Onuigbo MAC et al. - Contrary to previous retrospective reports, we observed that renal failure/ESRD in this older CKD patient population is common in patients with unilateral RAS lesions with dual kidneys; precipitating risk factors are often absent, and progression to ESRD with increased mortality is not infrequent. Older age, higher baseline creatinine (>2.0) and/or lower eGFR (<35) predicted ESRD. eGFR improved following discontinuation of RAAS blockade, generally.