Morbidity and mortality of orthostatic hypotension: implications for management of cardiovascular disease.
Am J Hypertens. 2011 Feb;24(2):135-44
Authors: Benvenuto LJ, Krakoff LR
Orthostatic hypotension (OH) is the fai…

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P values: use and misuse in medical literature.

Am J Hypertens. 2011 Jan;24(1):18-23

Authors: Cohen HW

P values are widely used in the medical literature but many authors, reviewers, and readers are unfamiliar with a valid definition of a P value, let alone how to interpret one correctly. Popular explanations such as “the probability that study results are due to chance” are wrong in a variety of ways and can lead to substantial errors in evaluating the evidence from research studies. Belief that “statistical significance” can alone discriminate between truth and falsehood borders on magical thinking. The article points out how to better interpret P values by avoiding common errors. Statistical analyses and P values are important tools in evidence-based medicine, but have to be used cautiously and with better understanding.

PMID: 20966898 [PubMed - indexed for MEDLINE]

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Cluster-randomized controlled trial of oscillometric vs. manual sphygmomanometer for blood pressure management in primary care (CRAB).

Am J Hypertens. 2009 Jun;22(6):598-603

Authors: Nelson MR, Quinn S, Bowers-Ingram L, Nelson JM, Winzenberg TM

BACKGROUND: Although mercury sphygmomanometers are seen as the gold standard instrument for blood pressure (BP) measurement, they are being withdrawn due to safety concerns. CRAB was a cluster-randomized controlled trial in 24 family practices in Tasmania, Australia, which aimed to determine the effect of an oscillometric device on BP management. METHODS: Cluster-randomized controlled trial. Intervention practices were supplied with automated monitors and control (usual care) practices used mercury or aneroid sphygmomanometers. They were subsequently audited by a research nurse. Usual care practice audit periods were matched to intervention practices. All analyses were intention-to-treat and adjusted for potential clustering. Differences in BP were analyzed using generalized estimating equations. All other outcomes were analyzed using multilevel mixed-effects Poisson regression. Post hoc analyses were performed to determine the mediators of changes in prescribing behavior. RESULTS: A total of 3,355 records were reviewed (828 visits had BP recordings). The percentage of BP recordings ending in "0" was significantly lower in intervention vs. usual care practices (systolic BP (SBP) 18% (107/587) vs. 71% (233/329), diastolic BP (DBP) 20% (119/584) vs. 70% (229/328), P < 0.001). The mean of SBP recordings in the intervention group was 7.5 mm Hg (95% confidence interval (CI) 5.2, 9.9 mm Hg, P < 0.001) higher than in the usual care group. Patients taking BP lowering drugs were more likely (incidence rate ratio (IRR) 1.3, 95% CI 1.1, 1.7, P = 0.01) to have a BP lowering drug prescribed if they were in the intervention compared to the usual care. CONCLUSIONS: Although digit preference was largely eliminated by oscillometric measurement, prescribing behavior was mediated by SBP.

PMID: 19300424 [PubMed - indexed for MEDLINE]

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Effects of renin-angiotensin system blockers on renal outcomes and all-cause mortality in patients with diabetic nephropathy: an updated meta-analysis.

Am J Hypertens. 2008 Aug;21(8):922-9

Authors: Sarafidis PA, Stafylas PC, Kanaki AI, Lasaridis AN

BACKGROUND: In contrast to previous studies, recent data questioned the ability of renin-angiotensin-aldosterone system (RAAS) blockers to delay progression of diabetic nephropathy. This study evaluated the effect of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin-receptor blockers (ARBs) in patients with diabetic nephropathy. METHODS: A systematic literature search of MEDLINE/PubMed and EMBASE databases was performed to identify randomized trials published up to June 2007 comparing the effects of ACEIs or ARBs with placebo and/or a regimen not including a RAAS blocker on the incidence of end-stage renal disease (ESRD), doubling of serum creatinine (DSC), or death from any cause in patients with diabetic nephropathy. Treatment effects were summarized as relative risks (RRs) using the Mantel-Haenszel fixed-effects model. RESULTS: Of the 1,028 originally identified studies, 24 fulfilled the inclusion criteria (20 using ACEIs and 4 using ARBs). Use of ACEIs was associated with a trend toward reduction of ESRD incidence (RR 0.70; 95% confidence interval (CI) 0.46-1.05) and use of ARBs with significant reduction of ESRD risk (RR 0.78; 95% CI 0.67-0.91). Both drug classes were associated with reduction in the risk of DSC (RR 0.71; 95% CI 0.56-0.91 for ACEIs and RR 0.79; 95% CI 0.68-0.91 for ARBs) but none affected all-cause mortality (RR 0.96; 95% CI 0.85-1.09 for ACEIs and RR 0.99; 95% CI 0.85-1.16 for ARBs). CONCLUSION: Treatment of patients with diabetic nephropathy with a RAAS blocker reduces the risks of ESRD and DSC, but does not affect all-cause mortality. These findings are added to the evidence of a renoprotective role of RAAS blockers in such patients.

PMID: 18535536 [PubMed - indexed for MEDLINE]

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Aliskiren fails to lower blood pressure in patients who have either low PRA levels or whose PRA falls insufficiently or reactively rises.

Am J Hypertens. 2009 Jan;22(1):112-21

Authors: Sealey JE, Laragh JH

BACKGROUND: Suppressed baseline plasma renin activity (PRA) levels or large reactive increases in renin secretion are two possible reasons for treatment failure with antirenin system drugs. METHODS: To investigate their prevalence we reanalyzed data from three published clinical trials of the renin inhibitor aliskiren. RESULTS: Aliskiren failed to lower systolic blood pressure (SBP) by at least 10 mm Hg in half of all patients. It was very effective in two-thirds of medium- to high-renin patients (-19 mm Hg). But BP did not fall in most low-renin patients, or in 30% of medium- to high-renin patients. BP actually rose by >10 mm Hg in 5% of patients taking aliskiren and in >10% of patients when aliskiren was added to an angiotensin receptor blocker (ARB) or angiotensin converting enzyme inhibitor (ACEI). PRA changed in parallel with BP. Although PRA fell in most patients, it actually rose in 5% and in up to 30% when aliskiren was added to an ARB or ACEI. CONCLUSIONS: There are two reasons for treatment failure with aliskiren. Many hypertensive patients have large BP falls. But, BP does not fall in most low-renin patients or in medium- to high-renin patients whose PRA levels do not fall sufficiently. If the concept of that treatment resistance is caused by excessive reactive increases in renin secretion is confirmed, then a PRA determination during treatment could be used to guide subsequent addition or subtraction of either natriuretic or antirenin drug types, to thereby correct BP and reduce cardiovascular risk.

PMID: 18802434 [PubMed - indexed for MEDLINE]

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Natriuretic peptides: an update on bioactivity, potential therapeutic use, and implication in cardiovascular diseases.

Am J Hypertens. 2008 Jul;21(7):733-41

Authors: Rubattu S, Sciarretta S, Valenti V, Stanzione R, Volpe M

The natriuretic peptide system includes three known peptides: atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP). They contribute to the regulation of cardiovascular homeostasis through diuretic, natriuretic, and vasodilatory properties. Among them, ANP has received particular attention because of its effects on blood pressure regulation and cardiac function. Although the potential for its therapeutic application in the treatment of hypertension and heart failure has been evaluated in several experimental and clinical investigations, no pharmacological approach directly targeted at modulation of ANP levels has ever reached the stage of being incorporated into clinical practice. Recently, ANP has also received attention as being a possible cardiovascular risk factor, particularly in the context of hypertension, stroke, obesity, and metabolic syndrome. Abnormalities in either peptide levels or peptide structure are thought to underlie its implied role in mediating cardiovascular diseases. Meanwhile, BNP has emerged as a relevant marker of left ventricular (LV) dysfunction and as a useful predictor of future outcome in patients with heart failure. This review deals with the major relevant findings related to the cardiovascular and metabolic effects of natriuretic peptides, to their potential therapeutic use, and to their role in mediating cardiovascular diseases.

PMID: 18464748 [PubMed - indexed for MEDLINE]

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