eGFR (estimated glomerular filtration rate)

Your kidneys filter blood through roughly a million tiny units each. The glomerular filtration rate is how fast that filtering happens, and because measuring it directly is impractical, labs estimate it from a creatinine blood test plus your age and sex. That estimate is the eGFR, reported in mL/min/1.73m². NIDDK, the NIH kidney institute, describes an eGFR of 60 or above as normal for most adults and a result below 60 that persists for three months or more as the definition of chronic kidney disease.

The reason this shows up in a GLP-1 glossary is the FLOW trial. Published in the New England Journal of Medicine in 2024, FLOW randomized 3,533 adults who had both type 2 diabetes and chronic kidney disease to semaglutide 1 mg or placebo. The primary kidney composite — kidney failure, a sustained 50% drop in eGFR, or death from kidney or cardiovascular causes — fell 24% on semaglutide (hazard ratio 0.76). The trial was stopped early because the benefit was clear.

That result changed a label. Ozempic now carries an indication to reduce the risk of sustained eGFR decline, end-stage kidney disease and cardiovascular death in adults with type 2 diabetes and chronic kidney disease — a kidney claim, sitting alongside the older blood-sugar and cardiovascular ones.

The common confusion is treating one low eGFR as a diagnosis. A single result can dip from dehydration, a recent illness, intense exercise or a protein-heavy meal. Chronic kidney disease requires the number to stay low across at least three months, usually alongside a urine albumin test. This matters on GLP-1 therapy specifically, because vomiting and diarrhea during titration can dehydrate you enough to push creatinine up temporarily.

Worth asking your clinician: what your current eGFR and urine albumin-to-creatinine ratio are, whether your GLP-1 dose needs adjusting at your kidney function, and how aggressively to replace fluids during a rough week of side effects. Our kidney-disease patient guide and FLOW trial page go further.