Establishing an Indicator of Hypokalemia in Patients Receiving Anti-Epidermal Growth Factor Receptor Antibodies.

Risk factors for hypokalemia were analyzed in patients who received anti-epidermal growth factor receptor monoclonal antibodies (anti-EGFR MoAbs) at Gifu Municipal Hospital between February 2010 and March 2013. Subjects were 51 patients (27 men and 24 women) with the median age (interquartile range) of 66 (63-72) years. The study period started from the initiation of anti-EGFR MoAbs administration and ended 4 weeks after administration was completed. Patients were categorized into the side effect group if both minimum serum potassium (Min S-K) grade and b grade (pre-treatment S-K grade-Min S-K grade) were B1; otherwise, they were placed into the no side effect group. Univariate analysis for factors to prevent the side effect identified the "concomitant use of hyperkalemia-inducing drugs" to be statistically significant (p=0.010). Multivariate analysis was conducted on factors with a p value of <0.25 in the univariate analysis and on "concomitant use of hyperkalemia-inducing drugs," which was likely to clinically affect S-K decrease, although its p value was >0.25. It showed that "concomitant use of hyperkalemia-inducing drugs" was a significant risk-prevention factor (odds ratio: 0.138, 95% confidence interval[CI]: 0.033-0.581, p=0.007). In conclusion, "concomitant use of hyperkalemia-inducing drugs" is a factor associated with preventing hypokalemia accompanying anti-EGFR MoAbs administration.