Reduced-osmolarity oral rehydration salts solution multicentre trial: implications for national policy

World Health Organization (WHO) recommended standard ORS solution has sodium (90 mmol/L) and glucose (111 mmol/L) almost in the ratio of 1:1 and a total osmolarity of 311 mmol/L. There are concerns that the sodium or glucose concentration and the overall osmolarity in the formulation is not appropriate. Therefore, the efficacy of standard and reduced-osmolarity ORS solutions in young children with acute diarrhea was evaluated in a recent WHO supervised multicentre trial conducted in India (New Delhi), Brazil, Mexico and Peru. The implications of trial results are discussed. In non-cholera diarrhea, both the standard and reduced osmolarity ORS solutions were effective in achieving clinical rehydration. The stool output was 39% higher in the standard ORS solution group as compared to the reduced-osmolarity ORS solution group. The duration of diarrhea was 22% higher in the standard ORS solution group. The risk of requiring supplementary intravenous infusion was increased in children treated with standard ORS solution [relative risk 1.4 (0.9-2.4)]; this benefit was not observed in Indian patients due to high breast feeding rate. The mean sodium concentration at 24 hours after admission was lower in the reduced osmolarity ORS solution group [135 (134-136) vs 138 (136-139), p < 0.01). The low osmolarity ORS deserves to be evaluated in adult cholera to determine its efficacy and any excess hyponatreamia. Meanwhile, it is reassuring that the WHO formulation was effective and its use was not associated with hypenatremia even in young children. Efforts must continue to be made to promote WHO-ORS while research to improve it further is welcome.