Influence of antiphospholipid antibody positivity on glomerular filtration rate markers in a group of systemic sclerosis patients – a 24-month observation

AIM OF THE STUDY The aim of the study was the assessment of changes in the glomerular filtration rate (GFR) during long-term observation in a group of systemic sclerosis (SSc) patients with and without chronic antiphospholipid (aPL) antibody positivity. MATERIAL AND METHODS The observation comprised 50 patients - 23 with diffuse cutaneous SSc - dcSSc and 27 limited cutaneous SSc - lcSSc. After 24 months we assessed 27 patients (9 died, 14 lost follow up); 24 patients (88%) were treated chronically with angiotensin-converting-enzyme inhibitors (ACEIs). Patients were investigated for the presence of aPL: to cardiolipin and to β2 glycoprotein I in IgM and IgG classes. Serum levels of creatinine (S-Cr), cystatin C and creatinine clearance values were determined in all patients. According to the presence of a significant level of at least one of aPL antibodies, pts were divided into groups: group I aPL positive: 14 patients, group II aPL negative - 13 patients. RESULTS We did not find significant differences in S-Cr, cystatin C levels and creatinine clearance before and after 24 months of observation between both groups. In follow up observations, the presence of anti-centromere antibodies was significantly more frequent in the aPL positive, as compared to the aPL negative group (p = 0.01). In follow up observations, the level of anticardiolipin antibodies in IgG class was significantly higher in dcSSc compared to lcSSc patients (p = 0.02). CONCLUSIONS In long-term observation chronic positivity for aPL antibodies does not significantly decrease the GFR in patients with SSc treated with ACEIs.