Brief Spanish Zung Self-Rating Anxiety Scale: Dimensionality, Internal Consistency, Nomological Validity, and Differential Item Functioning Among Chronic Obstructive Pulmonary Disease Patients in Colombia.

Background and purposes: The brief Spanish Zung Self-Rating Anxiety Scale is a ten-item tool available; however, there is little information about its psychometric performance. The study aimed to test the dimensionality, internal consistency, nomological validity, and gender differential item functioning of the scale in patients with chronic obstructive pulmonary disease (COPD) in Colombia. Methods: A psychometric study was designed. It participated in 408 COPD patients aged between 40 and 102 years. Results: The confirmatory factor analysis showed both one- and two-dimension structures with acceptable goodness-of-fit indicators. The brief Spanish Zung Self-Rating Anxiety Scale presented high internal consistency, acceptable nomological validity, and non-gender differential functioning. Conclusions: The brief Spanish Zung Self-Rating Anxiety Scale presents some good indicators of validity and reliability, and it can be used in the measurement of anxiety in COPD patients.

Quality of life and depression in COPD patients in the Colombian Caribbean.

OBJECTIVE: To establish the association between quality of life and depression among COPD patients of the Colombian Caribbean. METHOD: A cross-sectional study was carried out with the participation of adult COPD patients. COPD-related quality of life was quantified with the COPD Assessment Test (CAT) and depression using the Zung 10-item Self-rating Depression Scale (SDS-10). The relationship between COPD-related quality of life and depression with odds ratios (OR), crude and adjusted, was determined. RESULTS: 408 patients participated in the study. They were aged between 40 and 102 years (mean = 72.9, SD = 10.2) and 58.8% men. Two hundred eighty-four patients (69.6%) reported worse health status (CAT ≥10), and 114 patients (27.9%) scored for depression (SDS-10). Patients with worse health status presented more depression (OR = 5.85, 95% CI 3.01-11.36) and after adjusting for gender (OR = 5.70, 95% CI 2.92-11.13). CONCLUSIONS: In patients with COPD and CAT ≥10, there is a five times greater risk of depression than patients with CAT <10. However, the relationship may be bidirectional. It is essential to specify the direction of causality in future investigations.