Validation of the Distress Thermometer for detecting psychological distress in patients with stable chronic obstructive pulmonary disease: optimal cut-off score and influencing factors.

Background: Patients with chronic obstructive pulmonary disease (COPD) are at high risk for psychological distress, yet validated screening tools are not routinely used in clinical practice. The Distress Thermometer (DT), originally developed for cancer patients, is a brief screening tool for detecting psychological distress. However, the optimal cut-off in COPD patients remains unclear.

Aim: This study aims to validate the DT for use in stable COPD patients and to explore factors influencing psychological distress.

Methods: A cross-sectional study was conducted involving 386 stable COPD patients. Data were collected using sociodemographic questionnaires, the DT, and the Hospital Anxiety and Depression scale (HADS). Receiver Operating Characteristics (ROC) analysis was employed to determine the predictive metrics of various DT cut-off scores compared to the HADS. Bivariate binary logistic regression was used to identify factors influencing psychological distress.

Clinical trial number: This cross-sectional survey study did not involve experimental interventions and therefore did not require registration in a clinical trials platform. However, the study protocol can be retrieved from https://doi.org/10.17605/OSF.IO/C3N79 .

Results: The mean DT reported by patients was 3.77, while the mean total HADS score was 29.68. The DT score showed a high correlation with the total HADS score (r = 0.640). An optimal DT cut-off score of ≥ 5 was identified, yielding a Youden index of 0.815, with sensitivity and specificity of 97.40% and 84.14%, respectively. Using this cut-off score, the incidence of significant psychological distress was found to be 32.1%. Risk factors for psychological distress included gender, number of children, educational level, frequency of exercise, GOLD degree, and number of acute exacerbations.

Conclusions: The DT is a valid screening tool for identifying psychological distress among COPD patients. With an optimal cut-off score of ≥ 5, the DT offers high sensitivity and specificity, making it a reliable measure for clinical use. This study also highlights significant factors contributing to psychological distress, emphasizing the importance of integrating routine psychological assessments and care into the routine management of COPD to improve patient outcomes.