Changing the timing of antihypertensive therapy to reduce nocturnal blood pressure in CKD: an 8-week uncontrolled trial.

BACKGROUND: Nondipping status is associated with greater cardiovascular morbidity and mortality and faster progression of chronic kidney disease (CKD). We examined whether shifting 1 antihypertensive drug from morning to evening restores the circadian rhythm of blood pressure in nondipper patients with CKD. STUDY DESIGN: 8-week clinical trial without a control group. SETTING & PARTICIPANTS: We selected from our outpatient renal clinic 32 patients with CKD with estimated glomerular filtration rate less than 90 mL/min/1.73 m(2) and night-day ratio of mean ambulatory blood pressure (ABP) greater than 0.9, but with normal daytime ABP (<135/85 mm Hg) to avoid the required therapy intensification. INTERVENTION: Shifting 1 antihypertensive drug from morning to evening. OUTCOMES: Percentage of patients changing the night-day ratio of mean ABP from greater than 0.9 to 0.9 or less 8 weeks after the shift. MEASUREMENTS: Office blood pressure/ABP and proteinuria at baseline and after the shift. RESULTS: There were 55% men with a mean age of 67.4 +/- 11.3 years and estimated glomerular filtration rate of 46 +/- 12 mL/min/1.73 m(2). They were treated with 2.4 +/- 1.4 antihypertensive drugs. After the drug shift, the night-day ratio of mean ABP decreased in 93.7% of patients, with normal circadian rhythm restored in 87.5%. The nocturnal systolic and diastolic ABP decrease was not associated with an increase in diurnal ABP and was independent from number and class of shifted drug. Office blood pressure in the morning also decreased (from 136 +/- 16/77 +/- 10 to 131 +/- 13/75 +/- 8 mm Hg; P = 0.02). Urinary protein excretion decreased from 235 +/- 259 to 167 +/- 206 mg/d (P < 0.001). LIMITATIONS: Absence of a control group and patients with severe proteinuria or uncontrolled daytime ABP. CONCLUSIONS: In nondipper patients with CKD, changing the timing of antihypertensive therapy decreases nocturnal blood pressure and proteinuria.

Effects of age on hypertensive status in patients with chronic kidney disease.

OBJECTIVE: To evaluate effect of age on hypertensive status in chronic kidney disease (CKD). METHODS: We studied 459 prevalent CKD patients (stages 2-5, no dialysis), grouped by age (< 55, 55-64, 65-74, >or= 75 years), undergoing clinical blood pressure (CBP) and ambulatory blood pressure (ABP) measurement. RESULTS: Prevalence of diabetes, left ventricular hypertrophy and previous cardiovascular disease progressively increased with aging; glomerular filtration rate (GFR) and hemoglobin decreased. Achievement of CBP target decreased from 16% in patients < 55 years to 6% in those >or= 75 years (P = 0.023). ABP 24-h systolic rose while diastolic decreased, with a consequent pulse pressure increase from 45 +/- 8 to 65 +/- 14 mmHg (P < 0.0001). Age, proteinuria, diabetes, cardiovascular disease and anemia but not GFR predicted higher 24-h pulse pressure. CBP overestimated systolic/diastolic daytime ABP by 14 +/- 18/7 +/- 11 mmHg on average, a greater difference in older than younger groups (P < 0.005). Conversely, CBP night-time ABP difference did not vary among groups (24 +/- 20/16 +/- 11 mmHg). These age-dependent differences determined a rising prevalence of white-coat hypertension (from 19 to 40%, P = 0.001) and night/day ratio of at least 0.9 (from 43 to 66%, P = 0.0004). Age, diabetes, left ventricular hypertrophy and anemia but not GFR predicted nondipping status. Among the oldest patients, 13% had diastolic CBP below 70 mmHg, with 48% below the corresponding values of daytime (< 69 mmHg) or night-time ABP (< 60 mmHg). CONCLUSION: In CKD, prevalence of white-coat hypertension, nondipping status and potentially dangerous low diastolic ABP increases with aging. This suggests wider use of ABP monitoring in older patients and need for trials addressing identification of an age-specific blood pressure target.

Prevalence and clinical correlates of white coat hypertension in chronic kidney disease.

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.

Effects of efficiency and length of acetate-free biofiltration session on postdialysis solute rebound.

BACKGROUND: Postdialytic rebound (PDR) of plasma solutes is a relevant drawback of intermittent hemodialysis, but its pathophysiological process remains undefined. We assessed the independent effects of efficiency and length of dialytic session on PDR of urea, phosphate, and potassium. METHODS: Uremic patients were evaluated at the beginning and end of dialysis and after 180 minutes in 2 randomized crossover studies. In study 1, we compared the effect of standard versus higher efficiency acetate-free biofiltration (AFB) while maintaining the same duration of 4 hours. In study 2, we compared the effect of 3- versus 5-hour AFB sessions while maintaining similar efficiency. RESULTS: In study 1, greater Kt/V (1.49 +/- 0.20 versus 1.22 +/- 0.15; P < 0.0001) was coupled with significant increases in both absolute removal and PDR of urea and phosphate (PDR of urea, +45% versus +29%; PDR of phosphate, +79% versus +52%), but not of potassium. Similarly, in study 2, shortening the AFB session while maintaining similar absolute removal and Kt/V (1.28 +/- 0.09 versus 1.31 +/- 0.09) significantly increased PDR of urea and phosphate (PDR of urea, +32% versus +19%; PDR of phosphate, +63% versus +36%), but not of potassium. In both studies, greater PDRs of urea and phosphate were associated with estimated greater removal of these solutes per hour. CONCLUSION: The rate of removal of phosphate and urea is a critical determinant of their PDR; conversely, potassium is not influenced by removal rate, likely because of its marked cell compartmentalization.