Usefulness of heart rate to predict cardiac events in treated patients with high-risk systemic hypertension.

A high heart rate (HR) predicts future cardiovascular events. We explored the predictive value of HR in patients with high-risk hypertension and examined whether blood pressure reduction modifies this association. The participants were 15,193 patients with hypertension enrolled in the Valsartan Antihypertensive Long-term Use Evaluation (VALUE) trial and followed up for 5 years. The HR was assessed from electrocardiographic recordings obtained annually throughout the study period. The primary end point was the interval to cardiac events. After adjustment for confounders, the hazard ratio of the composite cardiac primary end point for a 10-beats/min of the baseline HR increment was 1.16 (95% confidence interval 1.12 to 1.20). Compared to the lowest HR quintile, the adjusted hazard ratio in the highest quintile was 1.73 (95% confidence interval 1.46 to 2.04). Compared to the pooled lower quintiles of baseline HR, the annual incidence of primary end point in the top baseline quintile was greater in each of the 5 study years (all p <0.05). The adjusted hazard ratio for the primary end point in the highest in-trial HR heart rate quintile versus the lowest quintile was 1.53 (95% confidence interval 1.26 to 1.85). The incidence of primary end points in the highest in-trial HR group compared to the pooled 4 lower quintiles was 53% greater in patients with well-controlled blood pressure (p <0.001) and 34% greater in those with uncontrolled blood pressure (p = 0.002). In conclusion, an increased HR is a long-term predictor of cardiovascular events in patients with high-risk hypertension. This effect was not modified by good blood pressure control. It is not yet known whether a therapeutic reduction of HR would improve cardiovascular prognosis.

Goldmann applanation tonometry free of the slitlamp.

A prototype device was developed for using the Goldmann applanation tonometer (GAT) without a slitlamp to make it potentially practical to measure intraocular pressure (IOP) away from the clinic. Inexpensive consumer video components and a small flashlight replaced the microscope and illuminator of the slitlamp in a device that was assembled to use a standard, unmodified GAT. The device was evaluated for IOP measurement by volunteer measurer-subjects, who had no experience using the GAT, on each other and also by volunteers on themselves (self-tonometry). In a single, short training session with the prototype, the naive volunteers learned to measure IOP with the GAT. Other naive volunteers made IOP measurements on themselves with the prototype that were comparable in reliability with those obtained with the prototype by a professional measurer.

A Bayesian sensitivity model for intention-to-treat analysis on binary outcomes with dropouts.

Intention-to-treat (ITT) analysis is commonly used in randomized clinical trials. However, the use of ITT analysis presents a challenge: how to deal with subjects who drop out. Here we focus on randomized trials where the primary outcome is a binary endpoint. Several approaches are available for including the dropout subject in the ITT analysis, mainly chosen prior to unblinding the study. These approaches reduce the potential bias due to breaking the randomization code. However, the validity of the results will highly depend on untestable assumptions about the dropout mechanism. Thus, it is important to evaluate the sensitivity of the results across different missing-data mechanisms. We propose here a Bayesian pattern-mixture model for ITT analysis of binary outcomes with dropouts that applies over different types of missing-data mechanisms. We introduce a new parameterization to identify the model, which is then used for sensitivity analysis. The parameterization is defined as the odds ratio of having an endpoint between the subjects who dropped out and those who completed the study. Such parameterization is intuitive and easy to use in sensitivity analysis; it also incorporates most of the available methods as special cases. The model is applied to TRial Of Preventing HYpertension.

A Bayesian model for longitudinal count data with non-ignorable dropout.

Asthma is an important chronic disease of childhood. An intervention programme for managing asthma was designed on principles of self-regulation and was evaluated by a randomized longitudinal study.The study focused on several outcomes, and, typically, missing data remained a pervasive problem. We develop a pattern-mixture model to evaluate the outcome of intervention on the number of hospitalizations with non-ignorable dropouts. Pattern-mixture models are not generally identifiable as no data may be available to estimate a number of model parameters. Sensitivity analyses are performed by imposing structures on the unidentified parameters.We propose a parameterization which permits sensitivity analyses on clustered longitudinal count data that have missing values due to non-ignorable missing data mechanisms. This parameterization is expressed as ratios between event rates across missing data patterns and the observed data pattern and thus measures departures from an ignorable missing data mechanism. Sensitivity analyses are performed within a Bayesian framework by averaging over different prior distributions on the event ratios. This model has the advantage of providing an intuitive and flexible framework for incorporating the uncertainty of the missing data mechanism in the final analysis.

Statistics by zooth. A primer.

In reading this and other journals, or when attending lectures, the practicing dentist is often "whelmed" if not overwhelmed by the welter of statistical terminology (and analyses). Wading through these seemingly formidable shoals toward the sea of scientific findings can be frustrating. The aim of this article is to summarize the nomenclature to permit the readership a more incisive and, it is hoped, relaxed, perusal of dental research. There are no formulas to confound or to become barriers to insight. Enjoy the cruise!

The Valsartan Antihypertensive Long-Term Use Evaluation (VALUE) trial: outcomes in patients receiving monotherapy.

In the main Valsartan Antihypertensive Long-Term Use Evaluation (VALUE) report, we investigated outcomes in 15 245 high-risk hypertensive subjects treated with valsartan- or amlodipine-based regimens. In this report, we analyzed outcomes in 7080 patients (46.4%) who, at the end of the initial drug adjustment period (6 months), remained on monotherapy. Baseline characteristics were similar in the valsartan (N=3263) and amlodipine (N=3817) groups. Time on monotherapy was 3.2 years (78% of treatment exposure time). The average in-trial blood pressure was similar in both groups. Event rates in the monotherapy group were 16% to 39% lower than in the main VALUE trial. In the first analysis, we censored patients when they discontinued monotherapy ("censored"); in the second, we counted events regardless of subsequent therapy (intention-to-treat principle). We also assessed the impact of duration of monotherapy on outcomes. No difference was found in primary composite cardiac end points, strokes, myocardial infarctions, and all-cause deaths with both analyses. Heart failure in the valsartan group was lower both in the censored and intention-to-treat analyses (hazard ratios: 0.63, P=0.004 and 0.78, P=0.045, respectively). Longer duration of monotherapy amplified between-group differences in heart failure. New-onset diabetes was lower in the valsartan group with both analyses (odds ratios: 0.78, P=0.012 and 0.82, P=0.034). Thus, despite lower absolute event rates in monotherapy patients, the relative risks of heart failure and new-onset diabetes favored valsartan. Moreover, these findings support the feasibility of comparative prospective trials in lower-risk hypertensive patients.

Effects of valsartan compared to amlodipine on preventing type 2 diabetes in high-risk hypertensive patients: the VALUE trial.

CONTEXT: Type 2 diabetes is emerging as a major health problem, which tends to cluster with hypertension in individuals at high risk of cardiovascular disease. OBJECTIVE: To test for the first time the hypothesis that treatment of hypertensive patients at high cardiovascular risk with the angiotensin-receptor blocker (ARB) valsartan prevents new-onset type 2 diabetes compared with the metabolically neutral calcium-channel antagonist (CCA) amlodipine. DESIGN: Pre-specified analysis in the VALUE trial. Follow-up averaged 4.2 years. The risk of developing new diabetes was calculated as an odds ratio (OR) with 95% confidence intervals (CI) for different definitions of diabetes. PATIENTS: A sample of 9995 high-risk, non-diabetic hypertensive patients. INTERVENTIONS: Valsartan or amlodipine with or without add-on medication [hydrochlorothiazide (HCTZ) and other add-ons, excluding other ARBs, angiotensin-converting enzyme (ACE) inhibitors, CCAs]. MAIN OUTCOME MEASURE: New diabetes defined as an adverse event, new blood-glucose-lowering drugs and/or fasting glucose > 7.0 mmol/l. RESULTS: New diabetes was reported in 580 (11.5%) patients on valsartan and in 718 (14.5%) patients on amlodipine (OR 0.77, 95% CI 0.69-0.87, P < 0.0001). Using stricter criteria (without adverse event reports) new diabetes was detected in 495 (9.8%) patients on valsartan and in 586 (11.8%) on amlodipine (OR 0.82, 95% CI 0.72-0.93, P = 0.0015). CONCLUSION: Compared with amlodipine, valsartan reduces the risk of developing diabetes mellitus in high-risk hypertensive patients.

Feasibility of treating prehypertension with an angiotensin-receptor blocker.

BACKGROUND: Prehypertension is considered a precursor of stage 1 hypertension and a predictor of excessive cardiovascular risk. We investigated whether pharmacologic treatment of prehypertension prevents or postpones stage 1 hypertension. METHODS: Participants with repeated measurements of systolic pressure of 130 to 139 mm Hg and diastolic pressure of 89 mm Hg or lower, or systolic pressure of 139 mm Hg or lower and diastolic pressure of 85 to 89 mm Hg, were randomly assigned to receive two years of candesartan (Atacand, AstraZeneca) or placebo, followed by two years of placebo for all. When a participant reached the study end point of stage 1 hypertension, treatment with antihypertensive agents was initiated. Both the candesartan group and the placebo group were instructed to make changes in lifestyle to reduce blood pressure throughout the trial. RESULTS: A total of 409 participants were randomly assigned to candesartan, and 400 to placebo. Data on 772 participants (391 in the candesartan group and 381 in the placebo group; mean age, 48.5 years; 59.6 percent men) were available for analysis. During the first two years, hypertension developed in 154 participants in the placebo group and 53 of those in the candesartan group (relative risk reduction, 66.3 percent; P<0.001). After four years, hypertension had developed in 240 participants in the placebo group and 208 of those in the candesartan group (relative risk reduction, 15.6 percent; P<0.007). Serious adverse events occurred in 3.5 percent of the participants assigned to candesartan and 5.9 percent of those receiving placebo. CONCLUSIONS: Over a period of four years, stage 1 hypertension developed in nearly two thirds of patients with untreated prehypertension (the placebo group). Treatment of prehypertension with candesartan appeared to be well tolerated and reduced the risk of incident hypertension during the study period. Thus, treatment of prehypertension appears to be feasible. (ClinicalTrials.gov number, NCT00227318.).

Trial of preventing hypertension: design and 2-year progress report.

The TRial Of Preventing HYpertension (TROPHY) study is an investigator-initiated trial to examine whether early pharmacological treatment in subjects with "high-normal" blood pressure (BP) might prevent or delay the development of clinical hypertension. This is a 4-year, multicenter, randomized, double-blind study in untreated subjects aged 30 to 65 years with entry BPs of 130 to 139/< or =89 or < or =139/85 to 89. The participants were randomized either to placebo or to a fixed (16 mg once daily) dose of candesartan cilexetil (candesartan). After 2 years, the candesartan group was switched to placebo, and the placebo group continued taking placebo. The main outcome measure was the development of clinical (treatment-requiring) hypertension assessed by an automated (blinded) BP measurement device. We randomized 809 subjects (59% males, average age 49.0+/-SD 8.1 years) in 71 study centers in the United States. The entry BP was 134+/-4.3/84.8+/-3.9 mm Hg. During the first 2 years, 187 subjects (23%) developed clinical hypertension. All have been given antihypertensive treatment, and 170 continue to be followed in study centers. The study dropout rate is 14.8% (120 subjects). The hypertension rates are higher than anticipated, whereas the rates of dropout are within the sample size projections; thus, the study will have sufficient power to evaluate its hypotheses. In this article, we describe baseline characteristics of TROPHY subjects and discuss novel analytical issues and statistical approaches to evaluate the findings in this trial of primary prevention of hypertension.

Blood pressure dependent and independent effects of antihypertensive treatment on clinical events in the VALUE Trial.

The Valsartan Antihypertensive Long-term Use Evaluation (VALUE) trial was designed to test whether, for the same achieved blood pressures, regimens based on valsartan or amlodipine would have differing effects on cardiovascular endpoints in high risk hypertension. But inequalities in blood pressure, favouring amlodipine, throughout the multiyear trial precluded comparison of outcomes. A technique of serial median matching, applied at 6 months when treatment adjustments intended to achieve control of blood pressure were complete, created 5006 valsartan-amlodipine patient pairs matched exactly for systolic blood pressure, age, sex, and the presence or absence of previous coronary disease, stroke, or diabetes. Subsequent combined cardiac events, myocardial infarction, stroke, and mortality were almost identical in the two cohorts, but admission to hospital for heart failure was significantly lower with valsartan. Reaching blood pressure control (systolic <140 mm Hg) by 6 months, independent of drug type, was associated with significant benefits for subsequent major outcomes; the blood pressure response after just 1 month of treatment predicted events and survival.

Expressive/suppressive anger-coping responses, gender, and types of mortality: a 17-year follow-up (Tecumseh, Michigan, 1971-1988).

OBJECTIVES: This study examined prospectively (1971-1988) the relationship between anger-coping responses, gender, and mortality (N = 91) in a representative sample of men (N = 324) and women (N = 372), aged 30 to 69, from the Tecumseh Community Health Study. METHODS: Anger-coping was measured by responses to hypothetical unfair anger-provoking situations. Cox proportional hazard regressions were used adjusted for seven health risk factors (age, smoking, relative weight, systolic blood pressure (SBP), bronchial problems, FEV1, and cardiovascular (CV) risk). RESULTS: Men's suppressed anger interacted significantly with SBP and also with bronchial problems to predict both all-cause and CV mortality. Women showed direct relationships between suppressed anger and early mortality (all-cause, CV, and cancer). Women also showed an interaction of spouse-suppressed anger and SBP for all-cause and CV mortality. Data suggest men who expressed their anger died earlier of cancer (N = 16) deaths. CONCLUSIONS: Suppressed anger at the time of an unjust attack may become chronic resentment (intermittent rage or hatred) about which little is known and requires research. The design for future research should experimentally measure both suppressed anger-coping responses (after an unfair attack) and morbidity (eg, blood pressure, bronchitis, immune disorder, etc.) to predict prospectively to earlier mortality.

Multicenter prospective validation of prehospital clinical spinal clearance criteria.

BACKGROUND: Spine immobilization is one of the most frequently performed prehospital procedures. If trauma patients without significant risk for spine injury complications can be identified, spine immobilization could be selectively performed. The purpose of this study was to evaluate five prehospital clinical criteria-altered mental status, neurologic deficit, spine pain or tenderness, evidence of intoxication, or suspected extremity fracture-the absence of which identify prehospital trauma patients without a significant spine injury. METHODS: Prospectively collected emergency medical services data items included the above-listed criteria. Outcome data include spine fracture or cord injury, and also the level and management of injuries. RESULTS: A total of 295 patients with spine injuries were present in 8,975 (3.3%) cases. Spine injury was identified by the prehospital criteria in 280 of 295 (94.9%) injured patients. The criteria missed 15 patients. Thirteen of 15 had stable injuries, the majority of which were stable compression or vertebral process injuries. The remaining two would have been captured by more accurate prehospital evaluation. CONCLUSION: Absence of the study criteria may form the basis of a prehospital protocol that could be used to identify trauma patients who may safely have rigid spine immobilization withheld. Evaluation of such a protocol in practice should be performed.