Efficacy and safety of oral rehydration solution with reduced osmolarity in adults with cholera: a randomised double blind clinical trial

Background The effects of oral rehydration solution (ORS) with reduced osmo larity on children with acute watery diarrhoea are known, but little is kno wn about the effects of such ORS on adults with cholera. We aimed to compar e the efficacy and safety of an ORS with reduced osmolarity with that of st andard WHO ORS in adults with cholera. Methods We undertook a double-blind, controlled clinical trial In adults wi th severe cholera at the International Centre for Diarrhoeal Disease Resear ch, Bangladesh. Our primary outcomes were mean stool output in the 24 h aft er randomisation. proportion of patients who needed unscheduled intravenous therapy, and proportion of patients with biochemical hyponatraemia 24 h ra ndomisation, unscheduled randomisation. Findings 147 patients received ORS with reduced osmolarity and 153 received standard WHO ORS. There was no significant difference between the two grou ps in terms of main outcome variables: mean initial 24 h and total stool ou tput (reduced osmolarity vs standard WHO ORS 212 [SE 8] vs 207 [8] and 284 [13] vs 273 [13] g/kg respectively), duration of diarrhoea (46 [1.5] vs 43 [1.5]). The proportion of patients vomiting during the first 24 h and the p roportion who received unscheduled intravenous infusion during the first 24 h was similar between groups. More patients on reduced osmolarity ORS than on standard WHO ORS developed hyponatraemia during the first 24 h, defined as serum sodium concentration below 130 mmol/L (29 of 142 vs 16 of 150; od ds ratio 2.1[95% CI 1.1-4.1]). However, all hyponatraemic patients in both groups were symptom-free and the proportion of patients with serum sodium c oncentration below 125 mmol/L was similar between groups. Interpretation There was no difference in clinical outcome between cholera patients treated with reduced osmolarity ORS solution and those treated wit h standard WHO ORS. The risk of increased incidence of symptom-free hyponat raemia in patients with cholera treated with an ORS with reduced osmolarity should be further assessed by meta-analysis. The risk should be taken Into account when choice of ORS is made in areas in which cholera is endemic.