Looking for more on sickle cell disease? Check out the following summaries on some of the cutting-edge research presented at the 2018 ASH Annual Meeting.
Cardiac Iron Overload in Sickle Cell Disease: When to Screen and How to Intervene
Researchers performed a retrospective chart review of patients with cardiac MRIs (cMRIs) and liver iron concentrations (LICs) by Ferriscan to identify risk factors for cardiac iron overload (CIO), as well as to characterize institutional practice for assessing cardiac iron in the absence of defined practice guidelines (Abstract 528). Of 36 evaluable patients who had undergone cMRI, there were 11 with CIO. Data showed that between patients who did and did not have CIO, there was no significant difference in average 1-year ferritin level (6,786 vs. 6,373 ng/mL, p=0.79), transfusion duration (103 vs. 123 months, p=0.41), or age (15 vs. 18 years, p=0.12). An interesting finding, according to researchers, is that CIO was seen as young as 7 years of age and after as little as 22 months of chronic transfusions, and with concurrent LIC values as low as 8.1 mg/g. CIO in SCD may be a more salient issue, and occur earlier, than previously described, researchers noted. “We did not find a strong relationship between CIO and ferritin levels or LIC by Ferriscan, but we did find that CIO was reversible with more aggressive chelation or the addition of partial manual exchange,” they wrote. “While guidelines for monitoring for CIO in SCD are largely extrapolated from thalassemia data, the rate and physiology of iron loading may be completely different. Due to a paucity of information in this area, more studies are needed to guide screening and to fully assess risk factors that may put certain individuals more at risk for cardiac iron loading.”
Poor Access to Care Is a Risk Factor for Iron Overload in Adults with Sickle Cell Disease in Southern California
Researchers performed a chart review of all patients with SCD who presented to either of two adult sickle cell clinics in Southern California: MLK Jr. Outpatient Center in Los Angeles and Center for Inherited Blood Disorders (CIBD) in Orange (Abstract 3527). Evaluable patients included those who had at least one visit to clinic with labs that included iron studies and/or MRI. “Iron saturations greater than 50 percent and/or a ferritin greater than 1,000 was deemed indicative of iron overload when combined with a history of prior transfusions,” according to study authors. They defined lack of access as the absence of appropriate care for SCD for at least 12 months prior to the initial visit in our clinics. Seventy-four patients were evaluated in the study. Fifty-three were Hgb SS, according to the investigators. Among these patients, 27 (50.9%) were not receiving appropriate SCD care; 20 (74.1%) of those patients were iron overloaded. According to the findings, there were nine patients with Hgb S/beta thalassemia; among these patients, five (55.6%) were not receiving appropriate SCD care for the prior 12 months; one (35.6%) was iron overloaded. Twelve patients had Hgb SC and while five (41.7%) of these patients were not receiving appropriate SCD care, none had evidence of iron overload. Utilizing this data, researchers reported that the odds ratio of having iron overload if a patient was out of appropriate SCD care for the 12 months prior to evaluation was 6.8. “Although guidelines exist to prevent unnecessary transfusions in adult patients with SCD; lack of access to knowledgeable providers both in the inpatient and outpatient setting places them at a nearly seven times higher risk for iron overload, a serious and preventable comorbidity,” study authors concluded. “Our study indicates that many adults with SCD are not appropriately monitored or treated for transfusion related iron overload using guideline-based care, placing avoidable burdens on individual health and adding to health care costs. Further education of providers to address this issue is warranted.”
Sickle Cell Disease and Venous Thromboembolism: Hospital Mortality, Length of Stay and Cost
Sickle cell disease, a prothrombotic state, can be complicated by venous thromboembolism (VTE) and recurrent VTE. With no specific guidelines for the treatment of VTE in the SCD population and limited research, investigators took a closer look at the impact of this complication (Abstract 2378). Using data from the Healthcare Cost and Utilization Project's National Inpatient Sample (NIS) from 1999-2014 the researchers examined national prevalence, mortality, length of stay, and cost for hospitalized patients. Over a 15 year period, from 1999-2014, a total of 217,791 (weighted N=1,073,215) admissions with SCD were identified. A total of 7,898 admissions were associated with VTE, according to study findings. Researchers reported that the mean age at admission of those with VTE was 27.42 (+/- 0.05) years and those without VTE was 34.00 (+/- 0.51) years. SCD patients with VTE had an average inpatient mortality was 3.08 percent (p < 0.0001) compared to a mortality of 0.27 percent in patients that did not have the complication. According to the findings, length of stay in the SCD with VTE group was 10.45 days (+/- 0.43) versus 5.09 days (+/- 0.02) (p < 0.0001) in SCD without VTE. Overall hospital cost was higher in those with VTE ($60,055) compared to those without VTE ($28,729). This study demonstrates that patients with SCD and VTE experience significant morbidity, mortality, prolonged hospitalization, and increased cost associated with this complication. Additionally, patients who experience VTE are younger than those who do not (mean age: 27 versus 34). “After controlling for multiple confounders like age, race, sex, income, comorbidities, the presence of VTE is associated with a significantly higher risk of mortality in SCD,” researchers concluded. “We recommend the use of antithrombotic prophylaxis or therapy in patients with SCD be evaluated in prospective studies.”