The molar ratio of serum retinol-binding protein (RBP) to transthyretin (TTR) is not useful to assess vitamin A status during infection in hospitalised children

Objective: To assess the usefulness of the molar ratio of serum retinol-bin ding protein (RBP) to transthyretin (TTR) to determine vitamin A (VA) statu s during infection. Design: We took advantage of previously collected data during a randomised double-blind, placebo-controlled clinical trial to conduct a secondary anal ysis of the RBP/TTR ratio and its relationship to infection and VA status. In this clinical trial, children were randomly assigned to one of three gro ups and received either one single oral high dose of VA (200 000 IU) on the day of admission and subsequently a placebo daily until discharge or daily oral low doses of VA (5000 IU) from admission until discharge or a placebo daily from admission until discharge. Setting: Lwiro pediatric hospital, Province of South Kivu, Democratic Repub lic of Congo. Subjects: A total of 900 children aged 0-72 months hospitalised consecutive ly between March 1994 and March 1996. Main outcome measures: RBP/TTR molar ratio after 7 days hospitalisation. Results: After 7 days hospitalisation, molar RBP:TTR ratio (mean +/- s.d.) of infected children (C-reactive proteins > 10 mg/l) was 0.67 +/- 0.31 in t he high-dose group (n = 81), 0.74 +/- 0.44 in the low dose group (n = 71) a nd 0.73 +/- 0.39 in the placebo group (n = 81). These values did not differ significantly (one-way ANOVA P = 0.472). In patients with baseline serum r etinol concentrations < 0.70 mu mol/l, changes in RBP:TTR ratio between adm ission and day 7 were not statistically different in the three groups (one- way ANOVA P = 0.548). Conclusions: In this population of malnourished hospitalised children, mola r RBP:TTR ratio does not appear to be useful to assess VA status during inf ection. Sponsorship: Our research was partially supported by a grant from the Fonds de la Recherche Scientifique et Medicale (contract 3.4505.94) and the Davi d and Alice Van Buuren Foundation.