A retrospective analysis of antineutrophil cytoplasmic antibody-associated vasculitis aiming for an equation prediction end-stage renal disease

We provided a predictable method that measures the risk of progression to end-stage renal disease (ESRD) in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) by using a few routine serum markers of kidney functions at diagnosis. In a retrospective cohort study, the medical records of 254 AAV patients were reviewed. We derived a novel equation for the prediction of the progression to ESRD using variables with a P-value < 0.1 in the multivariable Cox hazard model analysis. We assigned a weight to each variable according to the slopes like a coefficient of a linear equation. The median age of the AAV patients was 59 years and 42 AAV patients progressed to ESRD. In the multivariable Cox analysis using variables with significance in the univariable analysis, MPO-ANCA (or P-ANCA) positivity, blood urea nitrogen, serum creatinine, and serum albumin tended to be associated with the progression to ESRD (P-value < 0.1). We develop an Equation for predicting ESRD in AAV (EPEA) using those variables with the slope of each one. When the cut-off of EPEA was set as −0.094, AAV patients with EPEA ≥ −0.094 had a significantly higher risk of progression to ESRD than those with EPEA < −0.094 (RR, 39.622). AAV patients with EPEA ≥ −0.094 exhibited a significantly lower ESRD-free survival rate than those with EPEA < −0.094. We provided a method to obtain EPEA and demonstrated its predictive potential for ESRD in immunosuppressive drug-naïve AAV patients.Key points• A novel equation for the prediction of the progression to ESRD was developed using variables with a P-value < 0.1 in the multivariable Cox hazard model analysis. A weight was assigned to each variable according to the slopes like a coefficient of a linear equation.• An optimal cut-off of EPEA for progression to ESRD was obtained using the receiver operator characteristic (ROC) curve analysis.• AAV patients with EPEA more than the cut-off had a significantly higher risk of progression to ESRD than those without (RR, 39.622).• AAV patients with EPEA more than the cut-off exhibited a significantly lower ESRD-free survival rate than those without.