The effect of regionalization on outcome in pulmonary lobectomy: A Canadian national study

OBJECTIVE: To examine the effect of regionalization of thoracic surgery services in Canada by evaluating change over time in hospital volumes of pulmonary lobectomy and its impact on length of stay and in-hospital mortality. METHODS: Data on pulmonary lobectomy between 1999 and 2007 were abstracted from the Canadian Institute for Health Information Discharge Abstract Database. In-hospital mortality was analyzed by logistic regression, and log-transformed length of stay was analyzed by linear regression. Cross-sectional analysis of hospital volume, in-hospital mortality, and length of stay was performed, controlling for clustering. Within-hospital changes in annual volume on outcome was analyzed using multivariable logistic regression, controlling for Charlson comorbidity index and other confounders. RESULTS: Of 19,732 patients, 10, 281 (52%) were male, with an average age of 63.3 years. There was a 45% (95% confidence interval, 21–61; P = .001) relative risk reduction in in-hospital mortality with a 19% reduction in length of stay (95% confidence interval, 12–25; P < .0001). On comparison of volume between hospitals, an increase of 20 cases was associated with a 15% relative risk reduction (95% confidence interval, 9–19; P < .0001) in in-hospital mortality and a 5% relative decrease (95% confidence interval, 3–7; P < .001) in length of stay. Within hospitals there was a nonsignificant relationship between volume and in-hospital mortality. CONCLUSIONS: In-hospital mortality and length of stay for lobectomies have decreased in Canada. In multivariate analysis, volume was associated with improved in-hospital mortality, but there was no reduction in mortality when volume was increased within a given hospital. However, the proportion of patients treated in high-volume centers has increased over time, inferring the importance of high-volume centers in improved outcomes. This supports regionalization policies for pulmonary lobectomy.