Three months of weekly tirzepatide (2.5–5 mg), a dual GIP/GLP-1 receptor agonist, produced significant reductions in serum creatinine and corresponding increases in eGFR (both p < 0.001) among 36 adults with overweight or obesity in a real-world Italian outpatient clinic. Body weight, BMI, waist circumference, fasting glucose, HbA1c, insulin, HOMA-IR, and hs-CRP all declined significantly. Multiple regression identified ΔBMI as the primary independent predictor of ΔeGFR, explaining 19.4% of variance — suggesting the renal benefit is largely mediated through weight loss rather than a direct drug mechanism.
This finding lands at a clinically important intersection: obesity-driven CKD represents one of the fastest-growing causes of end-stage renal disease globally, yet therapeutic options beyond SGLT-2 inhibitors and RAS blockade remain limited. Tirzepatide's renal signal here is plausible — adipose-driven inflammation, glomerular hyperfiltration, and insulin resistance all improve with weight loss — but the mechanistic picture remains incomplete. Critically, this is a small retrospective cohort of just 36 participants with no control arm, a three-month horizon too short to assess hard renal endpoints like albuminuria progression or GFR decline over years, and doses capped at 5 mg (below the 10–15 mg range showing maximal weight loss in SURMOUNT trials). The finding is confirmatory and directionally consistent with emerging GLP-1 renal data, but incremental in isolation. Larger, longer, randomized trials with urinary albumin-to-creatinine ratios are needed before tirzepatide can be positioned as a kidney-protective therapy independent of its weight effects.
