Patients with severe chronic obstructive pulmonary disease (COPD) who stop smoking may be able to improve their rate of survival, despite the severity of their lung disease.
A new study in the November issue of CHEST, the peer-reviewed journal of the American College of Chest Physicians (ACCP), showed that patients with severe, early-onset COPD who continued to smoke had a risk of mortality that was almost three times that of patients who stopped smoking. The study also reported that greater smoking intensity increased the risk of mortality among COPD patients, with patients who had the greatest smoking intensity having the highest risk of mortality.
"Lifetime smoking intensity and current smoking status independently increased mortality in our patients with severe COPD," said Craig P. Hersh, MD, Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Boston, MA. "However, patients who continued smoking significantly reduced their survival rate, which confirms the importance of smoking cessation even in patients with the most advanced stages of lung disease."
Dr. Hersh and colleagues utilized data from the Boston Early-Onset COPD Study to determine the natural history of severe, early onset COPD and the survival rates of patients under age 53 during a follow-up period of 2 months to 8 years. Of the 139 patients (72.7 percent women) studied, 37 patients died within the study period, with the majority of deaths due to cardiorespiratory illness. Overall survival rates were 85 percent at 3 years and 72 percent at 5 years. Patients who smoked during the study period had a risk of mortality that was almost three times that of patients who stopped smoking. In addition, greater smoking intensity was associated with decreased survival, and the risk of mortality increased by 20 percent for each 10 pack- years of smoking.
"As age increases, so does the risk of mortality in patients with COPD," added Dr. Hersh. "Yet, the relatively young patients in our study had a high rate of mortality, despite their young age."
Although women made up the majority of patients in the study, both groups had similar rates of survival. In addition to age and gender, symptoms of chronic bronchitis, bronchodilator responsiveness, underweight, home oxygen use, pulmonary rehabilitation, and lung volume reduction surgery were not significant predictors of survival.
"The large number of female patients with severe, early-onset COPD has been an interesting finding of our study that we have not yet been able to explain fully," said Edwin K. Silverman, MD, PhD, the Principal Investigator of the Boston Early-Onset COPD Study and senior author of this manuscript. "It is possible that women are more susceptible to the harmful effects of cigarette smoke and that this increased susceptibility has not been appreciated due to the historically higher rates of smoking among men."
COPD is the fourth leading cause of death in the United States, with mortality rates significantly increasing among women each year. COPD is currently diagnosed in at least 10 million Americans, and the majority of cases are attributed to long-term cigarette smoking.
"As seen in this study and many others, the most effective treatment for COPD is smoking cessation," said Paul A. Kvale, MD, FCCP, President of the American College of Chest Physicians. "Regardless of a patient's age or disease severity, physicians should ask all patients about smoking status. Physicians also should encourage smoking cessation in all patients who smoke and continue to motivate their patients throughout the cessation process."