Development and Application of Patient-Reported Outcome Measures (PROMs) in Patients on Chronic Home Oxygen Therapy

Background/Objectives: Chronic home oxygen therapy-long-term oxygen therapy (LTOT)-improves survival and quality of life in chronic respiratory failure when used ≥15 h/day, but adherence is frequently suboptimal and specific patient-reported outcome measures (PROMs) are scarce. To develop, validate and apply a specific PROM for patients on LTOT. Methods: A prospective observational cohort study was conducted at San Juan de Alicante University Hospital (April 2024-December 2025) following a four-stage process: conceptual framework definition and expert workshop, content validation and item reduction, cognitive interviews with pilot reliability testing (n = 25), and field application to 120 consecutive chronic LTOT users. The LTOT-PROM was designed to capture the patient-perceived impact attributable to LTOT during the previous 4 weeks. Internal consistency was assessed with Cronbach's α and test-retest reproducibility with the intraclass correlation coefficient (ICC). Results: The final instrument comprises 15 scored items in two dimensions-Daily Activity (9 items) and Adverse Effects (6 items)-plus one ambulatory-only mobility item excluded from the total score. Cronbach's α was 0.814 (95% CI 0.681-0.906) for Daily Activity, 0.743 (95% CI 0.548-0.872) for Adverse Effects and 0.808 (95% CI 0.677-0.902) for the total scale; total ICC(A,1) was 0.890 (95% CI 0.767-0.950). Among the 120 patients (62 men, 58 women; mean age 78 ± 13 years; mean therapy duration 40 ± 32 months), 68% reported reduced effort for daily activities, 66% reported a reduction in dyspnoea and 67% reported improved self-confidence; 49% reported morning airway dryness and 7% abandoned the equipment due to nasal dryness or rhinitis. Conclusions: The LTOT-PROM is a brief, reliable and reproducible oxygen-specific instrument for assessing the recent patient-perceived impact of LTOT in routine clinical practice. Further studies should evaluate structural validity, external validity and the relationship between LTOT-PROM scores and objective adherence measures. The construct was predefined as the patient-perceived impact attributable to LTOT during a standardised 4-week recall window, and cognitive interviews confirmed that respondents interpreted the items as experienced benefit/burden during that period rather than as week-to-week symptom change.