Health system variation in COPD exacerbation rates

Lee TA, Bartle B, Weiss KB. Health system variation in COPD exacerbation rates. Poster session presented at: American Thoracic Society Annual International Conference; 2005 May 1; San Diego, CA.

RATIONALE: Annually about 300,000 patients with chronic obstructive pulmonary disease (COPD) use the Veterans Affairs (VA) health system, which is divided into regional service networks called VISNs. The VISNs function as independent healthcare networks in the VA system. Exacerbations are important disease events as they are relatively frequent, result in significant resource use and can indicate worsening disease. Little is known about population variations in exacerbations across health systems, our objective was to compare COPD exacerbation rates by VISN. METHODS: We identified a cohort of patients with a COPD diagnosis in Fiscal Year (FY) 2000 and followed them through FY2002. Exacerbations were defined as: 1) COPD-related hospitalization; 2) COPD-related ED visit; or 3) COPD-related outpatient visit with either an oral steroid or antibiotic dispensing. We used FY2000 as the baseline year and compared exacerbation rates in the follow-up period between VISNs, using negative binomial regression models. RESULTS: For this study, 198,891 patients with COPD were identified. During follow-up, there were 126,191 exacerbations experienced by 93,640 persons (47.1% of total cohort). Average exacerbation rate at baseline was 0.275 events per person. Rates ranged from 0.196 (95% CI, 0.185 to 0.208) in VISN 1 to 0.330 (95% CI, 0.313 to 0.346) in VISN 13. In the follow-up period, after controlling for baseline exacerbation rates, comorbidities and age the average exacerbation rate was 0.282 per person-year and varied from 0.175 (95% CI, 0.166 to 0.179) in VISN 1 to 0.349 (95% CI, 0.330 to 0.351) in VISN 13. CONCLUSIONS: Rates of COPD exacerbations varied nearly two-fold between VISNs with the highest and lowest rates. Understanding of the reasons underlying this variation in practice patterns may lead to improvements in care and outcomes.