A smoking cessation program slowed decline in lung function
ACP J Club. 1995 Mar-April;122:41. doi:10.7326/ACPJC-1995-122-2-041
Anthonisen NR, Connett JE, Kiley JP, et al. for the Lung Health Study Research Group. Effects of smoking intervention and the use of an inhaled anticholinergic bronchodilator on the rate of decline of FEV1. The Lung Health Study. JAMA. 1994 Nov 16;272:1497-1505.
To determine whether a smoking cessation program and use of an inhaled bronchodilator could slow the rate of lung function decline in persons who smoke cigarettes and who had signs of early chronic obstructive pulmonary disease (COPD).
Randomized, double-blind, placebo-controlled trial with 5-year follow-up.
10 clinical centers in North America.
5887 patients between 36 and 60 years of age (mean age 48 y, 63% men) who had smoked ≥ 10 cigarettes on ≥ 1 day during the 30 days previous to the first screening visit, had mild airways obstruction, and had a forced expiratory volume in 1 second (FEV1) between 55% and 90% of predicted normal value. Exclusion criteria were other serious disease or use of physician-prescribed bronchodilators or β-blockers. Follow-up was 94%.
Patients were stratified by center and allocated to smoking intervention and an inhaled bronchodilator, ipratropium bromide (Atrovent), 2 puffs 3 times/d (SIA) (n = 1961); to smoking intervention and inhaled placebo (SIP) (n = 1962); or to usual care (UC) (n = 1964). The smoking intervention was a cessation program consisting of 12 group meetings guided by a health educator emphasizing behavior modification techniques. Compliance was assessed by self-report, expired carbon monoxide and salivary cotinine levels, and inhaler canister weight. Patients had 5 annual follow-up visits.
Main outcome measures
Change in FEV1 and smoking status.
During the first year, mean FEV1 increased by 11.2 mL in the SIP group and 38.8 mL in the SIA group and decreased by 34.3 mL in the UC group (P < 0.005 for each comparison). Between the first and fifth year, mean FEV1 decreased at a similar rate in all 3 groups. Mean cumulative decreases from baseline to the fifth annual visit were 184 mL for the SIA group, 209 mL for the SIP group, and 267 mL for the UC group (P ≤ 0.002 for each comparison). At study end, 35% of participants in the intervention groups had quit smoking compared with 20% of UC participants. Over 5 years, those participants who quit smoking had a slower rate of decline in FEV1.
A smoking cessation program effectively slowed the decline in FEV1 in persons who smoke and have mild chronic obstructive pulmonary disease. The use of an inhaled bronchodilator increased FEV1 in the first year but did not affect the decline in lung function over 5 years.
Source of funding: National Heart, Lung, and Blood Institute.
For article reprint: Dr. J.E. Connett, Lung Health Study, 2221 University Avenue Southeast, Suite 200, Minneapolis, MN 55414, USA. FAX 612-626-0660.
COPD affects 13 million persons in the United States and is the fourth leading cause of death (1, 2). This elegant and methodologically rigorous randomized, double-blind, placebo-controlled trial is a landmark study for the fields of smoking cessation and COPD research.
The study bears good news: The short- and long-term benefits of quitting smoking are real and clinically important. A main outcome of the study shows that a smoking cessation program can slow the decline of FEV1 in patients who smoke. More valuable, however, is the secondary analysis showing that sustained quitters in the SIP group had an overall FEV1 5-year decline of 72 mL compared with continuing smokers, whose FEV1 declined by 301 mL. In fact, for the first 3 years, sustained quitters had a FEV1 that was higher than their baseline.
The bad news is that the early increase in FEV1 in the intervention groups was not a permanent change and was followed in years 2 to 5 by a decrease in FEV1. It is important to keep in mind that an age-related decline in FEV1 of about 30 mL/y occurs in middle-aged persons who do not smoke (3).
The results from this study give the strongest evidence to date that smoking cessation substantially benefits lung function and should be the first form of therapy for patients with mild airways obstruction. Other exciting results and questions will surely emerge when further secondary analyses are completed.
Jasjit A. Ahluwalia, MD, MPH, MS
Emory University School of MedicineAtlanta, Georgia, USA