automated peritoneal dialysis ( apd ) is increasingly used in patients with end - stage renal disease . there are multiple reasons for this , including factors related to peritoneal membrane transport characteristics and dialysis adequacy , lifestyle , and the increasing age1 ) . apd has been reported to have several advantages over continuous ambulatory peritoneal dialysis ( capd ) including lower incidence of peritonitis , better small solute clearances , reduced incidences of hernias , and better dialysis acceptability for workers2 - 4 ) . however , apd has potential disadvantages such as a more rapid loss of residual renal function , less sodium removal and more peritoneal protein loss5 - 10 ) . the short dwell times and less sodium and fluid removal of apd compared with capd seem to be associated with changes in hemodynamics and blood pressure control7 - 9 ) . cardiovascular disease is the most common cause of morbidity and mortality in patients with end - stage renal disease ( esrd)11 ) . hypertension in dialysis patients is an important risk factor for development of left ventricular hypertrophy ( lvh ) and for increased cardiovascular mortality . information on the compared ability of capd and apd to control blood pressure levels and prevent cardiovascular complications is very limited . the aim of this study is to investigate the influence of different peritoneal dialysis regimens on blood pressure control , the diurnal pattern of blood pressure and left ventricular hypertrophy in patients on peritoneal dialysis . a total of 44 stable patients undergoing peritoneal dialysis at chungbuk national university hospital for more than 6 months were enrolled in this study . patients were treated by different regimens of peritoneal dialysis : 26 patients on capd and 18 patients on apd . all patients performed 24-hour ambulatory blood pressure monitoring ( abpm ) and echocardiography . the abpm device ( 90207 abp monitor ; spacelabs healthcare inc . , issaquah , washington , usa ) was employed for measurement of blood pressure using an oscillometric technique . the monitor was automatically programmed to inflate every 30 minutes from 7 am until 11 pm ( daytime ) . from 11 pm to 7 am ( nighttime ) , the device inflated every 60 minutes . mean 24-hour , daytime , and nighttime systolic bp and diastolic bp were derived from 24-hour abpm as the average of measurements taken over the respective time period . abpm recordings were downloaded , evaluated , and analyzed in a blinded manner at spacelabs healthcare . during the monitoring period , patients were instructed to attend to their usual activities , diet , and medications . mean arterial pressure ( map ) was calculated as diastolic pressure plus one third of the difference between systolic and diastolic pressure . diurnal blood pressure variation was characterized by an index calculated as the ratio between the blood pressure difference of daytime and nighttime and the daytime blood pressure value , multiplied by 100 . non - dipper was defined as a reduction in nighttime systolic blood pressure or diastolic blood pressure less than 10% of the daytime blood pressure . systolic blood pressure load and diastolic blood pressure load were defined as the percentage of readings higher than 135/85 mmhg for daytime blood pressure , and 125/75 mmhg for nighttime blood pressure . a blood pressure load greater than 30% was considered significant14 ) . two - dimensional and m - mode echocardiography was performed using an ie 33 echocardiography system ( phillips medical systems , eindhoven , the nethelands ) . measurements of end - systolic and end - diastolic left ventricular internal dimensions , end - diastolic interventricular septal thickness , end - diastolic posterior wall thickness , aortic root dimension , and left atrial dimension were made according to the american society of echocardiography guidelines15 ) . criterias for lvh were left ventricular mass index ( lvmi ) 125 g / m for males and 100 g / m for females . left ventricular mass ( lvm ) was calculated by the formula derived by devereux and reichek16 ) ; lvm ( g ) = 1.04  [ ( lvidd + ivsd + lvpwd ) - ( lvids ) ] - 13.6 where lvidd is left ventricular end diastolic internal dimension , ivsd is interventricular septal thickness measured at end - diastole and lvpwd is posterior wall thickness . lvmi was standardized by dividing it to body surface area , which was calculated using dubois formula17 ) . the following data were collected for each patient : age , gender , body mass index , body weight , primary cause of esrd , duration of hypertension and peritoneal dialysis , use of erythropoietin , hemoglobin , hematocrit , serum blood urea nitrogen , creatinine , albumin , calcium , and phosphate . data of peritoneal dialysis therapy were collected , including peritoneal dialysis adequacy ( weekly kt / v and weekly creatinine clearance ) and peritoneal equilibration test ( pet ) . weekly kt / v was calculated as 7  ( 24-hour urea clearance / total body water ) , where total body water was estimated according to the formula of watson et al.19 ) . weekly creatinine clearance was calculated as 7  ( 24-hour creatinine clearance/1.73 m body surface area ) , where body surface was estimated by the method of dubois17 ) . in this study , capd patients were treated with 4 exchanges daily using 1,500 - 2,000 ml peritoneal dialysis solution containing 1.5% , 2.5% , or 4.25% dextrose for ultrafiltration as appropriate . for patients on apd , the cycler was programmed to deliver 4 - 5 cycles of 1,500 - 2,000 ml peritoneal dialysis solution during the night . a final exchange of 1,000 - 1,500 ml was introduced and allowed to remain in the peritoneal cavity until the next cyclic exchange at night . spss 12.0 for windows software was used for all statistical analysis ( spss inc , chicago , il , usa ) . values are expressed as mean  sd . the comparisons between groups were assessed by unpaired t - test or wilcox singed - rank test . chi - squre test was used for 2  2 contingency tables when appropriate for non - numeric data . this study group consisted of 44 patients on peritoneal dialysis ( 16 male , 28 female , mean age : 49.9  13.2 years ) , including 26 patients on capd ( 9 male , 17 female , mean age : 52.8  11.9 years ) and 18 patients on apd ( 7 male , 11 female , mean age : 45.7  14.2 years ) . mean time on pd was 48.7  32.6 months in capd and 47.5  38.4 months in apd group . primary causes of esrd were diabetic nephropathy ( n = 18 , 40.1% ) , hypertension ( n = 12 , 27.3% ) , chronic glomerulonephritis ( n = 7 , 15.9% ) , and unknown etiology ( n = 7 , 15.9% ) . there was no significant difference in gender , age , bmi , body weight , primary diagnosis for esrd , duration of dialysis and hypertension , use of erythropoietin , dialysate / plasma ( d / p ) creatinine ratio , weekly kt / v , weekly creatinine clearance , hemoglobin , hematocrit serum albumin , calcium , and phosphate . thirty - six ( 81.8% ) of the 44 pd patients were treated with antihypertensive agents , including angiotensin converting enzyme inhibitors , angiotensin receptor blocker , beta - blockers , calcium channel blockers , alpha - blockers , diuretics or combinations of such medications . there was no significant difference in total number of antihypertensives between the 2 groups ( table 2 ) . there were no significant differences in ambulatory mean systolic and diastolic blood pressure , daytime systolic and diastolic blood pressure , and nighttime systolic and diastolic blood pressure between the 2 groups ( table 3 ) . ambulatory systolic and diastolic blood pressure of 24-hour , daytime , and nighttime in the capd group were lower than those of the apd group , despite not reaching statistically significant levels . on analysis for diurnal variation of blood pressure , there was no difference in the non - dipper hypertension rate between 2 groups . twenty - three of 26 ( 88.5% ) capd patients were non - dipper , whereas 15 of 18 ( 83.3% ) apd patients were non - dipper . on comparing diurnal indices of systolic and diastolic blood pressure between two groups , no difference was found in both capd and apd groups ( table 4 ) . there were no significant differences in systolic and diastolic blood pressure load and lvmi between capd and apd groups ( table 5 ) . there were no significant correlations between lvmi and 24-hour mean systolic and diastolic blood pressure , daytime systolic and diastolic blood pressure , and nighttime systolic and diastolic blood pressures . lvmi was correlated with 24-hour systolic bp load ( r = 0.311 , p < 0.05 ) and daytime systolic bp load ( r = 0.360 , p < 0.05 ) ( fig . 1 and 2 ) . this study group consisted of 44 patients on peritoneal dialysis ( 16 male , 28 female , mean age : 49.9  13.2 years ) , including 26 patients on capd ( 9 male , 17 female , mean age : 52.8  11.9 years ) and 18 patients on apd ( 7 male , 11 female , mean age : 45.7  14.2 years ) . mean time on pd was 48.7  32.6 months in capd and 47.5  38.4 months in apd group . primary causes of esrd were diabetic nephropathy ( n = 18 , 40.1% ) , hypertension ( n = 12 , 27.3% ) , chronic glomerulonephritis ( n = 7 , 15.9% ) , and unknown etiology ( n = 7 , 15.9% ) . there was no significant difference in gender , age , bmi , body weight , primary diagnosis for esrd , duration of dialysis and hypertension , use of erythropoietin , dialysate / plasma ( d / p ) creatinine ratio , weekly kt / v , weekly creatinine clearance , hemoglobin , hematocrit serum albumin , calcium , and phosphate . thirty - six ( 81.8% ) of the 44 pd patients were treated with antihypertensive agents , including angiotensin converting enzyme inhibitors , angiotensin receptor blocker , beta - blockers , calcium channel blockers , alpha - blockers , diuretics or combinations of such medications . there was no significant difference in total number of antihypertensives between the 2 groups ( table 2 ) . there were no significant differences in ambulatory mean systolic and diastolic blood pressure , daytime systolic and diastolic blood pressure , and nighttime systolic and diastolic blood pressure between the 2 groups ( table 3 ) . ambulatory systolic and diastolic blood pressure of 24-hour , daytime , and nighttime in the capd group were lower than those of the apd group , despite not reaching statistically significant levels . on analysis for diurnal variation of blood pressure , there was no difference in the non - dipper hypertension rate between 2 groups . twenty - three of 26 ( 88.5% ) capd patients were non - dipper , whereas 15 of 18 ( 83.3% ) apd patients were non - dipper . on comparing diurnal indices of systolic and diastolic blood pressure between two groups , no difference was found in both capd and apd groups ( table 4 ) . there were no significant differences in systolic and diastolic blood pressure load and lvmi between capd and apd groups ( table 5 ) . there were no significant correlations between lvmi and 24-hour mean systolic and diastolic blood pressure , daytime systolic and diastolic blood pressure , and nighttime systolic and diastolic blood pressures . lvmi was correlated with 24-hour systolic bp load ( r = 0.311 , p < 0.05 ) and daytime systolic bp load ( r = 0.360 , p < 0.05 ) ( fig . 1 and 2 ) . there is an ongoing controversy in the literature as to whether apd is associated with less effective control of blood pressure as compared with capd . wang et al.20 ) found similar levels of blood pressure in patients on capd and apd , but a higher ventricular mass in patients on apd , which they attributed to potential diurnal hypervolemia in this therapy . ortega et al.21 ) detected higher systolic blood pressure levels in apd than in capd , but were unable to find a correlation between sodium removal and blood pressure levels . our study demonstrates that there were no significant differences in blood pressure control , diurnal variation of blood pressure , and left ventricular mass between capd and apd . left ventricular hypertrophy is a strong predictor of myocardial infarction , heart failure , sudden death , and stroke in patients with essential hypertension and in patients with esrd22 - 26 ) . there are reports of a high incidence of lvh in capd patients and that lvh seemed to be strongly associated with a significantly high cardiovascular morbidity and mortality in capd patients27 ) . it has reported that each 10 mmhg rise in average mean arterial blood pressure was associated with a 48% increased likelihood of having both concentric lvh and left ventricular dilation on second echocardiogram for patients with esrd28 ) . however , in this study , we have not observed significant difference in lvmi between capd and apd groups . ambulatory systolic and diastolic blood pressure at 24-hour , daytime and nighttime was not associated with lvmi . it has been reported that ambulatory nighttime systolic blood pressure load > 30% had an independent association with lvh20 ) . similarly , we found in our study that lvmi in patients on peritoneal dialysis correlated with 24-hour systolic blood pressure load and daytime systolic blood pressure load . diurnal blood pressure rhythm is known to be abnormal in chronic renal failure , dialysis and renal transplantation patients . it has been reported that non - dipper patients have increased risk of target organ damage and mortality in patients with hypertension29 - 31 ) . recently , reduced blood pressure diurnal variability has been reported as a risk factor for left ventricular dilatation in hemodialysis patents . although a number of factors such as autonomic dysfunction , increase in plasma volume , heart failure and sleep disorders have been implicated for abnormal circadian rhythm of bp in dialysis patients , the main reason of it was unclear . subjectively assessed sleep disturbance during overnight bp monitoring increases the nocturnal bp level and potentially attenuates the correlation with hypertension - related cardiac damage , even though habituation to overnight bp monitoring occurs32 ) . it has been suggested that apd may be less effective than capd for sodium and fluid removal , due to its semi - intermittent nature and frequently lower capacity for ultrafiltration , and also to the short dwell schedule that characterizes the night session in apd , which may result in significant sodium sieving and less efficient sodium removal32 ) . in addition , the alarms or noises of the apd machine may cause sleep disturbance in patients on apd . however , we found no difference in diurnal variation of blood pressure for apd compared with capd . recently , patients are increasingly selecting apd for lifestyle reasons rather than capd because they have high transport membrane characteristics , resulting in an increasing proportion of apd patients having low transport membrane characteristics . in this study , there was no difference in d / p creatinine and only 2 patients had high transporter membrane characteristics in the apd group . in this study , 81.8% of the peritoneal dialysis patients were receiving antihypertensive agents , and these medications themselves may affect blood pressure control and circadian blood pressure rhythm . the size of our study population was not large enough to compare the difference between capd and apd group . in addition , we did not evaluate the sodium removal and volume status between capd and apd groups . further study is needed to investigate whether the effect of the sodium and fluid removal according to capd regimen can influence the blood pressure control . it has been suggested that the use of a glucose polymeric solution , icodextrin 7.5% , is able to improve volume status in peritoneal dialysis patients due to an improved and prolonged ultrafiltration , especially during long dwells33 - 35 ) . further study is needed to study the influence of icodextrin for long dwells in apd on volume status and blood pressure control . in conclusion , we found no difference in blood pressure control , diurnal variation of blood pressure , and left ventricular hypertrophy for apd compared with capd . the different peritoneal dialysis regimens might not influence blood pressure control and diurnal variation of blood pressure in patients on peritoneal dialysis .
this study aimed to investigate the influence of different peritoneal dialysis regimens on blood pressure control , the diurnal pattern of blood pressure and left ventricular hypertrophy in patients on peritoneal dialysis . 
 forty - four patients undergoing peritoneal dialysis were enrolled into the study . 
 patients were treated with different regimens of peritoneal dialysis : 26 patients on continuous ambulatory peritoneal dialysis ( capd ) and 18 patients on automated peritoneal dialysis ( apd ) . 
 all patients performed 24-hour ambulatory blood pressure monitoring ( abpm ) and echocardiography . 
 echocardiography was performed for measurement of cardiac parameters and calculation of left ventricular mass index ( lvmi ) . 
 there were no significant differences in average of systolic and diastolic blood pressure during 24-hour , daytime , and nighttime between capd and apd groups . 
 there were no significant differences in diurnal variation of blood pressure , systolic and diastolic blood pressure load , and lvmi between capd and apd groups . 
 lvmi was associated with 24 hour systolic blood pressure load ( r = 0.311 , p < 0.05 ) and daytime systolic blood pressure load ( r = 0.360 , p < 0.05 ) . in conclusion 
 , this study found that there is no difference in blood pressure control , diurnal variation of blood pressure and left ventricular hypertrophy between capd and apd patients . 
 the different peritoneal dialysis regimens might not influence blood pressure control and diurnal variation of blood pressure in patients on peritoneal dialysis .