In one study, a J-shaped relationship between stroke and systolic BP was observed, with lowest stroke risk in the range of systolic BP between 120 and 129 mm Hg, and higher risk above and below this.158 A cohort study of 860 US veterans (comprising mainly men) with CKD (GFR o60 and a subset with GFR o30 ml/min/ ) showed greater mortality when systolic BP was o133 mm Hg or diastolic BP o65 mm Hg, although it appeared that the association might not be causal but instead related to atherosclerotic CVD as a co-morbidity.413 In summary, with respect to a lowest BP target, most of the relevant evidence is observational, derived from retro- spective analyses, and nearly all involves non-CKD popula- tions. No studies to date have specifically tested a strategy of reducing blood-pressure-lowering drug treatment if the BP falls below a certain limit. We anticipate that there would be major practical difficulties in implementing such a practice, particularly in patients with reduced conduit artery com- pliance and consequent increased pulse pressure (in whom a lower limit for diastolic BP might entail accepting an systolic BP much higher than the current targets). Although the available evidence is enough to support our guideline statements advising caution in those with co-morbidity, we do not consider it is robust enough to allow us to specify a lower limit for either systolic BP or diastolic BP, even though other organizations have done so.396 Although inferences can be drawn when treatment-related BP is too low, especially in patients with diabetes, the elderly and those with CVD, we are left without a lowest BP target. The NIH funded SPRINT trial currently recruiting patients in the US may clarify this issue. 