Determinants of polypharmacy and compliance with GOLD guidelines in patients with chronic obstructive pulmonary disease

Abstract

Background: Polypharmacy of respiratory medications is commonly observed in patients with chronic obstructive pulmonary disease (COPD). The aims of this study were to investigate determinants of polypharmacy and to study the consistency of actual respiratory drug use with current Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines in pulmonary rehabilitation candidates with COPD.

Methods: Data were extracted from the records of all patients with a diagnosis of COPD referred for pulmonary rehabilitation to CIRO+ between 2005 and 2009. Use of respiratory medications, self-reported COPD exacerbations, lung function, blood gases, exercise capacity, Medical Research Council (MRC) dyspnea grade, and St George's Respiratory Questionnaire (SGRQ) were recorded as part of assessment of health status.

Results: In total, 1859 COPD patients of mean age (± standard deviation) 64.3 ± 9.7 years and with a forced expiratory volume in one second (FEV(1)) of 44.7% ± 18.2% were included. On average, patients used 3.5 ± 1.5 respiratory medications; this number increased with increasing GOLD stage, MRC score, and SGRQ scores. FEV(1) (% predicted), SGRQ, and number of recent exacerbations were independent determinants of polypharmacy. Use of long-acting bronchodilators and inhaled corticosteroids was substantial and comparable in all GOLD stages. Use of corticosteroids was not restricted to patients with frequent exacerbations.

Conclusion: Polypharmacy of respiratory medications is common in COPD patients with persistent symptoms. In addition to severity of disease, health status is an independent predictor of polypharmacy. Actual drug use in COPD patients referred for pulmonary rehabilitation is partially inconsistent with current GOLD guidelines.

Keywords: chronic obstructive pulmonary disease; management; pharmacotherapy; polypharmacy; pulmonary rehabilitation; respiratory drug use.

Figure 1

Number of respiratory medications in patients with COPD (n = 1859). (A) Variation in number of respiratory drugs in patient population. (B) Number of respiratory drugs in different GOLD stages. ***P < 0.001, **P < 0.01 versus GOLD 1; ^###P < 0.001 versus GOLD 2; ^†††P < 0.001 versus GOLD 3. (C) Number of respiratory drugs for quartiles of health status, indicated by SGRQ. ***P < 0.001 versus quartile 1; ^###P < 0.001, ^##P < 0.01 versus quartile 2; ^†††P < 0.001 versus quartile 3. (D) Number of respiratory medications in relation to Medical Research Council (MRC) dyspnea score. **P < 0.01 versus MRC 0; ^###P < 0.001, ^#P < 0.05 versus MRC 1; ^†††P < 0.001 versus MRC 2; ^$$$P < 0.001 versus MRC 3; ^XXP < 0.01 versus MRC 4. Abbreviations: COPD, chronic obstructive pulmonary disease; GOLD, Global Initiative for Chronic Obstructive Lung Disease; MRC, Medical Research Council; SGRQ, St George’s Respiratory Questionnaire.

Figure 2

Proportion of COPD patients using various classes of inhaled respiratory medications, after stratification for GOLD stage. Black bars, short-acting bronchodilators; light gray bars, long-acting bronchodilators; dark gray bars, inhaled corticosteroids. Notes: Significance of differences between GOLD COPD stages is indicated by: ***P < 0.001, *P < 0.05 versus GOLD 1; ^###P < 0.001 versus GOLD 2; ^†††P < 0.001, ^†P < 0.05 versus GOLD 3. Abbreviations: COPD, chronic obstructive pulmonary disease; GOLD, Global Initiative for Chronic Obstructive Lung Disease.