Long-term oxygen therapy in COPD patients: population-based cohort study on mortality

Area of Science:

• Pulmonary Medicine
• Respiratory Health
• Clinical Epidemiology

Background:

• Chronic obstructive pulmonary disease (COPD) presents a significant global health challenge and socioeconomic burden.
• Long-term oxygen therapy (LTOT) is a guideline-recommended treatment for severe hypoxemia in COPD patients, shown to reduce mortality.
• Assessing mortality predictors in LTOT users is crucial for optimizing patient care and outcomes.

Purpose of the Study:

• To evaluate standardized mortality ratios (SMRs) for incident and prevalent users of long-term oxygen therapy (LTOT) in COPD patients.
• To identify key patient characteristics that predict mortality in COPD patients receiving LTOT.
• To analyze mortality differences between new (incident) and existing (prevalent) LTOT users.

Main Methods:

• A 2-year population-based cohort study was conducted in Bern, Switzerland, including all COPD patients on LTOT.
• Standardized mortality ratios (SMRs) were calculated and adjusted for age and sex.
• Incident (LTOT <6 months) and prevalent LTOT users were analyzed separately to mitigate immortal time bias.

Main Results:

• The study included 475 COPD patients on LTOT (20% incident users).
• Two-year mortality was 41% for incident users vs. 27% for prevalent users (p<0.007).
• SMRs were significantly higher for incident users (8.02) compared to prevalent users (5.90). Type 2 respiratory failure was linked to higher SMRs in incident users (60.57, p=0.038).

Conclusions:

• Despite some reduction compared to older cohorts, 2-year mortality for COPD patients on incident LTOT remains high, particularly for younger patients.
• Type 2 respiratory failure is a significant predictor of mortality in COPD patients initiating LTOT.
• Further strategies are needed to reduce mortality in COPD patients requiring LTOT, especially those with Type 2 respiratory failure.