The difference between patients with nephrotic syndrome and nephrotic-range proteinuria in IgA nephropathy: a propensity score matched cohort study.

OBJECTIVE

To date, nephrotic syndrome (NS) has not been well characterized in patients with IgA nephropathy (IgAN). Whether decline in serum albumin is an ominous sign in IgAN patients with massive proteinuria remains unknown. In this study, we evaluated clinical and pathological features of IgAN with NS and compared the differences for these features and long-term outcomes between patients with nephrotic syndrome and nephrotic-range proteinuria.

METHODS

A retrospective study was conducted, enrolling 1013 patients with biopsy-proven IgAN. The primary endpoint was the composite of a doubling of the base-line serum creatinine, 50% reduction in eGFR, ESKD (eGFR < 15 ml/min per 1.73 m) or death.

RESULTS

A total of 59 patients were presented with NS (5.8%). The patients with NS showed lower levels of hemoglobin, albumin and higher levels of serum creatinine, serum uric acid and urinary protein than patients without NS. As for pathological parameters, more patients with NS showed a higher prevalence of E1 lesions, T1/2 and C1/2 lesions. Furthermore, we used the propensity score matching method to select 57 patients with nephrotic-range proteinuria and normal serum albumin (NR group) who were comparable to 59 patients with NS. Patients with NS had lower levels of hemoglobin, albumin and IgG and higher levels of TC, LDL, FIB and D-dimer as well as more severe E1 and C1/2 lesions than those in NR group. The S1 lesion was more severe in the NR group than that in the NS group. There was no significant difference in long-term outcome between the two groups. In addition, we found that serum albumin level or the presence of hypoalbuminemia was not a risk factor affecting long-term outcome in patients with massive proteinuria.

CONCLUSIONS

A prevalence of 5.8% of NS was presented in IgAN adult patients in our study. IgAN with NS patients had low levels of hemoglobin, albumin, high levels of serum creatinine, serum uric acid, urinary protein and more acute lesions. The prognosis of NS in patients with IgAN was not inferior to that of patients with nephrotic range proteinuria and normal serum albumin.