Expert patients improve health literacy, self-care attitudes, and practices in people with diabetes: a quasi-experimental study in Tanzania

People living with diabetes require a long-term commitment to disease management to minimize and control the risk of developing different life-threatening health complications, high medical expenses, reduced quality of life, and mortality. This study evaluated the effectiveness of utilizing expert patients - selected patients who fulfilled set criteria and received brief training to act as peer educators, through a peer-to-peer learning strategy in enhancing health literacy, self-care attitudes, and practices among adult patients with diabetes. Quasi-experimental non-randomized, two-arm study involving 144 randomly selected participants, but non-randomly assigned to intervention (DDRH) and control (BMH) arms. A convenience method was applied to assign participants to the two groups, with 72 in the intervention group and 72 in the control group. The effectiveness of the Patient-Mediated Health Education (PMHE) Intervention using Expert Patients was evaluated by comparing outcomes in terms of medication adherence, health literacy, attitude, and self-care behaviour between the control group, which continued to receive conventional health education, and the intervention group, which received the PMHE intervention. Six expert patients were trained and conducted two one-hour face-to-face PMHE peer-to-peer learning sessions. A two-sample independent t-test was used to compare the mean difference between the two groups. p < 0.05 was considered to be significant The independent t-test revealed a significant difference between groups after the intervention, with mean scores in the post-test for health literacy showing: Intervention group post-test M = 63.18 (95% CI: 62.65-63.72); Control group post-test M = 54.73 (95% CI: 53.99-55.47); mean difference = 8.45, t = 9.327, p < 0.001. The self-care attitude at post-test was M = 30.31 (95% CI: 29.93-30.69) for the intervention group and M = 22.38 (95% CI: 18.59-26.15) for the control group (p-value < 0.001). Self-care practice after the intervention showed a M = 8.67 (95% CI: 8.54-8.79) for the intervention group and 5.85 (95% CI: 3.40-8.30) for the control group (p-value < 0.001). The findings demonstrate that a low-budget peer-to-peer learning approach utilizing expert patients is effective in enhancing health literacy and self-care behaviours among adults living with type 2 diabetes in a low-resource setting. We recommend the incorporation of this model into national diabetes care guidelines, emphasizing the utilization of expert patients within the peer learning framework. This approach has the potential to lower long-term healthcare costs while simultaneously improving patient outcomes.Trial registration This trial was registered retrospectively with the Pan African Clinical Trial Registry, with registration number PACTR202509776757091. The study was conducted in 2020, and trial registration was completed in 2025. We acknowledge that retrospective registration is a limitation that may affect the transparency and interpretability of findings. We strongly recommend prospective registration in all future trials.