Comprehensive management reduces incidence and mortality of acute chest syndrome in patients with sickle cell disease
Authors: Givi Basishvili, Joseph Gotesman, Kathy Vandervoort, Charleen Jacobs, Leena Vattappally, Caterina P. Minniti
Journal: American Journal of Hematology (2017)

Sickle cell disease (SCD) affects ∼100 000 individuals in the United States and millions worldwide, and is associated with significant morbidity and shortened lifespan.1-4 Affected individuals have high rates of healthcare utilization, with a mean of 2.6 and range from zero to over thirty encounters/person/year.5 Vaso-occlusive crises (VOC) is the most frequent reason for hospitalization, while acute chest syndrome (ACS) complicates ∼20% of VOC's4, 6, 7 and has been historically a leading cause of death. In 2015, Montefiore Medical Center instituted a Sickle Cell Center for Adults, comprised of nurse practitioners, a social worker, and a physician with expertise in SCD. The goal was to link outpatient and inpatient SCD care, reduce hospital admissions and length of hospital stay (LOS), and improve health outcomes. Intervention was implemented in two parts. In the initial phase the SCD team focused on outpatient care, patients were met in the ED and encouraged to attend outpatient clinic visits. Subsequently, SCD team also consulted on patients during hospitalizations. We conducted a retrospective study comparing LOS, VOC admission rate, ACS development rate and severity, ICU admissions and LOS, and packed red blood cell (PRBC) transfusions and exchanges among patients who developed ACS, in each of the three groups: prior to intervention (group 1), phase 1 (group 2), and phase 2 (group 3). Detailed methods are described in Supporting Information Appendix 1. From January 2014 through December 2016, 372 individual patients accounted for a total of 1499 SCD admissions with a diagnosis of VOC (Figure 1). Demographics in Supporting Information Table 1. Group 1, pre-intervention or "control" group, spanned 13 months; it included 206 patients for a total of 612 VOC admissions. Group 2, the "ED/clinic" SC team intervention, spanned 10 months, included 188 patients for a total of 377 admissions. Group 3, the "ED/clinic & inpatient" SC team intervention, spanned 13 months, it included 214 patients for a total of 509 VOC admissions. We observed shorter LOS for VOC of 1.4 days, (8.0 vs. 6.6, P > .0001) in group 2, and an additional 0.9 days, (total 2.3 days), (8.0 vs. 5.7, P > .0001) in group 3; fewer admissions per patient per year: from 3.0 to 2.0/year (P = .0003) in group 2, and from 3.0 to 2.4 (P = .0471) in group 3. Upon review of medical records, 49.5% of cases classified as ACS were misdiagnosed in group 1, 50.7% in group 2, and 54.8% in group 3. Methodology. 372 individuals with sickle cell disease (SS, Sβ, SC) with a total of 1499 VOC admission to Montefiore Medical Center were reviewed during the 2014–2016 period. The patients were divided into three groups: group 1—prior to intervention "control group" (13 months). Group 2—"ED/clinic" SCD team (10 months). Group 3—"ED/clinic & inpatient" SC team (13 months). The number of admissions are displayed in each corresponding box, followed by ACS complication rate per patient, followed by primary outcomes for all VOC admission, and primary outcomes of ACS only subgroup. LOS is reported in days. The subgroup analysis of patients with confirmed ACS included 98 individual patients with a total of 115 admissions. Forty-eight confirmed cases of ACS in group 1 (38.7%); 34 in group 2 (27.4%); and 33 in group 3 (26.1%) LOS was significantly reduced within the ACS subgroup: −4.8 days (P = .0043) in group 2 and −4.0 (P = .0261) in group 3. ACS incidence decreased from 23.3% to 18.3%, and to 15.4% (P = .2027, control vs. group 2) (P = .0407, control vs. group 3). We observed a steady decrease in the LOS in the ICU for patients with ACS with each intervention, from 3.4 to 2.5 to 1.6 days in groups 1, 2 and 3 respectively (Figure 2 and Supporting Information Table 2). Graphical representation of the primary and secondary outcomes divided in group 1—control, group 2—"ED/clinic only," group 3—"ED/clinic & inpatient." LOS measured in days. Transfusions were performed with packed red blood cells. Standard error bars are displayed. ACS: acute chest syndrome. VOC: vaso-occlusive crisis. ICU: intensive care unit. (A) VOC group: Compared to group 1, hospital LOS reduced by 1.4 days, 18% (8.0 vs. 6.6, P > .0001) in group 2, and by 2.3 days, 29% (8.0 vs. 5.7, P > .0001) in group 3. (B) Compared to group 1, ACS complication rate decreased from 23.3% to 15.4% (P = .0407). Compared to group 1, VOC admission rate decreased from 3.0 to 2.0 (P = .0003) in group 2, and from 3.0 to 2.4 (P = .0407) in group 3. ACS subgroup: Hospital LOS was reduced statistically significantly by 4.8 days, 37% (12.9 vs. 8.1, P > .0043) after "ED/clinic only" intervention, and by 4.0 days, 31% (12.9 vs. 8.9, P > .0261) after "ED/clinic & inpatient" intervention Sixty-seven percent (67%) of all confirmed cases of ACS received PRBC's, while exchange transfusions were necessary in 21%. Most patients that received an exchange had pre received a simple transfusion. There was only one death attributed to ACS during the study period, which occurred in group 3. This was a 26-year-old male who presented with chest pain and shortness of breath and expired despite intubation, exchange transfusion, and aggressive management. Our study demonstrates that the development of a dedicated sickle cell team within a large tertiary hospital leads to improvements in key quality care indicators, even with high volume of patients. We report significant decreases in LOS, number of yearly VOC admissions/patient, incidence and severity of ACS, as indicated by shorter LOS and less need for ICU admissions, rate and length of ACS. Our results align and expand recent reports of reduction in healthcare utilization in patients with SCD8 that have shown a 16%-50% reduction in uncomplicated SCD crises.9, 10 ACS is a life-threatening complication of VOC.4, 6, 7 We demonstrate a reduction of ACS development from 23.3% pre-intervention (similar to the reported values in the literature6, 11-13) to 15.4% (P = .0407). This reflects a 7.9% absolute, and a 34% relative decrease. Furthermore, we found a decreased ICU LOS within both the entire VOC group (3.4-1.6 days), as well as within the ACS subgroup (5.7-2.5 days). Finally, it is heartening to report that only one patient died from an ACS-related event during the almost three years of the study. It is important to point out that in our cohort the overall mortality of ACS was lower than previously reported in the literature,11 even before the SCD intervention. This finding may indicate improved recognition and treatment of ACS from hematologists and physicians in general. Of note is the high rate of erroneous ACS diagnosis, which is a pitfall of all EMR retrospective analysis, but also indicates difficulty in correctly diagnosing episodes with chest pain and some kind of infiltrates. In our study only 67% of patients with ACS required a blood transfusion/exchange, confirming recent data that question whether a transfusion is needed in all cases of ACS.14, 15 Thus, the observed improved outcome of ACS was not simply due to more transfusions, but possibly to an early and coordinated intervention and careful attention to all aspects of care, such as fluids management, pain control, and oxygenation. SCD intervention was limited to office hours, while SCD coverage after hours and during week-ends was provided by in-house hematology fellows and attendees. Their support, as well as the involvement and communication between hospital and ED staff were of paramount importance in achieving these results. In summary, we report that the implementation of a dedicated SCD team is successful in reducing hospital utilization and improving healthcare outcomes in patients with SCD. A proactive approach to SCD management translates in decreased healthcare utilization, cost savings and, most importantly, improved outcomes for adults with SCD.16 The authors thank Elena Crouch for expert editing. The authors declare no competing financial interests. GB and JG contributed equally to the research design, data collection, statistical analysis, interpretation of the data, and the writing of the manuscript; CM was the principal investigator and conceptualized the project, oversaw the research design, interpretation of data, and writing of the manuscript. CJ was the member of the SCD team, contributed to interpretation of data, and the writing of the manuscript. KV and LV contributed to the data collection and interpretation. Additional Supporting Information may be found online in the supporting information tab for this article. Supporting Information Supporting Information Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.