Reducing Insulin Self-Administration Errors in Adults With Diabetes: A Quasi-Experimental Study of a Structured Intervention

OBJECTIVE: To evaluate the effectiveness of a structured intervention based on Rapid-Cycle Deliberate Practice (RCDP) in reducing insulin self-administration errors in adults with diabetes. METHODS: A quasi-experimental single-group pretest-post-test study was conducted in 2 public outpatient clinics in Rio de Janeiro, Brazil, between March 2020 and June 2023. Participants performed insulin self-administration using procedure-specific structured checklists. The intervention consisted of a structured, feedback-driven approach based on RCDP, involving real-time error correction and repeated practice cycles, using a low-fidelity simulation pad. Outcomes included the error rate, participant satisfaction, and self-confidence. Statistical analyses included the McNemar test, a generalized mixed-effects model, and effect size estimation. RESULTS: A total of 103 participants were included. The error rate of insulin self-administration decreased from 47.2% at baseline to 5.7% after the intervention (P<0.001), representing a substantial reduction in unsafe practices. The intervention demonstrated a large effect size (Cohen d=1.55), indicating a marked improvement in procedural performance. Participants also reported high levels of satisfaction and self-confidence. CONCLUSIONS: A structured RCDP-based intervention significantly reduced insulin self-administration errors, addressing a critical gap in medication safety in outpatient care. By enabling patients to perform a high-risk procedure more safely, this approach represents a practical and scalable strategy to reduce preventable harm and improve the safety of diabetes self-management.