Sameena Iqbal

Vascular Access–Related Infections: Definitions, Incidence Rates, and Risk Factors

Hemodialysis is associated with a high risk of morbidity and mortality, often caused by infections. Infections account for approximately 15% of all deaths in this patient population (the second leading cause after cardiovascular events) and for about one-fifth of admissions. Approximately one-fourth of infection-related admissions are caused by dialysis-associated peritonitis or vascular access infection that may lead to such significant complications as endocarditis or death. Published studies that assessed the determinants of hemodialysis-related vascular infections reported inconsistent findings. Variations in the definitions of infection among these studies despite the existence of standard guidelines proposed by at least 3 major work groups may explain, at least in part, these inconsistencies. A comprehensive in-depth review of those studies is needed to examine the inconsistencies in the published results. We first revised the existing vascular access-related infection definitions, then conducted a narrative review of the published literature that examined predictors of vascular access-related infections, highlighting the heterogeneity in methods and findings. Better understanding of the risk factors for vascular access-related infections may inform efficacious prevention strategies and lead to early detection of infections and improved patient care.

Cardiac Surgery in Octogenarians: Long-Term Survival, Functional Status, Living Arrangements, and Leisure Activities

BACKGROUND A prospective study of survival, functional outcome, living arrangements, daily activities and leisure engagements among octogenarians up to 5 years after cardiac surgery was performed. METHODS The study consisted of a cohort of 300 consecutive octogenarians with three interviews made at 6-month intervals for a total of 593 postoperative interviews. Functional outcomes were measured using the Barthel index and Karnofsky performance scores and divided into autonomous, semiautonomous, or dependent. Living arrangements and leisure activities within the social, physical, cognitive, and creative domains were recorded in an open-ended questionnaire. RESULTS There were 150 men and 150 women with a mean age 82.6 years. The 30-day survival was 84.3%. Actuarial survival at 1, 3, and 5 years was 76.6%, 66.6%, and 57.8%, respectively. Among the survivors at the first interview, 2.2 years postoperatively, there were 63.9% autonomous, 31.7% semiautonomous, and 4.3% dependent patients versus at the last interview, 3.6 years postoperatively, in which there were 64.9% autonomous, 28.1% semiautonomous, and 9.2% dependent. At the first interview, 76.4% were at home, 19.2 % in a residence, and 4.3% in a supervised setting. At the third interview, 71.8% were at home, 21.2% in a residence, and 6.9% in a supervised setting. Nearly all patients were involved in leisure activities in the social (98.9%), cognitive (98.4%), and physical (93.1%) domains. At the end of the last interview, activities within the social and cognitive domains were maintained with a small decrease in the physical domain. CONCLUSIONS Surviving octogenarians remain at home, function independently, and engage in regular leisure activities years after cardiac surgery. This information might help physicians and surgeons regarding long-term outcome of open cardiac surgery in octogenarians.

Association of Dialysis Modality with Risk for Infection-Related Hospitalization: A Propensity Score–Matched Cohort Analysis

BACKGROUND AND OBJECTIVES Peritonitis is a well known complication of peritoneal dialysis (PD), whereas in hemodialysis (HD), bacteremia can be life threatening. Whether patients undergoing PD have higher risk than HD patients for infection-related hospitalizations (IRH) remains unknown. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS A propensity score-matched retrospective cohort of patients undergoing long-term dialysis between January 2001 and December 2007 was assembled. Propensity scores were calculated using multivariable (demographic characteristics, smoking, body mass index, comorbid conditions, and laboratory data) logistic regression to estimate probability of receiving PD versus HD. A comparison of IRH risk by dialysis modality was estimated using a counting-process survival model. RESULTS A total of 910 pairs of patients were matched by propensity scores. During a median follow-up of 2.1 years (interquartile range, 1.1-3.5 years), 341 patients were hospitalized once for an infection, 123 twice, and 106 at least three times. PD was associated with an increased risk for IRH compared with HD (propensity-matched hazard ratio [HR], 1.52). PD was associated with a reduced risk for septicemia (HR, 0.31) and pneumonia (HR, 0.58) but also an increased risk for dialysis-related infectious hospitalizations (HR, 3.44), defined as all cases of peritonitis and vascular access-related bacteremia, but not all septicemia cases. CONCLUSIONS PD patients are at higher risk for IRH than are HD patients. This risk is mostly explained by dialysis-related infections. However, further studies are needed to evaluate whether the severity of those hospitalizations is similar and whether this increased risk for IRH is associated with worse outcomes.

Vascular Access-Related Bloodstream Infections in First Nations, Community and Teaching Canadian Dialysis Units, and Other Centre-Level Predictors

Background/Aims: Vascular access-related bloodstream infection (BSI) is frequent among patients undergoing hemodialysis increasing their morbidity and mortality, but its occurrence across various dialysis centre types is not known. The aims of this study were to describe the incidence rates and assess the variability in BSI risk between dialysis centre types and other centre-level variables. Methods: We conducted a retrospective cohort study of 621 patients initiating hemodialysis in 7 Canadian dialysis centres. Cox regression models, where access type was continuously updated, were used to identify predictors of BSI occurrence. Results: During follow-up of the cohort (median age 68.1 years, 41.7% female, and 76.7% initiating with a central venous catheter, CVC), 73 patients had a BSI (rate: 0.21/1000 person-days). The BSI risk was not different in First Nation units (adjusted relative risk: 0.47, 95% confidence interval: 0.06–3.72) and teaching hospitals (1.33, 0.70–2.54) compared to community hospitals. No other centre-related variables were associated with the risk of BSI. Conclusion: We did not find differences in the BSI risk among dialysis unit types, or any other centre-related variables. The rates of BSI in our population were lower than those observed in other settings, but the high proportion of patients using CVCs is concerning.

Predictors for nephrology outpatient care and recurrence of acute kidney injury (AKI) after an in-hospital AKI episode

Acute kidney injury (AKI) is associated with increased long‐term risk of end‐stage kidney disease (ESKD) and mortality. Nephrology care following discharge from hospital may improve survival through prevention of recurrent AKI events. In this study, we examined the factors that were associated with outpatient nephrology follow‐up after the development of AKI on patients who had a nephrology in‐hospital consultation and were discharged from McGill University Health Centre between January 1, 2006 and December 31, 2010. The associated factors for AKI‐free survival postdischarge were assessed applying multivariate Cox hazard proportional models. Of 170 patients, only 22% of the AKI admissions studied were booked with nephrology follow‐up after discharge. The unadjusted hazard ratio (HR) of outpatient nephrology care postdischarge was 1.82 (95% confidence interval [CI] 0.93–3.56) for AKI‐free survival postdischarge. The adjusted HR was 2.04 (95% CI 1.01–4.12) when we adjusted for follow‐up with other medical clinics, significant stage 4 and stage 5 chronic kidney disease and diabetes status. Patients with less comorbidities and higher serum creatinine on discharge received outpatient nephrology care. Nephrology outpatient care is associated with decreased risk of recurrence of AKI after discharge from hospital.

Predictors of suboptimal and crash initiation of dialysis at two tertiary care centers

Many end‐stage renal disease patients do not have an optimal start to dialysis. Many patients have suboptimal initiation, while others “crash” start on dialysis without prior care from a nephrologist. We examined factors associated with suboptimal or crash starts. We conducted a retrospective cohort study of 377 incident dialysis patients at two tertiary care centers from January 2006 to April 2011. Logistic regression was used to identify factors associated with suboptimal and crash starts to dialysis. Out of 377 patients, 102 (27%) had optimal starts, 221 (59%) had suboptimal starts, and 54 (14%) had crash starts. Three hundred thirty‐four patients (89%) began with hemodialysis, while 11% started with peritoneal dialysis. Factors independently associated with a suboptimal start as opposed to an optimal start included nephrology care more than 12 months prior to initiation of dialysis (odds ratio [OR], 0.26; 95% confidence interval [CI], 0.12–0.58), Charlson Comorbidity Index (OR, 1.25 per 1 point; 95% CI, 1.09–1.43), and age (OR, 1.02 per 1 year; 95% CI, 1.00–1.04). In comparison, diabetic nephropathy (OR, 0.25; 95% CI, 0.12–0.54), a history of pulmonary edema within 6 months prior to initiation of dialysis (OR, 3.70; 95% CI, 1.77–7.75), and a diagnosis of chronic obstructive lung disease (OR, 0.07; 95% CI, 0.01–0.52) were independently associated with a crash start. There was a low incidence of optimal dialysis starts in our tertiary care dialysis population. Our study highlights that suboptimal and crash start patients are distinct populations. Modifying factors that predict nonoptimal dialysis starts will need to consider these distinctions.

Magnitude of discordance between registry data and death certificate when evaluating leading causes of death in dialysis patients

BackgroundDiscordance between dialysis registry and death certificate reported death has been demonstrated. Since cause of death is measured using registry data in dialysis patients and death certificate data in the general population, comparisons of cause of death proportions between dialysis patients and the general population may be biased. Our aim was to compare the proportion of deaths attributed to cardiovascular disease (CVD), malignancy, and infections between patients receiving dialysis and the general population using death certificates for both, and to quantify the magnitude of discrepancy between registry and death certificate estimates in dialysis patients.MethodsA retrospective cohort study of 5858 patients initiating maintenance dialysis between 2001 and 2007 was conducted. Cause of death was obtained from both registry and death certificate data for dialysis patients, and from death certificate data for the general population.ResultsCompared to the general population, use of death certificate data in dialysis patients resulted in smaller differences in the proportion of deaths attributed to CVD or infection than that from the registry. In the general population, the proportion of deaths due to CVD is 29.3% for men and 28.2% for women, and the proportion of deaths due to infection is 3.3% for men and 3.6% for women. For men, the proportion of deaths in dialysis patients due to CVD using registry data is 41.5%, compared with a proportion of 32.1% using death certificate data. Similarly for women, the proportion of deaths due to CVD using registry data is 35.2% and that using death certificate data 24.3%. The proportion of deaths due to infection in dialysis patients follows the same pattern: for men, the proportion of deaths due to infection using registry data is 9.9% and that from death certificate data at 5.0%; while for women the proportions are 11.6% and 4.8%, respectively.ConclusionsWhile absolute cause-specific mortality rates did differ, evaluation of causes of death using death certificate in dialysis patients in Quebec revealed that they do not have substantially different proportion of death due to CVD or infections than the general population. Infections appeared to be a frequent complication leading to death, suggesting that infections are an important target to consider for reducing mortality in dialysis populations.

Renal Disease in Diabetes Mellitus: Recent Studies and Potential Therapies

Diabetic kidney disease is the predominant cause of end stage kidney disease in North America, estimated to be 152 per million population in 2010. New guidelines published by KDIGO on Chronic Kidney Disease classification are discussed. In light of recent clinical trials, better insight has been gained on how improve management of diabetic patients to prevent renal disease and its progression, especially with regards to metabolic and blood pressure control. Unfortunately, studies of newer therapies such as endothelin 1 antagonists and bardoxolone methyl have been disappointing, but several other possible therapeutic agents are under investigation and may provide hope for patients with diabetes mellitus in the future.

The Evolution of Amputation in the Province of Quebec

ABSTRACT OBJECTIVE: Lower-extremity amputation rate is often used as an indicator of the quality of diabetes care. This study provides a long-term perspective on amputation in the Quebec population, estimating changes over time in rates of vascular amputation and comorbidity profile. METHODS: A population-based admission-to-discharge cohort study was conducted using hospital discharge data. The population consisted of all Quebec residents having an amputation from January 1, 1996, to December 31, 2004. The reason for amputation was defined by diagnostic code; the level of amputation was identified by treatment code; and the proportion of people with specific comorbidities was calculated for each year. Age-and sex-specific rates of amputation were calculated. RESULTS: A total of 10 834 people had 15 992 amputations. Of these people, 79% had vascular disease. Within this population, hypertension has increased by 27.2% (95% CI 22.9-31.6), renal disease by 14.9% (95% CI 11.1-18.7) and ischemic heart disease by 20.4% (95% CI 16.3-24.4). Length of hospital stay did not change over time; the median length of stay was 20 days (IQR: 8.5, 40, 658). Women having foot amputations, people having multiple amputations or people with a high Charlson index score were more likely to stay in hospital for more than 28 days. A linear decrease in the rate of vascular and diabetic amputations was observed for both men and women, with the greatest decrease being 8.1% (95% CI 5.8-10.4) among males with vascular disease. INTERPRETATION: Despite the decline in sex-specific, agestandardized rates of amputation, there was no decrease in the number of amputations being performed; this may reflect the increased prevalence of diabetes and standard of care being given. The implication for the changing profile of people having amputations are great: for example, post-amputation care needs to address the multiple comorbidities.