Chronic obstructive pulmonary disease was associated with progressively lower modeled life expectancy across worsening disease severity in a pooled analysis of 45,886 adults from 8 US population-based cohorts, according to a study published in JAMA Internal Medicine.
In the cohort study, researchers analyzed data from the National Heart, Lung, and Blood Institute Pooled Cohorts Study. The pooled cohorts enrolled adults aged 17 to 98 years from 1983 to 2011, with longitudinal follow-up through 2020.
Chronic obstructive pulmonary disease (COPD) was defined by a prebronchodilator forced expiratory volume in 1 second to forced vital capacity ratio of less than 0.70. Disease severity was categorized according to Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage, using forced expiratory volume in 1 second percent predicted: GOLD stage 1, greater than 80%; GOLD stage 2, 50% to less than 80%; GOLD stage 3, 30% to less than 50%; and GOLD stage 4, less than 30%.
COPD was present at baseline in 8,058 participants, including 4,166 with GOLD stage 1 disease, 3,225 with GOLD stage 2 disease, 561 with GOLD stage 3 disease, and 106 with GOLD stage 4 disease. During a median follow-up of 15.2 years, 13,869 participants died.
All-cause mortality rates increased with worsening GOLD stage. Deaths occurred at rates of 29 per 1,000 person-years among participants with GOLD stage 1 disease, 42 per 1,000 person-years among those with stage 2 disease, 68 per 1,000 person-years among those with stage 3 disease, and 115 per 1,000 person-years among those with stage 4 disease. The rate was 14 per 1,000 person-years among participants without airflow obstruction.
The researchers used Gompertz proportional hazards models to estimate survival, life expectancy, and years of life lost from the time of initial spirometry. Models estimating years of life lost were adjusted for age, age squared, sex, race, body mass index, educational attainment, smoking status, pack-years of smoking, diabetes, hypertension, and hypercholesterolemia.
In age-adjusted models, estimated remaining life expectancy for a participant aged 65 years was 21.5 years among those without COPD, 20.0 years among those with GOLD stage 1 disease, 16.4 years among those with stage 2 disease, 13.1 years among those with stage 3 disease, and 10.7 years among those with stage 4 disease.
Compared with participants without airflow obstruction, estimated years of life lost were 1.9 years among those with COPD overall. Years of life lost increased with worsening disease severity, from 0.7 years in GOLD stage 1 disease to 2.6 years in stage 2 disease, 5.1 years in stage 3 disease, and 7.1 years in stage 4 disease.
Similar modeled decreases were observed by smoking status. Estimated years of life lost associated with COPD were 2.0 years among adults who never smoked, 1.9 years among former smokers, and 1.9 years among current smokers.
The researchers also compared modeled years of life lost associated with COPD with those associated with other common risk factors in the same cohort. Years of life lost were 2.7 years for hypertension, 4.1 years for diabetes, 0.5 years for obesity, and 5.5 years for cigarette smoking. The researchers reported that years of life lost for moderate to very severe COPD were similar to or greater than those observed with hypertension and diabetes.
In a sensitivity analysis, results were similar when participants with spirometric restriction were excluded from the group without airflow obstruction.
An accompanying editorial by Teva D. Brender, MD, and Deborah Grady, MD, of the University of California, San Francisco, noted that the findings may help patients with COPD and their clinicians clarify the impact of the disease and its severity to guide clinical decision-making and care planning. The editorial cited one study estimate involving younger patients: among participants aged 45 years with GOLD stage 1 COPD, mean additional life expectancy was 29.6 years for current smokers and 37.0 years for former smokers.
The study had limitations. COPD and disease severity were based on prebronchodilator spirometry at baseline, and spirometry was not updated during follow-up. The researchers could not account for incident COPD, worsening disease severity, exact disease onset, or medication use. Smoking status was self-reported and assessed only at baseline, and the researchers did not exclude participants with asthma. Estimates in older age groups may also have been affected by survivor bias. Because the study was observational, the findings should be interpreted as associations rather than evidence that COPD directly caused shorter life expectancy.
The findings provide population-based, modeled estimates that may help physicians discuss prognosis and care planning with patients across COPD severity stages, while underscoring that the results reflect associations rather than causal effects.
Disclosures: The study was supported by the National Institutes of Health and the National Heart, Lung, and Blood Institute. Dr. Bhatt reported grants paid to his institution from Apreo, Sanofi, Uniquity, Connect Biopharma, Nuvaira, the COPD Foundation, and Genentech, as well as consulting, advisory board, and continuing medical education honoraria from multiple companies outside the submitted work. Several coauthors reported NIH or NHLBI funding. No other disclosures were reported. The editorialists reported no conflicts of interest.
Source: JAMA Internal Medicine
