This study designed as prospective observational study was approved by Institutional ethics committee. Sample size was calculated according to the study – “Triple blockade of RAAS in non-diabetic chronic kidney disease an open label cross over randomized controlled trial” [9]–and was found to be 15 (15 patients in each group). A total of 36 patients diagnosed to have refractory glomerular proteinuria (Resistant to conventional immunosuppressive treatment) in the age group of 5-50years, who were on triple combination therapy with ACE inhibitor, ARB and Aldosterone antagonist with GFR>60ml/mt were enrolled in the study from two different units of Nephrology Dept, Calicut Medical College. The study period was from August 2009 to August 2010. Exclusion criteria were pregnancy, lactation, GFR<60ml/mt and diabetes mellitus. GFR is approximately equal to creatinine clearance and was calculated by applying Cockroft -Gault formula.

According to Nephrology Unit 1 protocol, aliskiren was added to the above mentioned triple combination in patients with refractory proteinuria whereas in Nephrology Unit 2 the triple combination therapy was continued as such. Among the 36 recruited patients, 21 patients received treatment from Nephrology unit 1, and 15 patients from Unit 2. Nephrology unit 1 treatment named as Group A was the combination of following drugs.

The other patients recruited from Nephrology Unit 2 were to continue the triple combination (ACE inhibitor + ARB+ Aldosterone antagonist) and named as Group B [Table/Fig-1].

[Table/Fig-1]:

Flow diagram depicting the prospective observational study of efficacy of aliskiren in those patients with refractory proteinuria who are already on combined ACE inhibitor, ARB and Aldosterone antagonist.

All drugs except aliskiren were provided from the medical college pharmacy. Patients were asked to buy Aliskiren from outside as it was not available in medical college pharmacy. Total duration of treatment was 12 weeks. Informed consent was taken from all recruited patients. Complete history was elicited which covered personal data, duration of illness and other modalities of treatment as mentioned in proforma. Diagnosis was noted down according to the renal biopsy report. Thorough physical examination was done in two groups. Lab tests such as baseline 24hr urine protein (P0), S.Creatinine (C0), and Potassium (K0) were done. Review was done on 2^nd, 4^th, 8^th, 10^th and 12^th week of treatment period. The above mentioned lab tests were repeated during each visit. Safety was assessed by recording all adverse events and patients were instructed to report immediately if any untoward effects occurred. 3 among 21 patients who received treatment with Group A did not complete treatment. Two of them were drop outs during 8^th and 10^th weeks of treatment period. One patient reported 3weeks after starting treatment with increased oedema and hyperkalaemia following which the treatment was stopped. As per Naranjo algorithm the causality relationship of this adverse reaction was assessed as possible. Patients not responding to 12 weeks treatment were continued with non-specific reno protective regimen. (ACE inhibitor /ARB/Aldosterone antagonist).

Results were analysed using SPSS software. Unpaired t-test, Paired t-test and Chi-square test were done for analysis of data. Results were tabulated and significance was expressed according to the p-value<0.05(significant) and < 0.001 (Highly significant).

Baseline parameters such as age, sex, place and laboratory values of both groups A and B were assured to be comparable. Paired t-test was used to assess the difference in proteinuria before starting the treatment and after the completion of treatment. p-value for Group A is 0.009 (<0.05) and is significant whereas that of Group B is 0.174 (>0.05) and is not significant. Mean reduction in proteinuria with Group A is 1.56g with that of Group B is 0.74g. But when unpaired t-test was employed superiority of Group A over Group B was not statistically significant (p-value at 12^th week =0.278>0.05) [Table/Fig-2]. There is no statistically significant difference in S.potassium, S.creatinine values at the end of treatment when both groups are compared indicating that Group A and Group B has equal safety and tolerability profile [Table/Fig-3,4].

[Table/Fig-3]:

Changes in S.Creatinine with Group A and Group B.

X axis – C0 - S.Creatinine before treatment (0 week), C2 – S.Creatinine on 2^nd week, C4 – S. Creatinine on 4^th week, C8 – S.Creatinine on 8^th week, C10 – S.Creatinine on 10^th week, C12 – S.Creatinine on 12^th week

Y axis – S.Creatinine in mg/dl

[Table/Fig-4]:

Changes in S.Potassium with Group A and Group B.

X axis – K0- S.Potassium at before treatment (0 week), K2 – S. Potassium on 2^nd week, K4- S.Potassium on 4^th week, K8 – S.Potassium on 8^th week, K10 – S.Potasssium on 10^th week, K12- S.Potassium on 12^th week

Y axis – S.Potassim values in mEq/L

Proteinuria is a strong risk factor for progression of chronic kidney disease and its reduction improves renal function to a great extent. Hence antiproteinuric treatment offers immense renal protection. Refractory proteinuria is important because it is linked to the development of ESRD. The drugs that block RAAS such as ACE inhibitors, ARB and Aldosterone antagonist are routinely employed as renoprotective agents in refractory proteinuria. But these agents when used as mono therapy/ dual combination therapy [10] cannot cause complete blockade of RAAS and have their own limitations and side effects on its prolonged use. It is better to administer these three drugs together which cause triple blockade of RAAS and offset the problems met with their individual use and hence this triple blockade of RAAS is routinely used in refractory proteinuria. But due to remarkable complexity of RAAS, the triple blockade is not adequate to suppress its activity. The main limitations are [7,8]:

Taking all these mechanisms together DRI offers a more complete inhibition of RAAS. Aliskiren which is a DRI inhibit the rate limiting step in RAAS cascade and block the synthesis of all subsequent components of the cascade. This study assessed the efficacy and safety of complete RAAS blockade with DRI in those patients with refractory proteinuria who are already on ACE inhibitor, ARB and aldosterone antagonist. After statistical analysis it was demonstrated that addition of aliskiren to the combination therapy with ACE inhibitor, ARB and Aldosterone antagonist offers no advantage. But even though there was no statistical significance, mean reduction in proteinuria was more with Aliskiren group (Group A) [Table/Fig-5]. A 24hr urine protein values correlates significantly with GFR decline and progression of chronic renal disease to ESRD [11], whenever proteinuria is decreased by treatment progression, ESRD is reduced. Hence even a slight decrease in urine protein excretion improves renal function to a great extent. Thus Aliskiren+ACE inhibitor+ARB+Aldosterone antagonist combination is clinically superior to ACE inhibitor+ARB+ Aldosterone antagonist combination, with no alteration in safety and tolerability. Comparing with other studies, this study resulted in a moderate reduction (> 50%) in proteinuria [12].

[Table/Fig-5]:

Mean reduction in proteinuria with Group A and Group B.

X axis – P0 – Proteinuria before treatment (0 week), P2 – Proteinuria on 2^nd week, P4 – Proteinuria on 4^th week, P8 – Proteinuria on 8^th week, P10- Proteinuria on 10^th week, P12 – Proteinuria on 12^th week

Y axis – 24hr urine protein values in grams

The reduction in proteinuria was more with Group A compared to Group B. But this difference in 24hr urine protein was not statistically significant. Multicentre studies, bigger sample size and extended duration of treatment are required to reject null hypothesis. Fixed dose of aliskiren was given during the entire treatment period. Dose escalation was not done during the treatment period for better outcome as done in other studies. This is the first study of its kind in which aliskiren was added to the combination of ACE inhibitor + ARB+ Aldosterone antagonist. Based on this study, further studies should be conducted with more patients.

According to this study, addition of Aliskiren to combination therapy with ACE inhibitor+ARB+Aldosterone antagonist is clinically more efficacious than triple combination therapy with ACE inhibitor+ARB+Aldosterone antagonist in refractory proteinuria and the two modes of treatment has almost equal safety profile.