Incidence of and Frequency of Monitoring for Hyponatremia Associated with SSRIs: a Retrospective Chart Review at One Institution

Abstract

Specific Aims: To describe the incidence of hyponatremia in patients using SSRIs and to assess how often health care professionals obtain electrolyte panels after SSRI initiation. Also, to identify the most recent sodium level in patients and to compare sodium levels in a patient group using an SSRI and a control group not using an SSRI. Subjects: Patients who received care at a large multi-center ambulatory care clinic between January 1st, 2008 and December 31st, 2011. Methods: An electronic medical record database was used to identify potential patients through medication records reflecting SSRI use or diagnosis of low back pain, obesity, pruritis, rash, or fibromyalgia. The following data was collected: patient gender, age, weight, height, use/non-use of SSRI, plasma sodium level, and documented past hyponatremia diagnosis. Plasma sodium levels and hyponatremia incidence were compared from the SSRI group to the non-SSRI group. In addition, the SSRI group was analyzed for incidence of documented hyponatremia. Monitoring of sodium levels after SSRI initiation was also investigated. Main Results: Overall, 500 charts were reviewed. After inclusion and exclusion criteria were applied, 118 patients were included in the study (38 in the SSRI group, 80 in the control group). The incidence of hyponatremia in the SSRI group and control group was 2.63% and 1.25% respectively. There was no significant difference between groups (p=0.542). Sodium levels were monitored 19.2% of the time after SSRI initiation. Conclusion: The incidence of hyponatremia was similar between groups. Physicians are not adequately monitoring for hyponatremia after SSRI initiation.