Adherence to hydroxyurea and clinical outcomes among children with sickle cell anemia

Abstract

Objective Hydroxyurea lowers the incidence of vaso‐occlusive pain crises (VOC) and acute chest syndrome (ACS) among children with sickle cell anemia (SCA). Our objective was to assess the relationship between levels of adherence to hydroxyurea and clinical outcomes among children and adolescents with SCA. Methods This retrospective cohort study included Medicaid data (2005–2012) from Florida, Illinois, Louisiana, Michigan, South Carolina, and Texas. The study population consisted of children 1–17 years old with SCA enrolled in Medicaid for 3 years. Among children that initiated hydroxyurea, the medication possession ratio (MPR) was calculated as the proportion of days covered by hydroxyurea. Six months after initiation of hydroxyurea, clinical outcomes were assessed through the end of the study period: numbers of VOC‐related inpatient admissions and emergency department visits, and encounters for ACS. Multivariable Poisson models were used to predict outcomes by MPR quartile adjusting for previous healthcare utilization, state, and age. Results Hydroxyurea was initiated by 515 children. The median MPR was 0.53 (interquartile range = 0.3–0.8). The annual median number of visits was 0.0 for ACS, 1.3 for VOC‐related emergency department, and 1.4 for VOC‐related inpatient admissions. For each outcome, the highest quartile of MPR had the lowest predicted count; this difference was significant for ACS visits when compared with the lowest quartile of MPR. Conclusion This study demonstrated a high level of adherence (>75%) was essential to achieve a lower incidence of common negative clinical outcomes. Further, moderate and severe hydroxyurea nonadherence may be more common than previously appreciated among children, emphasizing the importance of developing and testing innovative strategies to increase adherence.

Review on Hydroxyurea Usage in Young Children with Sickle Cell Disease: Examining Hemoglobin Induction, Potential Benefits, Responses, Safety, and Effectiveness

“…Although regular peripheral blood counts and chemistries monitoring are necessary, the side effects of hydroxyurea, such as bone marrow suppression, are mostly reversible. The standard of care for infants between the ages of 6 to 9 months diagnosed with sickle cell anemia (SCA) and adults experiencing severe clinical symptoms of sickle cell disease is highly recommended [22].…”

Precision, integrative medicine for pain management in sickle cell disease

“…Each are underutilized, and transplantation is still considered experimental by many. When taken regularly, hydroxyurea reduces acute chest syndrome, ED visits, hospitalizations, "strong" opioid use, hospital days, health care costs (110)(111)(112), and lengthens life (113), but does not statistically significantly reduce daily pain in most patients (114). Similarly, though they reduce annualized hospitalizations, neither L-glutamine nor crizanlizumab were approved based on improvement in daily pain.…”

Comment on: “Adherence to hydroxyurea and clinical outcomes among children with sickle cell anemia”

“…We have read with great enthusiasm the article titled "Adherence to hydroxyurea and clinical outcomes among children with sickle cell anemia" by Reeves et al 1 We took great satisfaction in reading a study that was impeccably written and well-structured and that explored the association between adherence to hydroxyurea and clinical outcomes among children with sickle cell anemia (SCA). We fully agree with the authors' final conclusion that higher adherence levels are associated with a lower incidence of negative clinical outcomes.…”