Mesangial glomerulopathy in rheumatoid arthritis patients. Clinical follow-up and relation to antirheumatic therapy

23 patients (16 women, 7 men) with rheumatoid arthritis (RA) and renal biopsy-proven mesangial glomerulopathy (MGP) were followed for 4-117 months (median 42) in order to evaluate the clinical course of their renal disease. Urinalysis was made, and 24-hour urine protein excretion and serum creatinine were determined. At the time of renal biopsy, the clinical renal findings of the patients were isolated hematuria (n = 10), isolated proteinuria (n = 6) and hematuria combined with proteinuria (n = 7). Hematuria persisted and renal function remained normal in all patients with isolated hematuria. A possible association between the presence of hematuria and the use of antirheumatic drugs was not established in this study. Proteinuria was clinically closely associated with the use of antirheumatic drugs in 9 out of 13 cases (6 with gold sodium thiomalate, 2 with D-penicillamine and 1 with auranofin) suggesting that antirheumatic drugs are important contributors to proteinuria in these patients. Renal function, although initially reduced in some patients, remained stable in all but 1 patient with IgA glomerulonephritis who developed the nephrotic syndrome and died of uremia. In conclusion, the clinical course of MGP in RA patients is benign in most patients. Moreover, this nephropathy may not represent a clinical entity. Proteinuria was related to antirheumatic drugs in most patients whereas microhematuria was constant even after stopping the antirheumatic drugs.