evidence base. To examine how the new evidence may influence guideline updates, KDIGO convened a multidisciplinary Controversies Conference titled Blood Pressure in CKD in Edinburgh, Scotland in September 2017. Here, we summarize the points of consensus and controversy and identify knowledge gaps and research priorities. The conference agenda, discussion questions, and plenary session presentations are available at http://kdigo. org/conferences/controversies-conference-on-blood-pressure. BLOOD PRESSURE MEASUREMENT A major emphasis during the conference was on BP measurement methods. BP can differ widely depending on measurement setting (e.g., office or home) and the type of device used (e.g., manual or oscillometric sphygmomanometer). 5,6 Proper preparation prior to BP measurement is important (Table 1). Conference discussions focused primarily on the following 3 types of office-based BP measurements: (i) routine, or casual, office, which is conducted without following the recommended preparatory processes outlined in Table 1; (ii) standardized office, Correspondence: Alfred K. Cheung, Division of Nephrology and Hypertension, 295 Chipeta Way, Room 4000, Salt Lake City, UT 84108, USA. E-mail: alfred.cheung@hsc.utah.edu or Johannes F.E. Mann, KfH Kidney Center, 15 Isoldenstrasse, Munich 80804, Germany. E-mail: prof.j.mann@gmail.com 20See Appendix for list of other Conference Participants. Received 27 September 2018; revised 30 November 2018; accepted 6 December 2018 www.kidney-international.org KDIGO executive conclusions Kidney International (2019) 95, 1027–1036 1027 which adheres to these processes but is performed with a manual technique; and (iii) automated oscillometric office, which includes a 5-minute rest followed by a series of 2 to 3 BP measurements that are averaged, as described, for example, in the SPRINT protocol.12 Two types of out-of-office BP measurements were discussed: (i) home automated oscillometric, and (ii) 24-hour ambulatory. Pulse wave velocity and central aortic BP measurements were felt to be outside the scope of the conference. Non-cuff-based BP measurements are not sufficiently validated to guide practice13 and were not discussed. Comparisons of different types of BP measurements Casual office BP is generally 5–10 mm Hg higher than both standardized office and automated oscillometric office BP,14,15 whereas standardized office BP measurements are generally similar to those of automated oscillometric office BP.14 Casual office BP is often higher than awake ambulatory BP; in contrast, standardized office BP may be lower than awake ambulatory BP.14 In a subset of participants in the intensive treatment arm of the SPRINT study, mean automated office systolic blood pressure (SBP) was 119 mm Hg, whereas mean awake ambulatory SBP was 126 mm Hg.16 The differences in BP obtained using different types of measurements in CKD appear similar to those in the general population, but the available data are limited.6 The differences between methods as discussed are population means; in the individuals, those differences may vary drastically. Therefore, establishing conversion factors to translate a casual BP value into a standardized BP value is difficult. Out-of-office BP measurements Out-of-office BP measurement is required to diagnose white-coat hypertension (elevated office BP with controlled out-of-office BP) and masked hypertension (controlled office BP with elevated outof-office BP; Figure 1). The prevalence of white-coat hypertension in patients with CKD from several countries ranges from 2% to 41%,5,18–24 and the prevalence of masked hypertension ranges from 6% to 51%.5,18,19,21–25 Ambulatory BP provides important information on nocturnal BP. Patients with CKD are more likely to have an absence or even a reversal of normal nocturnal dipping, with prevalence ranging from 14% to 75%,18,20-22,26–34 which appears to increase with decreasing kidney function.31 In CKD, out-of-office BP may better predict kidney disease progression and cardiovascular events than office BP.18,20,23,24,27,35–50 Nocturnal BP can be treated specifically but whether this strategy improves clinical outcomes is unclear. In an 8-week, uncontrolled study of 32 nondipping patients with CKD, shifting 1 antihypertensive drug from morning to evening restored normal nocturnal dipping in 88% of patients.51 However, this study has yet to be replicated in a larger cohort with longer follow-up. No adequately-powered randomized controlled trials (RCTs) of BP control on clinical outcomes have targeted ambulatory or home BP in the CKD or general adult population. The sample size needed and the complexity of such a trial52 raise questions about its feasibility. In addition, in many regions of the world, home BP or ambulatory BP monitoring are impractical. Other BP variabilities Orthostatic hypotension is usually defined as a decrease in SBP of at least 20 mm Hg or a decrease in diastolic BP (DBP) of at least 10 mm Hg within 3 minutes of standing up.53 Orthostatic hypertension is usually defined as a rise in SBP of at least 20 mm Hg when standing. Estimates based on SPRINT study data indicate that among older, hypertensive patients, 5% have orthostatic hypotension and 5% have orthostatic hypertension.54 Both