IgA nephropathy in patients with spondyloarthritis followed-up at the Rheumatology Service of Hospital das Clinicas/UFMG

Objective: To determine the frequency of glomerulonephritis in patients with spondyloarthritis followed-up at a Brazilian Rheumatology Service, and to evaluate the clinical variables associated. Patients and methods: Patients were assessed for sociodemographic characteristics, type of spondyloarthritis, time since diagnosis and disease activity, non-steroidal anti-inflammatory drug use, HLA-B27 positivity, creatinine and urea serum levels, major comorbidities, hematuria and proteinuria. Patients with hematuria were subsequently assessed for the presence of dysmorphic red blood cells in urine, and those with proteinuria underwent 24-hour urine protein measurement. Renal biopsy was performed in patients with glomerular hematuria and/or proteinuria over 3.5 g/24-hour. Results: Seventy-six patients were assessed. Microscopic hematuria was the most frequently found abnormality in urinalysis (44.7%), usually intermittent and in spot urine samples during patients follow-up. In eight patients (10.5%), glomerular hematuria was suspected. Renal biopsy was performed in five of them, showing IgA nephropathy in four (5.3%) and thin membrane disease in one patient. Conclusions: A high frequency of urinalysis alterations was observed in that subgroup of patients, as well as a high prevalence of IgA nephropathy. Although further studies on this subject are needed to better clarify these results, periodic urinalysis of patients with spondyloarthritis should be recommended.