Evaluation of Serum Lipoprotein (a) Levels and Novel Lipid Indices in Patients with Chronic Kidney DiseaseA Case-control Study

Introduction: Majority of Chronic Kidney Disease (CKD) patients are more likely to die of cardiovascular complications, before reaching End Stage Renal Disease (ESRD). Although there are many risk factors contributing to pathogenesis of cardiovascular disease in CKD subjects, dyslipidemia represents one of the modifiable risk factors. American Heart Association has recommended that CKD patients should be classified in the highest risk group for developing cardiovascular events. Kidney Disease: Improving Global Outcome (KDIGO) recommends, these patients should be evaluated for dyslipidemia and for treatment to reduce the risk of cardiovascular events.

Aim: To evaluate serum Lipoprotein (a) {Lp(a)} levels and assess the significance of novel lipid indices in non dialysis patients of CKD.

Materials and Methods: This analytical case-control study was conducted from January 2016 to June 2016 at Government Stanley Medical College and Hospital, Chennai, Tamil Nadu, India. It included 70 non dialysis CKD subjects and 70 healthy control subjects, adhering to inclusion and exclusion criteria. Fasting Blood Samples (FBS) were collected and analysed for: Fasting blood glucose, Fasting Lipid Profile, Serum Lp(a). Serum Lp(a) was estimated by immunoturbidimetry method and lipid profile by enzymatic method. Estimated Glomerular Filtration Rate (eGFR) was calculated using Modification of Diet in Renal Disease (MDRD) formula and staging of CKD subjects was done, based on KDIGO guidelines. Novel lipid indices were calculated using appropriate formula. Statistical analysis of the tabulated data was done using Social Sciences of the Statistical Package (SPSS) software.

Results: There were significant differences in the levels of FBS, Triglycerides (TG), Lp(a) between controls and non dialysis CKD subjects (p<0.001). Among Lipid Indices, Atherogenic Index of Plasma (AIP) and Lipid Tetrad Index (LTI) values were significantly higher in CKD subjects compared to controls (p<0.001), but no significant difference was seen in Atherogenic Coefficient (AC), Castelli’s Risk Index-I (CRI-I) and CRI-II values. AIP and LTI showed significant positive correlation with Lp(a). LTI had the highest Positive Predictive Value (PPV) (77.8%) and Negative Predictive Value (NPV) (72.7%); AIP had PPV of 65.3% and NPV of 66.2%.

Conclusion: The present study concludes that, among lipid indices, AIP and LTI are the most suitable for assessment of atherogenicity in non dialysis CKD. In developing countries like India, owing to high cost of tests like Serum Lp(a), novel lipid index AIP can serve as a cost-effective screening tool for monitoring cardiovascular disease risk in CKD patients.