How to assess kidney outcomes in obese people with substantial weight loss: the case of GLP1- and dual-receptor agonists

Long-term kidney outcomes of semaglutide in obesity and cardiovascular disease in the SELECT trial

“…Error at extreme BMIs may occur because both muscle and fat mass are increased in obesity, and serum creatinine increases with increased muscle mass. When weight loss occurs, both lean muscle mass and fat mass are reduced, and this loss of muscle mass can cause an artifactual rise in the indexed eGFR 33 . A related issue is that the CKD-EPI equation we used was trained to predict mGFR indexed or standardized to BSA rather than unindexed mGFR.…”

“…Thus, whether the CKD-EPI creatinine-based eGFR is as reasonable a proxy for indexed mGFR in the settings of obesity and large changes in body weight is unclear, and studies of this question are conflicting [34][35][36][37] . A recent editorial advocated for the use of deindexed eGFR in the setting of weight loss 33,38 , but this is not a recommendation in the recent guidelines from the Kidney Disease Improving Global Outcomes (KDIGO) organization 39 . That said, a caveat of any reduction in estimated GFR based on creatinine in a trial where treatment is associated with weight (and, thereby, muscle mass) loss must consider contributions from both creatinine production and improved kidney The change in UACR was analyzed as the estimated mean ratio to baseline; for ease of interpretation; these ratios were converted to relative percentage changes from baseline using the formula (estimated ratio − 1) × 100.…”