OBJECTIVES: Chronic obstructive pulmonary disease (COPD) ranks third in the leading causes of mortality in the United States. This study aimed to measure the impact of risk factors on COPD.

METHODS: Adult patients (aged ≥18 years) with their first diagnosis for COPD (ICD-9-CM: 491, 492, 496; ICD-10-CM: J40-J44) were identified from the US Department of Defense (DoD) population from October 1, 2012-September 30, 2015 (identification period). For the COPD cohort, the first COPD diagnosis date was designated as the index date. A control cohort was generated for patients with no COPD diagnosis from October 1, 2011-September 30, 2016. A random index date within the identification period was selected for control patients. Study subjects were required to have continuous health plan enrollment for 12 months pre-index date (baseline period) and 12 months post-index date (follow-up period). Logistic regression was used to assess the odds of COPD, controlling for patient demographics (age, sex, geographic region), Charlson Comorbidity Index (CCI) score, and baseline health care utilization.

RESULTS: A total of 75,589 case-control pairs were identified; mean age was 62 years for case and 43 years for control patients (p<0.001). The majority (52%) of patients were male. The average CCI score was 1.9 for cases and 0.3 for controls (p<0.001). COPD patients were more likely to have baseline comorbidities, such as diabetes (35% vs 9%) and peripheral vascular disease (13% vs 1%), than controls. Increased age (odds ratio [OR]=6.32, 95% confidence interval [CI]=6.07-6.57 for age 41-64; OR=13.68, 95% CI=13.01-14.39 for age ≥65; reference: age 18-40), being male (OR=1.17, 95% CI=1.20-1.14), baseline CCI score (OR=1.59, 95% CI=1.57-1.62), and ER visits (OR=1.17, 95% CI=1.16-1.19) were associated with higher risk of COPD, among other factors.

CONCLUSIONS: In the US DoD population, baseline CCI score and increased age were positively associated with COPD.