We read with great interest the article by Carlo Custodero et al. recently published in Critical Care [1]. The authors concluded that NT-proBNP levels during the acute phase of sepsis may be a useful indicator of higher risk of long-term impairments in physical function and muscle strength in sepsis survivors. However, the article overlooks the association of NT-proBNP and renal function in septic patients. Studies have shown that acute kidney injury is a common complication of sepsis and is significantly associated with mortality [2, 3], whereas the studies by Gergei et al. [4] and Roberts et al. [5] indicated that NT-proBNP plasma level has shown an exponential increase with declining glomerular filtration rate. Thus, it did not seem persuasive that NT-proBNP could completely predict outcomes without adjusting for the covariate of renal function. We suggest the relationship of the NT-proBNP levels during the acute phase of sepsis and physical function and muscle strength outcomes in sepsis survivors be stratified based on the renal function.