The validity of the Distress Thermometer in patients with primary open-angle glaucoma.

OBJECTIVE

To validate the Distress Thermometer (DT) as a screening tool for psychosocial distress in primary open-angle glaucoma (POAG) patients and determine optimal cutoff score for clinical use.

DESIGN

Clinic-based cross-sectional study.

PARTICIPANTS

300 POAG patients without recent glaucoma surgery within past 6 months were recruited from Duke Eye Center clinics between September 2022 and August 2023.

METHODS

Participants completed the DT, Hospital Anxiety and Depression Scale (HADS), Self-Efficacy for Managing Chronic Disease 6-item scale (SE-6), Modified Medical Outcomes Study Social Support Survey 8-item scale (MOS-8), and National Eye Institute Visual Functioning Questionnaire 9-item scale (NEI VFQ-9) prior to clinic visit. Receiver Operating Characteristic (ROC) analysis compared DT cutoff scores (4, 5, 6) against HADS thresholds for overall distress, anxiety (HAD-A), and depression (HADS-D) subscales. Sensitivity, specificity, positive/negative predictive values, and area under the curve (AUC) were calculated. Associations between distress and demographic/clinical variables were also explored. Comparison of patient characteristics was conducted between groups correctly and incorrectly classified by the DT relative to the HADS.

MAIN OUTCOME MEASURES

Validity of DT in detecting clinically significant distress, as determined by HADS, with secondary outcomes of patient acceptability of DT and factors associated with distress.

RESULTS

The optimal DT cutoff was 5 for detecting overall distress (HADS ≥15; sensitivity 0.78, specificity 0.76) and depression (HADS-D ≥8; sensitivity 0.84, specificity 0.73), while a cutoff of 4 best identified anxiety (HADS-A ≥7; sensitivity and specificity both 0.75). AUC values were 0.83-0.84, indicating strong discriminative ability. DT negatively correlated with age, social support, self-efficacy, vision-related quality-of-life, IOP of the better eye, and SAP MD of the worse eye. DT was significantly associated with sex, marital status, income, and employment. Discrepancies between DT and HADS classification were linked to sex, distress, and social support. Patients found the DT highly acceptable (92% easy to complete; 88% not bothered by the question).

CONCLUSIONS

The DT is a valid, reliable, and acceptable screening tool for psychological distress in POAG patients. Its brevity and ease of use supports implementation into routine glaucoma care, enabling early identification and intervention to improve outcomes and quality of life for distressed POAG patients.