Impact of Oral -arginine Supplementation on Blood Pressure Dynamics in Children with Severe Sickle Cell Vaso-occlusive Crisis

Methods: A double-blind RCT of oral -arginine hydrochloride as adjuvant therapy for pain reduction was conducted in children with SCA-VOC, aged 5-17 years, over a 2-year period. The mean change in BP and the time to achieve BP <90 percentile was added as part of the outcome variables. The anthropometry, pain scores and mercury sphygmomanometry were done following standard procedures. BP percentiles were generated using the guidelines. Differences in the time to normalization of BP in the treatment arms were tested with Kaplan-Meier analysis.

Results: Sixty-six children (57.6% male) were randomized into -arginine (35 patients) or placebo (31 patients) arm. The prevalence of hypertension (BP ≥95 percentile) at presentation tended to increase as the pain scores increased, from a prevalence of 50% in patients with a score of 7 to 65% in those with score of 10 (systolic hypertension) and from 44.4% in patients with pain score of 7 to 50% in patients with pain score of 10 (diastolic hypertension). Patients that received arginine recorded a 12.8±3.2 mmHg decline in mean systolic BP compared to the placebo group, where a mean difference of 7.6±1.5 mmHg was observed, P<0.001. Similarly, the mean diastolic BP reduced by 13% in the arginine group and 7.5% in the placebo group, P<0.001. Children who received arginine tended to achieve BP normalization much faster than the placebo group (P=0.112), and no serious adverse events were documented related to the hypertension or arginine administration.

Conclusions: High blood pressure (≥95 percentile) is common amongst children with SCA-VOC and are mostly asymptomatic. Administration of oral arginine given for pain control achieves a reduction of the BP at a faster rate in children compared to placebo and it is safe.