Physician characteristics and knowledge of CKD management.

BACKGROUND: Many studies suggest that chronic kidney disease (CKD) care is suboptimal in the United States. However, it is not known whether knowledge of CKD management in primary care physicians (PCPs) might have an important role in the suboptimal care and whether PCP characteristics are associated with having adequate knowledge. STUDY DESIGN: Cross-sectional study. SETTING & PARTICIPANTS: Self-administered questionnaire sent to a random sample of 1,550 US PCPs in February 2007. PREDICTOR OR FACTOR: PCP characteristics, including age, sex, degree (MD versus DO), primary specialty, board certification, patient volume, percentage of time in patient care spent in the inpatient versus outpatient setting, and number of patients referred to nephrologists in a month. OUTCOMES & MEASUREMENTS: Regression analyses of the association between physician characteristics and overall physician knowledge of CKD management, as well as individual subdomains of CKD knowledge related to recognition of CKD and management of hypertension in the setting of CKD. RESULTS: 470 of 1,453 (32.4%) eligible PCPs returned a completed survey. PCPs show significant variation in their ability to recognize CKD stages 2 to 4, but most have appropriate blood pressure goals in patients with CKD and are knowledgeable of the role of angiotensin-converting enzyme inhibitors in managing proteinuria. For each 10-year increase in age, the odds of showing satisfactory knowledge of CKD management decreased by 26% (odds ratio, 0.74; 95% confidence interval, 0.60 to 0.92). PCPs with the primary specialty of internal medicine had a more than 3-fold greater odds of showing a satisfactory level of knowledge compared with family practice specialists (odds ratio, 3.40; 95% confidence interval, 2.17 to 5.32). LIMITATIONS: The study findings are limited by the potential presence of nonresponse bias, information bias, and results suggesting there are multiple knowledge subdomains that perhaps are not additive. CONCLUSION: There is need to improve CKD knowledge in PCPs, especially regarding recognition of CKD at an early stage.

History-adjusted marginal structural analysis of the association between hemoglobin variability and mortality among chronic hemodialysis patients.

BACKGROUND AND OBJECTIVES: Hemoglobin variability is common among dialysis patients, and has been associated with increased mortality. The causal nature of this association has been difficult to ascertain because of potential time-dependent confounding, for which traditional statistical methods do not control. DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS: A retrospective cohort of 34,963 Fresenius Medical care dialysis patients from 1996 was assembled. Hemoglobin variability, absolute hemoglobin level, and temporal hemoglobin trend were measured over rolling 6-mo exposure windows. Their association with mortality was estimated using history-adjusted marginal structural analysis that adjusts for time-dependent confounding by applying weights to observations inversely related to the predictability of observed levels of hemoglobin. RESULTS: In the primary analysis, each g/dl increase in hemoglobin variability was associated with an adjusted hazard ratio (HR) [95% confidence interval (CI)] for all-cause mortality of 1.93 (1.20 to 3.10). Neither higher absolute hemoglobin level nor increasing hemoglobin trend were significantly associated with mortality; adjusted HR (95% CI) 0.85 (0.64 to 1.11) and 0.60 (0.25 to 1.45), respectively. CONCLUSIONS: Marginal structural analysis demonstrates that hemoglobin variability is associated with increased mortality among chronic hemodialysis patients, and that this effect is more pronounced than appreciated using standard statistical techniques that do not take time-dependent confounding into account.

Hemoglobin variability and mortality in ESRD.

Hemoglobin levels vary substantially over time in hemodialysis patients, and this variability may portend poor outcomes. For a given patient, hemoglobin concentration over time can be described by absolute levels, rate of change, or by the difference between observed level and expected level based on the preceding trend (i.e., seemingly random variability). We investigated the independent associations of these different methods of describing hemoglobin over time with mortality in a retrospective cohort of 34,963 hemodialysis patients. Hemoglobin concentration over time was modeled with linear regression for each subject, and the model was then used to define the subject's absolute level of hemoglobin (intercept), temporal trend in hemoglobin (slope), and hemoglobin variability (residual standard deviation). Survival analyses indicated that each 1g/dl increase in the residual standard deviation was associated with a 33% increase in rate of death, even after adjusting for multiple covariates. Patient characteristics accounted for very little of the variation in our hemoglobin variability metric (R2 = 0.019). We conclude that greater hemoglobin variability is independently associated with higher mortality.

Use of antiepileptic drugs in patients with kidney disease.

The number of medications used to treat different types of seizures has increased over the last 10-15 years. Most of the newer antiepileptic drugs (AEDs) are likely to be unfamiliar to many nephrologists. For both the older and newer AEDs, basic pharmacokinetic information, recommendations for drug dosing in patients with reduced kidney function or who are on dialysis, and adverse renal and fluid-electrolyte effects are reviewed. Newer AEDs are less likely to have significant drug-drug interactions than older agents, but are more likely to need dosage adjustment in patients with reduced kidney function. The most common renal toxicities of these drugs include metabolic acidosis, hyponatremia, and nephrolithiasis; interstitial nephritis and other adverse effects are less common. Little is known about the clearance of most of the newer AEDs with high-efficiency hemodialyzers or with peritoneal dialysis. Monitoring of drug levels when available, careful clinical assessment of patients taking AEDs, and close collaboration with neurologists is essential to the management of patients taking AEDs.

Willingness of dialysis patients to participate in a randomized controlled trial of daily dialysis.

BACKGROUND: The National Institutes of Health (NIH) has proposed conducting randomized controlled trials comparing short, daily, in-center hemodialysis with conventional hemodialysis. However, there is concern that difficulties recruiting patients may prevent the successful completion of such trials if patients believe the inconveniences of daily dialysis outweigh any potential health benefits. METHODS: To gauge willingness to participate in a daily dialysis trial, we described a hypothetical, randomized controlled trial comparing conventional to daily hemodialysis to 209 chronic hemodialysis patients, and assessed their motivations for and concerns about participating. RESULTS: We found that 85 patients (41%) of 209 patients who agreed to be interviewed expressed some willingness to participate in the hypothetical trial. Patients who expressed greater willingness to participate were younger (OR for participating = 0.96 per year, 95% CI = 0.94 to 0.98, P= 0.001), less likely to smoke (OR = 0.38, 95% CI = 0.17 to 0.84, P= 0.017), more likely to have been hospitalized during the last 12 months (OR = 2.8, 95% CI = 1.5 to 5.5, P= 0.002), less likely to have reactive airway disease (OR = 0.21, 95% CI = 0.06 to 0.69, P= 0.01) or coronary artery disease (OR = 0.20, 95% CI = 0.08 to 0.53, P= 0.001), and less likely to be on the waiting list for a kidney transplant (OR = 0.23, 95% CI = 0.10 to 0.50, P < 0.0001). CONCLUSION: The study suggests that less than half of eligible patients would be willing to participate in the randomized controlled trial. Differing willingness to participate across patient subgroups suggests that certain subgroups (i.e., older patients and those with coronary artery disease) will need to be targeted to ensure that results are generalizable to most hemodialysis patients.