<prompt> Most common predisposing factor for chronic pyelonephritis is:Diabetes mellitusRenal stonePosterior urethral valveVesicoureteric reflux  <response>: Chronic pyelonephritis is so often associated with vesicoureteric reflux that some feel that it is better named Reflux nephropathy. It is impoant cause of renal damage and death from end - stage renal failure. 