Changes in Symptoms and Lung Function During Three Months of Individually Tailored Inhaled Therapy in Chronic Obstructive Pulmonary Disease: A Prospective Observational Cohort Study

Background. Randomised controlled trials have established what individual inhaled regimens can achieve in chronic obstructive pulmonary disease (COPD) under controlled conditions, but they recruit selected populations and enforce protocol-driven follow-up. How patients fare on regimens chosen individually for them in everyday care is less well characterised. Objective. To assess the change in symptoms and lung function over three months in a prospective cohort of patients with COPD whose inhaled treatment was tailored to the individual by the attending physician. Methods. Consecutive adults with stable, spirometrically confirmed COPD attending a single internal-medicine clinic were assessed at baseline and reassessed approximately three months later. Baseline regimens were short-acting beta2-agonist/short-acting muscarinic antagonist (SABA/SAMA), long-acting muscarinic antagonist (LAMA), long-acting beta2-agonist (LABA), LABA plus inhaled corticosteroid (ICS), LABA plus LAMA, or LABA plus LAMA plus ICS. The primary outcomes were the within-participant change in COPD Assessment Test (CAT) score and in forced expiratory volume in one second (FEV1) % predicted. Secondary outcomes were the proportion achieving the CAT minimal clinically important difference (MCID, defined as a reduction of at least two points), the proportion achieving a six-minute walk distance (6MWD) improvement of at least 30 m, change in modified Medical Research Council (mMRC) dyspnoea grade, body mass index–airflow obstruction–dyspnoea–exercise capacity (BODE) and age–dyspnoea–obstruction (ADO) indices, and clinical events. Paired changes were analysed with paired t-tests or Wilcoxon signed-rank tests and are reported with 95% confidence intervals (CIs). Results. Three hundred participants were enrolled. Recorded GOLD groups were A (n = 69), B (n = 158) and E (n = 73). Paired CAT and FEV1 data were available for 276 (92.0%) and 257 (85.7%) participants, all of whom were reassessed between 84 and 98 days after baseline (median 91 days). Across the cohort, mean CAT fell by 3.93 points (95% CI −4.43 to −3.44) and mean FEV1 rose by 2.20 percentage points (95% CI 1.78 to 2.63); one hundred and ninety-five of 276 participants (70.7%) reached the CAT MCID and 98 of 244 (40.2%) achieved a 6MWD gain of at least 30 m. Improvement was observed with every long-acting regimen. Participants receiving LABA + ICS improved by 4.18 CAT points (95% CI −5.24 to −3.12; p < 0.001) and 3.06 FEV1 percentage points (95% CI 2.16 to 3.95; p < 0.001), with 82.1% reaching the CAT MCID—a magnitude similar to that observed on LABA+LAMA. Participants on SABA/SAMA alone showed no improvement in either outcome. Sixty-three exacerbations, eleven hospitalisations and four cases of pneumonia occurred. Conclusions. During a reassessment interval of 84 to 98 days, patients with COPD receiving individually tailored long-acting inhaled therapy showed improvement in symptoms and lung function that exceeded the established MCID for the CAT, including patients treated with LABA+ICS. The study had no concurrent control group, no randomisation and no adjustment for baseline differences between regimens; the observed changes therefore describe the course of treated patients and cannot be attributed to any specific regimen.