Association of biochemical markers as predictors of nephrotic syndrome in patients with nephrotic syndrome and healthy children A case control Study

Introduction:

Nephrotic syndrome (NS) is the most common glomerulopathy in children between 2-18 years and  is a major contributing factor to the development of Chronic kidney disease(1,2,3).It is characterized by edema, heavy proteinuria (>1 g/m2 daily; >40 mg/m2/hr) and hypoalbuminemia (serum albumin <3 g/dL)(4,5) .The incidence ranges from 1.2 to 16.9 per 100,000 children annually(4,5).It is usually primary or idiopathic and may be associated with an underlying systemic illness in 5-10% of patients. There is a epidemiological evidence of higher incidence of nephrotic syndrome in children from South Asia (6).

Minimal change nephrotic syndrome (MCNS) accounts for 80% cases of nephrotic syndrome in children. Steroid sensitivity nephrotic syndrome is was usually MCNS (7). More than 90% of childhood nephrotic syndrome is primary (idiopathic).Other causes such as amyloidosis, vasculitis, systemic lupus erythematosus, post- infectious glomerulonephritis and hepatitis B nephopathy.GN and hepatitis nephropathy are infrequent(7). About 80% children with idiopathic nephrotic syndrome show remission of proteinuria following treatment with corticosteroids and are classified as ‘steroid sensitive’. Most patients have multiple relapses, placing them at risk for steroid toxicity, systemic infections and other complications. A small proportion of patients who are not steroid sensitive (steroid resistant) are also at risk for similar complications and renal insufficiency.(8,9).Frequent exacerbations  of  nephrotic syndrome in children can lead to end-stage renal disease, which usually necessitates transplantation of kidneys and/or weekly dialysis treatments  leading to outcomes that are associated with significant health, social, familial and financial burdens.(10).

 Blood protein leakage especially albumin into the urine  is the hallmark of NS.Damage to the glomerular basement membrane meshwork is the commom change which leads to the leakage of proteins from blood (11) Plasma proteins larger than 70 Kilo Dalton (kd) are known to be blocked from crossing the glomerular basement membrane in healthy kidneys by a charge- and size-selective barrier (8-10.Low molecular weight proteins may also be  markedly increased in urine albumin in nephrotic syndrome(12,13,14). This may potentially result in cardiovascular complications including coagulopathy .Because of increased excretion of albumin, liver produces more protein vital to upkeep of oncotic pressure. Theses  proteins include alpha 1- macro globulin and beta-lipoproteins. Despite the different causes of nephrotic syndrome, research reporting on proteinuria and oncotic pressure has a biased focus on albumin(10). The   significance of theses additional protein in nephrotic syndrome has not yet been fully studied especially in Indian setting  which could potentially have implications for clinical management of nephrotic syndrome . Therefore the study is planned to find out the association of biochemical markers in predicting the development of NS by identifying the variations in the biochemical markers in patients with steroid sensitive nephrotic syndrome and healthy children.

Primary objective:

To find out the association of biochemical markers in predicting the development of NS by identifying the variations in the biochemical markers in patients with nephrotic syndrome and healthy children

Secondary Objectives:

1.      To identify the variations in biochemical markers namely albumin and/or non albumin proteins in patients with nephrotic syndrome and healthy children .

2.      To determine oncotic pressure in patients with nephrotic syndrome and healthy children based on the biochemical markers

1.1 Source of Data: Children with nephrotic syndrome between the age 1-18 years coming to Paediatric nephrology OPD, Paediatric OPD and wards in

Dr.Prabhakar Kore Hospital and Medical Research Centre,Nehru Nagar, Belagavi during the study period.

Study Design: A case -control study

Study Period: 1 year

Sample size: 40 IN EACH GROUP

SAMPLING METHOD:

After obtaining ethical clearance, a observational case-control study will be conducted in  children who fulfil the eligibility criteria. Informed consent will be obtained before enrolling in the study. The participants will be divided into 2 groups as Cases and controls.

At enrolment a routine medical examination will be conducted and the socio demographic, clinical and anthropometric parameters will be collected and recorded in a pretested questionnnaire by the investigator. .To determine the BMI formula weight/height squared will be used.

Sampling- A 6ml venous sample will be  taken from each participant while taking the necessary precautions to prevent hemolysis. At 7 am in the morning, 2ml of each blood sample will be taken in an EDTA tube and 4ml in a tube containing gel separator for processing. After the sample in gel separator coagulates. It is centrifuged at three thousand revolutions per minute for 10minutes to obtain the sera. The concentration of  urea, creatinine, calcium,albumin and non-albumin fractions (alpha 1, alpha 2, beta 1, beta 2, C-reactive protein, transferrin, M-component and gamma globulin) were measured using the sera.The various proteins are determined by capillary electrophoresis.

The oncotic pressure is calculated using the formula COPpl= alpha (2.8c+0.18c2+0.012c3) +beta (0.9c+0.12c2+0.004c3) where alpha=albumin,beta=globulin and c= total protein.(23)