COPD: Progression and Mortality Risks
Drummond MB, Hansel NN, Connett JE, Scanlon PD, Tashkin DP, Wise RA
Am J Respir Crit Care Med. 2012;185:1301-1306
The Lung Health Study was a large long-term study of relatively young cigarette smokers. The trial began in the 1980s and included smokers with mild disease. They were followed for a total of 12 years, with regular assessments of lung function and mortality and other outcomes from which many important insights into the natural history of chronic obstructive pulmonary disease (COPD) have been obtained.
A new report focuses on the differential rate of decline in lung function and which spirometric measurements predict mortality. The 5887 participants, all regular smokers, were stratified by lung function at initiation. Associations were made between initial lung function and the subsequent decline in lung function and mortality.
The cohort was predominantly white and male, and the mean FEV1 was 78% ± 9% of the predicted value at enrollment. The principal finding was that lung function declined most rapidly in the subgroup that started with the lowest FEV1, -- the so-called "horse-racing effect." This was also the group that had the greatest risk for mortality from any cause 12 years later. A finding that was less predicted was that even slightly abnormal lung function at enrollment was associated with an increase in the subsequent rate of decline in lung function.
COPD is a progressive disorder in which lung function tends to decline over many years, a process that may continue long after smoking has ceased. Previous studies have also shown that the rate of decline of lung function is heterogeneous. The Lung Health Study was performed to enhance our understanding of the relevant factors. Its main outcomes, as reported in 1994, confirmed that smoking cessation decreased the rate of decline of lung function and that maintenance use of the anticholinergic bronchodilator ipratropium did not reduce the rate of decline of lung function.
The current further analysis of the Lung Health Study outcomes can help practitioners to identify patients who are at greatest risk for deteriorating lung function and death. A smoker who develops COPD has typically lost 50% of his or her predicted lung function (FEV1) at the time of diagnosis. It would be important to be able to predict at a much earlier stage which smokers are most at risk for rapid deterioration so that management can be tailored accordingly.
The current analysis found not only that persons with the lowest lung function deteriorated most rapidly, but also that lung function tended to deteriorate even in those with only minimally abnormal lung function. Clearly, even mildly abnormal lung function in a younger smoker, being a predictor of future problems, warrants interventions that will alter the course of the disease.
Smoking cessation is the most important such intervention. Others are the recommendation of prophylactic immunization against influenza each year, and against pneumococcal infection. Pulmonary rehabilitation and the use of bronchodilators to relieve symptoms as necessary could also be instituted.
Abstract
Spirometric Predictors of Lung Function Decline and Mortality in Early Chronic Obstructive Pulmonary Disease
Drummond MB, Hansel NN, Connett JE, Scanlon PD, Tashkin DP, Wise RA
Am J Respir Crit Care Med. 2012;185:1301-1306
Study Summary
The Lung Health Study was a large long-term study of relatively young cigarette smokers. The trial began in the 1980s and included smokers with mild disease. They were followed for a total of 12 years, with regular assessments of lung function and mortality and other outcomes from which many important insights into the natural history of chronic obstructive pulmonary disease (COPD) have been obtained.
A new report focuses on the differential rate of decline in lung function and which spirometric measurements predict mortality. The 5887 participants, all regular smokers, were stratified by lung function at initiation. Associations were made between initial lung function and the subsequent decline in lung function and mortality.
The cohort was predominantly white and male, and the mean FEV1 was 78% ± 9% of the predicted value at enrollment. The principal finding was that lung function declined most rapidly in the subgroup that started with the lowest FEV1, -- the so-called "horse-racing effect." This was also the group that had the greatest risk for mortality from any cause 12 years later. A finding that was less predicted was that even slightly abnormal lung function at enrollment was associated with an increase in the subsequent rate of decline in lung function.
Viewpoint
COPD is a progressive disorder in which lung function tends to decline over many years, a process that may continue long after smoking has ceased. Previous studies have also shown that the rate of decline of lung function is heterogeneous. The Lung Health Study was performed to enhance our understanding of the relevant factors. Its main outcomes, as reported in 1994, confirmed that smoking cessation decreased the rate of decline of lung function and that maintenance use of the anticholinergic bronchodilator ipratropium did not reduce the rate of decline of lung function.
The current further analysis of the Lung Health Study outcomes can help practitioners to identify patients who are at greatest risk for deteriorating lung function and death. A smoker who develops COPD has typically lost 50% of his or her predicted lung function (FEV1) at the time of diagnosis. It would be important to be able to predict at a much earlier stage which smokers are most at risk for rapid deterioration so that management can be tailored accordingly.
The current analysis found not only that persons with the lowest lung function deteriorated most rapidly, but also that lung function tended to deteriorate even in those with only minimally abnormal lung function. Clearly, even mildly abnormal lung function in a younger smoker, being a predictor of future problems, warrants interventions that will alter the course of the disease.
Smoking cessation is the most important such intervention. Others are the recommendation of prophylactic immunization against influenza each year, and against pneumococcal infection. Pulmonary rehabilitation and the use of bronchodilators to relieve symptoms as necessary could also be instituted.
Abstract
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