Presence of CKD in Sickle Cell Disease Worsens In-Hospital Outcomes

Chronic kidney disease (CKD) is a prevalent complication for people with sickle cell disease (SCD) and its presence was linked to a rise in mortality after hospitalization and increased hospital charges, according to a new analysis.¹

Assessment of the National Inpatient Sample (NIS) on the impact of CKD on in-hospital outcomes revealed those with CKD and SCD were more likely to need mechanical ventilation, blood transfusion, and develop sepsis, but less likely to experience in-hospital acute chest syndrome and pulmonary embolism, versus the non-CKD population.

“In our study, the CKD group had a higher comorbidity burden than the non-CKD cohort, which may have contributed to the greater severity of morbidity and, therefore, increased risk of mortality in this group,” wrote the investigative team led by Tempitope Ajibawo, MD, Multicare Auburn Medical Center.

End-organ damage is the main etiology of morbidity and death in SCD, with manifestations spanning multiple organ systems, including CKD, defined by a multifactorial decrease in renal function or damage.² Although CKD is a common complication in CKD, its impact on clinical outcomes after hospitalization is not well-defined.

In the current analysis, Ajibawo and colleagues explored the NIS to identify hospitalizations of patients aged ≥18 years diagnosed with SCD between 2016 and 2018.¹ The CKD cohort consisted of patients with ≥1 diagnostic or procedural code of CKD stage 3, 4, 5, and end-stage renal disease on either hemodialysis or peritoneal dialysis.

Overall, the primary study outcome was in-hospital mortality among the SCD with and without CKD populations. Secondary outcomes were defined as hospitalization costs, length of stay, and inpatient clinical outcomes, including blood transfusion, sepsis, mechanical ventilation, stroke, acute chest syndrome, and pulmonary embolism.

After excluding cases for missing information, 366,240 weighted SCD hospitalizations were identified between 2016 and 2018. Among these hospitalizations, only 5% (n = 19,365) exhibited CKD, while 95% (n = 346,875) did not have CKD. Those with CKD were significantly older, more likely to be male, and exhibited a greater number of comorbidities (all P <.01).

Ajibawo and colleagues performed 1:1 propensity-score matching, matching 18.250 CKD hospitalizations with 18,250 hospitalizations without CKD. Subsequent regression analyses were conducted to compare outcomes between the study cohorts.

In regression analysis, the CKD cohort demonstrated higher odds of in-hospital mortality (odds ratio [OR], 2.59; 95% CI, 1.63 - 4.12; P <.01), blood transfusion (OR, 1.67; 95% CI, 1.47 - 1.90; P <.01), mechanical ventilation (OR, 2.20; 95% CI, 1.56 - 3.12; P <.01, and sepsis (OR, 1.75; 95% CI, 1.46 - 2.10; P <.01).

The CKD cohort additionally incurred greater total hospital costs ($53,255 vs. $47,294; P <.001) but had lower odds of acute chest syndrome (OR, 0.71; 95% CI, 0.54 - 0.95; P = .02) and pulmonary embolism (OR, 0.45; 95% CI, 0.31 - 0.67; P <.01), compared with patients without CKD.

Ajibawo and colleagues found these reduced odds surprising, as evidence points to an increased risk in patients with CKD, noting it may be due to coding errors in the CKD population. The team also identified no statistically significant differences in the length of stay or stroke between the CKD and non-CKD cohorts.

“Though we observed a non-significant lower likelihood of developing stroke, we expected a higher likelihood of stroke because CKD has been identified as an independent risk factor for stroke in multiple previous studies, and the risk of stroke in CKD could be up to 30 times higher than in patients without CKD,” they wrote.

References

1. _{Ajibawo T, Okunowo O. Chronic kidney disease and outcomes in hospitalized sickle cell disease patients: A National Inpatient Sample analysis. Eur J Haematol. Published online March 21, 2024. doi:10.1111/ejh.14201}
2. _{Castro-Sesquen YE, Saraf SL, Gordeuk VR, Nekhai S, Jerebtsova M. Use of multiple urinary biomarkers for the early detection of chronic kidney disease in sickle cell anemia. Blood Adv. 2023;7(11):2606-2608. doi:10.1182/bloodadvances.2022008006}