The Impact of Sickle Cell Disease Severity on HRQOL and Economic Outcomes

Disease severity was strongly associated with health-related quality of life, moderately associated with use of disability insurance, and weakly associated with household income for patients with sickle cell disease.

In patients with sickle cell disease (SCD), disease severity was associated with worse self-reported health-related quality of life (HRQOL), an increased likelihood of collecting disability insurance, and even lower household incomes, according to a study published in Current Medical Research and Opinion.

The researchers surveyed US adults with a self-reported SCD diagnosis to better understand how new treatments for SCD that reduce disease severity “affect patients’ humanistic and economic outcomes,” the authors wrote.

SCD is a lifelong disease that affects approximately 100,000 people in the United States. The hallmarks of the disease are vaso-occlusive crises (VOCs) that “are the primary cause for hospitalization.”

“These recurrent episodes induce severe pain, can cause life-threatening complications, and are associated with increased risk of organ damage and mortality, and as such, affect a patient’s health related quality of life,” the authors wrote.

A total of 326 adults completed the survey; however, 25 were removed for failing quality checks or not answering key questions. Only 301 responses were in the final analytic sample. The average age of respondents was 34.4 years, 73.4% were female, and 1 respondent was nonbinary.

Only 264 individuals answered the question on income, and the mean household income for these respondents was $38,021 ($12,500-$140,938). More than half (52.5%) reported having higher-level education.

Approximately one-third (34.9%) of respondents were covered by private insurance, and 37.5% reported receiving public disability assistance. The majority (92.9%) were Black.

Most participants (79.4%) were classified as Severity Class III based on their self-report of VOCs and the presence of complications and organ damage. Nearly half (47.8%) said that 12 months prior they had experienced ≥ 4 VOCs. Only 8.4% said they had experienced 0 VOCs in the 12 months prior.

HRQOL was assessed using the EuroQoL Five Dimension 5 level (EQ-5D) scale during a VOC and not during a VOC. The average HRQOL was 0.311 (95% CI, 0.720-0.756) during a VOC and 0.738 (95% CI, 0.720-0.756) not during VOC, “indicating strong evidence of a difference.”

The estimated health utility values not during a VOC according to EQ-5D by severity class suggested > 5% worse health status utility in Severity Class III (0.733) compared with Severity Class II (0.775). “Patients with SCD Severity Class III had 34% worse HRQOL than those with SCD Severity Class II,” the authors wrote.

Among patients having 0 VOCs in the past year, there was an 8% chance they were receiving disability insurance compared with 53% of patients experiencing ≥ 4 VOCs. Patients with a more severe disease class were also more likely to receive disability insurance: 33% probability among patients with Severe Class asymptomatic/Class I vs 41% probability among Severity Class III.

There was a weak association between VOC frequency and household income. Patients experiencing 0 VOCs in the past year had a slightly higher predicted mean income compared with patients who had ≥ 4 VOCs ($46,194 vs $35,284, respectively). The average household income was lower for patients who had more severe disease, but “there was no statistical evidence of this relationship,” the researchers wrote.

They noted a few limitations, including that some respondents didn’t respond to all questions, that the sample skewed toward more severely ill patients compared with the general SCD population, and that responses were limited to English-speaking adults in the United States.

“While previous studies have estimated the economic and clinical burden of SCD compared to patients without the disease, this study explicitly examines how disease severity among patients with SCD affects these outcomes,” the authors concluded. “New treatments for SCD have the potential not only to impact patient clinical outcomes, but overall quality of life, patient productivity, and government costs for disability insurance.”

Reference

Shafrin J, Thom HHZ, Keeney E, et al.The impact of vaso-occlusive crises and disease severity on quality of life and productivity among patients with sickle cell disease in the US. Curr Med Res Opin. Published online March 27, 2021. doi:10.1080/03007995.2021.1897556