Diagnosing Hypertension by Intradialytic Blood Pressure Recordings

Background and objectives: The diagnosis of hypertension among hemodialysis patients by predialysis or postdialysis blood pressure (BP) recordings is imprecise and biased and has poor test-retest reliability. The use of intradialytic BP measurements to diagnose hypertension is unknown.

Design, setting, participants, & measurements: A diagnostic-test study was done with interdialytic ambulatory BP as reference standard. Index BP recordings tested were: predialysis (method 1), postdialysis (method 2), intradialytic (method 3), intradialytic including predialyis and postdialysis (method 4), and the average of predialysis and postdialysis (method 5). Each index BP was recorded over six consecutive dialysis treatments.

Results: There were differences among index BP measurements in reproducibility, bias, precision, and accuracy. Method 4 was the most reproducible (intraclass correlation coefficient = 0.70 for systolic and diastolic BP). All 5 measurement methods overestimated 44-h ambulatory systolic BP. Methods 2, 3, or 4 overestimated ambulatory systolic BP by only a small amount. Method 4 was the most precise and accurate. For diagnosis of hypertension, BP cut-point by method 4 of 135/75 mmHg, had a sensitivity of 90.4% and specificity of 75.9% for systolic BP (area under ROC curve 0.90). Median cut-off systolic BP of 140 mmHg from a single dialysis provides approximately 80% sensitivity and 80% specificity in diagnosing systolic hypertension; a median cut-off diastolic BP of 80 mmHg provides approximately 75% sensitivity and 75% specificity in diagnosing diastolic hypertension.

Conclusions: Consideration of intradialytic BP measurements together with predialysis and postdialysis BP measurements improves the reproducibility, bias, precision, and accuracy of BP measurement compared with predialysis or postdialysis measurements.

Hepatitis C Is Less Aggressive in Hemodialysis Patients than in Nonuremic Patients

Background and objectives: The severity of liver disease among hepatitis C patients on hemodialysis is controversial. The aim of this study was to compare the clinical, biochemical, and liver histologic characteristics of hepatitis C virus (HCV) in hemodialysis patients and in those with normal renal function.

Design, setting, participants, & measurements: A case-control study was carried out with 36 HCV patients on hemodialysis and 37 HCV patients with normal renal function matched for gender, age at infection, and estimated time of infection.

Results: HCV patients on hemodialysis had lower levels of alanina aminotransferase and lower viral load. Hepatic fibrosis was significantly higher in the patients with normal renal function (73%) than in hemodialysis patients (47.2%, P < 0.025); the same was observed for inflammatory activity (control group 59.5% versus hemodialysis patients 27.7%, P = 0.003). In addition, the risk of tissue inflammation was four times lower in hemodialysis patients (odds ratio = 0.23, P < 0.004), and severe inflammatory activity on biopsy was the only independent risk factor for fibrosis (P < 0.001).

Conclusions: The lower biochemical and inflammatory activities observed in hemodialysis patients suggest that hemodialysis and uremia may have a protective role against progression of the disease caused by HCV.

Associations of Kidney Function with Cardiovascular Medication Use after Myocardial Infarction

Background and objectives: It is unknown whether adherence to recommended medications after myocardial infarction (MI) differs by kidney function.

Design, setting, participants, & measurements: This was a retrospective cohort study of older patients who were discharged after MI in two Eastern states between 1995 and 2004. Patients were categorized as having ESRD, having chronic kidney disease (CKD), and being free from diagnosed CKD. Use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (ACEI/ARB), β blockers (BB), and statins was assessed within 30 d after discharge. Good adherence was defined as proportion of days covered >80% during the first year after discharge.

Results: Compared with patients with no CKD, patients with CKD had 22% lower adjusted use of ACEI/ARB but similar rates of BB and statin use. Patients with ESRD experienced 43% lower ACEI/ARB and 17% lower statin use. Only 64% (BB), 57% (statins), and 54% (ACEI/ARB) of patients had good 1-yr adherence. Adherence was similar between patients with CKD and with no CKD for all study drugs. Fewer patients with ESRD had good adherence to BB.

Conclusions: With the exception of lower ACEI/ARB use in patients with CKD, we found no differences between patients with CKD and with no CKD in their use of and adherence to these cardiovascular medications after MI. Patients with ESRD experienced lower use of ACEI/ARB and statins and lower adherence to BB regimens. Postulated differences in medication use after MI across levels of kidney function are unlikely to explain the observed differences in long-term outcomes.

Hand Hygiene: How Can We Improve?

Lisa Maragakis, MD, reviews in her videoblog the serious challenges of measuring and improving hand hygiene compliance in the healthcare setting.
Medscape Infectious Diseases

Should femoral catheterization for acute RRT be avoided to prevent infection?

Should femoral catheterization for acute RRT be avoided to prevent infection?

Nature Clinical Practice Nephrology 4, 466 (2008). doi:10.1038/ncpneph0885