Abstract
Background
Hydroxyurea is the primary disease modifying therapy for children and young adults with sickle cell disease (SCD) and is associated with decreased risk of pain crises and acute chest syndrome. The COVID 19 pandemic was a globally disruptive event that impacted medication regimens among people with chronic illnesses. SCD has been designated as a high-risk condition for COVID-19. People with SCD were 7 times more likely to be hospitalized due to COVID-19 compared to people without SCD, with the leading complications being pain crises. This underscores the importance of adherence to hydroxyurea during the COVID-19 pandemic. The impact of the COVID-19 pandemic on adherence to hydroxyurea among people with SCD is unknown. We hypothesized that children and young adults with SCD would have increased adherence to hydroxyurea during the pandemic.Objective
Evaluate changes in hydroxyurea adherence among children and young adults with SCD before and during the COVID 19 pandemic.Methods
Data was used from the Michigan Sickle Cell Data Collection Program, which combines multiple data sources to identify and follow those with SCD in Michigan to assess longitudinal healthcare utilization and outcomes. Individuals with SCD were identified using validated case definitions. The study population included individuals 25 years old and younger that were continuously enrolled in Medicaid from 2019-2021. The proportion of individuals with at least one filled hydroxyurea prescription was identified. In this population, monthly hydroxyurea adherence was assessed, defined as monthly hydroxyurea medication possession ratios (MPR). MPR was obtained by totaling the number of days in a filled prescription divided by the total number of days in the month accounting for inpatient admissions and overlapping prescriptions. Among individuals with at least one hydroxyurea prescription, an interrupted timed series analysis was conducted using linear regression with generalized estimating equations to account for multiple observations per participants was conducted to evaluate changes in monthly MPR before and during the COVID-19 pandemic. Models included indicators for periods before and during the pandemic and were adjusted for sex, race, and age. An interaction between age and time, defined as months during the observation period, as well as an interaction between the indicator for periods before and during the pandemic and time were also included.Results
There were 2234 individuals with SCD under the age of 25 included in the study population. 1940 (86%) identified as Black, 1146 (51%) were female, and the mean age was 11 (SD=8.53). Among these individuals, 293 (13%) had at least one hydroxyurea prescription. The average annual MPR in 2019 was .30 (SD=.40), in 2020 was .37 (SD=.42), and 2021 was .37 (SD=.42) (Figure). At the start of the COVID 19 pandemic, children and young adults increased their hydroxyurea adherence (MPR increase: .125 p<.01), but as the pandemic persisted, adherence declined for all ages (interaction between the indicator for periods before and during the pandemic and time effect: -.0078 p<.001) with older individuals having the greatest decline (interaction between age and time effect: -.0003 p<.01).Conclusion
Despite short term increases in hydroxyurea adherence at the start of the pandemic, hydroxyurea adherence declined as the pandemic persisted. Given the already low adherence to this critical preventive medication, additional efforts are necessary to emphasize the importance of this medication, particularly among young adults.Categories: Conference Abstracts/Posters