Prevalence of endemic distal renal tubular acidosis and renal stone in the northeast of Thailand.

We have previously reported a large group of patients with endemic distal renal tubular acidosis (EdRTA) admitted to the hospitals in the northeast of Thailand. Since large number of patients were identified in a relatively short period of time, and in an area whose population is homogeneous, we were led to investigate the prevalence of the condition in the area. A survey was conducted in five villages (total population of 3,606) within the northeast of Thailand. 3,013 villagers were examined for urinary citrate concentration and short acid loading test was performed in those with low urinary citrate. 2.8% of the population (2.2-3.4%, 95% confidence interval) failed to lower their urine pH after acid loading; within this group, 0.8% of the population had serum potassium less than or equal to 3.5 mEq/l. In addition a large number of villagers were found to have low urinary citrate concentration and there was concurrent high prevalence of renal stone. The prevalence of EdRTA and renal stone was higher in villagers with poorer socioeconomic status, suggesting that environmental factors play a major role in their pathogenesis. Villagers with acidification defect have 2.4 times the chance of having renal stone and/or nephrocalcinosis. EdRTA is therefore one of the important factors responsible for the high prevalence of renal stone in the area. In conclusion we have confirmed the high prevalence of EdRTA in the northeast of Thailand and provided data showing high prevalence of renal stone and hypocitraturia in the same population.