Delays in hydroxyurea initiation for patients with sickle cell disease in British Columbia
Bibliographic record
Abstract
Abstract Introduction: Sickle cell disease (SCD) is a hereditary hemoglobinopathy characterized by abnormal hemoglobin S that polymerizes to result in vaso-occlusive episodes (VOEs), chronic hemolysis, and progressive end organ dysfunction, ultimately reducing quality of life and life expectancy. Hydroxyurea (HU), the mainstay disease-modifying therapy, improves clinical outcomes and survival in SCD. Timely initiation is critical for disease control, decreasing rates of VOEs, hospitalizations, morbidity, and mortality. SCD is a low prevalence condition in British Columbia (BC), Canada, but rates are rising due to immigration. Newly relocated residents living with SCD often face delays in accessing HU due to system constraints. Currently, HU is a limited-coverage drug for SCD in BC. Patients must either pay directly for their medication, have private coverage through employment, or enroll in a publicly funded, deductible-based medication coverage plan which requires filing an income tax return and providing an income statement. Additionally, physicians must complete an approval request for coverage. In contrast, HU is listed as a Class I benefit for cancer indications which eliminates direct costs to patients and the need for private insurance or approval forms.This study aims to characterize the causes and consequences of delayed HU initiation in patients with SCD after relocating to BC. Methods: Patients with SCD who were new to the Adult Red Cell Disorders Program of BC between January 1, 2022 to February 28, 2025 were identified. Health records were retrospectively reviewed to identify baseline patient characteristics, baseline disease characteristics, date of first HU use in BC, reasons for HU delays, and complications prior to initiation. Outcomes included acute care utilization and disease-related morbidity prior to HU initiation. Descriptive analyses were applied. Results: A total of 57 patients were seen in initial consultation at the Adult Red Cell Disorders Program of BC during the study timeframe. Median age at time of consultation was 28 years old (range, 18 – 66 yrs). Most commonly, patients were female (61.4%) and of African descent (78.9%). Few were refugees (10.5%). The predominant genotype was Hb SS (75.4%), followed by Hb SC (21.1%). Concurrent alpha-thalassemia was present in 21.1%. Of the 57 patients, just over half (52.6%) had no prior HU use before relocating to BC. Of the 43.9% with prior use, approximately half (21.1%) discontinued treatment upon relocation due to lack of access. The average interval between arrival in BC and first hematology consultation was 1 year and 8 months, and the average time from consultation to HU initiation was 14 months. In total, 64.9% experienced a delay in HU initiation (defined as not initiating/continuing HU upon arrival), while only 26.3% did not experience a delay. For 8.8% of patients, a delay was not applicable either because there was a medical contraindication (1 patient) or it was not clinically indicated (4 patients). The most common causes of delay included lack of timely referral to a hematologist due to a lack of access to a referring/primary care physician (40.5%), and delays in obtaining medication financial coverage (29.7%). Among the 35 who experienced delays, 24 (68.6%) experienced a SCD complication prior to HU initiation including 51 VOEs requiring healthcare contact and 12 episodes of acute chest syndrome, among others. This led to 14 emergency department visits and 40 hospital admissions. No deaths occurred during the study period. Overall, the healthcare cost of acute care utilization for sickle cell disease complications prior to HU initiation greatly outweighed the cost of the medication. Conclusions: Patients with SCD who relocate to BC commonly experience delays in HU initiation due to referral lags to hematologists and systemic impediments in obtaining financial coverage. As a result, patients experience high rates of avoidable complications of SCD resulting in significant morbidity and acute care utilization. Efforts should be made to improve access by addressing system-level barriers that lead to delays, thereby improving patient health outcomes and reducing healthcare costs. Addressing this disparity would advance equity, bridging the gap between patients with SCD and those with malignancies, and ensuring that access to an essential medication is determined by clinical need, not diagnosis or systemic bias.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".