***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Residual renal function ( RRF ) in end-stage renal disease is clinical ly important as it contributes to adequacy of dialysis , quality of life , and mortality . This study was conducted to determine the predictors of RRF loss in a national r and om sample of patients initiating hemodialysis and peritoneal dialysis .  The study controlled for baseline variables and included major predictors . The end point was loss of RRF , defined as a urine volume < 200 ml/24 h at approximately 1 yr of follow-up . The adjusted odds ratios ( AOR ) and P values associated with each of the demographic , clinical , laboratory , and treatment parameters were estimated using an " adjusted " univariate analysis . Significant variables ( P < 0.05 ) were included in a multivariate logistic regression model . Predictors of RRF loss were female gender ( AOR = 1.45 ; P < 0.001 ) , non-white race ( AOR = 1.57 ; P = < 0.001 ) , prior history of diabetes ( AOR = 1.82 ; P = 0.006 ) , prior history of congestive heart failure ( AOR = 1.32 ; P = 0.03 ) , and time to follow-up ( AOR = 1.06 per month ; P = 0.03 ) . Patients treated with peritoneal dialysis  had a 65 % lower risk of RRF loss than those on hemodialysis ( AOR = 0.35 ; P < 0.001 ) . Higher serum calcium ( AOR = 0.81 per mg/dl ; P = 0.05 ) , use of an angiotensin-converting enzyme inhibitor ( AOR = 0.68 ; P < 0.001 ) . and use of a calcium channel blocker ( AOR = 0.77 ; P = 0.01 ) were independently associated with decreased risk of RRF loss . The observations of demographic groups at risk and potentially modifiable factors and therapies have generated testable hypotheses regarding therapies that may preserve RRF among end-stage renal disease patients Objective The goals for maintenance dialysis treatment are to improve patient survival , reduce patient morbidity , and improve patient quality of life . This is the first r and omized prospect i ve study comparing automated peritoneal dialysis ( APD ) and continuous ambulatory peritoneal dialysis ( CAPD ) treatment with respect to quality of life and clinical outcomes in relation to therapy costs . Design A prospect i ve , r and omized multicenter study . Setting Three Danish CAPD units . Patients Thirty-four adequately dialyzed patients with high or high-average peritoneal transport characteristics were included in the study . Twenty-five patients completed the study . Interventions After r and omization , 17 patients were allocated to APD treatment  and 17 patients to CAPD treatment for a period of 6 months . Medical and biochemical parameters were evaluated at monthly controls in the CAPD units . Quality -of-life parameters were assessed at baseline and after 6 months by the self-administered short-form SF-36 generic health survey question naire supplemented with disease- and treatment-specific questions . Therapy costs were compared by evaluating dialysis-related expenses . Main Outcome Measures Quality -of-life parameters , dialysis-related complications , dialysis-related expenses . Results The quality -of-life studies showed that significantly more time for work , family , and social activities was available to patients on APD compared to those on CAPD ( p < 0.001 ) . Although the difference was not significant , there was a tendency for less physical and emotional discomfort caused by dialysis fluid in the APD group . Sleep problems , on the other h and , tended to be more marked in the APD group . Any positive effect of APD compared to CAPD on dialysis-related hospital days or complication rates could not be confirmed . With larger patient sample s , it is possible , however , that a significant difference might have been achieved . The running costs for APD treatment were US $ 75 per day and for CAPD treatment US $ 61 per day . Conclusion If APD treatment can help to keep selected patients vocationally or socially active , paying the extra cost seems reasonable Both CAPD-Y and CCPD have been reported to reduce the high peritonitis rate of conventional CAPD . As peritonitis was the major complication of CAPD in our centre , both modifications were introduced in 1987 . Initially , treatment modalities were allocated to patients based on their ( doctor 's ) preference . A remarkable difference in peritonitis rate was encountered between patients on CCPD and those on CAPD-Y  ( 0.6 vs 1.2 episodes a year ) . As patient selection and doctor 's preference might have contributed to this hopeful result , a prospect i ve study was started . From January 1988 on , all new patients were at r and om assigned to CAPD-Y or CCPD in order to study the incidence of peritonitis in relation to the treatment modality . Up till November 1 , 1990 , 26 patients enrolled in the CAPD-Y group ( follow-up of 292 patient months ) , and 30 patients in the CCPD group ( follow-up of 337 patient months ) . This ongoing study reveals that CCPD patients remained peritonitis free significantly longer than those on CAPD-Y ( quartile time to first peritonitis greater than 12 vs 3 months , p less than 0.05 ) , and had a significantly lower peritonitis incidence ( median time to second peritonitis 18 vs 6 months , p = 0.016 ) . In conclusion , in an unselected patient population  CCPD was accompanied with a significant lower peritonitis incidence than Several centers have reported a lower rate of peritonitis among adult patients on continuous cyclic peritoneal dialysis ( CCPD ) as compared to those undergoing continuous ambulatory peritoneal dialysis ( CAPD ) .  Preliminary results of our ongoing prospect i ve r and omized study comparing CAPD-Y with CCPD also suggest a lower peritonitis incidence among CCPD-treated patients . To investigate whether the two dialysis regimens could result in differences in local host defense , we studied peritoneal macrophage ( PMO ) function and effluent opsonic activity in eight patients established on CAPD-Y matched with eight chronic CCPD patients . Since short and long dwell times are inherent to both dialysis modalities , and we previously found that dwell time has an impact on PMO function and effluent opsonic activity , patients were studied after both a short ( 4 hr ) and a long ( 15 hr ) dwell time . In both groups PMO phagocytic capacity increased significantly with dwell time ( 39 + /- 3.3 % at 4 hr vs. 58 + /- 4.2 % at 15 hr in CAPD patients , and 40 + /- 3.9 vs. 72 + /- 3.3 % in CCPD patients ; P less than 0.01 ) , as did PMO peak chemiluminescence response ( 31 + /- 4.9 vs. 77 + /- 7.2 counts.min-1/10(4 ) cells in CAPD , and 22 + /- 3.9 vs. 109 + /- 21.2 counts.min-1/10(4 ) cells in CCPD ; P less than 0.01 ) and effluent opsonic activity ( 41 + /- 7.6 vs. 73 + /- 5.8 % in CAPD and 39 + /- 6.2 vs. 70 + /- 5.9 % in CCPD ; P less than 0.01 ) . However , no significant difference was found in either variable between CAPD and CCPD patients when dwell times were equal . ( ABSTRACT TRUNCATED AT 250 WORDS BACKGROUND Fluid and sodium removal rates may not be equivalent in patients undergoing automated peritoneal dialysis ( APD ) and continuous ambulatory peritoneal dialysis ( CAPD ) .  This may influence compared cardiovascular outcomes in both groups . METHODS The authors compared prospect ively the time courses of ultrafiltration , sodium removal  , and residual renal function ( RRF ) in a group of incident patients treated with CAPD ( n = 53 ) or APD ( n = 51 ) for at least 1 year ( mean follow-up , 28.9 months ; range , 13 to 62 ) . The authors analyzed potential effects of these factors on blood pressure ( BP ) control and cardiovascular morbidity and mortality . RESULTS Ultrafiltration and sodium removal rates were consistently lower in APD patients ( mean differences , 236 mL/d ; P = 0.012 , and 36 mmol/d ; P = 0.018 , respectively , end of first year ) . Moreover , univariate and multivariate analysis indicated that APD therapy results in a moderate , but significantly faster decline of RRF than CAPD therapy . Analysis of clinical outcomes showed that CAPD ( versus APD ) therapy or higher ultrafiltration or sodium removal rates were associated with a better time course of systolic , but not diastolic , BP . We were unable to identify PD modality , ultrafiltration , or sodium removal rates as independent predictors of cardiovascular morbidity and mortality . CONCLUSION Ultrafiltration and sodium removal rates are consistently lower in incident APD patients than in their counterparts undergoing CAPD . Moreover , RRF declines faster during APD than during CAPD therapy , although this difference may be partially counteracted by a detrimental effect of ultrafiltration on RRF . Aside from a better control of systolic BP in CAPD patients , these differences do not portend significant cardiovascular consequences during the first years of PD therapy Objectives To compare sodium removal in continuous ambulatory peritoneal dialysis ( CAPD ) and automated peritoneal dialysis ( APD ) patients , and to identify the main factors that modify Na removal in clinical practice in these patients . Design Study in three steps . Cross-sectional observational ( Study A ) , and longitudinal interventional ( Studies B and C ) . Patients and Methods First ( Study A ) we carried out a cross-sectional survey of Na removal in 63 patients on CAPD and 78 patients on APD . Second ( Study B ) , we studied Na removal in 32 patients before and after changing from CAPD to APD therapy . Finally ( Study C ) , we analyzed the impact on Na removal of introducing icodextrin for the long dwell in 16 patients undergoing CAPD or APD . Results In Study A , total Na removal averaged 210 mmol/day for CAPD patients and 91 mmol/day for APD patients ( p < 0.001 ) ; Na removal was < 100 mmol/day in 7.1 % of CAPD patients and 56.4 % of APD patients . Multivariate analysis identified ultrafiltration [ B = 125 mmol/day , 95 % confidence interval ( CI ) 110 , 140 ] , CAPD therapy ( B = 60 mmol/day , 95%CI 37 , 83 ) , and residual diuresis ( B = 51 mmol/L , 95%CI 34 , 69 ) as independent predictors of Na removal ( adjusted r2 = 0.76 ) . For APD patients , longer nocturnal dwell times and performing a supplementary diurnal exchange were also independently associated with higher Na removal rates . In Study B , Na removal decreased from 192 to 92 mmol/day ( median ) after the change to APD ( p = 0.02 ) . In Study C , peritoneal Na removal increased from 98 to 148 mmol/day ( median ) ( p = 0.04 ) after introducing icodextrin . Conclusions St and ard APD schedules are frequently associated with poor Na removal rates . For any degree of ultrafiltration , Na removal is better in CAPD than in APD . Icodextrin , supplementary diurnal exchanges , and longer nocturnal dwell times improve Na removal in APD . Sodium removal can be estimated from ultrafiltration in patients on CAPD , but must be specifically monitored in patients on APD An increasing number of patients are prescribed a continuous-cycling regimen because st and ard manual peritoneal-dialysis exchanges alone are not sufficient in achieving adequate dialysis as defined by the Dialysis Outcome Quality Initiative . Consequently , the number of patients on continuous-cycler therapy  is increasing . There is controversy as to whether there are differences in the development of peritonitis between patients maintained on manual therapy  and those on  continuous cycling therapy . As a result , we retrospectively review ed the charts of all cycler peritoneal dialysis ( CPD ) patients maintained on either manual peritoneal dialysis ( Baxter UltraBag ; Group I ) or continuous cycler peritoneal dialysis ( Baxter HomeChoice Cycler ; Group II ) between 1 June 1994 and 31 December 1996 . A total of 239 patients were in Group I and 106 in Group II . Both groups were similar in age , race , gender , and presence of diabetes mellitus , coronary artery disease , peripheral vascular disease , and gastrointestinal disease . There was no difference in the overall rate of peritonitis between the two groups of patients [ 1 episode in 10.4 patient-months ( Group I ) vs. 1 in 10.0 patient-months ( Group II ) ; -0.01843 to 0.02619 ] . The rates of Staphylococcus aureus peritonitis [ 1 episode in 48.5 patient-months ( Group I ) vs. 1 in 141.8 patient months ( Group II 
    Output:
    
Another study found that patients on APD had significantly more time for work , family and social activities .
AUTHORS ' CONCLUSIONS APD has not been shown to have significant advantages over CAPD in terms of important clinical outcomes .
APD may however be considered advantageous in select group of patients such as in the younger PD population and those in employment or education due to its psychosocial advantages .