Effect of a single exacerbation on decline in lung function in COPD

Abstract

BackgroundCOPD exacerbations are associated with accelerated lung function decline, but whether they are causal is unknown. We evaluated the effect of a single exacerbation on rate of lung function change using data from the 4-year Understanding Potential Long-term Impacts on Function with Tiotropium (UPLIFT®) trial. MethodsRetrospective analysis of annual rates of decline in FEV1 and FVC before and after a single (and the only) moderate-to-severe exacerbation in patients during UPLIFT® (exacerbator subgroup), compared with changes between the first and second half of the study in a non-exacerbator subgroup. A sensitivity analysis examined annual rates of decline in matched pairs of exacerbators and non-exacerbators. ResultsFollowing the single moderate-to-severe exacerbation, mean annual decline in post-bronchodilator lung function increased compared with the rate of decline before the exacerbation (FEV1 76.5 vs. 39.1 mL/year, p = 0.003; FVC 106.5 vs. 34.7 mL/year, p = 0.011). In non-exacerbators, there were no differences in rates of decline between the first and second halves of the study (post-bronchodilator FEV1 38.2 vs. 41.8 mL/year, FVC 45.3 vs. 43.9 mL/year. Before the single (moderate-to-severe) exacerbation in the exacerbator subgroup, declines in post-bronchodilator FEV1 or FVC were similar to non-exacerbators in the first half of the study; after the single exacerbation they were significantly higher than for non-exacerbators in the second half of the study. The sensitivity analysis showed similar results. ConclusionA single COPD exacerbation may result in significant increase in the rate of decline in lung function.