Association between lipid-lowering agents and severe hyponatremia: a population-based case–control study

Purpose Drug-induced hyponatremia is common, with medications from many drug-classes implicated. Lipid-lowering agents are among the most prescribed drugs. Limited evidence suggests an inverse association between statins and hyponatremia, while data on other lipid-lowering agents is absent. The objective of this investigation was to study the association between lipid-lowering drugs and hospitalization due to hyponatremia. Methods This was a register-based case–control study of the general Swedish population. Those hospitalized with a main diagnosis of hyponatremia (n = 11,213) were compared with matched controls (n = 44,801). Multivariable logistic regression adjusting for co-medication, diseases, previous hospitalizations, and socioeconomic factors was used to explore the association between severe hyponatremia and the use of lipid-lowering drugs. Results Unadjusted ORs (95% CI) for hospitalization due to hyponatremia were 1.28 (1.22–1.35) for statins, 1.09 (0.79–1.47) for ezetimibe, 1.38 (0.88–2.12) for fibrates, and 2.12 (1.31–3.35) for resins. After adjustment for confounding factors the adjusted odds ratios (95% CI) compared with controls were 0.69 (0.64–0.74) for statins, 0.60 (0.41–0.86) for ezetimibe, 0.87 (0.51–1.42) for fibrates, and 1.21 (0.69–2.06) for resins. Conclusions Use of statins and ezetimibe was inversely correlated with severe hyponatremia. Consequently, these drugs are unlikely culprits in patients with hyponatremia, and they appear safe to initiate in hyponatremic patients. A potential protective effect warrants further studies on how statins and other lipid-lowering drugs are linked to dysnatremias.