Predictors of ICS/LABA prescribing in COPD patients: a study from general practice

A combination of inhaled corticosteroid and long-acting beta2 agonist (ICS/LABA) is used frequently to treat chronic obstructive pulmonary disease (COPD) patients. The aim of the study was to determine whether prescribing ICS/LABA to COPD patients in primary care in 2009/10 was within the GOLD guidelines and whether and to what degree patient characteristics were associated with prescription of these drugs by GPs.

This was a cross-sectional study in seven Norwegian GP practices. Patients registered with a diagnosis of asthma or COPD in the previous five years were included.

Among the 376 patients included in the analysis, 149 patients had COPD, defined as a post-bronchodilator FEV1/FVC <0.7 and 55.6% of these patients were treated with ICS/LABA. The rate of prescribing was significantly higher in the COPD patients also diagnosed with asthma than in those with COPD as the only diagnosis, 66.7%, and 39.0%, respectively (P = 0.001). The prescribing rate in the latter subgroup would have been 18.6% if the 2007 GOLD guidelines had been followed. One or more exacerbations in the previous year was the strongest predictor of ICS/LABA prescribing in the COPD patients who were not registered with a concomitant diagnosis of asthma (OR 3.2, 95% CI 1.0-10.0) but this association was limited to the patients with severe disease (FEV1% predicted <50) (OR 13.5, 95% CI 1.8-101.1). Cardiovascular disease was associated with decreased ICS/LABA prescribing (OR 0.4, 95% CI 0.2-0.8) in the COPD group. A Kappa coefficient of 0.32 was found between the actual prescribing rate and that recommended in the 2007 GOLD guidelines.

Overprescribing of ICS/LABA for the COPD patients was shown. Previous exacerbation was a strong predictor of ICS/LABA prescribing only in patients with severe COPD. Because of the low emphasis on previous exacerbation when prescribing for COPD patients with mild to moderate disease, the actual prescribing rate agreed more closely with the GOLD guidelines from 2007 than with those published in 2011. Cardiovascular disease was associated with decreased prescribing, indicating that GPs adjust the treatment in cases with multimorbidity.