Factorial analysis of N-acetylcysteine and propolis treatment effects on symptoms, life quality and exacerbations in patients with Chronic Obstructive Pulmonary Disease (COPD): a randomized, double-blind, placebo-controlled trial

Abstract

OBJECTIVE: Standard treatment for chronic obstructive pulmonary disease (COPD) includes inhalation therapy along with mucoactive drugs. The aim of this study was to assess the efficacy and safety of orally administered mucolytic N-acetylcysteine and propolis (NACp) in COPD patients. PATIENTS AND METHODS: A randomized, double-blind, prospective, interventional, 6 months study was conducted at the Institute for Pulmonary Diseases of Vojvodina, Sremska Kamenica, Serbia. Effects of daily NACp administration (600 mg, 1200 mg or placebo) on exacerbation, life quality (St. George's Respiratory Questionnaire-SGRQ), symptoms (COPD assessment test-CAT; Visual analogue cough scale-VAS; Leicester Cough Questionnaire-LCQ; Medical Research Council Dyspnoea scale-mMRC) and spirometric parameters in 120 COPD patients were assessed. Tests were conducted at three-time points: baseline, after three months and after 6 months of NACp treatment. RESULTS: Repeated measures ANOVA showed that pulmonary function parameters, 6-minute walk test and mMRC score did not significantly change during the study. Cough VAS and CAT scores were significantly different between groups as within experimental groups. LCQ and SGRQ scores did not differ between placebo, and both examined groups, but within each examined group statistically significant difference was confirmed in observed parameters during therapy. Factorial analysis and subsequent binary logistic regression revealed "Symptoms related factor" as the strongest predictor of exacerbation for supplemented groups (p<0.01). CONCLUSIONS: Treatment with high NACp for 6 months is safe and beneficial for cough and expectoration symptoms and improves the life quality. NACp significantly reduces acute exacerbation frequency in COPD patients by controlling COPD related symptoms.