UCLA

Hospital readmissions following acute exacerbations of chronic obstructive pulmonary disease (COPD) are frequent occurrences, resulting following one in five discharges. Readmissions are costly and also put patients at risk for adverse outcomes stemming from ongoing hospitalizations. Under the Hospital Readmissions Reduction Program, the Centers for Medicare and Medicaid Services have imposed penalties on excess readmissions for COPD, among other conditions. In this dissertation, we explore the effect of comorbidity, operationalized by the Charlson and Elixhauser indices, on readmission odds using multilevel logistic regression modelling and employing information criteria in order to determine which provides better fit in estimating readmissions. The Elixhauser index having prevailed, we estimated the readmission odds for returns related to an ongoing COPD diagnosis, versus for all other causes. We found that only 45% of returns were for ongoing COPD, and that those who returned for other reasons had substantially higher burdens of comorbidity. Finally, we evaluated the effect of the implementation of the Hospital Readmissions Reduction Policy on readmission rates for COPD, controlling for secular trends. We found that the addition of COPD to the list of penalized conditions did not significantly affect the already down-trending rates of readmissions when compared to non-penalized conditions or compared to the other penalized conditions of congestive heart failure, myocardial infarction, or pneumonia. Readmissions for COPD remain an ongoing problem for healthcare burden and cost, but overall readmissions do seem to be lessening. Understanding the effect of comorbidity on readmissions will help health systems better plan their efforts to improve care, and for policies like the Hospital Readmissions Reduction Program to adjust their expected readmission rates more fairly when applying penalties.