Hypokalemia, hypomagnesemia, and hyponatremia are associated with acute kidney injury in patients treated with cisplatin.

INTRODUCTION:Cisplatin-associated acute kidney injury (C-AKI) is common. Predictive factors include age >60 years, hypertension, cisplatin dose, diabetes, and serum albumin < 3.5 g/L. The association between C-AKI and hypokalemia, hypomagnesemia or hyponatremia has not been well characterized. METHODS:Data from a previous retrospective observational study was obtained. Patients were separated into three groups with similar cisplatin doses and schedules. Group A received cisplatin 60-100 mg/m2 every three weeks with laboratory assessments before treatment, group B received cisplatin 60-75 mg/m2 every three weeks with laboratory assessments before days 1 and 8 and group C had weekly cisplatin 40 mg/m2 with weekly laboratories assessments. The association between hypomagnesemia, hypokalemia, hyponatremia, and risk of AKI was determined using a counting process specification of Cox's regression models. RESULTS:A total of 1301 patients were separated into groups A (n = 713), B (n = 204), and C (n = 384). The proportion of patients with at least one event of hypokalemia, hypomagnesemia, or hyponatremia was lower in group A (29.2%, 57.6%, 36.2%) compared to groups B (43.6%, 67.2%, 59.8%) and C (49.0%, 78.7%, 51.0%). The incidence of all grade C-AKI was 35.6% (group A), 46.6% (group B), and 18.2% (group C). In group A, the risk of AKI doubled with hyponatremia or hypomagnesemia and tripled with hypokalemia. This association was not seen with other groups. CONCLUSION:Among patients with the highest doses of cisplatin, the presence of one electrolyte disorder was associated with an increased risk of C-AKI. Other studies are needed to characterize the presence of an electrolyte disorder as a predictive risk factor of C-AKI in this subpopulation.