[New frequent adverse reaction of PPI in older adults: mild hyponatremia].

Hyponatremia is a rare side effect described in the product characteristics of proton pump inhibitors (PPIs). Hyponatremia in the elderly (>65 years) was assessed in patients with exposure to PPIs for at least one year compared to controls not exposed to PPIs counterparts. Included 145 patients, twenty-four patients (16.6%) had moderate hyponatremia ([120-134] mEq/L). Forty-eight patients (33.1%) were treated with PPIs. In the end, 31.3% [18.7%-46.3%] of the treated population for more than a year by PPI suffered moderate hyponatremia against only 9.3% [14.3%-16.9%] in the rest of the population, giving an odds ratio of 4.4 ([1.8-11.1], p=0.001). The relationship between hyponatremia dose was not significant (R2=0.05, p=0.74). By our study, we show that the risk of moderate hyponatremia is increased by chronic use of PPI in the elderly population. We also specify a notion of prevalence between 18.7% and 46.3%.