Renal histological picture and steroid treatment in IgA nephropathy

IgA nephropathy (IgAN) progression seems to be negatively influenced by the severity of renal histological picture and positively by steroid treatment. Aim of this study was to evaluate how baseline histological picture can condition the efficacy of steroid treatment. This is the secondary analysis of a prospective, randomised study of 86 IgAN pts, with baseline serum creatinine ீ1.6 mg/dl and proteinuria of 1-3.5 g/24h, who were treated with steroids (T) (oral prednisone 0.5 mg/kg/body weight every other day for 6 months, and 3 i.v. pulses of methilprednisolone 1 g at months 1, 3 and 5) or were controls (C). Histological score was obtained by analyzing: global glomerular sclerosis, focal glomerular sclerosis, crescents, tubular atrophy, interstitial infiltrate, interstitial fibrosis, and vascular sclerosis. A score of 0-3 points was assigned to each lesion. The total score (0-21) was divided in: light (0-7), moderate (8-14) and severe (15-21). Pts distribution among the three classes of score was similar: light score 23 T (53%) and 26 C (60%), moderate 15 T (35%) and 15 C (35%), severe 5 T (12%) and 2 C(5%). At the multivariate Cox regression analysis, renal survival after 7 years was related to the severity of histological score, evaluated as each point increase (P = 0.001, RR = 1.22). After a median FU of 7 years (range 1-13) the doubling of serum creatinine was observed in 1 T and 13 C (RR=0.08), distributed in the score classes as follows: When we added the steroid treatment to multivariate Cox regression analysis, the severity of the histological score was not a significant prognostic variable (P = 0.856, RR = 0.96). In conclusion: 1) in untreated pts the risk of progression was directly correlated with the severity of the baseline histological score, 2) the light histological score did not prevent the possibility of progression 3) in treated pts steroids reduced the risk of progression with whatever baseline histological score, including the severe one.