Clinical decision support to improve blood pressure control in hemodialysis patients: a nonrandomized controlled trial.

BACKGROUND: Computer-based clinical decision support aims to improve the quality of patient care. The utility of decision support for improving blood pressure control in hemodialysis patients is unknown. METHODS: This was a nonrandomized controlled trial of adult patients receiving chronic in-center hemodialysis during the period of April 1, 2005, to September 30, 2006, in 1 of the 2 major university-based renal programs in Alberta, Canada. Physicians in the intervention center were provided with twice-monthly audits and printed management suggestions based on guideline-recommended blood pressure targets. The same data were available to physicians in the control group but without audit and feedback decision support. RESULTS: Eight hundred and thirty hemodialysis patients were receiving dialysis treatment at the time the study was initiated. Preintervention and postintervention blood pressure data were available for 361 patients. The primary outcome, the proportion of postdialysis systolic blood pressures at target over 12 months, did not differ between the intervention and the control programs (unadjusted odds ratio 0.59; 95% confidence interval [95% CI], 0.34-1.02, p = 0.06; adjusted odds ratio 0.62; 95% CI, 0.35-1.11, p = 0.11). There was no significant difference between the intervention and control groups in other measures of blood pressure such as the mean change in postdialysis systolic blood pressures (unadjusted mean difference 4 mm Hg, 95% CI, -1 to 9, p = 0.36; adjusted mean difference 2 mm Hg, 95% CI, -1 to 5, p = 0.19). CONCLUSIONS: In this population of chronic hemodialysis patients, a computer-based clinical decision support system was not associated with improved blood pressure control.

Effect of frequent nocturnal hemodialysis vs conventional hemodialysis on left ventricular mass and quality of life: a randomized controlled trial.

CONTEXT: Morbidity and mortality rates in hemodialysis patients remain excessive. Alterations in the delivery of dialysis may lead to improved patient outcomes. OBJECTIVE: To compare the effects of frequent nocturnal hemodialysis vs conventional hemodialysis on change in left ventricular mass and health-related quality of life over 6 months. DESIGN, SETTING, AND PARTICIPANTS: A 2-group, parallel, randomized controlled trial conducted at 2 Canadian university centers between August 2004 and December 2006. A total of 52 patients undergoing hemodialysis were recruited. INTERVENTION: Participants were randomly assigned in a 1:1 ratio to receive nocturnal hemodialysis 6 times weekly or conventional hemodialysis 3 times weekly. MAIN OUTCOME MEASURES: The primary outcome was change in left ventricular mass, as measured by cardiovascular magnetic resonance imaging. The secondary outcomes were patient-reported quality of life, blood pressure, mineral metabolism, and use of medications. RESULTS: Frequent nocturnal hemodialysis significantly improved the primary outcome (mean left ventricular mass difference between groups, 15.3 g, 95% confidence interval [CI], 1.0 to 29.6 g; P = .04). Frequent nocturnal hemodialysis did not significantly improve quality of life (difference of change in EuroQol 5-D index from baseline, 0.05; 95% CI, -0.07 to 0.17; P = .43). However, frequent nocturnal hemodialysis was associated with clinically and statistically significant improvements in selected kidney-specific domains of quality of life (P = .01 for effects of kidney disease and P = .02 for burden of kidney disease). Frequent nocturnal hemodialysis was also associated with improvements in systolic blood pressure (P = .01 after adjustment) and mineral metabolism, including a reduction in or discontinuation of antihypertensive medications (16/26 patients in the nocturnal hemodialysis group vs 3/25 patients in the conventional hemodialysis group; P < .001) and oral phosphate binders (19/26 patients in the nocturnal hemodialysis group vs 3/25 patients in the conventional dialysis group; P < .001). No benefit in anemia management was seen with nocturnal hemodialysis. CONCLUSION: This preliminary study revealed that, compared with conventional hemodialysis (3 times weekly), frequent nocturnal hemodialysis improved left ventricular mass, reduced the need for blood pressure medications, improved some measures of mineral metabolism, and improved selected measures of quality of life. TRIAL REGISTRATION: isrctn.org Identifier: ISRCTN25858715.

Expert-type knowledge structure in medical students is associated with increased odds of diagnostic success.

BACKGROUND: The relation between knowledge structure and diagnostic performance is unclear. Similarly, variables affecting knowledge structure are poorly understood. PURPOSE: The 1st objective was to examine the relation between concepts in knowledge structure and diagnostic performance. The 2nd objective was to examine the relation between the use of diagnostic schemes by small-group preceptors and knowledge structure of medical students. METHODS: This was a cross-sectional study of 1st-year medical students in 4 clinical presentations: hyponatremia, hyperkalemia, metabolic acidosis, and metabolic alkalosis. The 1st dependent variable was diagnostic success with the number of expert-type concepts in knowledge structure (determined by concept sorting), diagnostic scheme use by preceptors, and clinical presentation as independent variables. The 2nd dependent variable was the number of expert-type concepts in knowledge structure with diagnostic scheme use by preceptors and clinical presentation as independent variables. Data were analyzed using multiple logistic and linear regression. RESULTS: Thirty 1st-year medical students participated. After adjusting for clinical presentation and scheme use by preceptors, the number of expert-type concepts in knowledge structure was associated with increased odds of diagnostic success (odds ratio 1.18 [1.03, 1.35], p = .016). After adjustment for clinical presentation, scheme use by preceptors was associated with increased number of expert-type concepts in knowledge structure (2.22 vs. 1.86, p = .01, d = 0.23). CONCLUSIONS: The number of expert-type concepts in knowledge structure is associated with increased odds of diagnostic success. Scheme use by small-group preceptors is associated with an increased number of expert-type concepts in knowledge structure.

Can concept sorting provide a reliable, valid and sensitive measure of medical knowledge structure?

CONTEXT: Evolution from novice to expert is associated with the development of expert-type knowledge structure. The objectives of this study were to examine reliability and validity of concept sorting (ConSort) as a measure of static knowledge structure and to determine the relationship between concepts in static knowledge structure and concepts used during diagnostic reasoning. METHOD: ConSort was used to identify static knowledge concepts and analysis of think-aloud protocols was used to identify dynamic knowledge concepts (used during diagnostic reasoning). Intra- and inter-rater reliability, and correlation across cases, were evaluated. Construct validity was evaluated by comparing proportions of nephrologists and students with expert-type knowledge structure. Sensitivity and specificity of static knowledge concepts as a predictor of dynamic knowledge concepts were estimated. RESULTS: Thirteen first-year medical students and 19 nephrologists participated. Intra- and inter-rater agreement for determination of static knowledge concepts were 1.0 and 0.90, respectively. Reliability across cases was 0.45. The proportions of nephrologists and students identified as having expert-type knowledge structure were 82.9% and 55.8%, respectively (p=0.001). Sensitivity and specificity of ConSort((c)) in predicting concepts that were used during diagnostic reasoning were 96.8% and 27.8% for nephrologists and 87.2% and 55.1% for students. CONCLUSIONS: ConSort is a reliable, valid and sensitive tool for studying static knowledge structure. The applicability of tools that evaluate static knowledge structure should be explored as an addition to existing tools that evaluate dynamic tasks such as diagnostic reasoning.

One-year mortality in critically ill patients by severity of kidney dysfunction: a population-based assessment.

BACKGROUND: Kidney dysfunction in the intensive care unit (ICU) results in increased morbidity, mortality, and health care costs; however, long-term mortality has not been described across strata of severity in kidney dysfunction. METHODS: The primary objective is to describe and assess factors associated with 1-year mortality in critically ill patients stratified by severity of kidney dysfunction during admission to the ICU. Kidney dysfunction is defined by peak serum creatinine values and stratified by: (1) no dysfunction (creatinine < 1.7 mg/dL [<150 micromol/L]), (2) mild dysfunction (creatinine, 1.7 to 3.4 mg/dL [150 to 299 micromol/L]), (3) moderate dysfunction (creatinine >or= 3.4 mg/dL [>or= 300 micromol/L]), (4) severe acute dysfunction requiring renal replacement therapy (acute renal failure), or (5) preexisting end-stage kidney disease. Population-based surveillance was of adult residents of the Calgary Health Region (population, 1 million) admitted to any multidisciplinary ICU and a cardiovascular surgery ICU from May 1, 1999, to April 30, 2002. RESULTS: Of 5,693 admissions, 62% were men, median age was 64.9 years (interquartile range, 50.6 to 74.5 years), and mean Acute Physiology and Chronic Health Evaluation (APACHE) II score was 24.9 +/- 8.7 (SD). Case fatality rates stratified by renal dysfunction were 17% (763 of 4,411), 47% (370 of 790), 48% (77 of 160), 64% (153 of 240), and 40% (37 of 92) for no, mild, and moderate dysfunction; severe acute renal failure; and end-stage kidney disease, respectively. By means of multivariate analysis, 1-year mortality was associated independently with advancing age, medical diagnosis, higher APACHE II score, and presence and severity of kidney dysfunction, although no difference was evident comparing those with mild to moderate dysfunction. End-stage kidney disease was not associated independently with 1-year mortality. CONCLUSION: Severity of kidney dysfunction in patients in the ICU is associated with an incremental increase in long-term mortality. Although patients classified with either mild or moderate kidney dysfunction had an increased risk for death, use of serum creatinine level alone was poor at discriminating long-term outcome, suggesting this measure alone should not be used for defining long-term prognosis.

Prognosis for long-term survival and renal recovery in critically ill patients with severe acute renal failure: a population-based study.

INTRODUCTION: Severe acute renal failure (sARF) is associated with considerable morbidity, mortality and use of healthcare resources; however, its precise epidemiology and long-term outcomes have not been well described in a non-specified population. METHODS: Population-based surveillance was conducted among all adult residents of the Calgary Health Region (population 1 million) admitted to multidisciplinary and cardiovascular surgical intensive care units between May 1 1999 and April 30 2002. Clinical records were reviewed and outcome at 1 year was assessed. RESULTS: sARF occurred in 240 patients (11.0 per 100,000 population/year). Rates were highest in males and older patients (> or = 65 years of age). Risk factors for development of sARF included previous heart disease, stroke, pulmonary disease, diabetes mellitus, cancer, connective tissue disease, chronic renal dysfunction, and alcoholism. The annual mortality rate was 7.3 per 100,000 population with rates highest in males and those > or = 65 years. The 28-day, 90-day, and 1-year case-fatality rates were 51%, 60%, and 64%, respectively. Increased Charlson co-morbidity index, presence of liver disease, higher APACHE II score, septic shock, and need for continuous renal replacement therapy were independently associated with death at 1 year. Renal recovery occurred in 78% (68/87) of survivors at 1 year. CONCLUSION: sARF is common and males, older patients, and those with underlying medical conditions are at greatest risk. Although the majority of patients with sARF will die, most survivors will become independent from renal replacement therapy within a year.

Severe bloodstream infections: a population-based assessment.

OBJECTIVE: Although bloodstream infection commonly results in critical illness, population-based studies of the epidemiology of severe bloodstream infection are lacking. We sought to define the incidence and microbiology of severe bloodstream infection (bloodstream infection associated with intensive care unit admission within 48 hrs) and assess risk factors for acquisition and death. DESIGN: Population-based surveillance cohort. SETTING: Multidisciplinary and cardiovascular surgical intensive care units. PATIENTS: All adults with severe bloodstream infection in the Calgary Health Region (population approximately 1 million) during 2000-2002. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Three hundred forty patients had 342 episodes of severe bloodstream infection (15.7 per 100,000 population/year). Several demographic and chronic conditions were significant risk factors for acquiring severe bloodstream infection (relative risk, 95% confidence interval) including age > or =65 yrs (7.0, 5.6-8.7), male gender (1.3, 1.1-1.6), urban residence (2.4, 1.2-5.6), hemodialysis (208.7, 142.9-296.3), diabetes mellitus (5.9, 4.4-7.8), alcoholism (5.6, 3.8-8.0), cancer (7.5, 5.3-10.3), and lung disease (3.8, 2.6-5.4). The most common etiologies were Staphylococcus aureus, Escherichia coli, and Streptococcus pneumoniae (3.0, 3.0, and 1.9 per 100,000/year, respectively). The case-fatality rate was 142 of 340 (42%) for an annual mortality rate of 6.5 per 100,000. Increased Acute Physiology and Chronic Health Evaluation II score (odds ratio, 1.1 per point; 95% confidence interval, 1.1-1.2) and presence of a comorbidity (odds ratio, 2.5; 95% confidence interval, 1.4-4.3) were significant independent predictors of death. CONCLUSIONS: Bloodstream infections are commonly severe enough to require management in an intensive care unit and are associated with a high mortality rate. Identification of risk factors for severe bloodstream infection may allow targeting of preventive efforts to individuals at greatest potential benefit.

Why patients with ESRD do not select self-care dialysis as a treatment option.

BACKGROUND: In-center hemodialysis is the most prevalent (and resource-intense) form of dialysis in North America despite many patients being capable of performing dialysis themselves. The purpose of this study is to describe reasons in-center hemodialysis patients choose not to perform self-care dialysis and identify variables associated with a negative attitude toward self-care dialysis. METHODS: We conducted a cross-sectional survey (return rate, 83%) of prevalent in-center hemodialysis patients and combined this with demographic and comorbidity data obtained from our prospectively maintained database. We also performed multiple logistic regression to determine factors associated with the attitude, "patients should not perform dialysis without being supervised by a nurse." RESULTS: The most prevalent knowledge barrier was lack of a satisfactory explanation of the various techniques. The most prevalent attitude barriers were that patients should not dialyze without direct supervision, fear of failure to perform self-care dialysis adequately, and fear of social isolation. The most prevalent skill barriers were needle phobia and lack of space at home. Variables significantly associated with a negative attitude toward self-care dialysis were age/fear of substandard care (interaction), needle phobia, fear of change, fear of social isolation, and unwillingness to remain awake during dialysis. CONCLUSION: This study identified a variety of barriers to self-care dialysis, and these results are being used to direct changes to our program aimed at increasing the uptake of self-care hemodialysis, which we believe will benefit both patients and health care providers and may offer a solution to nursing and resource shortages.

Dialysis adequacy and health related quality of life in hemodialysis patients.

Patients with end-stage renal disease have significant impairments in health related quality of life (HRQOL). The determinants of HRQOL, including the effect of dialysis adequacy, have not been well studied. This study was designed to investigate whether dialysis adequacy is associated with HRQOL in hemodialysis patients. A cross-sectional survey of 128 patients who had been on hemodialysis for more than 6 months was conducted. Baseline information on demographic factors and detailed clinical information was collected. Average Kt/V levels (for the 3 months preceding HRQOL assessment) were determined. HRQOL was assessed with the Kidney Disease Quality of Life Short Form, the Short Form-36 (SF-36), and the EuroQol EQ-5D. Multiple linear regression was performed to control for differences in important baseline covariates. Patients with average Kt/V levels greater than or equal to 1.3 had better HRQOL as measured by significantly higher scores (p < 0.05) in 4 of 11 kidney disease targeted domains, 6 of 8 SF-36 domains, and on the EQ-5D visual analog scale and index score. Using multiple linear regression to control for important covariates, the adjusted EQ-5D index score was higher by 0.036 (95% confidence intervals 0.015, 0.057) for each 0.1 increment in Kt/V, which is both statistically and clinically significant. Dialysis adequacy was significantly associated with HRQOL in hemodialysis patients. Controlled studies that examine the effect of increasing Kt/V on HRQOL are needed.