Respiratory medicine
August 25, 2026 · via Europe PMC
Prolonged smoking duration is independently associated with mortality in former smokers with COPD regardless of pack-years.
Lee HW, Kim DK, Um SJ, +6 more, Lim SY.
AI summary — for doctors, generated from the abstract only
In a Korean COPD cohort, smoking duration of 40 years or more was independently associated with higher mortality regardless of cumulative smoking intensity (pack-years), suggesting that duration itself carries prognostic information beyond pack-years.
What was studied
A prospective multicenter cohort study (the Korea COPD Subtype Study, NCT02800499) of 2,166 patients with COPD, comparing the prognostic value of smoking duration (using a 40-year threshold) versus cumulative smoking intensity (using a 40 pack-year threshold) for predicting all-cause and cause-specific mortality over a median follow-up of 7 years, during which 210 deaths occurred.
Key findings
- Among 2,166 patients with COPD, 210 deaths occurred over a median 7-year follow-up.
- Smoking duration of 40 years or more was associated with increased all-cause mortality risk regardless of cumulative smoking intensity; the exact comparative statistic was truncated in the provided abstract.
- The study concludes that smoking duration was more strongly associated with mortality risk than cumulative smoking intensity alone, suggesting it may provide prognostic information beyond pack-years.
Clinical relevance
The findings suggest that when assessing mortality risk in former smokers with COPD, clinicians might consider smoking duration specifically, not just total pack-years, since it may better reflect prognostic risk; this could refine risk stratification and prognostic counseling for these patients, though further validation would be useful before formal incorporation into risk tools.
Who should care
Limitations
This is an observational cohort study, so the association between smoking duration and mortality cannot establish causation and could reflect confounding by other factors associated with prolonged smoking, such as other comorbidities or socioeconomic factors, not fully captured in the analysis; the exact comparative statistics for the primary finding were truncated in the provided abstract.
Smoking duration of 40 years or longer predicted higher mortality in COPD patients independent of total pack-years, suggesting duration itself carries prognostic value beyond the standard pack-year measure.
This is an AI-generated summary of the published abstract, not a clinical recommendation. It may not reflect the full text or subsequent updates — verify against the original source before acting on it.
Abstract
Background
Smoking exposure has been quantified using pack-years, which integrates smoking intensity and duration. However, pack-years may not fully capture the prognostic impact of prolonged exposure. We aimed to compare the prognostic value of smoking duration and cumulative smoking intensity for mortality risk stratification in patients with chronic obstructive pulmonary disease (COPD).
Methods
We analyzed data from the Korea COPD Subtype Study, an ongoing prospective multicenter cohort (NCT02800499). Smoking exposure was categorized using thresholds of 40 pack-years and 40 years of smoking duration. The primary outcome was all-cause mortality and the secondary outcome was cause-specific mortality.
Results
Among 2166 patients with COPD, 210 deaths occurred over a median follow-up of 7 years. Smoking duration ≥40 years was associated with increased all-cause mortality risk regardless of cumulative smoking intensity. Compared with patients with <40 pack-years and smoking duration <40 years, those with <40 pack-years but smoking duration ≥40 years had higher all-cause mortality risk (adjusted hazard ratio [aHR] = 1.66; 95% confidence interval [CI] = 1.01-2.73). Similarly, patients with ≥40 pack-years and smoking duration ≥40 years had increased all-cause mortality risk (aHR = 1.58; 95% CI = 1.15-2.16). In contrast, ≥40 pack-years without prolonged smoking duration was not associated with all-cause mortality. In cause-specific mortality analyses, prolonged smoking duration was also associated with increased cardiovascular and cancer-related mortality.
Conclusions
Smoking duration was more strongly associated with mortality risk than cumulative smoking intensity alone and may provide additional prognostic information beyond pack-years for mortality risk stratification in patients with COPD.
DOI
10.1016/j.rmed.2026.109128
PMID
42641996
Research metadata (titles, abstracts, authors, publication dates) is sourced from Europe PMC, which aggregates content from PubMed/MEDLINE, PubMed Central, and other providers under the U.S. National Library of Medicine (NLM/NCBI). NLM does not claim copyright on abstracts; the original journal publishers or authors may hold rights to the full articles. AI-generated summaries are derived only from the abstract, never the full text, and are always labeled as AI-generated.
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