Magnitude of the Difference Between Clinic and Ambulatory Blood Pressures and Risk of Adverse Outcomes in Patients With Chronic Kidney Disease

Abstract

Background Obtaining 24‐hour ambulatory blood pressure ( BP ) is recommended for the detection of masked or white‐coat hypertension. Our objective was to determine whether the magnitude of the difference between ambulatory and clinic BP s has prognostic implications. Methods and Results We included 610 participants of the AASK (African American Study of Kidney Disease and Hypertension) Cohort Study who had clinic and ambulatory BPs performed in close proximity in time. We used Cox models to determine the association between the absolute systolic BP ( SBP ) difference between clinic and awake ambulatory BPs (primary predictor) and death and end‐stage renal disease. Of 610 AASK Cohort Study participants, 200 (32.8%) died during a median follow‐up of 9.9 years; 178 (29.2%) developed end‐stage renal disease. There was a U‐shaped association between the clinic and ambulatory SBP difference with risk of death, but not end‐stage renal disease. A 5– to <10–mm Hg higher clinic versus awake SBP (white‐coat effect) was associated with a trend toward higher (adjusted) mortality risk (adjusted hazard ratio, 1.84; 95% CI, 0.94–3.56) compared with a 0– to <5–mm Hg clinic‐awake SBP difference (reference group). A ≥10–mm Hg clinic‐awake SBP difference was associated with even higher mortality risk (adjusted hazard ratio, 2.31; 95% CI, 1.27–4.22). A ≥−5–mm Hg clinic‐awake SBP difference was also associated with higher mortality (adjusted hazard ratio, 1.82; 95% CI, 1.05–3.15) compared with the reference group. Conclusions A U‐shaped association exists between the magnitude of the difference between clinic and ambulatory SBP and mortality. Higher clinic versus ambulatory BPs (as in white‐coat effect) may be associated with higher risk of death in black patients with chronic kidney disease.

Prognostic Significance of Ambulatory BP Monitoring in CKD: A Report from the Chronic Renal Insufficiency Cohort (CRIC) Study

“…6 In patients with CKD, studies have shown conflicting results: some studies show no association of white-coat effect and cardiovascular disease, 10 whereas others show that patients with a white-coat effect are at higher risk for mortality. 13 In our cohort of patients who were mostly treated for hypertension, the presence of white-coat effect was not associated with a higher risk for cardiovascular outcomes, kidney outcomes, and mortality compared with participants with controlled BP. However, white-coat hypertension when defined using the lower threshold of 130/80 mm Hg was associated with higher risk of mortality, and white-coat hypertension was associated with higher risk of the kidney outcome in participants with lower levels of GFR.…”

“…[10][11][12] However, studies evaluating the association between masked uncontrolled hypertension and progression of kidney disease have demonstrated conflicting results; some, 10,11 but not all, studies have shown a higher risk of progression of kidney disease in patients with masked uncontrolled hypertension. 13,14 In a large and diverse cohort of participants with CKD, we demonstrate that the presence of masked uncontrolled hypertension is associated with high risk of cardiovascular disease and progression of kidney disease. This risk is independent of other risk factors that may influence these outcomes, including office BP, and consistent across subgroups of age, sex, race, and diabetes.…”

“…9 Masked uncontrolled hypertension has been associated with higher risk of cardiovascular outcomes and mortality, [10][11][12] but association with progression of kidney disease has been inconsistent. 13,14 In addition, although nighttime BP is often elevated in patients with CKD, 15 the long-term prognostic significance of nighttime BP, independent of clinic BP, is unclear. 16 The objective of this paper is to evaluate the association between profiles of BP defined by ABPM (white-coat effect, masked uncontrolled hypertension, and sustained hypertension) and long-term kidney and cardiovascular outcomes, and mortality in patients with CKD, using data from the Chronic Renal Insufficiency Cohort (CRIC) Study.…”

Deoxycholic Acid and Risks of Cardiovascular Events, ESKD, and Mortality in CKD: The CRIC Study

“…To allow for flexibility in modeling the association between DCA and outcomes, we applied Cox proportional hazards models using penalized cubic splines with one knot. 24 We determined the optimal number of degrees of freedom (df) and placement of the knot in cubic splines by comparing models with different dfs and choosing the model with minimum AIC or BIC. 25,26 The knot was located at the median of DCA value 68.45 ng/ml, and was defined as the reference value (hazard ratio [HR] =1.0).…”

Hypertension Management in Patients with Chronic Kidney Disease

“… 12 Ku et al showed the clinical relevance of these conditions among 610 participants in the AASK trial, which revealed a U-shaped association between clinic and ambulatory SBP difference and an increased mortality but no ESKD risk. 26 However, the generalizability of this trial to all hypertensive CKD patients is unknown. The ongoing 4-year prospective randomized MASked-unconTrolled hypERtension management based on office BP or on ambulatory blood pressure measurement (MASTER) study may help clarify this ambiguity if it indicates that ABPM-based treatment strategies slow target organ damage and reduce future CV events.…”