Factors associated with poorly-controlled hypertension in continuous ambulatory peritoneal dialysis patients

PN Wong, SK Mak, KY Lo, GMW Tong, AKM Wong
Correspondence: Dr Ping-Nam Wong, apnwong@yahoo.com

ABSTRACT
Introduction Hypertension is highly prevalent among continuous ambulatory peritoneal dialysis (CAPD) patients and is a major risk factor for cardiovascular complications. This study examines the risk factors associated with poorly-controlled hypertension in CAPD.
Methods We performed a cross-sectional study of 66 stable adult CAPD patients to evaluate their hypertension control over a period of three to four months and their associations with other clinical and laboratory parameters.
Results The mean age of the patients was 56.7 (plus or minus 1.27) years. Their mean systolic and diastolic blood pressure were 139 (plus or minus 2.59) mmHg and 77 (plus or minus 1.35) mmHg respectively; 71 percent of them were on antihypertensive drugs. Thirty (45.5 percent) patients had high blood pressure greater than 140/90mmHg. Compared with patients with normal blood pressure, patients with high blood pressure received significantly more antihypertensive drugs (p-value equals 0.034) and were more likely to be clinically overloaded (p-value less than 0.001). Multivariate analysis showed that systolic blood pressure was predicted by volume expansion (p-value less than 0.001) while diastolic blood pressure was negatively predicted by age (p-value equals to 0.004). In addition, volume overload was predicted positively by dialysate/plasma creatinine (p-value equals 0.011) and negatively by serum albumin (p-value less than 0.001).
Conclusion Clinically-apparent volume overload was associated with poor systolic blood pressure control despite aggressive antihypertensive drug therapy. This finding underlines the importance of fluid control and could provide an explanation of the poor outcome observed in patients with high peritoneal transport.

Keywords: continuous ambulatory peritoneal dialysis, hypertension, peritoneum, ultrafiltration
Singapore Med J 2004; 45(11): 520-524