Subgroup analyses of individuals with Stage 3a-5 kidney disease that were: first wave patients; aged 65–74 and 85–94; female sex; never and current smoker; CRP ≥ 40 mg/dL; no hypertension; no diabetes; CFS 4 and CFS 5–6 were associated with increased mortality (Additional file 1: Fig. 1). Here, CRP is linked to diabetes mellitus.