BACKGROUND: Previous studies have examined control rates of office blood pressure (BP) in chronic kidney disease (CKD). However, recent evidence suggests major discrepancies between office and 24-hour BP values in hypertensive populations. This study examined concordance/discordance between office- and ambulatory-based BP control in a large cohort of patients with CKD.STUDY DESIGN: Cross-sectional.SETTING & PARTICIPANTS: 5,693 hypertensive individuals with CKD stages 1-5 from the Spanish ABPM (ambulatory BP monitoring) Registry.PREDICTORS: Thresholds of 140/90 and 130/80 mm Hg for office BP and 24-hour ambulatory BP, respectively. Age, sex, body mass index, waist circumference, hypertension duration, kidney measures, diabetes, dyslipidemia, target-organ damage, and cardiovascular comorbid conditions.OUTCOMES: Misclassification of BP control as "white-coat" hypertension (office BP ≥140/90 mm Hg, 24-hour BP <130/80 mm Hg) or masked hypertension (office BP <140/90 mm Hg, 24-hour BP ≥130/80 mm Hg).MEASUREMENTS: Standardized office-based BP and 24-hour ABPM.RESULTS: Mean age was 61.0 ± 13.9 (SD) years and 52.6% were men. The proportion with white-coat hypertension was 28.8% (36.8% of patients with office BP ≥140/90 mm Hg) and that of masked hypertension was 7.0% (but 32.1% of patients with office BP <140/90 mm Hg). Female sex, aging, obesity, and target-organ damage were associated with white-coat hypertension; aging and obesity were associated with masked hypertension. Only 21.7% and 8.1% of the CKD population had office BP <140/90 and <130/80 mm Hg, respectively. In contrast, 43.5% of individuals had average 24-hour BP <130/80 mm Hg.LIMITATIONS: Cross-sectional design, longitudinal associations cannot be established.CONCLUSIONS: Misclassification of BP control at the office was observed in 1 of 3 hypertensive patients with CKD. Ambulatory-based control rates were far better than office-based rates. Nevertheless, the burden of uncontrolled ambulatory BP and misclassification of BP control at the office constitutes a call for wider use of ABPM to evaluate the success of hypertension treatment in patients with CKD.