Acute Care Visits in Sickle Cell Disease: a Population-Based Multi- State Study

Background: The number of times a patient will seek acute care in the emergency department or require hospitalization for sickle cell related illness has not been described in a population-based manner. Twenty years ago, rates of acute care visits for 3,578 patients who were part of the Cooperative Study of Sickle Cell Disease were reported, eloquently describing patterns of acute care utilization for people followed at select centers. In that study, only 1% of patients had more than six visits per year and 5% of the population (who made three to 10 visits per year) accounted for almost one-third of all visits. The objective of this study is to describe the emergency department and hospital utilization for patients with sickle cell related conditions over a two- year period. This study will be the first to provide a complete assessment of the utilization patterns of patients with sickle cell disease, one that is multi-state, inclusive of all ages, all insurance types, and includes patients that are followed at community, academic and tertiary care centers.

Methods: We conducted a retrospective cohort study using 2005 and 2006 State Emergency Department and State Inpatient Databases that include encrypted personlevel identifiers to allow linkage of record level information. The data are from the Healthcare Cost and Utilization Project (HCUP), a Federal-State-Industry partnership sponsored by the Agency for Healthcare Research and Quality. Data for all sickle cell related emergency department visits and hospitalizations within the following seven states (Arizona, California, Florida, Missouri, South Carolina, Tennessee, and New York) were extracted for each patient. To be eligible, a patient had at least one sickle cell specific visit, defined as a visit with a principal diagnosis of sickle cell crisis or a secondary diagnosis of sickle cell disease with a principal diagnosis that was sickle cell related (e.g. pneumonia, stroke, fever). All sickle cell related visits were linked by unique personal identifiers, thus clustering visits by patient and allowing population-based statewide assessments of utilization. An emergency department visit on the same day as an inpatient hospitalization was counted only as an inpatient hospitalization to avoid over counting care-seeking visits. The distribution of acute care visits for each patient (presented as numbers of emergency department visits and hospitalizations over the two-year period) was determined for the entire cohort, then stratified as child versus adult.

Results: A total of 24,668 patients with sickle cell disease made 86,535 acute care visits during the two-year study period, 33,520 (38.7%) were emergency department visits and 53,015 (61.3%) were inpatient visits. Of the 24,668 patients, 8,895 (36.1%) were less than 18 years of age; 15,773 were adults. 52.8% of the entire cohort made one visit in the two year period. 1,320 (5.4%) patients had more than 12 visits over the two-year time period; 3,210 (13.0%) made 6–20 visits over two years, and accounted for 31,752 (36.7%) acute care visits. An additional 579 (2.4%) patients had more than 20 visits over two years, accumulating 18,701 (21.6%) acute care visits. Children were less likely to have more than 12 visits over the two years (1.9%) compared to adults aged 18–45 (8.1%) and were also less likely to be in the high utilization group of 6–20 visits over two years (9.9% of children compared to 15.8% of those 18–45 years old).

Conclusions: A significant proportion of patients with sickle cell disease seek acute care multiple times in an emergency department setting or through hospitalization. Our population-based study demonstrates an increased proportion of high utilizers compared to previous work, especially among adult patients. Our findings likely reflect the difference in healthcare utilization in the broader community as compared to that within a cooperative study in academic settings. It suggests that some patients, adults in particular, may have limited access to urgent care in a primary care setting and would benefit from better access and more aggressive preventive care. Further work on patterns of and reasons for utilization, especially emergency department care, in this high-utilizer group, would be helpful in targeting and improving overall care for these patients.