Henoch-Schonlein purpura nephritis: initial risk factors and outcomes in a Latin American tertiary center

The objective of this study was to evaluate prevalence, initial risk factors, and outcomes in Henoch-Schonlein purpura nephritis (HSPN) patients in Latin America. Two hundred ninety-six patients (validated EULAR/PRINTO/PRES HSP criteria) were assessed by demographic data, clinical/laboratorial involvements, and treatments in the first 3 months after diagnosis. They were followed-up in a Latin American tertiary center and were divided in two groups: with and without nephritis. Persistent non-nephrotic proteinuria, nephrotic proteinuria, and acute/chronic kidney injury were also systematically evaluated at 1, 5, 10, and 15 years after diagnosis. HSPN was evidenced in 139/296 (47%) in the first 3 months. The median age at diagnosis was significantly higher in HSPN patients compared without renal involvement [6.6 (1.5-17.7) vs. 5.7 (0.9-13.5) years, p = 0.022]. The frequencies of persistent purpura (31 vs. 10%, p < 0.0001), recurrent abdominal pain (16 vs. 7%, p = 0.011), gastrointestinal bleeding (25 vs. 10%, p < 0.0001), and corticosteroid use (54 vs. 41%, p = 0.023) were significantly higher in the former group. Logistic regression demonstrated that the independent variables associated with HSNP were persistent purpura (OR = 3.601; 95% CI (1.605-8.079); p = 0.002) and gastrointestinal bleeding (OR = 2.991; 95% CI (1.245-7.183); p = 0.014). Further analysis of patients without HSPN in the first 3 months revealed that 29/118 (25%) had persistent non-nephrotic proteinuria and/or hematuria in 1 year, 19/61 (31%) in 5 years, 6/17 (35%) in 10 years and 4/6 (67%) in 15 years after diagnosis. None of them had chronic kidney injury or were submitted to renal replacement therapy. The present study observed HSPN in almost one half of patients in the first months of disease, and HSPN was associated with persistent purpura and gastrointestinal bleeding. One fourth of patients had nephritis only evidenced during follow-up without severe renal manifestations.