Symptomatic hyponatremia during treatment of dehydrating diarrheal disease with reduced osmolarity oral rehydration solution.

CONTEXT In May 2002, the World Health Organization and the United Nations Children's Fund recommended that the formulation of oral rehydration solution (ORS) for treatment of patients with diarrhea be changed to one with a reduced osmolarity and that safety of the new formulation, particularly development of symptomatic hyponatremia, be monitored. OBJECTIVE To measure the rates of symptomatic hyponatremia during treatment of patients with diarrhea with reduced osmolarity ORS. DESIGN, SETTINGS, AND PATIENTS A phase 4 trial conducted at the Dhaka hospital (December 1, 2002-November 30, 2003) and Matlab hospital (February 2, 2003-January 31, 2004) of the International Centre for Diarrhoeal Disease Research Bangladesh: Centre for Health and Population Research, Dhaka, Bangladesh. All patients admitted with uncomplicated watery diarrhea were treated with the newly recommended ORS and monitored. Patients developing neurological symptoms (seizure or altered consciousness) were transferred to the special care ward for treatment and investigated to identify the cause of the symptoms. Patient records of the Dhaka hospital were reviewed during the previous year when the old ORS formulation was used. INTERVENTION Reduced osmolarity ORS. MAIN OUTCOME MEASURE Incidence rate of symptomatic hyponatremia in a 1-year period. RESULTS A total of 53,280 patients, including 22,536 children younger than 60 months, were monitored at the Dhaka and Matlab hospitals. Twenty-four patients, none older than 36 months, developed seizures or altered consciousness associated with hyponatremia, with an overall incidence rate of 0.05% (95% confidence interval [CI], 0.03%-0.07%) at the Dhaka hospital and 0.03% (95% CI, 0.01%-0.09%) at the Matlab hospital. During the previous year, 47 patients at the Dhaka hospital had symptoms associated with hyponatremia, for an estimated incidence rate of 0.10% (95% CI, 0.07%-0.13%). The reduction in the rates was statistically significant (odds ratio, 0.50; 95% CI, 0.29-0.85; P = .009). CONCLUSION The risk of symptoms associated with hyponatremia in patients treated with the reduced osmolarity ORS is minimal and did not increase with the change in formulation.