Effect of single agent high-dose methotrexate-related acute kidney injury on length of hospitalization and relative dose intensity in adult patients with central nervous system lymphoma.

Purpose Grade ≥3 adverse effects prolong hospitalization and reduce chemotherapy dose intensity. The purpose of this study was to evaluate the rate and severity of high-dose methotrexate-related acute kidney injury and analyze its effect on hospital length of stay and relative chemotherapy dose intensity. Methods This was a retrospective cohort analysis. Patients receiving ≥1 dose of high-dose methotrexate were analyzed for acute kidney injury and length of stay. Patients receiving ≥6 cycles of induction therapy were included in the analysis of relative chemotherapy dose intensity. Chi squared analysis was used to determine the differences between dichotomous data; Student's t-test for parametric data and Mann-Whitney U test for non-parametric data for continuous variables. Statistical analyses were performed with IBM SPSS Statistics (version 21). Results Twenty-six patients and 194 treatment encounters were identified. Thirteen patients were evaluated for relative chemotherapy dose intensity. Grade ≥3 acute kidney injury occurred in four patients (15% of patients; 2% of encounters). There were no grade 5 adverse events. Mean length of stay for encounters with grade ≥3 acute kidney injury was almost three times longer than for those with ≤ grade 2 acute kidney injury (p = 0.041). Mean relative chemotherapy dose intensity was reduced approximately in half for patients experiencing grade ≥3 acute kidney injury (p < 0.01). The most common adverse events were hypokalemia and nausea. Proton pump inhibitors were the most frequently co-administered medications with the potential to affect high-dose methotrexate pharmacokinetics. Conclusion At our cancer program, the rate of grade ≥3 acute kidney injury with high-dose methotrexate is similar to that reported by others. Grade ≥3 acute kidney injury following high-dose methotrexate administration significantly prolonged length of stay and reduced relative chemotherapy dose intensity.