The economic impact and cost-effectiveness of urinary neutrophil gelatinase-associated lipocalin after cardiac surgery.

BACKGROUND Acute kidney injury (AKI) is common after cardiac surgery, and expeditious recognition with specific biomarkers may help improve outcome. OBJECTIVE Because the economic impact of a biomarker-based diagnostic strategy is unknown, we assessed the cost-effectiveness of using urinary neutrophil gelatinase-associated lipocalin (NGAL) for the diagnosis of AKI after cardiac surgery compared with current diagnostic methods. METHODS A decision analysis model was developed using the societal perspective to evaluate the cost-effectiveness of NGAL. Cost per quality-adjusted life-year (QALY) was determined for NGAL and standard strategies. The base case was a 67-year-old male patient undergoing coronary artery bypass graft surgery in the United Kingdom. Multiple sensitivity analyses were performed to determine how cost-effectiveness would vary with changes in the underlying clinical and economic variables. RESULTS The base case yielded expected costs of £4244 and 11.86 QALYs for the NGAL strategy compared with £4672 and 11.79 QALYs for the standard therapy. The cost-effectiveness ratio for the NGAL strategy was £358/QALY compared with £396/QALY for the standard regimen. Cost-effectiveness increased as the treatment effect-defined as the ability to prevent progression of established AKI (kidney injury or failure)-for the therapy triggered by an elevated NGAL level rose. Sensitivity analysis demonstrated that the model was most responsive to the probability of developing AKI and least sensitive to the test cost for NGAL. Probabilistic sensitivity analysis supported the NGAL strategy as the most cost-effective option. Because this study was a decision analysis model incorporating a nonspecific treatment for AKI (as opposed to an observational study or controlled trial), model structural assumptions may therefore have underestimated mortality and the likelihood of developing AKI, although these were tested in multiple sensitivity analyses. Indirect costs were also not explicitly factored. CONCLUSION The use of urinary NGAL after cardiac surgery appears to be cost-effective in the early diagnosis of AKI.