Adherence to COPD treatment in Turkey and Saudi Arabia: results of the ADCARE study

Background: COPD affects millions of people worldwide. Poor treatment adherence contributes to increased symptom severity, morbidity and mortality. This study was designed to investigate adherence to COPD treatment in Turkey and Saudi Arabia. Methods: An observational, cross-sectional study in adult COPD patients in Turkey and Saudi Arabia. Through physician-led interviews, data were collected on sociodemographics and disease history, including the impact of COPD on health status using the COPD Assessment Test (CAT); quality of life, using the EuroQol Five-Dimension questionnaire (EQ-5D); and anxiety and depression using the Hospital Anxiety and Depression Scale (HADS). Treatment adherence was measured using the 8-item Morisky Medication Adherence Scale (MMAS-8). Multivariate logistic regression analysis examined the predictors of non-adherence and the impact of adherence on symptom severity. Results: Four hundred and five COPD patients participated: 199 in Turkey and 206 in Saudi Arabia. Overall, 49.2% reported low adherence (MMAS-8 < 6). Of those, 74.7% reported high disease impact (CAT > 15) compared to 58.4% reporting medium/high adherence (p = 0.0008). Patients with low adherence reported a lower mean 3-level EQ-5D utility value (0.54 +/- 0.35) compared to those with medium/high adherence (0.64 +/- 0.30; p < 0.0001). Depression with HADS score 8-10 or > 10 was associated with lower adherence (OR 2.50 [95% CI: 1.43-4.39] and 2.43 [95% CI: 1.39-4.25], respectively; p = 0.0008). Being a high school/college graduate was associated with better adherence compared with no high school (OR 0.57 [95% CI: 0.33-0.98] and 0.38 [95% CI: 0.15-1.00], respectively; p = 0.0310). After adjusting for age, gender, and country, a significant association between treatment adherence (MMAS-8 score >= 6) and lower disease impact (CAT <= 15) was observed (OR 0.56 [95% CI: 0.33-0.95]; p = 0.0314). Conclusion: Adherence to COPD treatment is poor in Turkey and Saudi Arabia. Non-adherence to treatment is associated with higher disease impact and reduced quality of life. Depression, age, and level of education were independent determinants of adherence.