Outpatient Follow-up and Rehospitalization for Sickle Cell Disease in Wisconsin Medicaid.

Abstract 2489

Poster Board II-466

Elevated hospitalization rates for patients with sickle cell disease are largely a result of frequent vaso-occlusive crises. Recent hospital utilization concerns have placed increasing emphasis on rehospitalization as a cost saving and quality of care measure. For sickle cell disease, 30 day rehospitalization has become a benchmark for care quality. Previous reports have shown 30 day rehospitalization rates as high as 30-47% and propose outpatient follow-up as a preventive measure. However, these studies have been limited to single centers and have focused only on specific age groups. Our study sought to examine the efficacy of outpatient follow-up on 30 day rehospitalization prevention across all ages in a statewide Medicaid program. We hypothesized that a post-discharge outpatient visit is associated with lower rehospitalization rates for patients with sickle cell disease. The study is a retrospective cohort using Wisconsin Medicaid claims data for hospitalized children and adults with sickle cell disease from January 1, 2003 to December 31, 2007. Patients at risk for rehospitalization were identified using sickle cell disease-related ICD-9 diagnosis codes (28241, 28242, 28260-28269) at inpatient discharge. The first hospitalization with a sickle cell diagnosis for each individual was extracted and then only those hospitalizations with a diagnosis of sickle cell crisis (28242, 28262, 28264, 28269) were included. Each patient participated in the study only once. The main outcome measure was a rehospitalization within 30 days of discharge from the previous hospitalization. Individuals were considered to have had an outpatient follow-up visit based on a claim for an outpatient visit within 30 days of discharge or prior to a rehospitalization if the rehospitalization occurred in fewer than 30 days. Outpatient visits that occurred on the same day as the rehospitalization were not included. Outpatient visits were calculated as rates to avoid the bias of those not being rehospitalized having more time for an outpatient visit. Multiple logistic regression was performed to evaluate the association between having an outpatient visit, disease severity, and asthma on the outcome of rehospitalization. Severe cases were defined as individuals with 3 or more hospitalizations within 1 year beginning 2 months after the index hospitalization. Patients were excluded from our study if the index hospitalization resulted in death, as they were not at risk for rehospitalization. Four hundred and eight patients with a hospitalization for sickle cell crisis were included in the analysis. Of these 408 patients, 70 (17%) were rehospitalized within 30 days following discharge from the index hospitalization. Of the 70 re-hospitalized patients, 35 (50%) were re-hospitalized within 11 days, and 54 (77%) were rehospitalized within 22 days from discharge. Multiple regression revealed that severe disease was associated with rehospitalization (4.693, 95% CI (2.674, 8.236)), but neither the outpatient visit rate (OR 0.970, 95% CI (0.367, 2.560)) nor a diagnosis of asthma (OR 0.862, 95% CI (0.467, 1.592)) were associated with rehospitalization. Of note, when the unadjusted analysis using the simple existence of an outpatient visit prior to rehospitalization was used, outpatient visits did show an association with decreased rehospitalizations; however this association was no longer significant when adjusted for the increased time for an outpatient visit in those not rehospitalized within 30 days. Contrary to our hypothesis, outpatient follow-up was not associated with fewer rehospitalizations in our study, when the outpatient follow-up rate was used to correct for the increased time for outpatient visits in those not rehospitalized. Disease severity was found to be the only statistically significant predictor of rehospitalization for patients with sickle cell disease.