Background: Acute exacerbations of COPD are a major cause of morbidity and mortality and have a heavy burden on healthcare resources. Pulmonary rehabilitation (PR) has been shown to reduce hospital admissions and improve quality of life, but few studies have investigated the effect of PR on exacerbation rate using routinely collected health records.

Methods: Primary care data from the Clinical Practice Research Datalink and Hospital Episode Statistics (HES) on acute exacerbations were combined to determine the effects of PR on acute exacerbations of COPD one year before and after PR in patients who received PR compared to patients who did not.

Findings: 108,042 patients were included in the analysis between 1st January 2004 and 31st March 2014. Of those, 38,952 (36%) were not eligible for PR. Of the 69,090 eligible; 6,436 (9.3%) were recorded a having received PR, 62,019 (89.8%) were not referred and 634 (0.9%) were referred but declined. When combining primary care events with HES events, people who received PR had a higher incidence rate (IR) of acute exacerbations (IR = 3.18 95% CI: 3.02, 3.35) compared to people who did not receive PR (IR = 3.04 95% CI: 2.88, 3.20).

Conclusions: This study highlights that a high proportion of COPD patients eligible for PR in the UK are not being referred. In addition, poorer outcomes (defined as acute exacerbations) following PR suggest that either higher risk patients are being referred for PR, or PR as currently delivered is ineffective. Higher quality, standardised PR programmes should be encouraged to ensure outcomes from randomised controlled trials can be replicated in real life.