Braden J. Manns

Relation Between Kidney Function, Proteinuria, and Adverse Outcomes

CONTEXT The current staging system for chronic kidney disease is based primarily on estimated glomerular filtration rate (eGFR) with lower eGFR associated with higher risk of adverse outcomes. Although proteinuria is also associated with adverse outcomes, it is not used to refine risk estimates of adverse events in this current system. OBJECTIVE To determine the association between reduced GFR, proteinuria, and adverse clinical outcomes. DESIGN, SETTING, AND PARTICIPANTS Community-based cohort study with participants identified from a province-wide laboratory registry that includes eGFR and proteinuria measurements from Alberta, Canada, between 2002 and 2007. There were 920 985 adults who had at least 1 outpatient serum creatinine measurement and who did not require renal replacement treatment at baseline. Proteinuria was assessed by urine dipstick or albumin-creatinine ratio (ACR). MAIN OUTCOME MEASURES All-cause mortality, myocardial infarction, and progression to kidney failure. RESULTS The majority of individuals (89.1%) had an eGFR of 60 mL/min/1.73 m(2) or greater. Over median follow-up of 35 months (range, 0-59 months), 27 959 participants (3.0%) died. The fully adjusted rate of all-cause mortality was higher in study participants with lower eGFRs or heavier proteinuria. Adjusted mortality rates were more than 2-fold higher among individuals with heavy proteinuria measured by urine dipstick and eGFR of 60 mL/min/1.73 m(2) or greater, as compared with those with eGFR of 45 to 59.9 mL/min/1.73 m(2) and normal protein excretion (rate, 7.2 [95% CI, 6.6-7.8] vs 2.9 [95% CI, 2.7-3.0] per 1000 person-years, respectively; rate ratio, 2.5 [95% CI, 2.3-2.7]). Similar results were observed when proteinuria was measured by ACR (15.9 [95% CI, 14.0-18.1] and 7.0 [95% CI, 6.4-7.6] per 1000 person-years for heavy and absent proteinuria, respectively; rate ratio, 2.3 [95% CI, 2.0-2.6]) and for the outcomes of hospitalization with acute myocardial infarction, end-stage renal disease, and doubling of serum creatinine level. CONCLUSION The risks of mortality, myocardial infarction, and progression to kidney failure associated with a given level of eGFR are independently increased in patients with higher levels of proteinuria.

Effectiveness of quality improvement strategies on the management of diabetes: a systematic review and meta-analysis

BACKGROUND The effectiveness of quality improvement (QI) strategies on diabetes care remains unclear. We aimed to assess the effects of QI strategies on glycated haemoglobin (HbA(1c)), vascular risk management, microvascular complication monitoring, and smoking cessation in patients with diabetes. METHODS We identified studies through Medline, the Cochrane Effective Practice and Organisation of Care database (from inception to July 2010), and references of included randomised clinical trials. We included trials assessing 11 predefined QI strategies or financial incentives targeting health systems, health-care professionals, or patients to improve management of adult outpatients with diabetes. Two reviewers independently abstracted data and appraised risk of bias. FINDINGS We reviewed 48 cluster randomised controlled trials, including 2538 clusters and 84,865 patients, and 94 patient randomised controlled trials, including 38,664 patients. In random effects meta-analysis, the QI strategies reduced HbA(1c) by a mean difference of 0·37% (95% CI 0·28-0·45; 120 trials), LDL cholesterol by 0·10 mmol/L (0·05-0.14; 47 trials), systolic blood pressure by 3·13 mm Hg (2·19-4·06, 65 trials), and diastolic blood pressure by 1·55 mm Hg (0·95-2·15, 61 trials) versus usual care. We noted larger effects when baseline concentrations were greater than 8·0% for HbA(1c), 2·59 mmol/L for LDL cholesterol, and 80 mm Hg for diastolic and 140 mm Hg for systolic blood pressure. The effectiveness of QI strategies varied depending on baseline HbA(1c) control. QI strategies increased the likelihood that patients received aspirin (11 trials; relative risk [RR] 1·33, 95% CI 1·21-1·45), antihypertensive drugs (ten trials; RR 1·17, 1·01-1·37), and screening for retinopathy (23 trials; RR 1·22, 1·13-1·32), renal function (14 trials; RR 128, 1·13-1·44), and foot abnormalities (22 trials; RR 1·27, 1·16-1·39). However, statin use (ten trials; RR 1·12, 0·99-1·28), hypertension control (18 trials; RR 1·01, 0·96-1·07), and smoking cessation (13 trials; RR 1·13, 0·99-1·29) were not significantly increased. INTERPRETATION Many trials of QI strategies showed improvements in diabetes care. Interventions targeting the system of chronic disease management along with patient-mediated QI strategies should be an important component of interventions aimed at improving diabetes management. Interventions solely targeting health-care professionals seem to be beneficial only if baseline HbA(1c) control is poor. FUNDING Ontario Ministry of Health and Long-term Care and the Alberta Heritage Foundation for Medical Research (now Alberta Innovates--Health Solutions).

Risk of coronary events in people with chronic kidney disease compared with those with diabetes: a population-level cohort study

BACKGROUND Diabetes is regarded as a coronary heart disease risk equivalent-ie, people with the disorder have a risk of coronary events similar to those with previous myocardial infarction. We assessed whether chronic kidney disease should be regarded as a coronary heart disease risk equivalent. METHODS We studied a population-based cohort with measures of estimated glomerular filtration rate (eGFR) and proteinuria from Alberta, Canada. We used validated algorithms based on hospital admission and medical-claim data to classify participants with baseline history of myocardial infarction or diabetes and to ascertain which patients were admitted to hospital for myocardial infarction during follow-up (the primary outcome). For our primary analysis, we defined baseline chronic kidney disease as eGFR 15-59·9 mL/min per 1·73 m(2) (stage 3 or 4 disease). We used Poisson regression to calculate unadjusted rates and relative rates of myocardial infarction during follow-up for five risk groups: people with previous myocardial infarction (with or without diabetes or chronic kidney disease), and (of those without previous myocardial infarction), four mutually exclusive groups defined by the presence or absence of diabetes and chronic kidney disease. FINDINGS During a median follow-up of 48 months (IQR 25-65), 11,340 of 1,268,029 participants (1%) were admitted to hospital with myocardial infarction. The unadjusted rate of myocardial infarction was highest in people with previous myocardial infarction (18·5 per 1000 person-years, 95% CI 17·4-19·8). In people without previous myocardial infarction, the rate of myocardial infarction was lower in those with diabetes (without chronic kidney disease) than in those with chronic kidney disease (without diabetes; 5·4 per 1000 person-years, 5·2-5·7, vs 6·9 per 1000 person-years, 6·6-7·2; p<0·0001). The rate of incident myocardial infarction in people with diabetes was substantially lower than for those with chronic kidney disease when defined by eGFR of less than 45 mL/min per 1·73 m(2) and severely increased proteinuria (6·6 per 1000 person-years, 6·4-6·9 vs 12·4 per 1000 person-years, 9·7-15·9). INTERPRETATION Our findings suggest that chronic kidney disease could be added to the list of criteria defining people at highest risk of future coronary events. FUNDING Alberta Heritage Foundation for Medical Research.

Adapting the charlson comorbidity index for use in patients with ESRD

BACKGROUND Accurate prediction of survival for patients with end-stage renal disease (ESRD) and multiple comorbid conditions is difficult. In nondialysis patients, the Charlson Comorbidity Index has been used to adjust for comorbidity. The purpose of this study is to assess the validity of the Charlson index in incident dialysis patients and modify the index for use specifically in this patient population. METHODS Subjects included all incident hemodialysis and peritoneal dialysis patients starting dialysis therapy between July 1, 1999, and November 30, 2000. These 237 patients formed a cohort from which new integer weights for Charlson comorbidities were derived using Cox proportional hazards modeling. Performance of the original Charlson index and the new ESRD comorbidity index were compared using Kaplan-Meier survival curves, change in likelihood ratio, and the c statistic. RESULTS After multivariate analysis and conversion of hazard ratios to index weights, only 6 of the original 18 Charlson variables were assigned the same weight and 6 variables were assigned a weight higher than in the original Charlson index. Using Kaplan-Meier survival curves, we found that both the original Charlson index and the new ESRD comorbidity index were associated with and able to describe a wide range of survival. However, the new study-specific index had better validated performance, indicated by a greater change in the likelihood ratio test and higher c statistic. CONCLUSION This study indicates that the original Charlson index is a valid tool to assess comorbidity and predict survival in patients with ESRD. However, our modified ESRD comorbidity index had slightly better performance characteristics in this population.

Guidelines for the management of chronic kidney disease

New guidelines for the management of chronic kidney disease have been developed by the Canadian Society of Nephrology (Appendix 1 contains the full-text guidelines; available at [www.cmaj.ca/cgi/content/full/179/11/1154/DC1][1]). These guidelines describe key aspects of the management of chronic

Renal replacement therapy in patients with acute renal failure: a systematic review

CONTEXT Acute renal failure requiring dialytic support is associated with a high risk of mortality and substantial morbidity. OBJECTIVES To summarize current evidence guiding provision of dialysis for patients with acute renal failure, to make recommendations for management, and to identify areas in which additional research is needed. DATA SOURCES Systematic searches of peer-reviewed publications in MEDLINE, EMBASE, and All EBM Reviews through October 2007. STUDY SELECTION Randomized controlled trials (RCTs) and prospective cohort studies studying dialytic support in adults with acute renal failure that reported the incidence of clinical outcomes such as mortality, length of stay, need for chronic dialysis, or development of hypotension. DATA EXTRACTION Quality was independently assessed by 2 reviewers using the Jadad score (RCTs) and the Downs and Black checklist (cohort studies). A single reviewer extracted data, which were independently verified by a second reviewer. Results of RCTs were pooled using a random-effects model. DATA SYNTHESIS From 173 retrieved articles, 30 RCTs and 8 prospective cohort studies were eligible. No conclusions could be drawn about optimal indications for or timing of renal replacement. Available data comparing continuous renal replacement therapy (CRRT) with intermittent hemodialysis demonstrated no clinically relevant difference between modalities, including for all-cause mortality (relative risk [RR], 1.10; 95% confidence interval [CI], 0.99-1.23; I2 = 0%) or for the requirement for chronic dialysis treatment in survivors (RR, 0.91; 95% CI, 0.56-1.49; I2 = 0%). For patients treated with CRRT, limited data suggest that bicarbonate may be preferable to other forms of dialysate alkali and that citrate infusion may be an alternative to systemic anticoagulation in patients at high risk of bleeding. Among patients treated with continuous venovenous hemofiltration (CVVHF), the risk of death was lower at doses of 35 mL/kg per hour (RR of death compared with doses of 20 mL/kg per hour, 0.74; 95% CI, 0.63-0.88). The use of unsubstituted cellulosic membranes should be avoided in intermittent hemodialysis (RR of death compared with biocompatible membranes, 1.23; 95% CI, 1.01-1.50). CONCLUSIONS Based on current data, intermittent hemodialysis and CRRT appear to lead to similar clinical outcomes for patients with ARF. If CVVHF is used, a dose of 35 mL/kg per hour should be provided. Given the paucity of good-quality evidence in this important area, additional large randomized trials are needed to evaluate clinically important outcomes.

Oral Phosphate Binders in Patients with Kidney Failure

Hyperphosphatemia, which is nearly universal in kidney failure, is accompanied by low serum levels of vitamin D and hypocalcemia. Without treatment, severe secondary hyperparathyroidism occurs, which may result in painful fractures, brown tumors, and generalized osteopenia. This article reviews the rationale for treatment with oral phosphate binders, discusses evidence supporting the use of available agents, and suggests an approach for clinical practice.

Cost of acute renal failure requiring dialysis in the intensive care unit: clinical and resource implications of renal recovery.

ObjectiveAcute renal failure can be treated with continuous renal replacement therapy (CRRT) or intermittent hemodialysis. There is no difference in mortality, although patients treated with CRRT may have a higher rate of renal recovery. Given these considerations, an estimate of the costs by modality may help in choosing the method of dialysis. As such, the objective of this study was to estimate the cost of CRRT and intermittent hemodialysis in the intensive care unit and to explore the impact of renal recovery on subsequent clinical outcomes and costs among survivors. DesignRetrospective cohort study of all patients who developed acute renal failure and required dialysis between April 1, 1996, and March 31, 1999. SettingTwo tertiary care intensive care units in Calgary, Canada. PatientsA total of 261 critically ill patients. InterventionsNone. MeasurementsAll patients were followed to determine in-hospital and subsequent clinical outcomes (survival and frequency of renal recovery). The immediate and potential long-term costs of CRRT and intermittent hemodialysis were measured. Main ResultsThe cost of performing CRRT ranged from Can

Associations Between Acute Kidney Injury and Cardiovascular and Renal Outcomes After Coronary Angiography

3,486 to Can

Glomerular filtration rate, proteinuria, and the incidence and consequences of acute kidney injury: a cohort study

5,117 per week, depending on the modality and the anticoagulant used, and it was significantly more expensive than intermittent hemodialysis (Can