CST3 and hydrops fetalis: CKD prevalence higher when estimated by cystatin C vs. creatinine (61% vs. 46%)Patients with CKD had worse baseline function and ~2× higher risk of worsening HFRelative benefit of tirzepatide on CV death/worsening HF preserved across CKD strata; absolute risk reduction larger in CKD patientsTransient dip in eGFR‐creatinine at 12 weeks, but eGFR improved by 52 weeks (especially by cystatin C)Discordance between creatinine and cystatin C suggests body‐composition changes (weight/muscle loss) affect creatinine‐based eGFR; interpret renal changes cautiously during weight loss