A Risk Analysis of Continuous Ambulatory Peritoneal Dialysis-Related Peritonitis

Objective

We studied the clinical characteristics that influence the risk of dialysis-related peritonitis complication in incident Chinese patients undergoing continuous ambulatory peritoneal dialysis (CAPD).

Methods

A single center, retrospective, observational cohort study was carried out to examine the risk factors of developing a first episode of dialysis-related peritonitis.

Results

Between 1995 and 2004, 246 incident CAPD patients were recruited for analysis. During the study period of 897.1 patient-years, 85 initial episodes of peritonitis were recorded. The median peritonitis-free time for diabetic subjects was significantly worse than for nondiabetic subjects (49.0 ± 10.5 vs 82.3 ± 12.6 months, p = 0.0019). The difference was due mainly to a higher likelihood of developing peritonitis with gram-negative organisms in patients with diabetes mellitus ( p = 0.038). Low serum albumin concentration was also associated with worse peritonitis-free survival. There was a nonsignificant trend toward an increased risk for peritonitis in the group of patients with cerebrovascular disease. According to multivariate Cox proportional hazards model for the analysis of time to first peritonitis episode, the two independent risk factors were presence of diabetes mellitus and initial serum albumin concentration. In particular, diabetes mellitus was associated with a hazard ratio of 1.50 and a 95% confidence interval of 1.05 – 2.40 ( p = 0.030) to develop an initial peritonitis. Lower serum albumin level at the start of CAPD was a significant predictor of peritonitis, with hazard ratio of 1.67 for every decrease of 10 g/L, and 95% confidence interval 1.08 – 2.60 ( p = 0.021).

Conclusions

Our results confirm the susceptibility of diabetic CAPD and hypoalbuminemic patients to peritonitis, and highlight the role of further studies in reducing this complication.

Touch Contamination of Connection Devices in Peritoneal Dialysis-Aquantitative Microbiologic Analysis

Objective

To determine the level of bacterial contamination associated with touch contact of a connector set during peritoneal dialysis (PD).

Design

The experiment utilized a laboratory-based simulation of a bag exchange procedure. Deliberatetouch contamination of the connector set spike was followed by quantitative recovery of micro-organisms from the connector and, in some cases, the dialysis bag.

Subjects

Patients undergoing PD were used as the “test” group. Departmental secretarial and laboratory staff served as the comparative control group.

Setting

The patients were voluntary subjects from a PD outpatients unit and were tested in their own homes.

Outcome

The numbers of micro-organisms contaminating a connector set and entering the dialysis bag during a touch-contamination event were determined. Additionally we identified hand hygiene and, in particular, the care taken to dry the hands after washing as being highly relevant to microbial touch-contamination levels. Patient hand disinfection, as practised in most PD units, effectively reduced touch contamination to low levels.

Results

Touch contamination of a connector set with unprepared hands led to fewer than 100 micro-organisms translocating from fingers to the spike. If the hands were washed but not dried before touch contact was made, up to 4500 micro-organisms trans located to the connector set spike. Air-towel drying of washed hands before touch contact reduced the translocating numbers by 95% -99%. Hand disinfection, as routinely practiced by PD patients, reduced the bacterial numbers reaching the peritoneal cavity after touch contamination to <5. The range of micro-organisms isolated from the fingers of PD patients using hand disinfectants on a regular basis showed considerably more diversity than the control group.

Conclusion

Hand care prior to bag exchange has a major effect on touch-contamination levels. Accidental touch contact of connecting devices by unprepared hands using a PD-bag exchange procedure leads to the translocation of 500 micro-organisms or fewer to the connector device. If the hands are wet at the time of contact the number translocating can be as high as 4500. Hand drying with an air towel before touch contact reduces the numbers translocating by 95% -99%. Hand disinfection procedures carried out prior to bag exchange minimizes touch-contamination levels.

Changes in Causative Organisms and Their Antimicrobial Susceptibilities in Capd Peritonitis: A Single Center's Experience over one Decade

Background

In recent years, the rate of peritonitis during continuous ambulatory peritoneal dialysis (CAPD) has been significantly reduced. However, peritonitis remains a major complication of CAPD, accounting for considerable mortality and hospitalization among CAPD patients.

Objective

To generate a “center tailored” treatment protocol for CAPD peritonitis by examining the changes of causative organisms and their susceptibilities to antimicrobial agents over the past 10 years.

Method

Retrospective review of the medical records of 1015 CAPD patients (1108 episodes of peritonitis) who were followed up from 1992 through 2001.

Results

The overall incidence of peritonitis was 0.40 episodes/patient-year. The annual rate of peritonitis and the incidence of peritonitis caused by a single gram-positive organism were significantly higher in 1992 and 1993 compared with those in the rest of the years ( p < 0.05). The incidence of peritonitis due to coagulase-negative staphylococcus (CoNS) decreased significantly over time, whereas there was no significant change in the incidence of Staphylococcus aureus (SA)-induced peritonitis. Among CoNS, resistance to methicillin increased from 18.4% in 1992 – 1993 to 41.7% in 2000 – 2001 ( p < 0.05). In contrast, the incidence of methicillin-resistant SA was not different according to the calendar year. Catheter removal rates were significantly higher in peritonitis due to a single gram-negative organism (16.6%) compared with gram-positive peritonitis (4.8%, p < 0.005). The mortality associated with peritonitis was also higher in gram-negative (3.7%) compared with gram-positive peritonitis (1.4%), but there was no statistical significance. Among single gram-positive organism-induced peritonitis, catheter removal rates were significantly higher in SA (9.3%) than those in CoNS (2.9%, p < 0.01) and other gram-positive organisms (2.9%, p < 0.05). In peritonitis caused by CoNS, the methicillin-resistant group showed significantly higher removal rates than the methicillin-susceptible group (8.2% vs 1.0%, p < 0.01).

Conclusion

The incidence of peritonitis for 2001 decreased to less than half that for 1992, due mainly to a significant decrease in CoNS-induced peritonitis, whereas the proportions of peritonitis due to a single gram-negative organism and methicillin-resistant CoNS increased. These findings suggest that it is necessary to prepare new center-based guidelines for the initial empirical treatment of CAPD peritonitis.

Prevention of Catheter Related Infections in Patients on CAPD

Catheter-related infections remain a serious problem for patients on peritoneal dialysis. Such infections can be reduced by careful patient selection and training, by the use of the best connection technology and screening and treating nasal carriage. To date, treatment is less than optimal and therefore, the primary goal should be prevention of catheter-related infections. Prevention is based on improving catheter design and implantation technique, while providing careful exit-site care. Regardless of how it is implemented, we must aggressively pursue the prevention of catheter-related infections by eradicating S.aureus exit-site carriage in PD patients. Based on its effectiveness in adult PD patients, its low rate of adverse effects, and its reasonable cost-effectiveness, application of mupirocin ointment at the exit-site is the current method of choice for preventing PD catheter infections caused byS. aureus. In addition to reducing S. aureus exit-site infections, mupirocin seems to reduce the rates of staphylococcal peritonitis and PD catheter loss. Whether the ointment should be applied in the nares, to the exit-site or both, and whether it should be used only in staphylococcal nasal carriers or all PD patients requires further study.

Peritoneal Dialysis-Related Peritonitis: Can We Predict It?

Peritonitis complicating peritoneal dialysis represents a major cause of technique failure, hospitalization, and increased mortality. Peritonitis tends to be recurrent and clustered within particular patients at risk. The aim of this review is to evaluate the potential predictive factors for development of peritoneal dialysis-associated peritonitis based on currently available evidence. Risk factors were divided into medical and non-medical ones, and characterized by a schema of fixed versus modifiable factors. A new direction in the landscape change of the risk factors of peritonitis appears to focus on psychosocial aspects and patient training. Identification of these factors have important clinical implications because of the hitherto lack of well-established strategies to prevent peritonitis complicating peritoneal dialysis. It is hoped that better understanding of the risk factors will allow us to take tangible steps toward minimizing the infectious burden from the Achilles' heel of peritoneal dialysis.

Antimicrobial agents for preventing peritonitis in peritoneal dialysis patients

BACKGROUND

Peritoneal dialysis (PD) is an important therapy for patients with end-stage kidney disease and is used in more than 200,000 such patients globally. However, its value is often limited by the development of infections such as peritonitis and exit-site and tunnel infections. Multiple strategies have been developed to reduce the risk of peritonitis including antibiotics, topical disinfectants to the exit site and antifungal agents. However, the effectiveness of these strategies has been variable and are based on a small number of randomised controlled trials (RCTs). The optimal preventive strategies to reduce the occurrence of peritonitis remain unclear.This is an update of a Cochrane review first published in 2004.

OBJECTIVES

To evaluate the benefits and harms of antimicrobial strategies used to prevent peritonitis in PD patients.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant's Specialised Register to 4 October 2016 through contact with the Information Specialist using search terms relevant to this review. Studies contained in the Specialised Register are identified through search strategies specifically designed for CENTRAL, MEDLINE, and EMBASE; handsearching conference proceedings; and searching the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

RCTs or quasi-RCTs in patients receiving chronic PD, which evaluated any antimicrobial agents used systemically or locally to prevent peritonitis or exit-site/tunnel infection were included.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed risk of bias and extracted data. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratio (RR) with 95% confidence intervals (CI).

MAIN RESULTS

Thirty-nine studies, randomising 4435 patients, were included. Twenty additional studies have been included in this update. The risk of bias domains were often unclear or high; risk of bias was judged to be low in 19 (49%) studies for random sequence generation, 12 (31%) studies for allocation concealment, 22 (56%) studies for incomplete outcome reporting, and in 12 (31%) studies for selective outcome reporting. Blinding of participants and personnel was considered to be at low risk of bias in 8 (21%) and 10 studies (26%) for blinding of outcome assessors. It should be noted that blinding of participants and personnel was not possible in many of the studies because of the nature of the intervention or control treatment.The use of oral or topical antibiotic compared with placebo/no treatment, had uncertain effects on the risk of exit-site/tunnel infection (3 studies, 191 patients, low quality evidence: RR 0.45, 95% CI 0.19 to 1.04) and the risk of peritonitis (5 studies, 395 patients, low quality evidence: RR 0.82, 95% CI 0.57 to 1.19).The use of nasal antibiotic compared with placebo/no treatment had uncertain effects on the risk of exit-site/tunnel infection (3 studies, 338 patients, low quality evidence: RR 1.34, 95% CI 0.62 to 2.87) and the risk of peritonitis (3 studies, 338 patients, low quality evidence: RR 0.94, 95% CI 0.67 to 1.31).Pre/perioperative intravenous vancomycin compared with no treatment may reduce the risk of early peritonitis (1 study, 177 patients, low quality evidence: RR 0.08, 95% CI 0.01 to 0.61) but has an uncertain effect on the risk of exit-site/tunnel infection (1 study, 177 patients, low quality evidence: RR 0.36, 95% CI 0.10 to 1.32).The use of topical disinfectant compared with standard care or other active treatment (antibiotic or other disinfectant) had uncertain effects on the risk of exit-site/tunnel infection (8 studies, 973 patients, low quality evidence, RR 1.00, 95% CI 0.75 to 1.33) and the risk of peritonitis (6 studies, 853 patients, low quality evidence: RR 0.83, 95% CI 0.65 to 1.06).Antifungal prophylaxis with oral nystatin/fluconazole compared with placebo/no treatment may reduce the risk of fungal peritonitis occurring after a patient has had an antibiotic course (2 studies, 817 patients, low quality evidence: RR 0.28, 95% CI 0.12 to 0.63).No intervention reduced the risk of catheter removal or replacement. Most of the available studies were small and of suboptimal quality. Only six studies enrolled 200 or more patients.

AUTHORS' CONCLUSIONS

In this update, we identified limited data from RCTs and quasi-RCTs which evaluated strategies to prevent peritonitis and exit-site/tunnel infections. This review demonstrates that pre/peri-operative intravenous vancomycin may reduce the risk of early peritonitis and that antifungal prophylaxis with oral nystatin or fluconazole reduces the risk of fungal peritonitis following an antibiotic course. However, no other antimicrobial interventions have proven efficacy. In particular, the use of nasal antibiotic to eradicate Staphylococcus aureus, had an uncertain effect on the risk of peritonitis and raises questions about the usefulness of this approach. Given the large number of patients on PD and the importance of peritonitis, the lack of adequately powered and high quality RCTs to inform decision making about strategies to prevent peritonitis is striking.

Risk factors associated with peritoneal-dialysis-related peritonitis

Background. Peritonitis represents a major complication of peritoneal dialysis (PD). The aim of this paper was to systematically collect data on patient-related risk factors for PD-associated peritonitis, to analyze the methodological quality of these studies, and to summarize published evidence on the particular risk factors. Methods. Studies were identified by searches of Pubmed (1990–2012) and assessed for methodological quality by using a modified form of the STROBE criteria. Results. Thirty-five methodologically acceptable studies were identified. The following nonmodifiable risk factors were considered valid and were associated with an increased risk of peritonitis: ethnicity, female gender, chronic lung disease, coronary artery disease, congestive heart failure, cardiovascular disease, hypertension, antihepatitis C virus antibody positivity, diabetes mellitus, lupus nephritis or glomerulonephritis as underlying renal disease, and no residual renal function. We also identified the following modifiable, valid risk factors for peritonitis: malnutrition, overweight, smoking, immunosuppression, no use of oral active vitamin D, psychosocial factors, low socioeconomic status, PD against patient's choice, and haemodialysis as former modality. Discussion. Modifiable and nonmodifiable risk factors analyzed in this paper might serve as a basis to improve patient care in peritoneal dialysis.

An International Perspective on Peritoneal Dialysis among Indigenous Patients

Objective

To review utilization rates, outcomes, and barriers to peritoneal dialysis (PD) in indigenous peoples from an international perspective.

Methods

Articles were obtained from Medline and EMBASE and from author name and reference searches. Data from census bureaus and renal registries in Australia, Canada, New Zealand, and the United States were used. Studies were included if they contained information on utilization of, outcomes of, or barriers to PD in indigenous populations.

Results

In 2007, of all prevalent PD patients, 7.0%, 5.1%, 28.2%, and 1.3% in Australia, Canada, New Zealand, and the United States respectively were of indigenous background. The proportions of prevalent renal replacement therapy patients on PD reflected the national rates—New Zealand being the highest at 0.29, and the United States the lowest at 0.05. Mortality was generally higher in indigenous than in non-indigenous PD patients. Variations in mortality study results likely reflect differences in the definitions of explanatory variables such as rurality and in the availability of local specialty care services. Technique failure and peritonitis rates were higher among indigenous than among non-indigenous patients.

Conclusions

The less favorable outcomes in indigenous PD patients across countries may, in part, be a manifestation of reduced access to resources. Understanding the effects of socio-economic, geographic, cultural, and language issues, and of health literacy discrepancies on various aspects of PD education, training, and outcomes can potentially identify ways in which outcomes might be improved among indigenous patients on PD.

Surgical outcomes in American Indian veterans: a closer look

BACKGROUND

American Indian/Alaska Native (AI/ANs) male veterans have considerably higher postoperative mortality rates than their Caucasian counterparts, but similar postoperative morbidity rates even after adjusting for major preoperative risk factors. This study seeks to explain the discrepancy in morbidity and mortality.

STUDY DESIGN

We obtained data from the Veterans Affairs National Surgical Quality Improvement Program on major, noncardiac, surgical procedures performed from 1991 to 2002 for all AI/AN men (n = 2,155), and a random sample of Caucasian men (n = 2,264), matched by site. We compared the number and types of postoperative complications and mortality rates for those patients in whom complications developed. We also examined complication and mortality rates by whether they occurred after hospital discharge, or by specific type of surgical procedure. Preoperative risk factors were assessed in patients who died. Chi-square or Fisher's exact tests were used for all comparisons.

RESULTS

AI/ANs and Caucasians did not differ by number of complications but Caucasian patients had considerably higher rates for three specific complications. There was no difference in deaths after discharge or in mortality rates after specific surgical procedures. The groups differed considerably in the types of procedures performed. Among patients who died, three preoperative risk factors, ie, hemiplegia, diabetes, and wound infection, occurred more frequently among AI/AN than Caucasian veterans.

CONCLUSIONS

We cannot fully explain higher postoperative mortality rates experienced by AI/AN relative to Caucasian veterans after examining complications, types of procedures, and other relevant factors. AI/ANs with certain preoperative risk factors can be vulnerable to 30-day postoperative mortality and benefit from closer postoperative surveillance.

Surgical Morbidity and Mortality among American Indian and Alaska Native Veterans: A Comparative Analysis

BACKGROUND

Few studies have examined surgical risk factors and outcomes in American Indians and Alaska Natives (AI/ANs). My colleagues and I sought to determine if prevalence of preoperative risk factors for morbidity and mortality differed between male AI/AN and Caucasian surgical patients, and to determine if AI/ANs had an increased risk of surgical morbidity or mortality.

STUDY DESIGN

We obtained data from the Veterans Affairs National Surgical Quality Improvement Program on major, noncardiac, surgical procedures performed between 1991 and 2002 for all AI/AN men (n = 2,155) and a random sample of Caucasian men (n = 2,264), matched by facility. Chi-square and t-test analyses were used to assess differences in preoperative risk factors between the two groups. Logistic regression was used to determine whether AI/AN race was independently associated with 30-day morbidity (defined as 1 or more of 21 postoperative complications) or 30-day all cause mortality after adjustment for major risk factors.

RESULTS

Prevalence of major preoperative risk factors for morbidity and mortality often differed between the groups. Compared with Caucasians, AI/AN race did not predict morbidity (adjusted odds ratio, 0.92; 95% CI, 0.75-1.13), but AI/ANs were at higher risk for 30-day all cause postoperative mortality (adjusted odds ratio, 1.56; 95% CI, 1.04-2.35).

CONCLUSIONS

Our results add postoperative mortality to health disparities experienced by AI/ANs. Future research should be conducted to identify other factors that contribute to this disparity.

Use and Outcomes of Peritoneal Dialysis among Aboriginal People in Canada

There has been a dramatic increase in the incidence of ESRD among Aboriginal people in North America. Although peritoneal dialysis (PD) seems to be the dialysis modality of choice for this often rural-dwelling population, few data exist to confirm this. This study was conducted to evaluate rates of PD use, technique failure, and mortality among incident Aboriginal dialysis patients. Adults of white or Aboriginal race who initiated dialysis in three Canadian provinces between January 1, 1990, and December 31, 2000, were included and followed until December 31, 2001. Logistic regression and Cox proportional hazards models were used to examine adjusted associations between Aboriginal race and PD use, technique failure, and mortality. Among the 3823 patients of white (n = 3138; 82.1%) or Aboriginal (n = 685; 17.9%) race, 835 (21.8%) initiated dialysis on PD. After adjustment for age and comorbidity and comparison with white patients, Aboriginal patients were significantly less likely to initiate therapy on PD compared with white patients (odds ratio, 0.51; 95% confidence interval, 0.40 to 0.65), with a nonsignificant trend toward a higher risk for technique failure (hazards ratio, 1.46; 95% confidence interval, 0.95 to 2.23). Adjusted survival among Aboriginal PD patients seemed similar to both white PD patients and Aboriginal patients who were treated with hemodialysis. In summary, among people who were treated with dialysis in Canada, PD was used less frequently in Aboriginal patients than in those of white race. Although Aboriginal patients who initiate dialysis on PD seemed more likely to experience technique failure, their adjusted risk for death was similar to that of white patients. Future studies should address barriers to the initiation and maintenance of PD in the Aboriginal population, especially those who reside in rural locations.

Catheter type, placement and insertion techniques for preventing peritonitis in peritoneal dialysis patients

BACKGROUND

As many as 15-50% of end-stage kidney disease patients are on peritoneal dialysis (PD), but peritonitis limits its more widespread use. Several PD catheter-related interventions have been purported to reduce the risk of peritonitis in PD.

OBJECTIVES

To evaluate the use of catheter-related interventions for the prevention of peritonitis in PD.

SEARCH STRATEGY

The Cochrane Renal Group's specialised register (June 2004), The Cochrane CENTRAL Register of Controlled Trials (The Cochrane Library Issue 2 2004), MEDLINE (1966-April 2004), EMBASE (1988-April 2004) and reference lists were searched without language restriction

SELECTION CRITERIA

Trials comparing different catheter insertion techniques, catheter types, use of immobilisation techniques or different break in periods were included. Trials of different PD sets were excluded.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Statistical analyses were performed using a random effects model and the results expressed as relative risk (RR) with 95% confidence intervals (CI).

MAIN RESULTS

Seventeen eligible trials (1089 patients) were identified, eight of surgical strategies of catheter insertion, eight of straight versus coiled catheters, one of single cuff versus double cuff catheters and one of an immobiliser device. The methodological quality was suboptimal. There were no significant differences with laparoscopy compared with laparotomy for peritonitis, the peritonitis rate, exit-site/tunnel infection or catheter removal/replacement. Standard insertion with resting but no subcutaneous burying of the catheter versus implantation and subcutaneous burying was not associated with a significant reduction in peritonitis rate, exit-site/tunnel infection rate or all-cause mortality. Midline compared to lateral insertion showed no significant difference in the risk of peritonitis or exit-site/tunnel infection. There was no significant difference in the risk of peritonitis, peritonitis rate, exit-site/tunnel infection, exit-site/tunnel infection rate or catheter removal/replacement between straight versus coiled intraperitoneal portion catheters. One trial compared single versus double cuffed catheters and showed no significant difference in the risk of peritonitis, exit-site/tunnel infection or catheter removal/replacement. One trial compared immobilisation versus no immobilisation of the PD catheter and showed no significant difference in the risk of peritonitis and exit-site/tunnel infection. No trials of different break-in periods were identified.

REVIEWERS' CONCLUSIONS

No major advantages from any of the catheter-related interventions which have been purported to reduce the risk of PD peritonitis could be demonstrated in this review. The frequency and quality of available trials are suboptimal.

Antimicrobial agents for preventing peritonitis in peritoneal dialysis patients

BACKGROUND

Peritoneal dialysis (PD) is used as substitutive treatment of renal function in a large proportion (15-50%) of the end-stage kidney disease (ESRD) population. The major limitation is peritonitis which leads to technique failure, hospitalisation and increased mortality. Oral, nasal, topical antibiotic prophylaxis, exit-site disinfectants and other antimicrobial interventions are used to prevent peritonitis.

OBJECTIVES

The objective of this systematic review of randomised controlled trials (RCTs) was to evaluate what evidence supports the use of different antimicrobial approaches to prevent peritonitis in PD.

SEARCH STRATEGY

The Cochrane CENTRAL Registry (issue 1, 2004), MEDLINE (1966-May 2003), EMBASE (1988-May 2003) and reference lists were searched for RCTs of antimicrobial agents in PD.

SELECTION CRITERIA

Trials of the following agents were included: antibiotics by any route (oral, nasal, topical), exit-site disinfectants (chlorhexidine, povidone iodine, soap and water), vaccines, and ultraviolet germicidal devices.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data on the number of patients with one or more episodes and rates of peritonitis and exit-site/tunnel infection, catheter removal, catheter replacement, technique failure, toxicity of antibiotic treatments, all-cause mortality. Statistical analyses were performed using the random effects model and the results expressed as relative risk (RR) with 95% confidence intervals (CI).

MAIN RESULTS

Nineteen trials, enrolling 1949 patients met our inclusion criteria. Nasal mupirocin compared with placebo significantly reduced the exit-site and tunnel infection rate (one trial, 2716 patient months, RR 0.58, 95% CI 0.40 to 0.85) but not peritonitis rate (one trial, 2716 patient months, RR 0.84, 95% CI 0.44 to 1.60). Perioperative intravenous antibiotics compared with no treatment significantly reduced the risk of early peritonitis (four trials, 335 patients, RR 0.35, 95% CI 0.15 to 0.80) but not exit site and tunnel infection (three trials, 114 patients, RR 0.32, 95% CI 0.02 to 4.81). No intervention reduced the risk of catheter removal or replacement.

REVIEWERS' CONCLUSIONS

This review demonstrates that nasal mupirocin reduces exit-site/tunnel infection but not peritonitis. Preoperative intravenous prophylaxis reduces early peritonitis but not exit-site/tunnel infection. No other antimicrobial interventions have proven efficacy. Given the large number of patients on PD and the importance of peritonitis, the lack of adequately powered RCTs to inform decision making about strategies to prevent peritonitis is striking.

Association between AGT codon 235 polymorphism and variation in serum concentrations of creatinine and urea in Canadian Oji-Cree

Finding the genetic determinants of intermediate quantitative traits, such as serum creatinine and urea, might aid in finding the determinants of disease phenotypes, such as renal failure, that are, in part, defined according to threshold values imposed upon such traits. We evaluated the association between common variation in the gene encoding angiotensinogen, AGT, and the serum concentrations of creatinine and urea in non-diabetic Canadian Oji-Cree. We determined genotypes of the AGT codon 235 polymorphism among 502 non-diabetic Oji-Cree. We used multivariate analysis of variance to identify significant determinants of variation in serum concentrations of creatinine and urea and of systolic and diastolic blood pressure. We found significant associations between the AGT codon 235 genotype and serum concentrations of creatinine and urea (p = 0.017 and 0.049, respectively) and systolic blood pressure (p = 0.041). Compared with subjects with the other two genotypes, homozygotes for AGT T235/T235 had significantly lower serum concentrations of creatinine and urea and significantly higher mean systolic blood pressure. The findings suggest that the AGT T235 allele is a determinant of intermediate traits related to renal function in these aboriginal Canadians.

Association between AGT T235 variant and microalbuminuria in Canadian Oji-Cree with type 2 diabetes mellitus

OBJECTIVE

To assess the association between the common variation in the gene encoding angiotensinogen, AGT, and the presence of microalbuminuria in Canadian Oji-Cree with type 2 diabetes mellitus.

RESEARCH DESIGN AND METHODS

We compared the frequencies of the AGT promoter and M235T polymorphisms among three subgroups of adult Oji-Cree: 50 subjects who had type 2 diabetes with microalbuminuria, 6 subjects who had type 2 diabetes without albuminuria and 302 non-diabetic, normotensive subjects.

RESULTS

We found the AGT T235 allele was present at a significantly higher frequency, and that T235/T235 homozygotes were significantly more prevalent, among the subjects who had type 2 diabetes with microalbuminuria than among the subjects in the other two groups.

CONCLUSIONS

The findings suggest that the AGT T235 allele is a determinant of the nephropathy susceptibility related to type 2 diabetes in these aboriginal Canadians.