Cost of hemodialysis versus fomepizole-only for treatment of ethylene glycol intoxication

To the Editor:

Levine et al. recently published a study describing the use of fomepizole therapy alone in the treatment of ethylene glycol (EG) intoxication in patients without renal compromise or acidosis on arrival.¹ Our toxicology service was recently involved in managing such a patient. We performed an estimate of the cost (not charge) at our institution of fomepizole therapy alone and fomepizole with hemodialysis (HD) and described the practical challenges associated with fomepizole-alone therapy.

Case presentation

A 70-kg female patient presented one-hour following ingestion of antifreeze. Laboratories revealed a venous blood pH of 7.37, pCO2 of 37 mm Hg, and measured bicarbonate of 21 mMol/L, creatinine 0.88 mg/dL, anion gap of 14, serum osmolality of 301 mOsm/kg, and osmolar gap of 20. Ethanol, salicylates, and acetaminophen were not present on blood testing. The patient received one dose of fomepizole (15 mg/kg) and underwent one 4-hour HD treatment. Venous blood pH of 7.39, pCO2 of 37 mm Hg, measured bicarbonate of 27 mM/L, and osmolar gap of 1 were obtained three hours postdialysis. A serum EG concentration obtained at presentation resulted three days later at 113 mg/dL. Based on the absence of acidemia, anion gap, or osmolar gap on repeated laboratories, the patient was medically cleared. Costs (not charges) subsequent to emergency department and medical toxicology evaluation, initial laboratories, and initial dose of fomepizole (identical for each patient regardless of subsequent treatment) are detailed below:

Table

Fomepizole Alone	Hemodialysis
Inpatient Room: $793	HD w/nursing care: $785 (inclusive of all supplies/ access)
Provider Care: $214
Direct Observation “Sitter”: $140	Nephrology Consult: $572
Daily chemistry and osmolality: $24	Repeat chemistry/ osmolality: $24
Twice daily fomepizole (10 mg/kg): $952	Cost: $1381
Repeat EG concentration: $24
Total daily (24 h) Cost: $2123

Discussion

In our institution, HD is associated with cost savings when compared with “fomepizole-only” therapy. Our institution and many others do not have EG concentrations immediately available and rely on “send-outs” with results available 2–3 days later. In the absence of a nontoxic EG concentration, the end-point of “fomepizole-only” therapy remains largely unknown. Assuming an elimination half-life of 14 hours and treatment to an EG concentration less than 20 mg/dl as described,¹ our patient would have required at least 37 hours with a resulting cost of $4246 (two-hospital days). Our patient was admitted briefly awaiting psychiatric placement. Assuming costs for a 24-hr stay (our patient was admitted for 12 hours), the total cost of HD therapy would have been $2576 (HD cost plus inpatient costs minus fomepizole and EG concentration). Some patients in Levine's cohort had an elimination half-life as long as 23 hours necessitating longer fomepizole therapy, longer hospital stays, and increased associated cost. Costs and charges are institution specific. The costs cited here may not apply to all care settings. HD is not without risk. However, advances in technology have significantly reduced these risks.² Inpatient hospitalization is similarly not without risk.³ While treatment with fomepizole alone for selected EG poisoned-patients is possible, it may be associated with greater cost as compared to HD and is highly reliant on the availability of EG concentrations to determine when to stop treatment.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.