Semaglutide increases plasma creatinine and BTP without altering measured GFR in T2D patients.
Background
Accurate assessment of glomerular filtration rate (GFR) is crucial for managing type 2 diabetes (T2D) and chronic kidney disease (CKD) progression. While semaglutide, a GLP-1 receptor agonist, is known for its glucose-lowering, cardiovascular, and kidney-protective effects, its influence on endogenous filtration markers like creatinine and cystatin C, which are used to estimate GFR (eGFR), remains unclear. This ambiguity can complicate the interpretation of kidney function changes in patients receiving semaglutide, potentially masking true GFR stability or decline.
Study Design
This post hoc analysis of a randomized, double-blind, placebo-controlled clinical trial included 48 participants with T2D and albuminuria. Participants were randomized 1:1 to receive semaglutide 1 mg weekly or matching placebo for 26 weeks, alongside empagliflozin. Measured GFR (mGFR) was determined by 99m-Tc-DTPA plasma clearance. Estimated GFR (eGFR) was calculated using CKD-EPI equations based on plasma creatinine (eGFRcre), cystatin C (eGFRcys), their combination (eGFRcomb), or a panel including creatinine, cystatin C, beta-trace protein (BTP), and beta-2 microglobulin (B2M) (eGFRpanel).
Results
Among the 48 participants (median age 70 years; 16.7% female), semaglutide treatment led to a small but significant increase in plasma creatinine and BTP compared with placebo. Notably, there was no significant change in cystatin C or B2M. Crucially, semaglutide treatment was not associated with a significant change in mGFR (median [IQR] change of 0 [-7.5 to 10.3] mL/min/1.73 m2) when compared to placebo (median [IQR] change of -2 [-11.3 to 3.0] mL/min/1.73 m2). This indicates that the observed increase in creatinine does not reflect a true decline in kidney filtration capacity. Both eGFRcre and eGFRcys were consistently outperformed by eGFRcomb and eGFRpanel at both baseline and end-of-treatment, suggesting multi-marker equations offer superior accuracy.
Semaglutide treatment did not significantly change measured GFR, despite increasing plasma creatinine and beta-trace protein.
Key Findings
- Semaglutide significantly increased plasma creatinine levels compared to placebo.
- Plasma beta-trace protein (BTP) also significantly increased with semaglutide treatment.
- Semaglutide did not cause a significant change in measured glomerular filtration rate (mGFR).
- eGFR equations combining multiple markers (eGFRcomb, eGFRpanel) outperformed single-marker eGFRcre and eGFRcys.
- Cystatin C and beta-2 microglobulin (B2M) levels were not significantly altered by semaglutide.
Why It Matters
This study clarifies that semaglutide's kidney-protective effects are likely not mediated by direct changes in glomerular filtration rate, but rather through other mechanisms not captured by GFR. Clinicians should be aware that a slight increase in plasma creatinine in patients on semaglutide may not signify a true decline in kidney function, as measured GFR remains stable. This finding is critical for interpreting routine lab results and avoiding unnecessary alarm or intervention based solely on creatinine-based eGFR. For biohackers and peptide users, this suggests that monitoring mGFR or using multi-marker eGFR equations (eGFRcomb, eGFRpanel) might provide a more accurate picture of kidney health when using semaglutide, compared to relying solely on creatinine-derived estimates.
semaglutide
type-2-diabetes
kidney-function
egfr
mgfr
creatinine