Chest. 2014 May 15. [Epub ahead of print] 50368 (6/2014)
From the author:
This was a one-year double-blind placebo controlled (HIACE) trial conducted in Kwong Wah Hospital, Hong Kong. 120 Chinese stable COPD patients were randomly assigned to received either high dose NAC (600mg BID) or placebo and were subsequently under regular follow-up for exacerbation, admission, symptoms and lung functions. At 1 year, there were significant reductions in exacerbation in NAC group compared to placebo (0.96 vs 1.71 times/year, p=0.019) and there was also significant improvement in small airway parameters including FEF25-75% and forced oscillation technique (FOT) parameters. However, the symptoms, 6-minute walking distance and St. George Respiratory Questionnaire scores showed no difference between the 2 groups. Further post-hoc subgroup analysis suggested that high dose NAC could reduce exacerbations and prolonged time to first exacerbations in the ‘high-risk/exacerbation-susceptible phenotype’ as defined as patients with a history of two or more exacerbations per year or %FEV1<50% but such benefits of NAC were not observed in the low-risk COPD patients.