Volume overload in patients treated with continuous ambulatory peritoneal dialysis associated with reduced circadian blood pressure variation.
BACKGROUND
While a high blood pressure (BP) in patients receiving maintenance ambulatory peritoneal dialysis (CAPD) is associated with congestive heart failure and an increased mortality, the relevance of diurnal variations in BP is unknown.


METHODS
In a prospective study, we enrolled 76 prevalent patients receiving stable CAPD (age 60.4 +/- 13.8 years; 37 males). BP was measured over 24 h using an automated device. We also performed routine clinical and biochemical measurements, as well as the Karnofsky index to evaluate physical activity. Volume status was assessed using bioimpedance analysis.


RESULTS
69 patients (with an average time on dialysis of 24.4 +/- 22.5 months) completed the study. Of these, 16 patients experienced a drop in BP >10% at night (dippers), while 53 patients did not (non-dippers). Comparing these two groups, dippers had significantly lower extracellular water (ECW) (13.8 +/- 2.1 vs. 15.9 +/- 3.3 l; p < 0.05), normalized extracellular water (nECW) (0.22 +/- 0.05 vs. 0.26 +/- 0.04 l/m; p < 0.05), and serum albumin (38.2 +/- 2.9 vs. 35.9 +/- 3.7 g/l; p < 0.05). Age, Karnofsky index, vintage, residual renal Kt/V and peritoneal Kt/V, total Kt/V, dose of antihypertensive drugs, mean systolic and diastolic BP did not significantly differ between these groups. Correlation analysis showed the coefficient of variation (CV) of BP positively correlated with E/T (r(2) = 0.292; p < 0.05), diabetic (r(2) = 0.267; p < 0.05), male (r(2) = 0.257; p < 0.05), nECW (r(2) = 0.278; p < 0.05) and ECW (r(2) = 0.249; p < 0.05) negatively correlated with albumin (r(2) = -0.280; p < 0.05). Furthermore, in a multivariate linear regression model, E/T, albumin and sex were independently associated with CV for BP.


CONCLUSIONS
We show that reduced BP variation is common in CAPD patients and associated with volume overload and hypoalbuminemia. Furthermore, the relationship between nutritional, inflammatory status and dipping needs further studies.
Yang
Ji-Hong
JH
Division of Nephrology, Peking University Third Hospital, Beijing, China.
Cheng
Li-Tao
LT
Gu
Yue
Y
Tang
Li-Jun
LJ
Wang
Tao
T
Lindholm
M Bengt
MB
Axelsson
Jonas
J
D000368:Aged; D001794:Blood Pressure; D005260:Female; D006333:Heart Failure / Q000097:blood / Q000209:etiology / Q000401:mortality / Q000503:physiopathology; D006801:Humans; D034141:Hypoalbuminemia / Q000097:blood / Q000209:etiology / Q000401:mortality / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010531:Peritoneal Dialysis, Continuous Ambulatory / Q000009:adverse effects*; D011446:Prospective Studies