R.S.LIM1, S.M.GOH1, S.C.YEO1
Tan Tock Seng Hospital1
The risk of progressive kidney function decline in IgA Nephropathy (IgAN) is heterogeneous, a reliable risk prediction model is important for the guidance of renal prognosis and clinical management. We aim to externally validate the new International IgAN prediction tool, consist of 2 full models (with or without race) in our Singapore IgAN cohort.
By using external validation of survival prediction models (Royston and Altman), the model fit, discrimination, and calibration of the models were assessed using Akaike Information Criterion (AIC), R2D measure, C statistics, and calibration plot.
We included 119 patients; mean age 43.3 (± 16.66) years; 62 (52.1%) male; 90 (75.6%) Chinese, 12 (10.1%) Malay, 7 (5.9%) Indian and 10 (8.4%) other ethnicity. Complete case analysis was done with 93 patients. The 5-year risk of the primary outcome (50% reduction in estimated glomerular filtration rate or End Stage Kidney Disease) was 14.3% (95% CI, 8.5%-22.2%). We removed Oxford T2 histologic score from the full model analysis due to the low number of observations (n=2). The AIC were 107.35 and 111.90 for full models with and without race respectively. The R2D for the full models with and without race when applied to our validation cohort were 39% and 32% respectively. The C statistics for the full model with race was 0.858 (95% CI, 0.687-1.000), without race was 0.811 (95% CI, 0.599-1.000).
Both full models showed good discrimination, calibration and were proven to be validated in our multi-ethnic Singapore IgAN cohort for predicting disease progression.