Adjusted death risk rose stepwise as eGFR fell below 60 mL/min/1.73m2, from HR 1.2 (eGFR 45–59) up to HR 5.9 (eGFR <15), in a cohort of 1.12 million adults
Causal status: Causal support strong; graded, dose-dependent association independent of comorbidities
Reliability / bias notes: Single-measurement creatinine-based eGFR; residual confounding by unmeasured comorbidity possible