<qa>  What is the maximum attrition rate for patients?- Impact of potential confounders has been minimised through strict entry criteria and follow-up protocol. A 30 attrition rate has been allowed for in our sample size calculation to accommodate changes in patients clinical status that may account for observed changes in cardiac measurements, such as rapid decline in renal function, MI or death during trial follow-up, pre-emptive kidney transplantation, CaxP product 5mmolL, Hb 10 or 13gm and persistent high office BP 15090mmHg. 