Time series changes in pseudo-R2 values regarding maximum glomerular diameter and the Oxford MEST-C score in patients with IgA nephropathy: A long-term follow-up study

Abstract

There is no effectual pathological factor to predict the long-term renal prognosis of IgA nephropathy. Glomerular hypertrophy plays a crucial role in kidney disease outcomes in both experimental models and humans. This study aimed to 1) confirm the long-term prognostic significance of a maximal glomerular diameter (Max GD) � 242.3 μm, 2) test a renal prognosis prediction model adding Max GD � 242.3 μm to the Oxford classification (MEST-C), and 3) examine the time series changes in the long-term renal prognosis of patients with IgA nephropathy. The study included 43 patients diagnosed with IgA nephropathy from 1993 to 1998 at Kameda General Hospital. Renal prognosis with the endpoint of a 50% reduction in estimated glomerular filtration rate (eGFR) or the development of end-stage renal disease requiring dialysis was examined using logistic regression analysis, Cox regression analysis, and the Kaplan-Meier method. Pathological evaluation was performed using MEST-C and Max GD, and the validity of the prediction model was evaluated. Patients with Max GD � 242.3 μm had significantly poor renal prognosis with multivariate Cox analysis (P = 0.0293). The results of the Kaplan-Meier analysis showed that kidney survival rates in the high-Max GD group were significantly lower than those in the low-Max GD group (log rank, P = 0.0043), which was confirmed in propensity score-matched models (log rank, P = 0.0426). Adding Max GD � 242.3 μm to MEST-C improved diagnostic power of the renal prognosis prediction model by renal pathology tissue examination (R 2 : 3.3 to 14.5%, AICc: 71.8 to 68.0, C statistic: 0.657 to 0.772). We confirm that glomerular hypertrophy is useful as a long-term renal prognostic factor.

Visceral to subcutaneous fat ratio as an indicator of a ≥30% eGFR decline in chronic kidney disease

“…Furthermore, considering that multifaceted and comprehensive judgments based on abundant medical information are required in the treatment of patients in real clinical settings, there is merit in evaluating various cut-off values in various sub-cohorts, at various follow-up periods, for prognostic factors of importance. In fact, the adequate cut-off value for a risk factor depends on the handling of the risk factor [38][39][40], the cohort evaluated [38,39,41,42], and the observation period [19,21]. Fat distribution generally differs between the sexes; men have relatively more visceral fat and women have relatively more subcutaneous fat.…”

“…However, until recently, time-series changes in the prognostic ability of prognostic factors have not received much attention. We recently decided to evaluate the time-series changes in pseudo-R 2 values in our clinical studies, based on the fact that the prognostic abilities of risk factors vary with time [19,21]. The most significant contribution of the pseudo-R 2 values for the renal outcome is the ability to distinguish between short-term and long-term prognostic power.…”

“…Increased production of proinflammatory adipokines is involved in the pathogenesis of CKD, causing oxidative stress, inflammation, endothelial dysfunction, hyperfiltration, activation of the sympathetic and renin-angiotensin systems in the kidneys, and insulin resistance [9][10][11][12][13][14]. Histological glomerular hypertrophy [15][16][17][18][19][20][21][22], which represents glomerular inflammation and glomerular hyperfiltration, is recognized as an early marker of obesity-related or metabolic kidney damage [22][23][24][25][26]. However, to our knowledge, there is no report clearly demonstrating an association between the V/S ratio and renal prognosis in patients with CKD.…”

“…Furthermore, considering that cut-off values are needed to guide clinical decision-making [27], research evaluating the appropriate cut-off values for various sub-cohorts is desired. We believe that an analysis of the time-series changes in pseudo-R 2 values [19,21] is suitable in the context of these considerations. Variables that maintain a high pseudo-R 2 value during followup or show an increasing pattern in pseudo-R 2 values over time are considered useful as medium-term and long-term prognostic factors [19].…”

Sex Differences in Time-Series Changes in Pseudo-R2 Values Regarding Hyperuricemia in Relation to the Kidney Prognosis

“…Finally, considering that cutoff values are needed to guide the clinician in decision-making [ 30 ], research evaluating the appropriate cutoff values for various sub-cohorts is desired. We believe that an analysis of the time-series changes in pseudo- R 2 values [ 31 , 32 ] is suitable in the context of these considerations. Furthermore, we hypothesized that the kidney pathophysiology of hyperuricemia differs between male and female patients with CKD.…”