Hematuria duration does not predict kidney function at 1 year in ANCA-associated glomerulonephritis

Semin Arthritis Rheum. 2014 Oct;44(2):198-201. doi: 10.1016/j.semarthrit.2014.03.008. Epub 2014 Mar 28.

Abstract

Objectives: Hematuria is considered a marker of active renal disease in ANCA-associated glomerulonephritis (ANCA-GN) with induction immunosuppression often continued until hematuria has resolved. We aim to determine whether longer hematuria duration is associated with lower estimated glomerular filtration rate (eGFR) at 1 year.

Methods: We conducted a retrospective study of 55 patients with biopsy-proven ANCA-GN. Linear regression models were constructed to determine predictors of eGFR at 1 year. The primary exposure was hematuria (>5 rbc/hpf) duration, defined as <90 days vs. ≥ 90 days following renal biopsy. Covariates included age, gender, ANCA type, baseline eGFR, and baseline proteinuria.

Results: Mean age at diagnosis was 58 years (53% male, 80% Caucasian, 38% PR3-ANCA, and 45% MPO-ANCA). At baseline, all patients had hematuria, 95% had proteinuria, and mean serum creatinine was 3.1 [standard deviation (SD) = 2.3]mg/dL. Overall, 93% were treated with steroids in combination with either cyclophosphamide or rituximab. Mean hematuria duration was 92 (SD = 77) days with 34 (62%) patients having hematuria resolution within 90 days. Older age and lower baseline eGFR were associated with lower eGFR at 1 year (p = 0.03 and p < 0.001, respectively). Hematuria resolution (<90 days vs. ≥ 90 days) was not predictive of eGFR at 1 year (p = 0.93).

Conclusions: In ANCA-GN, hematuria duration does not predict eGFR at 1 year. Our findings provide support that among individuals who are otherwise considered to be in clinical remission, the persistence of hematuria should not delay transition from induction to maintenance immunosuppression.

Keywords: ANCA; Glomerulonephritis; Hematuria; Renal function.

MeSH terms

  • Adult
  • Aged
  • Antibodies, Antineutrophil Cytoplasmic / physiology*
  • Biopsy
  • Female
  • Glomerular Filtration Rate / physiology
  • Glomerulonephritis / physiopathology*
  • Hematuria / complications
  • Hematuria / physiopathology*
  • Humans
  • Kidney / pathology
  • Kidney / physiopathology*
  • Linear Models
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Retrospective Studies
  • Time Factors

Substances

  • Antibodies, Antineutrophil Cytoplasmic