The influence of high doses of N-acetylcysteine alone or in combination with inhaled corticosteroids on quality of life in patients with COPD

Background: The aim of our study was to evaluate the effects of 6-month oral N-acetylcysteine (NAC) treatment 1200 mg/day alone or in combination with inhaled corticosteroids (ICS) on health-related quality of life (QOL) in outpatients with COPD. Methods: A total of 62 patients with stable COPD (36 males, mean age 66.8 years, GOLD stage I-IV) were included and divided into two treatment groups. Group 1 received bronchodilators and NAC. Group 2 received NAC and ICS in addition to bronchodilators. Clinical examination, pulmonary function tests and QOL were measured at baseline and repeated after 6 months of treatment with the Short Form 36 Questionnaire (SF-36) and St. George's Respiratory Questionnaire (SGRQ). Results: SGRQ symptoms, total score and SF-36 social function score at baseline were higher in group 2 (p<0.05). SGRQ symptoms, impact, activity and total scores recorded significant improvements (p<0.0001) after NAC treatment with greater changes in group 2. All improvements recorded by SGRQ scores were higher than the 4 units' threshold for the minimum clinically important difference for both groups. The SF-36 scores indicated significant improvement in QOL in both groups, especially in physical functioning, role-physical functioning, bodily pain, general health, role-emotional and mental health domains scores. Reduction of respiratory symptoms was registered even after 1 month of NAC treatment. Nevertheless lung function parameters did not change over 6 months. Conclusion: Long-term treatment of stable COPD patients with NAC 1200 mg/day improves QOL measured both SF-36 and SGRQ with greater changes in combination of NAC with ICS.