angiotensin blockade improves outcome but our study suggests that there may be a point beyond which further blockade is unsafe and without additional benefit. Acute kidney injury is associated with an increased risk of subsequent progression of chronic kidney disease20; whether the increased risk of acute kidney injury from intensive angiotensin blockade counteracts the beneficial effects with respect to progression and the risk of ESRD is not known. It is possible that the cumulative effect of greater acute kidney injury in the combination