Development of Turkish Treatment Adherence Scale Among Adult Patients

Introduction: Treatment adherence reflects a patient’s commitment to prescribed lifestyle changes and therapy, encompassing both engagement and ongoing management beyond medication intake. Materials & Methods The study (Aug–Oct 2021) included 264 adults from internal and family medicine clinics. A 29-item scale was developed, piloted, and analyzed using SPSS 26.0. Reliability (Cronbach’s α > 0.7), test-retest, and item-total correlations were assessed. Factor analyses indicated acceptable structure (χ²/df 2–5, GFI/CFI > 0.90, RMSEA < 0.1), with non-parametric tests (Chi-square, Somers’ D) for non-normal data. Internal consistency was assessed via Cronbach’s α (> 0.7 = high), test-retest correlation, and item-total correlations. Exploratory and confirmatory factor analyses evaluated scale structure, with χ²/df between 2–5, GFI and CFI > 0.90, and RMSEA < 0.1 considered acceptable. Results Among 264 participants (mean age 61.4 ± 17.7; 52% male), adherence scores were 64% ≥20 on the 12-item and 76% ≥9 on the 6-item scale, with higher adherence associated with marital status (χ²=31.75, p = 0.046), income (χ²=32.18, p < 0.044), number of children (p < 0.001), smoking (χ2 = 22.507, df = 10, Somer's d=-0.150), and city residence(χ2 = 47.243, df = 20, Somer's d = 0.025). Exploratory factor analysis removed items with factor load < 0.30 or inter-factor differences > 0.10. The 12-item scale showed KMO = 0.869, Bartlett’s p < 0.001, and explained 63.5% of variance; the 6-item scale showed KMO = 0.814, Bartlett’s p < 0.001, and explained 65.9% of variance. In the confirmatory factor analysis, the 12-item scale showed Cronbach’s α = 0.85, test-retest r = 0.746, Cmin/df = 4.892, CFI = 0.827, NFI = 0.867, and RMSEA = 0.138. The 6-item scale demonstrated Cronbach’s α = 0.861, r = 0.731, Cmin/df = 2.82, CFI = 0.988, NFI = 0.973, and RMSEA = 0.056. Based on these statistical values, the 12-item and 6-item Turkish Treatment Adherence Scales are reliable and valid instruments for the Turkish population. Discussion Treatment adherence depends on patient, social, and economic factors, and is hindered mainly by financial burden, forgetfulness, complexity of treatment, and lifestyle disruption.