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The following is a summary of “Predictive enrichment for the need of renal replacement in sepsis-associated acute kidney injury: combination of furosemide stress test and urinary biomarkers TIMP-2 and IGFBP-7,” published in the July 2024 issue of Critical Care by Palmowski et al.

In sepsis, while fluid resuscitation is followed by aiming for negative fluid balance, predicting whether early renal replacement therapy (RRT) or diuretics alone is sufficient for patients with sepsis-associated acute kidney injury (SA-AKI) remains challenging, as neither Furosemide Stress Test (FST) nor urinary TIMP-2*IGFBP-7 alone offers clear guidance.

Researchers conducted a retrospective study testing the hypothesis that combines an upstream FST with downstream urinary TIMP-2*IGFBP-7 measurements to enhance the accuracy of predicting the need for RRT.

They involved 100 patients with sepsis (diagnosed within 48 hours), AKI stage ≥2, and needing a negative fluid balance (February 2020 to December 2022). Each patient underwent an FST, and serial measurement of urinary biomarkers TIMP-2*IGFBP-7 was performed, starting immediately before the FST and continuing for up to 12 hours afterward. The primary concern was the need for RRT within a week of enrollment.

The result showed that within 7 days, 32% (32 out of 99) of patients with SA-AKI required RRT. Following the FST, urinary TIMP-2IGFBP-7 levels decreased from 3.26 ng²/mL²/1000 (IQR:1.38–5.53) to 2.36 ng²/mL²/1000 (IQR: 1.61–4.87) in patients who eventually needed RRT, while levels in patients with non-RRT dropped from 1.68 ng²/mL²/1000 (IQR: 0.56–2.94) to 0.27 ng²/mL²/1000 (IQR: 0.12–0.89). The TIMP-2IGFBP-7 concentrations were lower in patients with non-RRT for up to 12 hours but rebounded in patients with RRT after 6 hours. The TIMP-2IGFBP-7 before FST (accuracy 0.66; 95%-CI 0.55–0.78) and the FST (accuracy 0.66; 95%-CI 0.55–0.78) showed moderate predictive accuracy for RRT requirement. A combined approach using FST as an initial screen followed by TIMP-2IGFBP-7 measurement after 2 hours improved predictive accuracy to 0.83 (95%-CI 0.74–0.90, P=0.03), with a positive predictive value of 0.86 0.86 (95%-CI 0.64–0.97) and specificity of 0.96 (95%-CI 0.88–0.99).

Investigators concluded that combining upstream FST with urinary TIMP-2*IGFBP-7 measurements precisely identified patients with SA-AKI who required RRT, and further trials should determine whether early RRT initiation was advantageous for the high-risk subgroup.

Source: annalsofintensivecare.springeropen.com/articles/10.1186/s13613-024-01349-4