Glycaemic control during continuous subcutaneous insulin infusion vs. multiple daily insulin injections in type 2 diabetes: individual patient data meta-analysis and meta-regression of randomised controlled trials.

OBJECTIVE To compare glycemic control during CSII and multiple daily insulin injections (MDI) in type 2 diabetes to identify patient characteristics that determine those best treated by CSII. RESEARCH DESIGN AND METHODS Randomised controlled trials were selected comparing HbA1c during CSII vs. MDI in people with type 2 diabetes. Data sources included Cochrane database and Ovid Medline. We explored patient-level determinants of final HbA1c and insulin dose using Bayesian metaregression models of individual patient data, and summary effects using two-step meta-analysis. Hypoglycemia data was unavailable. RESULTS Five trials were identified, with 287 patients randomised to MDI and 303 to CSII. Baseline HbA1c was the best determinant of final HbA1c: HbA1c difference (%) = 1.575 – (0.216 [95% credible interval 0.371 to 0.043] x baseline HbA1c) for all trials, but with largest effect in the trial with pre-randomisation optimisation of control. Baseline insulin dose was best predictor of final insulin dose: insulin dose difference (units/kg) = 0.1245 – (0.382 [0.510 to 0.254] x baseline insulin dose). Overall HbA1c difference was -0.40 (-0.86 to 0.05)%, -4.4 (-9.4 to 0.6) mmol/mol. Overall insulin dose was reduced by -0.25 (-0.31 to -0.19) units/kg (26% reduction on CSII), and by -24.0 (-30.6 to -17.5) units/day. Mean weight did not differ between treatments (0.08 [-0.33 to 0.48] kg). CONCLUSIONS CSII achieves better glycemic control than MDI in poorly controlled type 2 diabetes, with approximately 26% reduction in insulin requirements and no weight change. The best effect is in those worst controlled and with highest insulin dose at baseline.