Measuring care quality and health outcomes in patients with sickle cell disease

Background. Pain is the leading cause of morbidity for patients with sickle cell disease (SCD). Hydroxyurea is the first therapy proven in clinical trial to reduce pain episodes, as well as acute chest syndrome and the number of hospitalizations for patients with SCD. Since its approval, many eligible patients are not treated with hydroxyurea. This dissertation explores factors that are related to the prescribing of hydroxyurea and assesses the outcome of treatment when given in usual care settings.;Objectives. Two main objectives were set for this study: (1) to create a risk-adjusted predictive model of disease-related morbidity with regards to treatment with hydroxyurea, and (2) to explore the health outcomes of patients with SCD in relation to the structure and process of health care.;Methods. Florida Medicaid data were used to meet the goals of this project. For objective 1, principal components analysis was used to create a composite measure of morbidity which was based on the number of emergency department visits and hospitalizations for SCD complications. Stepwise multiple regression was applied to predict morbidity before HU initiation and again after therapy was initiated. Creating the two predictive models allowed post-treatment reductions in morbidity to be measured. For objective 2, physician specialty and provider practice location were examined as structural factors related to prescribing hydroxyurea. Instrumental variable analysis was used to estimate these associations and subsequent outcomes.;Results. Hydroxyurea was associated with a reduction in morbidity by greater than 20% from pretreatment to post-treatment. Significant predictors of morbidity were decreasing age, comorbid diseases, and increasing number of prescriptions for opiate drugs. SCD-specialists were more likely than non-specialists to prescribe hydroxyurea. When compared to patients not treated with hydroxyurea, morbidity was lower for treatment patients. This difference was not statistically significant.;Conclusion. SCD patients can experience a reduction in disease-related complications with hydroxyurea, though not all patients will have a positive treatment response. Efforts to improve prescribing of hydroxyurea should be targeted towards nonspecialists as well as SCD-specialists.