Prognostic factors for renal allograft survival in patients with immunoglobulin A nephropathy: a case control study

Renal Outcomes in Brazilian Patients with Immunoglobulin A Nephropathy and Cellular Crescentic Lesions

BACKGROUND AND AIM

Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulopathy. The Oxford classification was recently updated to include crescents as markers of poor prognosis. The aim of this study was to evaluate the impact of cellular crescents on the prognosis of patients with IgAN in Brazil.

METHODS

This was a single-centre retrospective analysis of medical records and renal biopsies in patients with IgAN. The renal biopsy findings were classified according to the revised Oxford classification: mesangial hypercellularity, endocapillary hypercellularity (E), segmental glomerulosclerosis (S), tubular atrophy or interstitial fibrosis (T), and crescent formation (C). We evaluated a composite outcome (progression to end-stage renal disease or creatinine doubling). We performed analyses between the patients with crescents in the renal biopsy specimen (C1/C2 group) and those without such crescents (C0 group).

RESULTS

We evaluated 111 patients, of whom 72 (65.0%) were women, 80 (72.0%) self-identified as White, 73 (65.6%) were hypertensive, and 95 (85.6%) had haematuria. The distribution of patients according to cellular crescentic lesions was: C0, 80 (72%); C1, 27 (24.4%); C2, 4 (3.6%). The composite outcome was observed in 33 (29.72%) of the 111 patients. In comparison with the C0 group, the C1/C2 group had higher proportions of patients with hypertension (p = 0.04), haematuria (p = 0.03), worse serum creatinine (p = 0.0007), and worse estimated glomerular filtration rate (p = 0.0007). The C1/C2 group also had higher proportions of patients in whom the biopsy specimen was classified as E1 (p = 0.009), S1 (p = 0.001), or T1/T2 (p = 0.03), In addition, the mean follow-up period was shorter in the C1/C2 group (p < 0.0001). Furthermore, the composite outcome was observed in a greater proportion of patients and in a shorter length of time in the C1/C2 group than in the C0 group (p = 0.002 and p = 0.0014, respectively). In a Cox regression analysis, the independent risk factors for the composite outcome had Oxford classifications of S1, T1/T2, and C1/C2.

CONCLUSION

Oxford classification findings of S1, T1/T2, or C1/C2 were independent risk factors for the composite outcome, corroborating previous studies.

Clinical Features, Treatment and Prognostic Factors of Post-Transplant Immunoglobulin A Nephropathy

Background

Initially described as a relatively benign condition, recent studies report graft loss in up to 50% of the patients with post-transplant IgA nephropathy. There is no evidence for the best therapeutic approach, and prognostic factors remain to be elucidated.

Material/Methods

Single center retrospective analysis of patients >12 years old, with clinically relevant post-transplant IgA nephropathy (proteinuria ≥1.0 g/g and/or graft dysfunction) and ≥6 months follow-up after diagnosis (n=47).

Results

Living donor transplants represented 85% of cases. Dysmorphic hematuria (100%), blood pressure elevation (95.7%), renal dysfunction (70.2%) and subnephrotic proteinuria (60.6%) predominated at presentation. Using the Oxford Classification, mesangial proliferation was the main histological lesion (91%). Treatment consisted mostly of blockade of the renin angiotensin system (89.4%) and modification of immunosuppression (85.1%), mainly by increasing oral steroids dose (83%), with venous pulse therapy in 63.8% of cases. Partial and complete remission occurred in 48.9% and 17% of cases, respectively. One patient died (sepsis) and 15 patients (31.9%) lost their grafts due to nephropathy. The percentage of decrease in glomerular filtration rate at diagnosis was independently associated with partial remission (HR 0.97, 95% CI 0.94–0.99, p=0.01) and graft loss (HR 1.13, 95% CI 1.06–1.20, p<0.001). Deceased donor (HR 28.04, 95% CI 4.41–178.39, p<0.001) and donor age (HR 1.1, 95% CI 1.04–1.16, p=0.001) were also risk factors for graft loss.

Conclusions

Despite treatment, most patients with post-transplant IgA nephropathy in this cohort study presented unfavorable outcomes, and graft dysfunction at diagnosis appeared to be the main prognostic marker.