A Risk for Adverse Events in Cancer Meds Cleared Renally


For patients receiving renally cleared cancer medications, therapeutic drug levels are higher and adverse events were more frequent for those whose cystatin C-based estimated glomerular filtration rate (eGFR) was more than 30% lower than their serum creatinine–based eGFR, a recent study suggests.


  • The cohort study included 1869 adult patients with cancer who had simultaneous serum creatinine–based eGFR (eGFRcr) and cystatin C-based eGFR (eGFRcys) measured. 

  • The primary exposure was eGFR discordance, defined as an eGFRcys > 30% lower than the eGFRcr.

  • The primary outcome was risk of medication-related adverse events associated with vancomycin, trimethoprim-sulfamethoxazole, baclofen, or digoxin.


  • Roughly 29% of patients (n = 543) had eGFRcys more than 30% lower than their eGFRcr.

  • These patients were more likely to experience medication-related adverse events, including supratherapeutic vancomycin levels (24% vs 9% of patients), trimethoprim-sulfamethoxazole-related hyperkalemia (22% vs 12%), baclofen toxic effect (26% vs 0%), and high digoxin levels (29% vs 0%).

  • Even after adjusting for age, sex, race and ethnicity, baseline comorbidities, laboratory studies, and medication use, patients with an eGFRcys more than 30% lower than the eGFRcr had a significantly increased risk of 30-day mortality (adjusted hazard ratio, 1.98).


“We found a considerably higher rate of supratherapeutic drug levels and [adverse events] associated with select renally cleared medications and increased risk of death in patients with an eGFRcys that was more than 30% lower than the eGFRcr compared with patients with a concordant eGFR or those whose eGFRcys was more than 30% higher than the eGFRcr,” the authors reported.


This study, led by Paul Hanna, MD, with Massachusetts General Hospital, Boston, was published online July 5 in JAMA Network Open


The study likely overestimated the rate of eGFR discordance and used a one-time assessment of serum creatinine and cystatin C, which may not reflect a steady state at the time of measurement.


The authors report no relevant financial relationships. The study reported no specific funding.

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