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Stuart Pocock

Publications and source records attributed to Stuart Pocock.

At least 19 recordsLinked to original sources
PubMed2006

Clinical correlates and consequences of anemia in a broad spectrum of patients with heart failure: results of the Candesartan in Heart Failure: Assessment of Reduction in Mortality and Morbidity (CHARM) Program.

BACKGROUND: We wished to determine the prevalence of, potential mechanistic associations of, and clinical outcomes related to anemia in patients with heart failure and a broad spectrum of left ventricular ejection fraction (LVEF). METHODS AND RESULTS: In multivariable analyses, we examined the associations between hemoglobin and baseline characteristics, laboratory variables, and outcomes in 2653 patients randomized in the CHARM Program in the United States and Canada. Anemia was equally common in patients with preserved (27%) and reduced (25%) LVEF but was more common in black and older patients. Anemia was associated with ethnicity, diabetes, low body mass index, higher systolic and lower diastolic blood pressure, and recent heart failure hospitalization. More than 50% of anemic patients had a glomerular filtration rate <60 mL.min(-1).1.73 m(-2) compared with <30% of nonanemic patients. Despite an inverse relationship between hemoglobin and LVEF, anemia was associated with an increased risk of death and hospitalization, a relationship observed in patients with both reduced and preserved LVEF. There were 133 versus 69 deaths and 527 versus 352 hospitalizations per 1000 patient-years of follow-up in anemic versus nonanemic patients (both P<0.001). The effect of candesartan in reducing outcomes was independent of hemoglobin. CONCLUSIONS: Anemia was common in heart failure, regardless of LVEF. Lower hemoglobin was associated with higher LVEF yet was an independent predictor of adverse mortality and morbidity outcomes. In heart failure, the causes of anemia and the associations between anemia and outcomes are probably multiple and complex.

Aged↗
PubMed2006

Renal function as a predictor of outcome in a broad spectrum of patients with heart failure.

BACKGROUND: Decreased renal function has been found to be an independent risk factor for cardiovascular outcomes in patients with chronic heart failure (CHF) with markedly reduced left ventricular ejection fraction (LVEF). The aim of this analysis was to evaluate the prognostic importance of renal function in a broader spectrum of patients with CHF. METHODS AND RESULTS: The Candesartan in Heart Failure:Assessment of Reduction in Mortality and Morbidity (CHARM) program consisted of three component trials that enrolled patients with symptomatic CHF, based on use of ACE inhibitors and reduced (< or =40%) or preserved LVEF (>40%). Entry baseline creatinine was required to be below 3.0 mg/dL (265 micromol/L). Routine baseline serum creatinine assessments were done in 2680 North American patients. An analysis of the estimated glomerular filtration rate (eGFR), using the Modification of Diet in Renal Disease equation and LVEF on risk of cardiovascular death or hospitalization for heart failure, as well as on all-cause mortality, was conducted on these 2680 patients. The proportion of patients with eGFR <60 mL/min per 1.73 m2 was 36.0%; 42.6% for CHARM-Alternative, 33.0% for CHARM-Added, and 34.7% for CHARM-Preserved. During the median follow-up of 34.4 months (total 6493 person-years), the primary outcome of cardiovascular death or hospital admission for worsening CHF occurred in 950 of 2680 subjects. Both reduced eGFR and lower LVEF were found to be significant independent predictors of worse outcome after adjustment for major confounding baseline clinical characteristics. The risk for cardiovascular death or hospitalization for worsening CHF as well as the risk for all-cause mortality increased significantly below an eGFR of 60 mL/min per 1.73 m2 (adjusted hazard ratio, 1.54 for 45 to 60 mL/min per 1.73 m2 and 1.86 for <45 mL/min per 1.73 m2 for the primary outcome, both P<0.001, and hazard ratio of 1.50, P=0.006, and 1.91, P=0.001, respectively, for all-cause mortality). The prognostic value of eGFR was not significantly different among the three component trials. There was no significant interaction between renal function, the effect of candesartan, and clinical outcome. CONCLUSIONS: Impaired renal function is independently associated with heightened risk for death, cardiovascular death, and hospitalization for heart failure in patients with CHF with both preserved as well as reduced LVEF. There was no evidence that the beneficial effect of candesartan was modified by baseline eGFR.

Aged↗
PubMed2006

Hormone replacement therapy and acute myocardial infarction: a large observational study exploring the influence of age.

BACKGROUND: We examined whether the discrepancy between observational studies and randomized clinical trials (RCTs) on the effect of hormone replacement therapy (HRT) on myocardial infarction (MI) could be explained by differences in age of participants at the time of either HRT initiation or the MI event. METHODS: A matched case-control study was performed using the General Practice Research Database. Cases (n = 22 225) had a first diagnosis of MI between 1987 and 2001; up to six controls (n = 144 085) were matched to each case based on age, sex, and practice. Conditional logistic regression was performed adjusting for traditional cardiovascular risk factors, as well as, cardiovascular drug use and consultation rate. RESULTS: HRT users had a lower overall risk of MI compared with never users [odds ratio (OR): 0.76; 95% confidence interval (95% CI) 0.68-0.86); results were similar for opposed (OR: 0.73; 95% CI 0.68-0.86) and unopposed (OR: 0.79; 95% CI 0.66-0.96) therapy. This apparent benefit increased with older age at HRT initiation(18-44 years: OR = 0.99; 95% CI 0.74-1.33; 45-54 years: OR = 0.84; 95% CI 0.71-1.00; 55-64 years: OR = 0.67; 95% CI 0.54-0.82; 65-74 years: OR = 0.50; 95% CI 0.34-0.74; >75 years: OR = 0.55; 95% CI 0.23-1.32). Moreover, the cardioprotective effect was greater for MIs occurring at older ages (P-value for interaction = 0.003). CONCLUSION: The effect of HRT on MI becomes more pronounced with older age at initiation and at older ages at the time of an MI event. These findings contradict the hypothesis that the apparent protection seen in observational studies was due to the inclusion of younger participants.

Adolescent↗
PubMed2005

Influence of ejection fraction on cardiovascular outcomes in a broad spectrum of heart failure patients.

BACKGROUND: Left ventricular function is a principal determinant of cardiovascular risk in patients with heart failure. The growing number of patients with preserved systolic function heart failure underscores the importance of understanding the relationship between ejection fraction and risk. METHODS AND RESULTS: We studied 7599 patients with a broad spectrum of symptomatic heart failure enrolled in the Candesartan in Heart failure: Assessment of Reduction in Mortality and morbidity (CHARM) Program. All patients were randomized to candesartan at a target dose of 32 mg once daily or matching placebo and followed up for a median of 38 months. We related left ventricular ejection fraction (LVEF), measured before randomization at the sites, to cardiovascular outcomes and causes of death. Mean LVEF in patients enrolled in CHARM was 38.8+/-14.9% (median LVEF 36%). Patients with lower LVEF tended to have higher baseline New York Heart Association class. The hazard ratio for all-cause mortality increased by 39% for every 10% reduction in ejection fraction below 45% (hazard ratio 1.39, 95% CI 1.32 to 1.46), with adjustment for baseline covariates. All-cause mortality, cardiovascular death, and all components of cardiovascular death declined with increasing ejection fraction until an ejection fraction of 45%, after which the risk of these outcomes remained relatively stable with increasing LVEF. The absolute change in rate per 100 patient-years for each 10% reduction in LVEF was greatest for sudden death and heart failure-related death. The effect of candesartan in reducing cardiovascular outcomes was consistent across LVEF categories. CONCLUSIONS: LVEF is a powerful predictor of cardiovascular outcome in heart failure patients across a broad spectrum of ventricular function. Nevertheless, once elevated to a range above 45%, ejection fraction does not further contribute to assessment of cardiovascular risk in heart failure patients.

Aged↗
PubMed2005

The data monitoring experience in the Candesartan in Heart Failure Assessment of Reduction in Mortality and morbidity (CHARM) program.

BACKGROUND: The CHARM program was designed as 3 separate randomized trials comparing candesartan with placebo in patients with chronic heart failure (CHF) who (1) were intolerant to angiotensin-converting enzyme inhibitor and had left ventricular ejection fraction (LVEF) < or =0.40; (2) were on angiotensin-converting enzyme inhibitor and had LVEF < or =0.40; or (3) had LVEF >0.40. CHARM provides an interesting example of the challenges faced by a Data and Safety Monitoring Committee (DSMC). METHODS: Although the primary efficacy end point for each component trial was cardiovascular (CV) death or hospitalization for CHF, the primary outcome for the overall program was all-cause mortality. The DSMC received monthly safety reports and also met every 6 months (7 times in all) to review interim reports. Statistical stopping guidelines were predefined for all-cause mortality in the overall program. The overarching principle of the DSMC was proof beyond a reasonable doubt that would be likely to influence clinical practice. RESULTS: There were significant treatment differences in all-cause mortality for the overall program at several interim analyses, and the statistical stopping guideline was reached on one occasion. However, even a conventional level of statistical significance (P < .050) was achieved in only 1 of the 3 component trials. The DSMC consistently recommended that the program continue as planned. The final published result for all-cause death over a median of 3.1 years was a 9% reduction in hazard (95% CI 0%-17%, P = .055), whereas for CV death or hospitalization for CHF, there was a 16% reduction in hazard (95% CI 9%-23%, P < .0001). Subsequent exploratory analyses suggest that the hazard reduction in CV death was more marked in the first year after randomization and that, if real, this apparent treatment-time interaction offers a plausible explanation for why the interim mortality data showed statistically more extreme findings than the overall final results. CONCLUSION: The DSMC experience in the CHARM program illustrates the importance of continuing a trial to its scheduled completion unless there is proof beyond a reasonable doubt that would influence clinical practice rather than strict reliance on a statistical stopping guideline.

Angiotensin II Type 1 Receptor Blockers↗
PubMed2005

Apparent effect on blood pressure is only partly responsible for the risk reduction due to antihypertensive treatments.

The mechanism of risk reduction obtained by blood pressure-lowering pharmacological treatment remains unclear. We explored the amount of risk reduction attributable to the apparent effect of antihypertensive medicines on blood pressure by using the capture approach. Five randomized, placebo or nil controlled trials with a total of 28,997 subjects and 1,935 cardiovascular fatal or non-fatal events from the INDANA database met the eligibility criteria. Computations were performed on the original individual records using multiple Cox's proportional hazard regression models designed for meeting the assumed treatment mode of action and comparing relevant assumptions. For coronary event, the results are inconclusive essentially because the risk reduction is mild. However, for stroke the risk reduction adjusted for baseline risk factors is 34% (P<0.0001). The part explained by the effect of treatment on systolic blood pressure is 49% of this reduction, with 95% confidence interval not including 100%. This result suggests that the apparent effect on blood pressure is not the only cause of stroke risk reduction in hypertensive subjects submitted to an antihypertensive medicine.

Antihypertensive Agents↗
PubMed2005

Low hematocrit predicts contrast-induced nephropathy after percutaneous coronary interventions.

BACKGROUND: The relationship between low hematocrit and contrast-induced nephropathy has not been investigated. METHODS: Of 6,773 consecutive patients treated with percutaneous coronary intervention, contrast-induced nephropathy (an increase of >/=25% or >/=0.5 mg/dL in preprocedure serum creatinine, at 48 hours postprocedure) occurred in 942 (13.9%) patients. RESULTS: Rates of contrast-induced nephropathy steadily increased as baseline hematocrit quintile decreased (from 10.3% in the highest quintile to 23.3% in the lowest quintile) (chi(2) for trend, P < 0.0001). Stratification by baseline estimated glomerular filtration rate (eGFR) and baseline hematocrit showed that the rates of contrast-induced nephropathy were the highest (28.8%) in patients who had the lowest level for both baseline eGFR and hematocrit. Patients with the lowest eGFR but relatively high baseline hematocrit values had remarkably lower rates of contrast-induced nephropathy (15.8%, 12.3%, 17.1%, and 15.4% in 2nd, 3rd, 4th, and 5th quintiles of baseline hematocrit, respectively) (P < 0.0001). The rates of contrast-induced nephropathy increased with increment in change in hematocrit. Patients in the lowest quintile of baseline hematocrit with absolute hematocrit drop >5.9% had almost doubled rates of contrast-induced nephropathy compared with patients with hematocrit change <3.4% (38.1% vs. 18.8%, respectively) (P < 0.0001). By multivariate analysis, lower baseline hematocrit was an independent predictor of contrast-induced nephropathy; each 3% decrease in baseline hematocrit resulted in a significant increase in the odds of contrast-induced nephropathy in patients with and without chronic kidney disease (11% and 23%, respectively). When introduced into the multivariate model instead of baseline hematocrit, change in hematocrit also showed a significant association with contrast-induced nephropathy. CONCLUSION: Lower hematocrit is an important risk factor for contrast-induced nephropathy. Whether correcting the hematocrit prepercutaneous coronary intervention might decrease the rates of contrast-induced nephropathy should be addressed in a prospectively designed trial.

Adult↗
PubMed2005

Data monitoring in randomized controlled trials: surveys of recent practice and policies.

BACKGROUND: Data Monitoring Committees (DMCs) are increasingly involved in the conduct of randomized controlled trials, but there is little documented evidence of what they do. Three interlinked surveys were carried out as part of the DAMOCLES project to explore recent and current DMC practice and policy. METHODS: 1) A questionnaire about DMC practice was sent to sample of 45 authors of trials published in selected journals in 2000. The sample was stratified by centre (single/multiple), disease area, and presence of DMC. 2) A sample of investigators in trials ongoing in the United Kingdom in 2001-02 was also sent a questionnaire about DMC practice. The sample was drawn from trials funded by the Medical Research Council, the United Kingdom Department of Health's Health Technology Assessment Programme, and a local and a multicentre research ethics committee. The sample was additionally stratified by funder (public/industry), centre (single/ multiple), and disease area. 3) A sample of major organisations involved in randomised controlled trials was sent a questionnaire about DMC policies. RESULTS: Information about DMC practice from the first survey was obtained from 31 trials (69%), of which four had a DMC. Information about DMC practice from the second survey was obtained about 36 trials (90%), of which 20 had a DMC. Information about DMC policy from the third survey was obtained from 25 out of 25 organisations. There was general agreement about the sorts of trials particularly needing independent DMCs, but there were few uniform approaches to their modes of functioning, and few of the organisations surveyed had developed formal policies. CONCLUSIONS: The roles of existing DMCs and policies governing DMC functioning vary widely across trials and organisations that sponsor or oversee trials, both within the UK and internationally. These findings reinforce previous calls for development of such policies across a wider range of organisations, better means to monitor their implementation within trials, and wider use of structured "charters", which set out DMC modus operandi in advance. Clinical Trials 2005; 2: 22-33. www.SCTjournal.com

Clinical Trials Data Monitoring Committees↗
PubMed2004

Effect of candesartan on cause-specific mortality in heart failure patients: the Candesartan in Heart failure Assessment of Reduction in Mortality and morbidity (CHARM) program.

BACKGROUND: Patients with heart failure are at increased risk of sudden death and death attributed to progressive pump failure. We assessed the effect of candesartan on cause-specific mortality in patients enrolled in the Candesartan in Heart failure Assessment of Reduction in Mortality and morbidity (CHARM) program. METHODS AND RESULTS: The CHARM program consisted of 3 component trials that enrolled patients with symptomatic heart failure: CHARM-Alternative (n=2028; LVEF<=40% [corrected] and ACE intolerant), CHARM-Added (n=2548; LVEF<=40%, [corrected] already on ACE inhibitors), and CHARM-Preserved (n=3023; LVEF >40%). Patients were randomized to candesartan, titrated to 32 mg QD, or placebo and were followed up for a median of 37.7 months. All deaths were reviewed by a blinded adjudication committee and categorized according to prespecified definitions on the basis of a narrative and source documentation. The number and rate of deaths by cause were calculated for each of the component trials and the overall program. Of all the patients, 8.5% died suddenly, and 6.2% died of progressive heart failure. Candesartan reduced both sudden death (HR 0.85 [0.73 to 0.99], P=0.036) and death from worsening heart failure (HR 0.78 [0.65 to 0.94], P=0.008). These reductions were most apparent in the patients with LVEF<=40% [corrected]. CONCLUSIONS: Candesartan reduced sudden death and death from worsening heart failure in patients with symptomatic heart failure, although this reduction was most apparent in patients with systolic dysfunction.

Aged↗
PubMed2004

The data monitoring experience in the MOXCON trial.

AIMS: This article describes a challenging data monitoring experience that occurred in a major international randomized placebo-controlled trial in patients with heart failure, in which the accumulating interim data showed an excess of deaths on the active treatment. METHODS AND RESULTS: The MOXonidine CONgestive Heart Failure trial was a randomized comparison of moxonidine, a central sympathetic inhibitor, with placebo. It was planned to recruit 4500 patients with heart failure. The primary endpoint was all-cause mortality, and average follow-up was anticipated to be around 2.5 years until 724 deaths occurred. The trial Data Monitoring Board (DMB) was to conduct safety monitoring reviews of interim data at least every six months, and make their recommendations to the Executive Committee. Within a few months of the study starting, the Data Monitoring Board (DMB) observed an emerging trend of an excess of deaths on moxonidine compared with placebo. This article describes the sequence of events that unfolded: several DMB meetings to evaluate the accumulating evidence, a DMB recommendation to stop the trial, consequent dialogue with the Executive Committee and sponsor leading to a final decision to stop the trial. Ten months after the first patient was randomized, the study was stopped based on 46 versus 25 deaths in 990 moxonidine and 943 placebo patients, respectively, P=0.01. The final published evidence had 54 versus 32 deaths, P=0.012. CONCLUSIONS: This study illustrates the problems faced by a DMB, and subsequently the trial Executive Committee and sponsor, in deciding how to act in the face of an emerging (and agonizing) negative trend for mortality in a major international trial.

Clinical Trials Data Monitoring Committees↗
PubMed2004

Issues in regulatory guidelines for data monitoring committees.

As clinical trials have emerged as the major research method for evaluating new interventions, the process for monitoring intervention safety and benefit has also evolved. The Data Monitoring Committee (DMC) has become the standard approach to implement this responsibility for many Phase III trials. Recent draft guidelines on the operation of DMCs by the Food and Drug Administration (FDA) have raised issues that need further clarification or discussion, especially for industry sponsored trials. These include, the time when DMCs are needed, the role of the independent statistician to support the DMC, and sponsor participation at DMC meetings. This paper provides an overview of these issues, based on the discussions at the January, 2003 workshop sponsored by Duke Clinical Research Institute.

Clinical Trials Data Monitoring Committees↗
PubMed2004

The Society for Clinical Trials supports United States legislation mandating trials registration. Position paper.

The official position of the Society for Clinical Trials is to support legislation in the United States and internationally that mandates registration of all controlled clinicals trials at or before enrollment of the first participant. The major trial sponsor would be responsible for ensuring contribution of trial information. The mechanism for registering trials would be through research ethics review boards, and registration would be required for ethics approval and before trial initiation. Standardized data and a unique identification number would be available for each registered trial.

Controlled Clinical Trials as Topic↗
PubMed2003

Effects of candesartan on mortality and morbidity in patients with chronic heart failure: the CHARM-Overall programme.

BACKGROUND: Patients with chronic heart failure (CHF) are at high risk of cardiovascular death and recurrent hospital admissions. We aimed to find out whether the use of an angiotensin-receptor blocker could reduce mortality and morbidity. METHODS: In parallel, randomised, double-blind, controlled, clinical trials we compared candesartan with placebo in three distinct populations. We studied patients with left-ventricular ejection fraction (LVEF) 40% or less who were not receiving angiotensin-converting-enzyme inhibitors because of previous intolerance or who were currently receiving angiotensin-converting-enzyme inhibitors, and patients with LVEF higher than 40%. Overall, 7601 patients (7599 with data) were randomly assigned candesartan (n=3803, titrated to 32 mg once daily) or matching placebo (n=3796), and followed up for at least 2 years. The primary outcome of the overall programme was all-cause mortality, and for all the component trials was cardiovascular death or hospital admission for CHF. Analysis was by intention to treat. FINDINGS: Median follow-up was 37.7 months. 886 (23%) patients in the candesartan and 945 (25%) in the placebo group died (unadjusted hazard ratio 0.91 [95% CI 0.83-1.00], p=0.055; covariate adjusted 0.90 [0.82-0.99], p=0.032), with fewer cardiovascular deaths (691 [18%] vs 769 [20%], unadjusted 0.88 [0.79-0.97], p=0.012; covariate adjusted 0.87 [0.78-0.96], p=0.006) and hospital admissions for CHF (757 [20%] vs 918 [24%], p<0.0001) in the candesartan group. There was no significant heterogeneity for candesartan results across the component trials. More patients discontinued candesartan than placebo because of concerns about renal function, hypotension, and hyperkalaemia. INTERPRETATION: Candesartan was generally well tolerated and significantly reduced cardiovascular deaths and hospital admissions for heart failure. Ejection fraction or treatment at baseline did not alter these effects.

Adolescent↗
PubMed2002

Coping with missing data in clinical trials: a model-based approach applied to asthma trials.

In most clinical trials, some patients do not complete their intended follow-up according to protocol, for a variety of reasons, and are often described as having 'dropped out' before the conclusion of the trial. Their subsequent measurements are missing, and this makes the analysis of the trial's repeated measures data more difficult. In this paper we briefly review the reasons for patient drop-out, and their implications for some commonly used methods of analysis. We then propose a class of models for modelling both the response to treatment and the drop-out process. Such models are readily fitted in a Bayesian framework using non-informative priors with the software BUGS. The results from such models are then compared with the results of standard methods for dealing with missing data in clinical trials, such as last observation carried forward. We further propose the use of a time transformation to linearize an asymptotic pattern of repeated measures over time and therefore simplify the modelling. All these ideas are illustrated using data from a five-arm asthma clinical trial.

Asthma↗
PubMed2002

J-shaped relationship between blood pressure and mortality in hypertensive patients: new insights from a meta-analysis of individual-patient data.

BACKGROUND: Population-based longitudinal studies of hypertension have usually shown a continuous and positive relationship between blood pressure and mortality. However, several studies in hypertensive patients receiving treatment have described this relationship as J-shaped, with an increased risk for events in patients with low blood pressure. OBJECTIVE: To assess the evidence for a J-shaped relationship between blood pressure and mortality and its relation to treatment. DESIGN: Meta-analysis of individual-patient data. SETTING: Seven randomized clinical trials from the INDANA (INdividual Data ANalysis of Antihypertensive intervention) database. PATIENTS: 40 233 persons with hypertension (mean follow-up, 3.9 years). INTERVENTION: Primarily beta-blockers or thiazide diuretics versus placebo or no treatment. MEASUREMENTS: Diastolic and systolic blood pressure and number of cardiovascular, noncardiovascular, and all-cause deaths in yearly periods of follow-up. RESULTS: The analysis included data on 1655 deaths (56% cardiovascular). A J-shaped relationship between diastolic blood pressure and risk for death was observed for total and cardiovascular mortality in treated patients (nadir, 84 and 80 mm Hg, respectively) and untreated patients (nadir, 90 and 85 mm Hg, respectively). For noncardiovascular deaths, the relationship was J-shaped in the treated group (nadir, 84 mm Hg) and negative in the control group. Similar results were observed for systolic blood pressure. The presence of patients with wide pulse pressure did not explain these findings. CONCLUSIONS: The increased risk for events observed in patients with low blood pressure was not related to antihypertensive treatment and was not specific to blood pressure-related events. Poor health conditions leading to low blood pressure and an increased risk for death probably explain the J-shaped curve.

Antihypertensive Agents↗
PubMed2002

Pulsatile blood pressure component as predictor of mortality in hypertension: a meta-analysis of clinical trial control groups.

OBJECTIVE: Although current guidelines rest exclusively on the measurement of systolic and diastolic blood pressures, the arterial pressure wave is more precisely described as consisting of a pulsatile (pulse pressure) and a steady (mean pressure) component. This study explored the independent roles of pulse pressure and mean pressure as predictors of mortality in a wide range of patients with hypertension. DESIGN AND METHODS: This meta-analysis, based on individual patient data, has combined results from the control groups of seven randomized clinical trials conducted in patients with systolo-diastolic or isolated systolic hypertension. The relative hazard rates associated with pulse pressure and mean pressure were calculated using Cox's proportional hazard regression models with stratification for the seven trials and with adjustment for sex, age, smoking and the other pressure. RESULTS: A 10 mmHg wider pulse pressure at baseline, which corresponds to approximately one-half of its standard deviation, was independently associated with an increase in risk by 6% for total mortality (P = 0.001), 7% for cardiovascular mortality (P = 0.01), and 7% for fatal coronary accidents (P = 0.03). The corresponding increase in risk of fatal stroke was similar (+6%, P = 0.27) but there were too few strokes to reach statistical significance. In similar analyses, mean pressure was not identified as an independent predictor of these outcomes. Significant interactions of pulse pressure or mean pressure with age suggested that the prognostic power of pulse pressure for fatal stroke was more important at higher age (P = 0.04), whereas the prognostic power of mean pressure for coronary mortality was greatest in the young (P = 0.01). CONCLUSIONS: In hypertensive patients pulse pressure, not mean pressure, is associated with an increased risk of fatal events. This appears to be true in a broad range of patients with hypertension.

Age Factors↗
PubMed2001

Experience collecting interim data on mortality: an example from the RALES study.

INTRODUCTION: The Randomized Aldactone Evaluation Study (RALES) randomized 822 patients to receive 25 mg spironolactone daily and 841 to receive placebo. The primary endpoint was death from all causes. Randomization began on March 24, 1995; recruitment was completed on December 31, 1996; follow-up was scheduled to continue through December 31, 1999. Evidence of a sizeable benefit on mortality emerged early in the RALES. The RALES data safety monitoring board (DSMB), which met semiannually throughout the trial, used a prespecified statistical guideline to recommend stopping for efficacy. At the DSMB's request, its meetings were preceded by an 'endpoint sweep', that is, a census of all participants to confirm their vital status. METHODS: We used computer simulation to evaluate the effect of the sweeps. RESULTS: The sweeps led to an estimated 5 to 8% increase in the number of reported deaths at the fourth and fifth interim analyses. The data crossed the statistical boundary at the fifth interim analysis. If investigators had reported all deaths within the protocol-required 24-h window, the DSMB might have recommended stopping after the fourth interim analysis. DISCUSSION: Although endpoint sweeps can cause practical problems at the clinical centers, sweeps are very useful if the intervals between patient visits or contact are long or if endpoints require adjudication by committee, reading center, or central laboratory. CONCLUSION: We recommend that trials with interim analyses institute active reporting of the primary endpoints and endpoint sweeps.

Journal Article↗