The Bronchitis Randomized on NAC Cost-Utility Study (BRONCUS): hypothesis and design

Chronic obstructive pulmonary disease (COPD) is an irreversible disorder ch aracterized by airflow obstruction and a progressive decline in forced expi ratory volume in one second (FEV1). At present, no treatment except quittin g smoking appears to affect the progression of the disease. Oxidative stres s has been implicated in its pathogenesis. The Bronchitis Randomized on NAC Cost-Utility Study (BRONCUS) is a phase II I, randomized, double-blind, placebo-controlled, parallel group, multicentr e study designed to assess the effectiveness of the antioxidant agent N-ace tylcysteine (NAC) in altering the decline in FEV1, exacerbation rate, and q uality of life in patients with moderate to severe COPD. In addition, cost- utility of the treatment will be estimated. Patients will be followed for 3 yrs and evaluated every 3 months. The necessary sample size to demonstrate an effect on the decline in FEV1 of 20 mL(.)yr(-1) was estimated to be 478 patients. Five hundred and twenty-three patients with moderate to severe COPD were re cruited from 10 European countries from June 1, 1997-December 31, 1999. The y were 63 +/-8 yrs old and consisted of 243 (46%) current smokers and 280 ( 54%) exsmokers. Patients had on the average 4.9 +/-1.6 exacerbations during the last 2 yrs. Postbronchodilator FEV1 averaged 57 +/-9% and the reversib ility after 400 pg of Salbutamol averaged 4 +/-4% predicted. The final results of the trial will be available in about 2 yrs. The study will provide objective data on the effects of N-acetylcysteine on outcome v ariables in chronic obstructive pulmonary disease.