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