cochrane collaboration’s tools. After evaluating and extracting the data, the
common results of the selected papers were entered in RevMan. Furthermore, in the cases that studies were homogeneous, meta-analysis was performed; in the cases that studies were heterogeneous, the findings were reported in a qualitative form.

From the first found essays, 12 were elected for studying, including a total of 3208 patients with type 2 diabetes. The trial duration was between 12 weeks and 34.5 months. The study results presented a reduction in HbA1c and insulin dose in the combination therapy with pioglitazone arm. In our meta-analysis, the mean reduction in HbA1c was equal to 0.64%, i.e., significant [95% Confidence Interval (CI): -0.86 to -0.41, P<0.00001].

This systematic review indicated that in patients with type 2 diabetes, the addition of pioglitazone to the insulin regimen, compared to the insulin regimens, reduced HbA1c.