Early treatment response markers, for example, improvement in forced expiratory volume in 1 second (FEV1) and St George's Respiratory Questionnaire (SGRQ) total score, may help clinicians to better manage patients with chronic obstructive pulmonary disease (COPD). We investigated the prevalence of clinically important improvements in FEV1 and SGRQ scores after 2-month budesonide/formoterol or formoterol treatment and whether such improvements predict subsequent improvements and exacerbation rates.
This post hoc analysis is based on data from three double-blind, randomized studies in patients with moderate-to-very-severe COPD receiving twice-daily budesonide/formoterol or formoterol alone for 6 or 12 months. Prebronchodilator FEV1 and SGRQ total score were measured before treatment and at 2 and 12 months; COPD exacerbation rates were measured during months 2-12. Responders were defined by ≥100 mL improvement in prebronchodilator FEV1 and ≥4-point decrease in SGRQ total score.
Overall, 2,331 and 1,799 patients were included in the 0-2- and 0-12-month responder analyses, respectively, and 2,360 patients in the 2-12-month exacerbation rate analysis. At 2 months, 35.1% of patients were FEV1 responders and 44.3% were SGRQ responders. The probability of response was significantly greater with budesonide/formoterol than with formoterol or placebo for both parameters. Two-month responders had a greater chance of 12-month response than 2-month nonresponders for both FEV1 (odds ratio, 5.57; 95% confidence interval, 4.14-7.50) and SGRQ (odds ratio, 3.87; 95% confidence interval, 2.83-5.31). Two-month response in FEV1 (P<0.001), but not SGRQ (P=0.11), was associated with greater reductions in exacerbation risk.
Early FEV1 and SGRQ treatment responses relate to their changes at 12 months. FEV1 response, but not SGRQ response, at 2 months predicts the risk of a future COPD exacerbation in some, but not all patients. This is potentially useful in clinical practice, although more sensitive and specific markers of favorable treatment response are required.