Effects of a health coaching program based on Cox’s interaction model in older adults with diabetes mellitus in Korea: a quasi-experimental study

Purpose: This study aimed to evaluate the effects of a health coaching program based on Cox’s interaction model in adults aged 65 years or older with diabetes mellitus.Methods: A quasi-experimental design with a non-equivalent control group and pretest–posttest measures was employed. Fifty-nine participants were assigned to either the experimental group (n = 30) or the control group (n = 29). The 8-week intervention included 16 sessions of group coaching, health education, stress management, and health monitoring. Outcome measures included physiological indicators (glycated hemoglobin, fasting blood glucose, total cholesterol, high-density lipoprotein cholesterol, and blood pressure), self-care behaviors, diabetes distress, and health conservation.Results: The experimental group demonstrated significant reductions in glycated hemoglobin (t = 4.59, p < .001), fasting blood glucose (t = 6.66, p < .001), total cholesterol (t = 2.90, p = .005), systolic blood pressure (t = 2.32, p = .024), and diastolic blood pressure (t = 2.94, p = .005) versus the control group. Psychosocial outcomes also improved, with increased self-care behaviors (t = 4.04, p < .001) and health conservation (t = 3.20, p = .002), along with decreased diabetes distress (t = 3.80 , p < .001).Conclusion: The health coaching program based on Cox’s interaction model significantly improved both physiological and psychosocial outcomes in older adults with diabetes. These findings support the model’s applicability for designing patient-centered nursing interventions to promote self-management and enhance community-based chronic care.