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F K Port

Publications and source records attributed to F K Port.

At least 73 records · Page 4Linked to original sources
PubMed1997

Vascular access survival among incident hemodialysis patients in the United States.

Vascular access failure causes substantial morbidity to hemodialysis patients. We sought to identify factors determining survival of the permanent vascular access in use at the start of end-stage renal disease during 1990 in a national sample of 784 incident hemodialysis patients insured by Medicare. Medicare claims records were used to identify access failures or revisions among patients with an arteriovenous (AV) fistula (n = 245) and an AV vascular graft (n = 539). A proportional hazards analysis of time to first failure or revision, controlled by stratification for sex, race, and cause of end-stage renal disease, was used to determine the effect of age, access type, and peripheral vascular disease on vascular access survival. Patients with an AV fistula and who were older than 65 years had a risk of access failure that was 24% lower than similar patients with an AV graft (P < 0.02). The relative risk of access failure for an AV fistula, but not an AV graft, varied significantly with age for patients younger than 65 years (P < 0.01). The relative risk of access failure for a patient with an AV fistula, compared with a patient of the same age with an AV graft, was 67% lower at the age of 40 years, 54% lower at the age of 50 years, and 24% lower at the age of 65 years. A history of peripheral vascular disease was associated with a 24% higher risk of AV graft or fistula failure (P = 0.05). Measures to decrease vascular access-related morbidity among hemodialysis patients should include reversing the current trend toward increasing use of AV grafts, particularly in patients younger than 65 years.

Age Factors↗
PubMed1997

Withdrawal from dialysis: a review with an emphasis on the black experience.

Withdrawal from dialysis has been shown to be a common occurrence in treated end-stage renal disease. Interestingly, there have been several reports documenting that blacks withdraw from dialysis one half to one third the rate of whites. There has been little research into the reasons for this marked discrepancy. This article reviews the existing literature on the different rates of withdrawal in blacks compared with whites. It then draws on a broad range of literature, including sociology, psychiatry, and anthropology, to propose possible reasons for the differences. From this review, it would seem that both medical and cultural factors play important roles in the decisions about withdrawal, but that cultural beliefs and attitudes are more important. More research is needed in both the medical and cultural aspects of rates of withdrawal to help explain the observed differences in blacks compared with whites.

Black or African American↗
PubMed1997

An analysis of risk factors for withdrawal from dialysis before death.

Withdrawal from dialysis has been a significant cause of mortality among dialysis patients, accounting for 6 to 22% of deaths. Since 1990, a new death notification form has allowed more detailed analyses of withdrawal from dialysis separate from causes of death. Using the U.S. Renal Data System data base, this study examined 116,829 deaths in adult patients from 1990 to 1995. Adjusted odds ratios were calculated for the risk of withdrawal using logistic regression. Adjustments included age at death, ethnicity, gender, cause of death, primary cause of end-stage renal disease, time on dialysis, and dialysis modality. In addition, odds ratios of withdrawal were calculated for deaths in patients who started dialysis after age 65. Death was preceded by withdrawal significantly more frequently in women than in men, more than twice as frequently in Caucasians than in African-Americans or Asians, and more frequently in older than in younger age groups. Patients who died of chronic diseases (e.g., dementia, malignancy) were much more likely to withdraw before death, whereas patients who died from more acute causes (e.g., coronary artery disease) were less likely to withdraw before death. It is concluded that patients who are Caucasian, female, older, or die of chronic or progressive diseases are more likely to withdraw from dialysis before death. The ethnic and gender differences in withdrawal do not appear to have a medical explanation from this analysis. Further research along sociologic lines is needed to better explain the differences in withdrawal from chronic dialysis.

Adolescent↗
PubMed1996

Epidemiological perspective on infections in chronic dialysis patients.

Infectious complications are a source of substantial morbidity and a common cause of death among dialysis patients. This article considers the magnitude and impact of the problem of infection among patients treated with hemodialysis (HD) and peritoneal dialysis (PD) using data from national registries and large cohort studies of patients with end-stage renal disease (ESRD). United States Renal Data System (USRDS) data indicate that in the United States for years 1991 to 1992, infection accounted for 12% of all deaths among HD patients and 15% of all deaths among PD patients. Septicemia was the underlying cause in 76% of these infectious deaths among HD patients, of which the vascular access, peritonitis, peripheral vascular disease, and other causes accounted for 12%, 5%, 24%, and 59% respectively. Among PD patients, septicemia accounted for 79% of infectious deaths. Of these deaths attributable to septicemia, peritonitis, peripheral vascular disease, and other causes were reported as the cause in 35%, 23%, and 41% respectively. Infection is also a major cause of morbidity in the dialysis population. Among HD patients, an average of 7.6 bacteremic episodes per 100 patient years (0.076 per year) has been described, of which 48% were associated with access infections. Among PD patients, studies have reported peritonitis rates ranging from 1 in 7.6 to 21.5 months (0.56 to 1.58 per patient year) and exit and/or tunnel infections occurring at a rate of 0.6 episodes per year. The known predictors of infectious complications among these populations are reviewed.

Humans↗
PubMed1996

Comparison of mortality with home hemodialysis and center hemodialysis: a national study.

We sought to determine whether lower mortality rates reported with hemodialysis (HD) at home compared to hemodialysis in dialysis centers (center HD) could be explained by patient selection. Data are from the United States Renal Data System (USRDS) Special Study Of Case Mix Severity, a random national sample of 4,892 patients who started renal replacement therapy in 1986 to 1987. Intent-to-treat analyses compared mortality between home HD (N = 70) and center HD patients (N = 3,102) using the Cox proportional hazards model. Home HD patients were younger and had a lower frequency of comorbid conditions. The unadjusted relative risk (RR) of death for home HD patients compared to center HD was 0.37 (P < 0.001). The RR adjusted for age, sex, race and diabetes, was 44% lower in home HD patients (RR = 0.56, P = 0.02). When additionally adjusted for comorbid conditions, this RR increased marginally (RR = 0.58, P = 0.03). A different analysis using national USRDS data from 1986/7 and without comorbid adjustment showed patients with training for self care hemodialysis at home or in a center (N = 418) had a lower mortality risk (RR = 0.78, P = 0.001) than center HD patients (N = 43,122). Statistical adjustment for comorbid conditions in addition to age, sex, race, and diabetes explains only a small amount of the lower mortality with home HD.

Adolescent↗
PubMed1996

The dose of hemodialysis and patient mortality.

The relationship between the delivered dose of hemodialysis and patient mortality remains somewhat controversial. Several observational studies have shown improved patient survival with higher levels of delivered dialysis dose. However, several other unmeasured variables, changes in patient mix or medical management may have impacted on this reported difference in mortality. The current study of a U.S. national sample of 2,311 patients from 347 dialysis units estimates the relationship of delivered hemodialysis dose to mortality, with a statistical adjustment for an extensive list of comorbidity/risk factors. Additionally this study investigated the existence of a dose beyond which more dialysis does not appear to lower mortality. We estimated patient survival using proportional hazards regression techniques, adjusting for 21 patient comorbidity/risk factors with stratification for nine Census regions. The patient sample was 2,311 Medicare hemodialysis patients treated with bicarbonate dialysate as of 12/31/90 who had end-stage renal disease for at least one year. Patient follow-up ranged between 1.5 and 2.4 years. The measurement of delivered therapy was based on two alternative measures of intradialytic urea reduction, the urea reduction ratio (URR) and Kt/V (with adjustment for urea generation and ultrafiltration). Hemodialysis patient mortality showed a strong and robust inverse correlation with delivered hemodialysis dose whether measured by Kt/V or by URR. Mortality risk was lower by 7% (P = 0.001) with each 0.1 higher level of delivered Kt/V. (Expressed in terms of URR, mortality was lower by 11% with each 5 percentage point higher URR; P = 0.001). Above a URR of 70% or a Kt/V of 1.3 these data did not provide statistical evidence of further reductions in mortality. In conclusion, the delivered dose of hemodialysis therapy is an important predictor of patient mortality. In a population of dialysis patients with a very high mortality rate, it appears that increasing the level of delivered therapy offers a practical and efficient means of lowering the mortality rate. The level of hemodialysis dose measured by URR or Kt/V beyond which the mortality rate does not continue to decrease, though not well defined with this study, appears to be above current levels of typical treatment of hemodialysis patients in the U.S.

Female↗
PubMed1996

Relationship of dose of hemodialysis and cause-specific mortality.

A number of studies have found a relationship of lower all-cause mortality risk for ESRD patients treated with increasing dose of dialysis. The objective of this study was to determine the relationship of delivered dose of dialysis with cause-specific mortality. Data from the USRDS Case Mix Adequacy Study, which includes a national random sample of hemodialysis patients, were utilized. To minimize the contribution of unmeasured residual renal function, the sample used in this analysis (N = 2479) included only patients on dialysis for one year or more. Cox proportional hazards models, stratified for diabetes, were used to analyze the effect of delivered dose of dialysis (measured and reported by both Kt/V and URR) on major causes of death and withdrawal from dialysis, adjusting for other covariates including demographics, comorbid diseases present at start of study, functional status, laboratory values and other dialysis parameters. Patient follow-up for mortality was censored at the earliest of time of transplantation, 60 days after a switch to peritoneal dialysis or at the time of data abstraction. For each 0.1 higher Kt/V, the adjusted relative risk of death due to coronary artery disease was 9% lower (RR = 0.91, P < 0.05), due to other cardiac causes was 12% lower (RR = 0.88, P < 0.01), due to cerebrovascular disease (CVD) was 14% lower (RR = 0.86, P < 0.05), due to infection was 9% lower (RR = 0.91, P = 0.05), and due to other known causes was 6% lower (RR = 0.94, P < 0.05). There was no statistically significant relationship of Kt/V and risk of death among patients who died of malignancy (RR = 0.84, P = 0.10) or among patients whose death cause was missing (RR = 0.95, P = 0.41). The risk of withdrawal from dialysis prior to death due to any cause was 9% lower (RR = 0.91, P < 0.05) for each 0.1 higher Kt/V. The relationships of delivered dose of dialysis, as measured by URR, and cause-specific mortality were essentially similar in relative magnitude and statistical significance as the relationships observed using Kt/V as the measurement of dialysis dose, with the exception that the relationship was less significant for cerebrovascular disease and withdrawal from dialysis. The relationship of dialysis dose with risk of death due to each cause of death category except other cardiac causes and "other" causes appeared to be of greater magnitude and of greater statistical significance among diabetics than non-diabetics. These results indicate that low dose of dialysis is not associated with mortality due to just one isolated cause of death, but rather is due to a number of the major causes of death in this population. This study is consistent with hypotheses that low doses of dialysis may promote atherogenesis, infection, malnutrition and failure to thrive through a variety of pathophysiologic mechanisms. Further study is necessary to confirm these results and to test hypotheses that are developed.

Adult↗
PubMed1996

Effect of the dialysis membrane on mortality of chronic hemodialysis patients.

Mortality of prevalent chronic hemodialysis patients remains high. The potential effect of the dialysis membrane on this mortality has not been previously investigated in a large population of chronic hemodialysis patients. Using data from the United States Renal Data System (USRDS), we analyzed a random sample of 6,536 patients receiving hemodialysis on December 31, 1990. The study design was a historical prospective study. By limiting the study to patients dialyzed for at least one year with bicarbonate dialysate, in whom the dose of dialysis could be calculated, and in whom dialysis membrane and co-existing morbidities were defined, the sample size was reduced to 2,410 patients. A Cox proportional hazards model was used to estimate relative mortality risk. The types of dialysis membranes used were broadly classified into three categories: unsubstituted cellulose, modified cellulose (generally cellulose membranes that have been modified by substitutions of some or most of their hydroxyl moieties) and synthetic membranes that are not cellulose-based. The results of the study suggest that after adjusting for the dose of dialysis and the presence of co-morbid factors, the relative risk of mortality of patients dialyzed with modified cellulose or synthetic membranes was at least 25% less than that of patients treated with unsubstituted cellulose membranes (P < 0.001). To account for the possibility that these differences were due to regional practice patterns, we further stratified the data for nine different regions. There was still a 20% difference in relative risk of mortality between membrane groups with the mortality statistically significantly less in patients treated with synthetic membranes (P < 0.045) compared to patients dialyzed with unsubstituted cellulose membranes. The results of this study suggest that the dialysis membrane plays an important role in the outcome of chronic hemodialysis patients. However, more definitive studies are needed before a cause and effect relationship can be proven.

Cellulose↗
PubMed1996

Using USRDS generated hospitalization tables to compare local dialysis patient hospitalization rates to national rates.

Hospitalization tables of the U.S. Renal Data System allow description of national hospitalization rates among incident and prevalent dialysis patients in five-year age groups. These rates are further stratified by sex, race, and four primary disease categories. Based on these tables derived from the data on over 250,000 incident and prevalent patients during 1991 to 1993, a methodology is described that allows comparison of local (for example, dialysis facility) or regional "first admission" rates among incident and prevalent dialysis patients to the national rates. A standardized hospitalization ratio is introduced to facilitate such comparisons, and methods for assessing statistical significance are discussed. Since this methodology allows adjustment for age, race, sex, and primary disease, it can serve as useful tool for dialysis research. It can also be used at the dialysis facility level, alone or in conjunction with the standardized mortality ratio, to facilitate local quality assurance.

Adolescent↗
PubMed1996

ESRD patient mortality with adjustment for comorbid conditions in Lombardy (Italy) versus the United States.

The present study evaluated end-stage renal disease (ESRD) patient survival in Lombardy, Italy, and the United States (U.S.) using data from two registries, the Lombardy Dialysis and Transplant Registry (RLDT) and the U.S. Renal Data System (USRDS), respectively. For this purpose, 4,196 white patients (2,900 from the USRDS Case Mix Severity Study and all 1296 from RLDT) who started renal replacement therapy in 1986 and 1987 were studied. Compared to Lombardy patients, those in the USA were significantly older (mean age 59.9 +/- 16.4 vs. 55.9 +/- 14.7 years), had a lower proportion of males (53.7 vs. 62.1%), a greater proportion with diabetic nephropathy (29.9 vs. 9.7%) and a significantly greater proportion of patients with the recorded comorbid conditions (heart disease, peripheral vascular disease, cirrhosis, cachexia, malignancy). U.S. patients were less frequently treated with peritoneal dialysis (PD) by day 30 of ESRD (21.2 vs. 30.7). Survival was compared in the Cox proportional hazard regression model, using age, sex, comorbid conditions and early modality of treatment as explanatory covariates. Overall, 48% of the 4196 patients died during the 48 to 72 months follow-up to 12/31/91. Per 100 patient-years the gross death rate for USRDS patients was 28.7 compared to 13.0 of RLDT patients. The unadjusted death relative risk for RLDT was 0.439, that is, 56% lower death rate compared to USRDS patients. Age, sex, diabetic status, each of the recorded comorbid conditions and treatment modality were significantly related to survival and included in the model. The Cox cumulative survival adjusted for all these explanatory covariates survival was for U.S. patients 84.4% at one year, 67.0% at two years and 33.4% at five years, and for RLDT patients 88.3% at one year, 75.9% at two years and 45.9% at five years. The relative mortality risk (RR) for the patients treated in Lombardy adjusted for all the reported covariates was 29% lower than for US patients (RR = 0.71; P < 0.0001). This comparative risk varied significantly by age (P < 0.0001) and was 65 percent lower for Lombardy compared to U.S. patients in the age range 25 to 44 years (RR = 0.35) and about 20% lower for patients over age 65 years (RR = 0.80). This relative risk was mainly related to hemodialysis and was not statistically significant for PD patients. The observed lower mortality risk in Lombardy was less pronounced when adjusted for demographic and comorbid covariates, but was still large and therefore suggests the need for further studies regarding treatment related factors and unmeasured patient factors, particularly in hemodialysis patients.

Adult↗
PubMed1996

The effects of recombinant human erythropoietin on functional health and well-being in chronic dialysis patients.

As a component of the open-label, multicenter National Cooperative Recombinant Human Erythropoietin (Epo) Study, the health-related quality-of-life effects of Epo therapy were assessed in 484 dialysis patients who had not previously been treated with Epo therapy (New-to-Epo) and 520 dialysis patients who were already receiving Epo therapy at the time of study enrollment (Old-to-Epo). Using scales from the Medical Outcomes Study 36-item Short Form Health Survey (SF-36), health-related quality of life was assessed on study enrollment (baseline) and at an average of 99 days follow-up. At baseline, SF-36 scores for Old- and New-to-Epo patients were well below those observed in the general population, reflecting substantial impairments in functional status and well-being among patients with chronic renal failure. Significant improvements from baseline to follow-up were observed among New-to-Epo patients in vitality, physical functioning, social functioning, mental health, looking after the home, social life, hobbies, and satisfaction with sexual activity (P < 0.05 for each). The mean improvements in hematocrit values among New-to-Epo and Old-to Epo patients were 4.6 and 0.3, respectively. At the time of follow-up, SF-36 scores for New-to-Epo patients were comparable with those observed among Old-to-Epo patients, whose scores did not change significantly from baseline to follow-up. Analysis of the relationship between Epo therapy, hematocrit values, and health-related quality of life suggest that some of the beneficial quality-of-life effects of Epo are mediated through a change in hematocrit level.

Activities of Daily Living↗
PubMed1996

Gender discrepancies in living related renal transplant donors and recipients.

Renal transplantation is the most successful treatment strategy for patients with ESRD to improve survival and quality of life. The study presented here examines the relationship of gender and living related (LR) transplantation donor and recipient rates in the United States. National data from the United States Renal Data System (USRDS) were used for this study. All LR transplants occurring between 1991 and 1993 among blacks and whites were included (N = 6193). Transplantation and donation rates for men and women were calculated. Poisson regression was used to calculate female/male transplantation and donation rate ratios. Overall, women were 10% less likely to receive a LR transplant than men (rate ratio [RR] = 0.90, P < 0.001). This gender difference increased over time from 1991 (Female/Male RR = 0.95, P = not significant [NS]) to 1993 (RR = 0.85, P < 0.001). In contrast, women were significantly more likely to donate a kidney than men (RR = 1.28, P < 0.001 and RR = 1.29, P < 0.001 among whites and blacks, respectively). Analyses by age subgroups revealed that only among ESRD patients aged 20 to 44 yr was the likelihood of receiving a LR kidney transplant equal for men and women. Higher donation rates among women compared with men were observed in all donor age and race subgroups except young blacks (aged 0 to 19 yr). Recipient gender appeared to influence donation rates. The female-to-male relative donation rates were higher when donations were to female, compared with male, recipients. This study of national data suggests an imbalance in LR donation and transplantation between men and women. Women are more likely to donate a kidney but are less likely to receive a LR transplant than men. Several potential explanatory factors are explored. These findings suggest a need for the development of gender-appropriate interventions to encourage donation among men and LR transplantation among women, to ultimately facilitate greater use of this ESRD treatment modality.

Adolescent↗
PubMed1995

Transient effects in the Cox proportional hazards regression model.

We consider a model for mortality rates that includes both the long and short term effects of switching from an initial to a second state, for example, when patients receive an initial treatment and then switch to a second treatment. We include transient effects associated with the switch in the model through the use of time-dependent covariates. One can choose the form of the time-dependent covariate to correspond with a variety of possible transition patterns. We use an exponential decay model to compare the survival experience of transplant versus dialysis treatment of end stage renal disease (ESRD) patients from the Michigan Kidney Registry (MKR). This model involves a hazard function that has an initial effect in mortality at the time of transplant, expected to be higher, followed by a smooth exponential decay to a long term effect, expected to be lower than the risk for those remaining on dialysis. Cox and Oakes used this model to analyse the Stanford Heart Transplant data. The model implicitly suggests there is a time at which the hazard curves (and survival curves) for the treatment groups cross. Those crossing times are useful in advising patients who have the option of receiving a transplant. We describe methods for obtaining estimates of the crossing times and their associated variances, and then apply them in analysing the MKR data.

Cadaver↗
PubMed1995

The low birth weight hypothesis as a plausible explanation for the black/white differences in hypertension, non-insulin-dependent diabetes, and end-stage renal disease.

It is well known that black Americans have a higher risk for low birth weight (LBW) than white Americans. In addition, blacks are at a higher risk for hypertension (HT), non-insulin dependent diabetes mellitus (NIDDM), and end-stage renal disease (ESRD), particularly ESRD attributed to HT (ESRD-HT) and NIDDM (ESRD-NIDDM). It has been shown that LBW is associated with postpartum anatomic and functional alterations in the kidney and pancreas as well as with progressive renal damage in animals and increased risk for HT and NIDDM during adulthood in humans. Based on these empirical findings, it is here proposed that a greater risk of HT, NIDDM, and ESRD, particularly ESRD-HT and ESRD-NIDDM, in black Americans during adulthood may be partly related to their higher risk of LBW. However, LBW is proposed here as a component factor rather than a sufficient cause or a necessary factor for the development of these diseases. The ultimate contribution of LBW to the black/white disparities regarding HT, NIDDM, and ESRD may depend not only on the black/white differences in LBW but also on the race-specific prevalences of other component factors, both environmental/behavioral and genetic, that may or may not require the presence of LBW to cause each of these diseases.

Birth Weight↗
PubMed1995

Relative impact of donor type on renal allograft survival in black and white recipients.

Renal allograft survival of organs from living-related donors (LRDs) is superior to that of organs from cadaveric donors (CAD). Allograft survival rates are lower in black recipients of both CAD and LRD transplants compared with recipients of other races. It is not known whether the superior donor effect of LRD varies between races. We investigated the graft survival outcome of first renal transplants performed in the United States in 1986 and 1989 to determine whether the donor effect differs between black and white recipients. A measurement of "donor type effect" is introduced. There were 7,002 and 7,307 first renal transplants in 1986 and 1989, respectively, for which allograft survival data were available from the United States Renal Data Systems. Both black and white recipients showed a greater than 50% reduction in the risk of allograft loss at all the points studied up to 5 years posttransplant when LRD was chosen over CAD transplantation. A measurement of donor type effect indicates that graft loss is reduced by 7 to 21 percentage points at 1 and 5 years posttransplant. The donor type effect is proportionally equal in both races. Therefore, kidney donation from living relatives as a first transplant should be encouraged for all medically suitable end-stage renal disease patients as a means of improving outcome and reducing CAD transplantation waiting time for patients in whom LRD transplants cannot be performed.

Black People↗