FACTORS ASSOCIATED WITH LONGITUDINAL TRAJECTORIES OF HYDROXYUREA ADHERENCE AMONG INDIVIDUALS WITH SICKLE CELL DISEASE: A GROUP-BASED TRAJECTORY MODELING STUDY
Author(s)
Blessing I. Okoye, MS, Godwin Okoye, MS, Jamie C. Barner, PhD;
The University of Texas at Austin College of Pharmacy, Health Outcomes Division, Austin, TX, USA
The University of Texas at Austin College of Pharmacy, Health Outcomes Division, Austin, TX, USA
OBJECTIVES: While overall hydroxyurea adherence is low, examining longitudinal real-world trajectory adherence patterns may help identify intervention timepoints and targeted patient characteristics. This study described hydroxyurea adherence trajectories and identified factors associated with adherence trajectory membership among individuals with sickle cell disease (SCD).
METHODS: A retrospective analysis of Texas Medicaid data (01/2016-08/2023) included individuals with ≥3 SCD medical claims within the study period, ≥1 hydroxyurea claim without a claim in the 6 months pre-index period, aged 2-63 years on the index date (first hydroxyurea claim), and continuously enrolled 6 months pre- and 12 months post-index. Mean monthly adherence was measured using proportion of days covered (PDC) for 12 months post-index. Group-based trajectory modeling (GBTM) was used to identify adherence trajectory groups. Multivariable multinomial logistic regression was used to examine sociodemographic and clinical factors associated with hydroxyurea adherence trajectory membership.
RESULTS: A total of 1,246 individuals (mean age=18.1±12.7, 50.8% female) were included. GBTM revealed 5 membership groups: consistent adherence (16.1%; mean PDC=89.2±8.5%), fluctuating adherence (28.7%; mean PDC=52.6±12.8), sharp decline and fluctuating adherence (16.5%; mean PDC=26.2±8.8), rapidly decreasing adherence (22.2%; mean PDC=25.6±10.3), and early and consistent nonadherence (16.5%; mean PDC=8.4±1.3). Early trough adherence timepoints occurred at months 2, 3, and 5. Age groups 16-21, 22-34, and ≥35 years (reference: 2-15 years), and an increasing number of vaso-occlusive crises (VOC) in the pre-index period were significantly associated with higher odds (adjusted odds ratio (aORs) range: age groups-2.2-8.7; VOC-1.2-1.4) of being in the less-adherent trajectory groups compared to the consistent adherence trajectory group.
CONCLUSIONS: This is one of the first trajectory analyses in Medicaid SCD populations, and unique trajectory patterns with critical timepoints for intervention were observed. To improve adherence, individualized and timely interventions should be tailored to young adults and adults with SCD, as well as those experiencing frequent VOC.
METHODS: A retrospective analysis of Texas Medicaid data (01/2016-08/2023) included individuals with ≥3 SCD medical claims within the study period, ≥1 hydroxyurea claim without a claim in the 6 months pre-index period, aged 2-63 years on the index date (first hydroxyurea claim), and continuously enrolled 6 months pre- and 12 months post-index. Mean monthly adherence was measured using proportion of days covered (PDC) for 12 months post-index. Group-based trajectory modeling (GBTM) was used to identify adherence trajectory groups. Multivariable multinomial logistic regression was used to examine sociodemographic and clinical factors associated with hydroxyurea adherence trajectory membership.
RESULTS: A total of 1,246 individuals (mean age=18.1±12.7, 50.8% female) were included. GBTM revealed 5 membership groups: consistent adherence (16.1%; mean PDC=89.2±8.5%), fluctuating adherence (28.7%; mean PDC=52.6±12.8), sharp decline and fluctuating adherence (16.5%; mean PDC=26.2±8.8), rapidly decreasing adherence (22.2%; mean PDC=25.6±10.3), and early and consistent nonadherence (16.5%; mean PDC=8.4±1.3). Early trough adherence timepoints occurred at months 2, 3, and 5. Age groups 16-21, 22-34, and ≥35 years (reference: 2-15 years), and an increasing number of vaso-occlusive crises (VOC) in the pre-index period were significantly associated with higher odds (adjusted odds ratio (aORs) range: age groups-2.2-8.7; VOC-1.2-1.4) of being in the less-adherent trajectory groups compared to the consistent adherence trajectory group.
CONCLUSIONS: This is one of the first trajectory analyses in Medicaid SCD populations, and unique trajectory patterns with critical timepoints for intervention were observed. To improve adherence, individualized and timely interventions should be tailored to young adults and adults with SCD, as well as those experiencing frequent VOC.
Conference/Value in Health Info
2026-05, ISPOR 2026, Philadelphia, PA, USA
Value in Health, Volume 29, Issue S6
Code
PT13
Topic
Health Service Delivery & Process of Care
Disease
SDC: Rare & Orphan Diseases, SDC: Systemic Disorders/Conditions (Anesthesia, Auto-Immune Disorders (n.e.c.), Hematological Disorders (non-oncologic), Pain)