Background: The role of white coat hypertension (WCH) in the poor control of blood pressure (BP) in chronic kidney disease (CKD) is ill defined.
Methods: We measured systolic clinical (CBP) and ambulatory blood pressure (ABP) in 290 consecutive patients with non-dialysis CKD [glomerular filtration rate (GFR) <60 ml/min/1.73 m(2)]. We defined normotension (NOR) if CBP and daytime ABP <130 mmHg, sustained hypertension (SH) when both BP >or=130 mmHg, WCH if only daytime ABP <130 mmHg, and masked hypertension (MH) when only CBP <130 mmHg.
Results: NOR patients were 15.5%, WCH 31.7%, SH 46.9% and MH 5.9%. Due to the high prevalence of WCH, achievement of BP target (<130 mmHg) was more than doubled by daytime ABP than CBP (47.2 vs 21.4%). WCH was characterized by prevalence of diabetes (31.5%), left ventricular hypertrophy (LVH; 50.0%) and CBP values (146 +/- 12 mmHg) lower than in SH (41.9%, 71.3% and 158 +/- 18 mmHg) but greater than in NOR (17.8%, 37.8% and 118 +/- 7 mmHg). Among patients with CBP >or=130 mmHg, the independent risk of having SH rather than WCH increased in the presence of higher CBP [Odds ration (OR) 1.61, 95% confidence intervals (CI) 1.29-2.02], LVH (OR 1.94, 95% CI 1.03-3.63) and proteinuria (OR 3.12, 95% CI 1.31-7.43). In the WCH group, 24 h, daytime and nighttime ABP were 118 +/- 7/68 +/- 8, 120 +/- 7/71 +/- 8 and 112 +/- 12/63 +/- 9 mmHg, respectively.
Conclusions: In CKD, WCH is highly prevalent and can be predicted in the absence of higher CBP, LVH and proteinuria. In these patients, pursuing a low BP target may not be safe because of the risk of cardio-renal hypoperfusion especially at nighttime.