Background Renal involvement is one of the main prognostic factor of systemic lupus erythematosus (SLE) through chronic kidney disease (CKD) development. It was shown, that hyperfiltration is the one of the main insult of CKD progression and in SLE plays a part like a immune activity. Hyperfiltration may be detected by determination of decreased renal function reserve (RFR) in earliest stages of CKD; hypertension and proteinuria act together decreasing RFR.
Objectives The goal of the study is evaluation of renal function reserve in patients with SLE and to study the role of hypertension and proteinuria in RFR of SLE patients
Methods 30 SLE patients (3 men and 30 women) has been examined, without of CKD criteria's. Patients were 34,3±12,8 yeas old with disease duration 77,6±75,6 month. Disease activity was determined by SLEDAI was 11,0±4,5 points. 19 patients had arterial hypertension. Renal functional reserve was evaluated in the acute pharmacological test with dopamine. We studied the level of creatinine in blood and in urine before and after the test and the volume of urine an hour before and after the test. Glomerular filtration rate (GFR) was also calculated. RFR was evaluated as the difference between the original and stimulated GFR and regarded as normal if it was more or equal to 15% and decreased – less than 15% and negative quantities. Comparison group included 40 healthy people matched according to age and sex.
Results All healthy volunteers has had normal RFR, 41,4±25.5%. In SLE patients we found significantly decreased level RFR – 8,1±53,8%, p=0,001. Normal RFR was determined in 18 patients, in 15 SLE patients RFR was decreased (54,2±28,9 vs -37,9±28,1%). The groups were found to have significantly different level of disease activity (SLEDAI 8,69±3,24 vs 13,38±4,66), hypertension and proteinuria level has not been different (1,50±2,85 g/24h vs 1,30±1,47 g/24h). Level of RFR inversely correlate with disease activity; correlation is more significant in patients with normal RFR (p=0,001). In patients with decreased RFR hypertension level and it's fact correlates significantly with RFR data's. Normal RFR group showed significant correlation with proteinuria level.
Conclusions In SLE patients without CKD showed high frequency of decreased RFR. Disease activity is main determinative factor of RFR level in SLE patients without CKD and preserved RFR. Arterial hypertension plays the main role in CKD progression in the case of decreased RFR.
Disclosure of Interest None declared