Nightly Intermittent Peritoneal Dialysis to Initiate Peritoneal Dialysis

0 downloads 0 Views 182KB Size Report
for patients starting PD with residual renal func- ... tients with residual renal function regardless of ... dialysis was defined as cycler dialysis with a day dwell.
Advances in Peritoneal Dialysis, Vol. 19, 2003

Santhanam Ramalakshmi, Judith Bernardini, Beth Piraino

Nightly intermittent peritoneal dialysis (NIPD) with no day dwell has the potential to enhance peritoneal host defenses. We evaluated outcomes in 24 patients who had been placed on NIPD at the start of peritoneal dialysis as compared with outcomes of 24 control patients on standard continuous cycling peritoneal dialysis (CCPD). As compared with patients on CCPD, patients on NIPD had a lower peritonitis rate (0.34 episodes/year vs. 0.59 episodes/year, p < 0.03) and fewer hospital admissions (1.0 admission/year vs. 1.6 admissions/ year, p = 0.003). The weekly initial KtV was similar in NIPD and CCPD, but NIPD had significantly higher creatinine clearances owing to higher glomerular filtration rates (GFRs) among the patients (7.8 mL/min vs. 4.8 mL/min, p < 0.02). Technique and patient survival were similar in both groups after controlling for the difference in initial GFR. We conclude that NIPD is a good modality choice for patients starting PD with residual renal function and that it present a low peritonitis risk. As GFR declines, a last fill can be added to maintain adequate clearances. Key words Nocturnal peritoneal dialysis, peritonitis, cycler peritoneal dialysis, hospitalization Introduction Initiating peritoneal dialysis (PD) using nightly intermittent peritoneal dialysis (NIPD) is feasible in patients with residual renal function regardless of transport category. A “dry day” may improve peritoneal host defenses (1). Many practitioners reserve NIPD for high transporters (2). Our purpose in the present study was to evaluate outcomes when NIPD was used to initiate dialysis as compared with continuous cycling peritoneal dialysis (CCPD). From: Renal-Electrolyte Division, University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A.

Nightly Intermittent Peritoneal Dialysis to Initiate Peritoneal Dialysis Patients and methods All study data were prospectively collected in patients who had given consent for the PD Registry, as approved by the appropriate institutional review boards. The data were collected between 1995 and 2001 from 5 centers, with retrospective analysis from the data base. All patients initiating PD with NIPD were included in the study. Nightly intermittent peritoneal dialysis was defined as cycler dialysis with a day dwell ≤ 0.75 L. Continuous cycling peritoneal dialysis (CCPD) was defined as cycler dialysis with a day dwell > 0.75 L. Each patient on NIPD was matched to a CCPD patient for age, insulin dependence, Charlson comorbidity index (obtained at the start of PD), Staphylococcus aureus nasal carriage (obtained at the start of PD, based on one nose culture), prophylaxis for S. aureus, and type of connection device (use of an assist device for spiking dialysate bags, or manual spiking). Glomerular filtration rate (GFR, calculated as the average of urea and creatinine clearances in a 24-hour urine collection), serum albumin, normalized protein nitrogen appearance (nPNA, Randerson formula adjusted by ideal body weight), and total weekly Kt/V (using the Watson formula and creatinine clearance per 1.73 m2) were obtained during the first month on PD. All hospitalizations and peritonitis episodes that occurred during each patient’s study time on NIPD or CCPD were recorded. Peritonitis was considered to be present if the patient had cloudy fluid or abdominal pain (or both) and if the effluent white blood cell (WBC) count was 100 cells/µL, or higher, with 50% or more polymorphonuclear cells. Infection data were calculated as the number of infections per dialysis years at risk. Hospitalizations and peritonitis were expressed as events per time at risk. Time at risk for hospitalization and peritonitis ran from the first day on NIPD until the last day on NIPD (or the corresponding period for CCPD controls). Time at risk for survival outcomes

Ramalakshmi et al.

112 ran from the first day of PD training until death on PD or until within 30 days after transfer from PD. Transplantation and permanent transfer to hemodialysis were censored. Technique survival was censored for death and transplant. Data are presented as mean ± standard deviation unless otherwise indicated. Nominal data were compared by paired t-test and analysis of variance. Proportions were compared by chi-square test or Mann–Whitney U-test depending on data distribution. Rates were compared by Poisson analysis. Patient and technique survival were determined by Kaplan–Meier curves and compared by the log-rank test. The Cox proportional hazard model was used to evaluate variables influencing survival. Results Patients who initiated PD using NIPD were very well matched to the case control patients on CCPD for age, sex, race, diabetes, comorbidity, albumin, and nPNA, as shown in Table I. Of the 24 patients on NIPD, 16 had no day dwell. Among the remaining 8 patients, 2 had a day dwell of 0.2 – 0.3 L, 5 had a day dwell of 0.5 L, and 1 had a day dwell of 0.75 L. However, on NIPD, the median day dwell was 0 L as compared with 2 L on CCPD. Average time on NIPD time was TABLE I

CCPD

Rates of peritonitis and hospitalization in nightly intermittent peritoneal dialysis (NIPD) and continuous cycling peritoneal dialysis (CCPD) groups TABLE II

Peritonitis Hospitalization

Patient characteristics and initial clearance NIPD

1.5 years. As expected, GFR was higher for patients who began dialysis using NIPD as compared with CCPD (Table I). The initial Kt/V, obtained during the first month of therapy, was similar for the two groups, but peritoneal Kt/V was higher for CCPD and renal Kt/V was slightly higher for NIPD. Table II shows rates of peritonitis and hospitalization. Admission rates in the two groups were similar for uremia, peritonitis, and volume status. Patients on CCPD had more admissions for cardiovascular causes excluding volume status (0.38/year vs. 0.22/ year, p = 0.06) and for other infections excluding peritonitis (0.51/year vs. 0.22/year, p = 0.007) than did NIPD patients. Patient survival for total time on PD was not different between the two groups (Figure 1), nor was technique survival (Figure 2). Controlling for GFR, still no differences were observed in patient survival [relative risk (RR): 0.98; p = 0.75; 95% confidence interval (CI): 0.84 to 1.13] or technique survival (RR: 0.97; p = 0.72; CI: 0.80 to 1.17).

NIPD

CCPD

0.34 1.04

0.59 1.6

p Value