In myeloperoxidase-positive patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) linked to glomerulonephritis, use of a nomogram was shown to improve the accuracy of renal survival prediction.
A retrospective cohort study was conducted among patients with AAV who were admitted to the First Affiliated Hospital of Zhejiang University Hospital of Medicine in Zhejiang, China, from February 2004 through December 2020. Results of the study were published in The Journal of Rheumatology.
AAV, which is considered a systemic vasculitis, includes granulomatosis with polyangiitis, microscopic polyangiitis, and eosinophilic granulomatosis with polyangiitis. In individuals with AAV, renal involvement usually presents with rapidly progressive glomerulonephritis, which is also known as ANCA-associated glomerulonephritis (AAGN). Patients with severe AAGN often have a poor prognosis.
The researchers of the current study sought to validate and modify the renal risk score for AAGN in a Chinese cohort of patients in which a majority of the individuals had been diagnosed with myeloperoxidase-ANCA glomerulonephritis.
Read more about AAV
Study inclusion criteria were 1) newly diagnosed, previously untreated AAV, based on Chapel Hill Conference criteria and 2) renal involvement confirmed on a renal biopsy.
Two hundred eighty-five individuals with AAV were enrolled in the study. The average patient age was 59.3±12.5 years. For construction and validation of the nomogram, all participants were randomly assigned to 1 of 2 sets: the development set (n=201) or the validation set (n=84). Clinical and laboratory parameters were examined, renal histopathology was performed, and a renal risk score was calculated.
Results of the study revealed that over a median follow-up of 41.3 months (range, 20.0-63.8 months), 17.5% (50 of 285) of participants died and 29.5% (84 of 285) of patients reached end-stage renal disease.
Read more about AAV prognosis
In the development set, independent risk factors for end-stage renal disease, which were included in the nomogram, were as follows:
- Hypertension: hazard ratio (HR), 2.16; 95% CI, 1.08 to 4.32; P =.03
- High serum creatinine: HR, 1.002; 95% CI, 1.001 to 1.003; P <.001
- High daily urinary protein: HR, 1.34; 95% CI, 1.15 to 1.57; P <.001
- High glomerular sclerosis: HR, 13.98; 95% CI, 3.50 to 55.92; P <.001
- Interstitial fibrosis >50%: HR, 4.18; 95% CI, 1.90 to 9.19; P <.001
The C-indices of the nomogram model, which were higher than those of the renal risk score model, are indicated below:
- Development set (n=201): 0.838 (range, 0.785-0.891)
- Validation set (n=84): 0.794 (range, 0.774-0.814)
- All-data set (N=285): 0.822 (range, 0.775-0.869)
The C-indices of the renal risk score model were as follows:
- Development set (n=201): 0.801 (range, 0.748-0.854)
- Validation set (n=84): 0.746 (range, 0.654-0.838)
- All-data set (N=285): 0.783 (range, 0.736-0.830)
“The net reclassification improvement and the integrated discrimination improvement further illustrated the higher predictive ability of the nomogram,” the researchers highlighted. “We present the nomogram as a practical tool to predict renal outcomes in Chinese patients with MPO-ANCA glomerulonephritis,” they concluded.
Ni A, Chen L, Lan L, et al. Validation of the antineutrophil cytoplasmic antibody renal risk score and modification of the score in a Chinese cohort with a majority of myeloperoxidase-positive patients. J Rheumatol. Published online May 1, 2023. doi:10.3899/jrheum.220818