Predicting the risk for dialysis or death in IgA nephropathy

Abstract

For the individual patient with primary IgA nephropathy (IgAN), it remains a challenge to predict long-term outcomes for patients receiving standard treatment. We studied a prospective cohort of 332 patients with biopsy-proven IgAN patients followed over an average of 13 years. We calculated an absolute renal risk (ARR) of dialysis or death by counting the number of risk factors present at diagnosis: hypertension, proteinuria ≥1 g/d, and severe pathologic lesions (global optical score, ≥8). Overall, the ARR score allowed significant risk stratification (P < 0.0001). The cumulative incidence of death or dialysis at 10 and 20 years was 2 and 4%, respectively, for ARR=0; 2 and 9% for ARR=1; 7 and 18% for ARR=2; and 29 and 64% for ARR=3, in adequately treated patients. When achieved, control of hypertension and reduction of proteinuria reduced the risk for death or dialysis. In conclusion, the absolute renal risk score, determined at diagnosis, associates with risk for dialysis or death.

Figure 1.

Kaplan-Meier survival curves without D/D according to the presence/absence at diagnosis of: HT (A), proteinuria ≥1 g/d (B), and GOS of ≥8 (C); D/D (primary event); comparison of curves by the log-rank test; cumulative incidence of event = (1 − survival).

Figure 2.

Kaplan-Meier survival curves without: D/D (A), dialysis alone (B), and CKD-stage 3+ (C), according to the ARR scoring at diagnosis; D/D (primary event); CKD-stage 3+ = chronic kidney disease stage 3 and up, defined as eGFR <60 ml/mn per 1.73 m² S (secondary event); comparison of curves by the log-rank test; cumulative incidence of event = (1 − survival).

Figure 3.

Kaplan-Meier survival curves without D/D according to: the control of hypertension (absence, controlled, and uncontrolled) (A), the reduction of proteinuria ≥1 g/d (low/absent, reduced, and unreduced) (B), the control of both HT and proteinuria (both, none, and only one controlled) (C), and steroid treatment for severe renal lesions (no or yes) at last follow-up (D); D/D (primary event); comparison of curves by the log-rank test; cumulative incidence of event = (1 − survival).