Lipoprotein (a) as a Predictor of Steroid Dependence in Paediatric Steroid Sensitive Nephrotic Syndrome

Abstract

Introduction: Lipoprotein a {Lp(a)} increases in Nephrotic Syndrome (NS). Although the majority of paediatric NS are steroid sensitive, relpase and steroid dependence are commonly seen in this cases. Lp(a) is an LDL-like lipoprotein that consists of an LDL particle to which the glycoprotein apolipoprotein(a) {apo(a)} is attached. Aim: To evaluate the potential of Lp(a), measured on admission, for the prediction of relapse/steroid dependency. Materials and Methods: Children (n=36) with first episode NS were recruited in this prospective observational case-control study and followed up for one year. They were tested at presentation for Lp(a) (mg/dL) and standard tests such as haemoglobin, albumin, protein, cholesterol, triglyceride, and urine protein. Children received standard therapy for NS, and were followed for a period of one year from diagnosis to record days to initial remission, relapse episodes, steroid dependence etc. Patients were categorised as: no relapse (NR), Infrequent Relapse (IFR), frequent relapse (FR) and Steroid Dependent (SD) as per standard definitions. Fifteen healthy volunteers were also tested for lipid profile and Lp(a) levels. Results: Of 36 cases (median age 3 years, 19 males), there were 15NR, 7IFR, 2FR and 12SD. The mean Lp(a) of the NS group (165.2±120.4 mg/dL) was higher than controls (30.52±21.9 mg/dL) (p<0.0001). All the lipid parameters except HDL-cholesterol were significantly higher in the NS group. Within the NS group, Lp(a) showed significant correlation (Spearman-rho) with albumin (p=0.0062,r=0.47), but no correlation with lipid parameters or urine protein. Comparison of Lp(a)levels in the NS groups revealed that the SD patients had a high Lp(a)(222.0±115.7 mg/dL) compared to NR (129.7±120.1 mg/dL) (p=0.02). Conclusion: Concentration of plasma Lp(a) in patients with SDNS was higher compared to patients who did not suffer any relapse, and this concentration may serve as a marker for prediction of SDNS.