Hospital Readmissions Among People With Sickle Cell Disease

Abstract

Importance: While advances in the management and treatment of sickle cell disease (SCD), the most common inherited disorder in the United States, have improved outcomes, hospital readmissions remain a significant concern. Thirty-day hospital readmissions is a key quality-of-care indicator; however, there are limited contemporary nationally representative data on SCD readmissions.

Objective: To characterize national trends in SCD-related readmissions in the United States and describe factors associated with readmission among patients with SCD.

Design, setting, and participants: This cohort study included patients with SCD aged 18 years and older. Patients were identified in the Nationwide Readmissions Database (NRD), an all-payer database of US hospitalizations, using International Statistical Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes. Data were collected from January 2016 to December 2021 and analyzed from May to September 2024.

Main outcomes and measures: Readmission was defined as subsequent admission within 30 days of hospitalization discharge using the Centers for Medicare & Medicaid Services methodology. The 30-day all-cause unplanned readmission risk among adults with SCD was estimated, and the trend in 30-day readmissions among adults with and without SCD was assessed by calendar year from 2016 to 2021. Survey-weighted mixed-effect Poisson regressions were used to identify factors associated with readmission.

Results: From 2016 to 2021, 140 096 807 all-cause index hospitalizations and 592 951 SCD-related index hospitalizations were analyzed. Patients with SCD had a stable readmission risk of approximately 34% (annual range, 32.6%-34.3%), significantly higher per year than the approximately 12% readmission risk among patients without SCD (annual range, 12.0%-12.2%) (P < .001). In 2021, there were 92 536 index admissions from 37 410 unique patients with SCD (median [IQR] age, 34 [26-46] years; 22 484 [60.1%] female), with 30 467 readmissions. Younger patients (aged 18-29 years) had the highest readmission risk at 35.1%. In multivariable model among patients with SCD, patients from the highest-income zip codes had lower readmission risk than those from lower-income areas (adjusted risk ratio [aRR], 0.90; 95% CI, 0.84-0.97). Admissions paid by Medicare and Medicaid were associated with higher readmission risk than private insurance (Medicare: aRR, 1.67; 95% CI, 1.56-1.78; Medicaid: aRR,1.53; 95% CI, 1.43-1.63). Vaso-occlusive crises at index admission were associated with higher readmission risk (aRR, 1.31; 95% CI, 1.25-1.37). Fewer readmissions were observed in patients receiving simple (aRR, 0.86; 95% CI, 0.82-0.91) and exchange (aRR, 0.78; 95% CI, 0.61-0.99) red blood cell transfusions.

Conclusions and relevance: In this cohort study with nationally representative data, patients with SCD had a significantly higher readmission risk than patients without SCD. Preventative, disease-modifying, and curative interventions are needed to reduce readmission risks and improve outcomes for patients with SCD.

Figure 1.. Trends in 30-Day All-Cause Unplanned Readmission Risk for People With and Without Sickle Cell Disease (SCD), 2016-2021

There were 24 242 217 index admissions in 2016 (24 138 568 non-SCD and 103 649 SCD), 24 457 913 in 2017 (24 354 459 non-SCD and 103 454 SCD), 24 352 383 in 2018 (24 251 266 non-SCD and 101 117 SCD), 24 339 493 in 2019 (24 236 784 non-SCD and 102 709 SCD), 21 259 030 in 2020 (21 169 545 non-SCD and 89 486 SCD), and 21 445 771 in 2021 (21 353 235 non-SCD and 92 536 SCD).

Figure 2.. Flowchart of the Index Admissions and Readmissions in 2021 With the Unweighted Sample Sizes and Weighted Population Sizes

One person may contribute to 1 or more index hospitalizations in the study population. The subcategories may overlap among the excluded index admissions, so the excluded numbers exceed the total. The analysis follows the 2023 Hospital-Wide All-Cause Unplanned Readmission Measure. NRD indicates Nationwide Readmissions Database; SCD, sickle cell disease.

Figure 3.. 30-Day All-Cause Unplanned Readmission Risk Among People With Sickle Cell Disease in 2021 in the Nationwide Readmissions Database

The number and percentage of readmissions are among the index admissions presented. One person may contribute to 1 or more index admissions. Risk ratios (RRs) are from the crude model; adjusted RRs (aRRs) are from multivariable model (ie, multivariable model including all variables in this figure). Both estimates were obtained using mixed-effects Poisson regressions. Other payer includes Worker’s Compensation, CHAMPUS, CHAMPVA, Title V, and other government programs. Nonteaching status includes metropolitan nonteaching and nonmetropolitan hospitals. APR DRG indicates All Patient Refined Diagnosis Related Groups; NA, not applicable.