A Retrospective Review to Determine If Children with Sickle Cell Disease Receive Hydroxyurea Monitoring

Abstract

Introduction:Sickle cell disease guidelines recommend that patients on hydroxyurea receive monitoring at least every 2–3 months, but it is unknown if this occurs in clinical practice. This study aimed to determine if patients with sickle cell disease at Nationwide Children’s Hospital had at least 4, in-person monitoring visits during a 12-month period and if frequent monitoring was associated with hydroxyurea adherence and clinical outcomes.Methods:We performed a retrospective analysis of children on hydroxyurea for at least 12 months during 2010–2015. Patients’ demographics, laboratory studies, prescriptions, and number of hydroxyurea and acute visits were recorded from their 12-month period that met eligibility criteria. Patients were considered frequently monitored if they had ≥ 4 hydroxyurea visits and adherent if they had prescriptions for hydroxyurea for ≥ 80% of the days in their 12-month period.Results:Seventy-four children met the eligibility criteria and 57 (77%) had frequent monitoring. The most common reason for not obtaining frequent monitoring was missing a scheduled appointment. A greater proportion of frequently monitored patients were adherent to hydroxyurea (66.7% versus 17.7%; P < 0.001), and they had significantly fewer acute visits (median 1 versus 2 visits; P = 0.032) compared with infrequently monitored patients.Conclusions:Our study shows that most children on hydroxyurea at Nationwide Children’s Hospital received frequent monitoring and that it was associated with improved adherence and outcomes. Our results suggest that frequent in-person monitoring could be an opportunity to identify poorly adherent patients. These data inform our next quality improvement initiative that will maximize adherence to these monitoring guidelines.

Treatment patterns and economic burden of sickle-cell disease patients prescribed hydroxyurea: a retrospective claims-based study

“…The HU treatment guidelines for SCD patients recommend monitoring at least every 8–12 weeks. Evidence suggests that SCD patients treated with HU who received frequent monitoring had improved medication adherence and clinical outcomes [40]. A study showed monitoring of SCD patients on HU occurred every 4–6 weeks during escalation of therapy and every 8–12 weeks upon achievement of maximal tolerated dose (MTD).…”

Impact of hydroxyurea dose and adherence on hematologic outcomes for children with sickle cell anemia

“…36 Furthermore, our definition of higher hydroxyurea exposure (>20 mg/kg/day) was chosen, as guidelines recommend initiating 20 mg/kg/day and many children in clinical practice receive less than this because they are nonadherent. 6,9,[11][12][13][14][15][16] However, this may be too conservative for subsequent trials that seek to determine if higher exposure improves outcomes in high-income settings, as average exposure in the superior arm in the dose-escalation trial in sub-Saharan Africa was 29 mg/kg/day. 10 Notably, MCV, a parameter that increases quickly with hydroxyurea treatment, 2 increased among both the lower and higher exposure groups.…”

“…These studies should consider including patients who are frequently admitted as they still can require acute visits for complications that hydroxyurea may ameliorate and VOC episodes that do not result in an acute care visit since VOC episodes are frequently treated at home in high‐income settings 36 . Furthermore, our definition of higher hydroxyurea exposure (>20 mg/kg/day) was chosen, as guidelines recommend initiating 20 mg/kg/day and many children in clinical practice receive less than this because they are nonadherent 6,9,11–16 . However, this may be too conservative for subsequent trials that seek to determine if higher exposure improves outcomes in high‐income settings, as average exposure in the superior arm in the dose‐escalation trial in sub‐Saharan Africa was 29 mg/kg/day 10 …”

“…These findings suggest that increasing hydroxyurea exposure is highly effective in improving outcomes in sub‐Saharan Africa, but the tremendous disparities in resources, treatment paradigms, adherence behavior, and ability to access acute care for common SCA complications in high‐income settings compared to low‐income settings may limit the generalizability of these findings. Thus, additional studies are needed to better understand the impact of hydroxyurea exposure on outcomes in high‐income settings where dosing and adherence are more variable 6,11–19 …”

“…Thus, additional studies are needed to better understand the impact of hydroxyurea exposure on outcomes in high-income settings where dosing and adherence are more variable. 6,[11][12][13][14][15][16][17][18][19] To address this gap, rigorous quantitative methods must be utilized to measure hydroxyurea adherence. Directly observed therapy and electronic pill bottles are considered the gold standard methods to quantify medication adherence.…”