Urinary tract infection is associated with hypokalemia: a case control study

Background: Hypokalemia is a common clinical problem. The association between urinary tract infection (UTI) and hypokalemia is not clear. Hypokalemia is common in patients with UTI in clinical observation. The aim of the study is to determine if UTI is associated with hypokalemia.

Methods: Patients hospitalized with UTI and the control group were retrieved from the Longitudinal Health Insurance Database 2005. The control group was patients hospitalized with other reasons and were matched for the confoundings of UTI and hypokalemia. We analyze the risk of hypokalemia using logistic regression and calculate the odds ratio (OR) and 95% confidence interval (CI) of OR.

Results: We analyzed 43,719 UTI patients and control patients. Hypokalemia was found in 4540 (10.4%) patients with UTI and 1842 (4.2%) control patients. The percentage of patients with hypokalemia was higher in UTI patients (chi-square, p < 0.001). UTI was associated with hypokalemia and the odds ratio (OR) was 2.27 [95% confidence interval (CI): 2.17-2.41]. Cerebrovascular accident, chronic obstructive pulmonary disease, hypertension, congestive heart failure, diarrhea, medications including thiazides, sulfonamides, xanthines, and laxatives were independently associated with hypokalemia. Recurrent UTI was associated with hypokalemia in UTI patients (OR: 1.13, 95% CI: 1.05-1.23, p < 0.001).

Conclusions: Urinary tract infection is associated with hypokalemia among inpatients. The association is independent of patients' comorbidities and medications. Recurrent UTI is associated with increased hypokalemia in UTI patients.

Keywords: Comorbidities; Diarrhea; Hypokalemia; Recurrent UTI; Sulfonamides; Thiazides; UTI.