Long-term follow-up of IgA nephropathy: clinicopathological features and predictors of outcomes

Abstract

Background The establishment of the Oxford classification and newly developed prediction models have improved the prognostic information for immunoglobulin A (IgA) nephropathy. Considering new treatment options, optimizing prognostic information, and improving existing prediction models are favorable. Methods We used random forest survival analysis to select possible predictors of end-stage kidney disease among 37 candidate variables in a cohort of 232 patients with biopsy-proven IgA nephropathy retrieved from the Norwegian Kidney Biopsy Registry. The predictive value of variables with relative importance > 5% was assessed using concordance statistics and the Akaike information criterion. Pearson's correlation coefficient was used to identify correlations between the selected variables. Results The median follow-up period was 13.7 years. An isolated analysis of histological variables identified six variables with relative importance > 5%: T %, segmental glomerular sclerosis without characteristics associated with other subtypes (NOS), normal glomeruli, global sclerotic glomeruli, segmental adherence, and perihilar glomerular sclerosis. When histopathological and clinical variables were combined, estimated glomerular filtration rate (eGFR), proteinuria, and serum albumin were added to the list. T % showed a better prognostic value than tubular atrophy/interstitial fibrosis (T) lesions with C-indices at 0.74 and 0.67 and was highly correlated with eGFR. Analysis of the subtypes of segmental glomerulosclerosis (S) lesions revealed that NOS and perihilar glomerular sclerosis were associated with adverse outcomes. Conclusions Reporting T lesions as a continuous variable, normal glomeruli, and subtypes of S lesions could provide clinicians with additional prognostic information and contribute to the improved performance of the Oxford classification and prognostic tools.

Machine learning-based diagnosis and prognosis of IgAN: A systematic review and meta-analysis

“…After excluding papers with irrelevant topics, 1 studies [ 27 ] with fewer than 50 cases, 6 [ 9 , 15 , 18 , 24 , 28 , 29 ] with insufficient statistics, and 5 [ [30] , [31] , [32] , [33] , [34] ] reported in Child were excluded according to a full-text review, the remaining 47 [ 7 , 14 , [20] , [21] , [22] , [23] , [35] , [36] , [37] , [38] , [39] , [40] , [41] , [42] , [43] , [44] , [45] , [46] , [47] , [48] , [49] , [50] , [51] , [52] , [53] , [54] , [55] , [56] , [57] , [58] , [59] , [60] , [61] , [62] , [63] , [64] , [65] , [66] , [67] , [68] , [69] , [70] , [71] , [72] , [73] , [74] , [75] ] studies were eligible for meta-analysis. Of the 47 eligible studies, 12 and 27 [ 7 , 14 , [20] , [21] , [22] ...…”

“…2 ). It's worth noting that three studies [ 20 , 21 , 53 ] introduced new pathological variables (tubular necrosis and arteriole lesion) into modeling. Six studies [ 47 , 51 , 70 , [76] , [77] , [78] ] of them added additional variables after the introduction of IIgAN-RPT, and the study [ 51 ] that included urine biomarkers and serum Gd-IgA1 achieved the highest NRI (0.82 [0.50–1.14]).…”

“…To this end, efforts have been made to develop models to predict the time to ESRD [ [16] , [17] , [18] , [19] ]. Moreover, to deal with the difficulty of limited long-term follow-up, long-term risk prediction models have also received attention [ 20 , 21 ].…”

Mortality in IgA Nephropathy: A Long-Term Follow-Up of an Eastern European Cohort

“…Few studies specifically focus on mortality as a separate endpoint in IgAN (Table 3), often combining it with ESKD in a composite endpoint and not detailing each event individually [32,33]. Addressing vital survival separately is crucial, particularly given IgAN's impact on a younger demographic and its significant social and economic effects [34].…”