Effect of a theory of planned behaviour-based self-care education programme on glycaemic control in patients with diabetic retinopathy: a quasi-experimental study.

Diabetic retinopathy (DR) is a leading cause of preventable blindness, particularly in regions with poor glycemic control and limited access to structured education. Theory-driven interventions such as the Theory of Planned Behaviour (TPB) may enhance self-care and improve clinical outcomes. To evaluate the effectiveness of a TPB-based self-care education programme on glycemic control, knowledge, self-care behaviours, and TPB constructs among patients with diabetic retinopathy. This quasi-experimental pretest-posttest-controlled study was conducted between September 2024 and August 2025 among 200 patients with diabetic retinopathy attending a tertiary diabetes centre in Erbil, Iraq. Participants were allocated to an intervention group (n = 100) receiving a structured three-session TPB-based education programme or a control group (n = 100) receiving standard care. Outcomes were assessed at baseline and 3 months. The primary outcome was HbA1c. Secondary outcomes included diabetes knowledge, self-care practices, and TPB constructs. Statistical analyses included paired and independent t-tests, chi-square tests, and effect size estimation. At 3 months, HbA1c significantly decreased in the intervention group (-0.50%) but increased in controls (+1.06%), yielding a significant between-group difference (-1.50%, 95% CI: -1.93 to -1.07; p < 0.001; d = 0.97). Significant improvements were observed in systolic blood pressure, total cholesterol, and LDL cholesterol. Diabetes knowledge improved markedly, with 56% achieving high knowledge versus 0% in controls (p < 0.001). Self-care behaviours and TPB constructs also improved significantly (all p < 0.001). A brief TPB-based education programme significantly improved glycemic control and self-management in patients with DR. This low-cost intervention offers a scalable strategy for reducing diabetes-related complications in resource-limited settings.

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