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Biomedical subjects

B Prowant

Publications and source records attributed to B Prowant.

At least 19 recordsLinked to original sources
PubMed2001

Clinical performance measures: the changing status of peritoneal dialysis.

BACKGROUND: The Peritoneal Dialysis-Clinical Performance Measures Project (PD-CPM) characterizes peritoneal dialysis within the U.S. Current survey results are reported and compared to those of previous years. METHODS: Prevalence data from random national samples of adult peritoneal dialysis (PD) patients participating in the United States End-Stage Renal Disease (ESRD) program have been collected annually since 1995. RESULTS: In 1995, 79% of the respondents used continuous ambulatory peritoneal dialysis (CAPD) rather than automated peritoneal dialysis (APD). The mean hematocrit (Hct) of PD patients was 32% and only 66% of individuals had a measurement of dialysis adequacy reported. The mean weekly Kt/Vurea (wKt/V) and weekly creatinine clearance (wCCr) reported for CAPD patients in 1995 were 1.9 and 67 L/1.73 m2/week, respectively. In 2000 the median age of PD patients was 55 years and 63% were white. The leading cause of ESRD was diabetes mellitus (34%) and 54% of adult PD patients performed some form of APD rather than CAPD. Age, sex, size, hematocrit, peritoneal permeability, dialysis adequacy, residual renal function and nutritional indices did not differ between APD and CAPD patients. The mean hemoglobin (Hb) for the 2000 PD-CPM population was 11.6 +/- 1.4 g/dL (mean +/- 1 SD) and 11% of patients had an average Hb below 10 g/dL. The average serum albumin was 3.5 +/- 0.5 g/dL by the bromcresol green method and 56% of subjects had an average serum albumin equal to or above 3.5 g/dL (or 3.2 g/dL by bromcresol purple). In 2000 85% of patients had a dialysis adequacy measurement reported and the mean calculated wKt/V and wCCr were 2.3 +/- 0.6 and 72.7 +/- 24.9 liters/1.73 m2/week for CAPD patients and 2.3 +/- 0.6 and 71.6 +/- 25.1 L/1.73 m2/week for APD patients. PD subjects had a mean body weight of 76 +/- 19 kg and body mass index (BMI) of 27.5 +/- 6.4 kg/m2. The protein equivalent of nitrogen appearance (nPNA) of these patients was 0.95 +/- 0.31 g/kg/day, their normalized creatinine appearance rate (nCAR) equaled 17 +/- 6.5 mg/kg/day, resulting in a percent lean body mass (%LBM) of 64 +/- 17% of actual body weight. Serum albumin correlated in a positive fashion with BMI, nPNA, nCAR and %LBM, but not with wCCr. CONCLUSIONS: The majority of indicator variables monitored by the PD-CPM have improved since 1995. PD patients have higher hemoglobins and a greater proportion of patients meet the criteria for adequate dialysis. Serum albumin values, however, remain marginal and unchanged over the five-year project. Furthermore, serum albumin values fail to correlate with the intensity of renal replacement therapy and are not strongly correlated with alternative estimates of nutritional status.

Adult↗
PubMed2001

Effect of cause and time of dropout on the residual GFR: a comparative analysis of the decline of GFR on dialysis.

BACKGROUND: The decline of residual renal function (RRF) on dialysis has been reported to be slower in peritoneal dialysis (PD) then hemodialysis (HD). However, some clinicians have questioned whether this reported difference might not be caused by selection bias. In particular, if continuous ambulatory PD (CAPD) delivers only marginally adequate therapy as some clinicians speculate, then perhaps those patients on CAPD with low glomerular filtration rate (GFR) are purposefully switched to HD. If true, transferring CAPD patients with low GFR to HD could create a selection bias that very well may account for the differences in GFR between PD and HD. This is particularly problematic if one then censors patients at the time of transfer from PD to HD from analysis (that is, patients are no longer followed in the study once they have switched treatment modalities). When this occurs, the data are said to be informatively censored, a term used by statisticians to describe any kind of systematic bias associated with censored or incomplete data. In particular, informative censoring occurs when patients who die or transfer to another modality very early have an associated lower starting GFR or higher rate of decline of GFR than patients who either complete the study or who die or transfer much later. If patient dropout is indeed related to the rate of decline in GFR and if this relationship differs between PD and HD but is ignored in the analysis, then the results of such analysis may be biased. METHODS: This article analyzes the decline in GFR among 141 incident dialysis patients (39 HD and 102 PD) undergoing either HD or PD at the University of Missouri-Columbia. The decline in GFR was modeled as a nonlinear function of time, taking into account the possibility that missing values of GFR may be associated with patient dropout (death, transfer to another modality, or transplantation). To safeguard against this possibility, we utilized a conditional nonlinear mixed-effects model. The model was used to fit and compare each patient's GFR data to time adjusting for the patient's treatment modality (HD vs. PD), cause of dropout (death, transfer, transplant, lost to follow-up/study ended), and time to dropout. The model allowed a comparison of the starting GFR and the rate of decline in GFR between PD and HD adjusting for these three factors. RESULTS AND CONCLUSIONS: The results of our analysis suggest that such informative censoring is independent of treatment modality and that even after correcting for dropout caused by death or transfer to another modality, patients starting on PD have a lower rate of decline in GFR (that is, better preservation of GFR) than patients starting on HD.

Aged↗
PubMed1999

1997 Peritoneal Dialysis-Core Indicators Study: Dialysis Adequacy and Nutritional Indicators Report.

The 1997 Peritoneal Dialysis-Core Indicators Study: Dialysis Adequacy and Nutritional Indicators Report documents the current status of peritoneal dialysis within the United States. A national random sample of adult peritoneal dialysis (PD) patients participating in the United States End Stage Renal Disease (ESRD) program was surveyed. PD subjects were large, with a mean body weight of 76 +/- 18.9 kg (mean +/- 1 SD) and a body mass index (BMI) of 27 +/- 6.4. The dialysis prescriptions documented achieved a mean weekly Kt/Vurea (wKt/V) and weekly creatinine clearance (wCrCl) of 2. 45 +/- 2.29 and 65.5 +/- 35.2 L/wk/1.73m2, respectively. The serum albumin of these patients was 3.5 +/- 0.48 g/dL, their normalized protein equivalent of nitrogen appearance (nPNA) 1.0 +/- 0.63 g/kg/d, and their normalized creatinine appearance rate (nCAR) 14 +/- 6.0 mg/kg/d. Serum albumin correlated meagerly but in a positive fashion with BMI, nPNA, and nCAR, and negatively with wCrCl. Among adult US PD patients, serum albumin values appear to correlate poorly with alternative measures of nutritional status and are inversely related to the intensity of renal replacement therapy. The presumptive dietary protein intake (nPNA) and creatinine appearance rate (nCAR) derived for PD patients do correlate in a positive fashion with dialysis delivery, at least up to a wCrCl of 60 to 80 L/wk/1.73 m2 and wKt/V = 2.1, but their values suggest that 30% to 50% of PD patients have marginal nutritional status.

Adolescent↗
PubMed1999

Cycler adequacy and prescription data in a national cohort sample: the 1997 core indicators report. Health Care Financing Administration Peritoneal Dialysis Core Indicators Study Group.

BACKGROUND: The Health Care Financing Administration Peritoneal Dialysis Core Indicator Project obtains data yearly in four areas of patient care: dialysis adequacy, anemia, blood pressure, and nutrition. METHODS: Adequacy and dialysis prescription data were obtained using a standardized data abstraction form from a random sample of adult U.S. peritoneal dialysis patients who were alive on December 31, 1996. RESULTS: For the cohort receiving cycler dialysis, 22% were unable to meet the National Kidney Foundation Dialysis Outcome Quality Initiatives (NKF-DOQI) dialysis adequacy guidelines because they did not have at least one adequacy measure during the six-month period of observation. Thirty-six percent of patients met NKF-DOQI guidelines for weekly Kt/V urea, 33% met guidelines for weekly creatinine clearance (CCr), and 24% met guidelines for both urea and creatinine clearances. The mean weekly adequacy values were 2.24 +/- 0.56 for Kt/V urea and 67.5 +/- 24.4 liter/1.73 m2 for CCr, and the median values were 2.20 and 62.25 liter/1.73 m2, respectively. The mean prescribed 24-hour volume was 12,040 +/- 3255 ml, and the median prescribed volume was 11,783 ml. Only 60% of patients were prescribed at least one daytime dwell. By logistic regression analysis, risk factors for an inadequate dose of dialysis included being in the highest quartile of body surface area (odds ratio = 3.3 for CCr and 3.4 for Kt/V urea) and a duration of dialysis greater than two years (odds ratio = 4.2 for CCr and 2.1 for Kt/V urea). CONCLUSION: There is much room for improvement in providing an adequate dose of dialysis to cycler patients. Practitioners should be more aggressive in increasing dwell volumes, adding daytime dwells, and adjusting nighttime dwell times in order to compensate for the loss of residual renal function over time. These changes can only be accomplished if practitioners measure periodically the dose of dialysis as outlined in the NKF-DOQI guidelines.

Adolescent↗
PubMed1994

Lean body mass estimation by creatinine kinetics.

A new technique for estimating lean body mass (LBM) from creatinine kinetics has been developed. It is based on the principle that creatinine production is proportional to LBM and that, in the steady state, creatinine production is equal to the sum of creatinine excretion (urinary and dialytic) and metabolic degradation. This technique was applied to 17 normal subjects, 26 stable, chronic hemodialysis (HD) patients, and 71 stable, chronic peritoneal dialysis (PD) patients. In the HD group, LBM was also determined by bioimpedance in 11 patients and calculated from total body water, measured as the volume of urea distribution of a sterile urea infusion, in 15 patients. In normal subjects and in the PD group, LBM was assessed by creatinine kinetics as well as by bioimpedance, near infrared, and anthropometric techniques. In the HD patients, LBM by creatinine kinetics correlated significantly with LBM from total body water and the bioimpedance technique. There was no statistical difference between the total body water and creatinine kinetics techniques, but the bioimpedance values were systematically higher than those obtained by the kinetic technique. In the PD group and in normal volunteers, LBM values by creatinine kinetics correlated significantly with the other methods but were lower. Forty-seven percent of the HD patients and 66% of the PD patients had significantly lower LBM by creatinine kinetics than expected for their sex and age. Estimation of LBM by creatinine kinetics is proposed as a simple and convenient technique for the routine nutritional assessment of dialysis patients.

Anthropometry↗
PubMed1993

Age and indices of adequacy and nutrition in CAPD patients.

We have examined the correlations of age with 95 demographic, clinical, and laboratory parameters in a continuous ambulatory peritoneal dialysis (CAPD) population. Significant inverse correlations were found with lean body mass, dialysate creatinine concentration, serum creatinine concentration, and dialysate creatinine nitrogen output in grams per week; all these findings are compatible with the well-known decrease in muscle mass with aging. Urea nitrogen output in dialysate and urine predicts Kjeldahl nitrogen output in urine and dialysate applying the Randerson equation similarly in older and younger CAPD patients. The relationship of normalized net protein catabolic rate to weekly urea clearance normalized to total body water is similar for older and younger CAPD patients. Older and younger patients have similar values for serum albumin concentration. In conclusion, the findings suggest that comparable weekly creatinine clearances should yield much lower serum creatinine concentrations in older patients. Poor protein intakes in the elderly should not be attributed to age if weekly urea clearances are low. Increases in protein intake in response to increases in urea clearances are similar in older and younger CAPD patients.

Adult↗
PubMed1993

Cross sectional assessment of weekly urea and creatinine clearances and indices of nutrition in continuous ambulatory peritoneal dialysis patients.

OBJECTIVE: To perform a cross sectional analysis in 71 patients on continuous ambulatory peritoneal dialysis (CAPD) to identify significant correlations of weekly small solute clearances and indices of nutritional status with each other and with patient demographics and other commonly monitored clinical and laboratory parameters. DESIGN: This was a retrospective, cross sectional analysis in 71 patients on CAPD from less than 1 to 105 patient-months (average, 20 months). SETTING: An outpatient CAPD program. PATIENTS: All patients on CAPD in our program at the time of the study willing to undergo the clearance and nutritional status measurements. INTERVENTIONS: No interventions other than the monitoring of their status. MAIN OUTCOME MEASURES: Weekly small solute clearances, dietary protein intake, serum albumin, lean body mass, net protein catabolic rate, and urinary and dialysate nitrogen. RESULTS: Weekly Kt/V urea (weekly urea clearance normalized to total body water) of at least 1.7 and weekly total creatinine clearances (liter/week/1.7 m2) of at least 50 are associated with net protein catabolic rates (PCR) greater than 0.9 g/kg of normalized body weight in average CAPD patients. Kt/V urea and net PCR correlate significantly with serum albumin. High transporters identified by the peritoneal equilibration test have greater albumin losses and lower serum albumin concentrations. Estimates of lean body mass correlate significantly with serum albumin and net PCR; lean body mass correlates significantly and inversely with age. CONCLUSIONS: Greater small solute clearances are associated with better nutritional status.

Adult↗
PubMed1990

Plasma and dialysate immunoglobulin G in continuous ambulatory peritoneal dialysis patients: a multicenter study.

Peritoneal dialysate immunoglobulin (Ig)G concentrations were measured in 120 continuous ambulatory peritoneal dialysis (CAPD) patients evaluated at four dialysis centers in different countries to assess the normal range for dialysate IgG and to investigate the relationships of this protein levels with peritoneal episodes, For 65 of these patients, plasma IgG levels were determined, and IgG clearances were calculated. The mean dialysate concentration of IgG was 6.9 +/- 4.2 mg/dl, and there was no difference between men and women or between patients who had or had not previously undergone hemodialysis. Dialysate IgG concentrations were significantly related to residual renal creatinine clearance and negatively correlated with dialysate volume, plasma albumin and total protein. There were no significant correlations between IgG levels in the dialysate and age, protein losses in the dialysate, time on CAPD or time from the last peritonitis episode. Plasma and dialysate IgG were unrelated to the incidence of peritonitis, statistical analysis being performed with different methods. These results suggest that IgG levels in the dialysate or plasma are not a major factor in the prevention of CAPD peritonitis.

Ascitic Fluid↗
PubMed1990

Defining adequacy of CAPD with urea kinetics.

The purpose of this paper is to explore the validity of applying urea kinetic indices to CAPD. According to the peak concentration hypothesis, the values of Kt/V required for adequate dialysis are lower for CAPD than for hemodialysis because of the continuous steady state nature of CAPD. Pilot clinical studies were undertaken in 19 patients to correlate the (Kt/V)urea index with clinical assessment of adequacy based on a 12 parameter score. The data shows that the correlation between serum urea nitrogen (Kt/V)urea and protein catabolic rate (PCR) are in keeping with the theoretical predictions of the urea kinetic model. PCR and dietary protein are well correlated. Also, PCR and Kt/V had a high degree of positive correlation. Serum creatinine was inversely correlated with (Kt/V)creatinine. In 74% of the patients, the clinical assessment of adequacy was in agreement with the (Kt/V)urea domains of adequacy established from the peak concentration hypothesis and the urea kinetic model. The lack of correlation in the remaining 26% is being investigated.

Blood Urea Nitrogen↗
PubMed1986

Peritonitis in continuous ambulatory peritoneal dialysis: analysis of an 8-year experience.

Experiences with peritonitis in a continuous ambulatory peritoneal dialysis (CAPD) program at a single center over 8 years were reviewed. Home-acquired peritonitis rates have been less than 1 episode per patient year since 1982. Gram-positive organisms continue to account for most episodes in a similar proportion. Actual known contamination could be pinpointed in only 7.4% of cases, but was strongly suspected in 35.8% of episodes. Exit site and/or tunnel infections were thought to have caused 20% of the cases. Intrinsic peritonitis probably accounted for 10.5%. Recurrence of peritonitis with the same organisms following cessation of antibiotics represented only 2.1% of cases.

Bacterial Infections↗
PubMed1980

Continuous ambulatory peritoneal dialysis: three-year experience at one center.

Three years of clinical experience with continuous ambulatory peritoneal dialysis are summarized. Serum urea nitrogen, creatinine, hematocrit, nerve conduction velocity, calcium, inorganic phosphorus, serum proteins, and electrolytes have been maintained in acceptable ranges. Peritonitis, although reduced in incidence because of solutions in plastic bags and a new adapter, is still a problem. Excessive carbohydrate absorption, obesity, and high serum triglyceride concentrations may be long-term problems in some patients.

Adolescent↗
PubMed1979

Follow-up of peritoneal clearances in patients undergoing continuous ambulatory peritoneal dialysis.

Continuous ambulatory peritoneal dialysis (CAPD) might result in peritoneal membrane changes. First, CAPD exposes essentially continuously the peritoneum to peritoneal dialysis solutions. Such solutions differ from the usual extracellular fluid bathing peritoneal tissues. Second, this technique may be complicated by an increased frequency of peritonitis when compared to intermittent peritoneal dialysis. We undertook a prospective study of patients undergoing CAPD to determine if there were decreases in peritoneal clearances and if the peritoneal microcirculation maintained its responsiveness to nitroprusside. Peritoneal transport, as assessed by the clearances of urea, creatinine, inulin, and dialysate protein concentration, with and without nitroprusside addition in the dialysis solution, is unchanged in patients undergoing CAPD for up to 1 year, despite frequent episodes of peritonitis.

Adult↗