Impact of Hydroxyurea Starting Dose on Pain Outcomes in Patients with Sickle Cell Disease

In patients with sickle cell disease, hydroxyurea decreases the number of pain crises experienced. This study aimed to evaluate the difference in pain outcomes between patients started on a guideline concordant, weight-based starting dose of at least 15 mg/kg/day of hydroxyurea and those not. The first prescription of hydroxyurea was the baseline date, follow-up was a visit 60-120 days after baseline. The primary outcome was the change in opioid prescribing between baseline and follow-up. 138 patients met inclusion criteria; of these, 55 were started on a guideline concordant dose of hydroxyurea. Greater white blood cell count (9.5 vs 12.0; p < 0.01) was statistically associated with subtherapeutic dosing. Greater actual body weight (68.0 vs 72.1 kg; p = 0.16) also appeared higher in the non-guideline concordant group. No statistically significant difference in opioid prescribing was observed between those started on a guideline concordant dose of hydroxyurea and those who were not. In the guideline concordant starting dose group, 42% had a reduction in pain scores at first follow up, compared to 35% with a non-guideline recommended starting dose. (p = 0.41). While this difference is in the direction that would be expected based on the guidelines, the difference does not appear to be clinically meaningful.