Search PubMed⌕ Search

Biomedical subjects

F Gueyffier

Publications and source records attributed to F Gueyffier.

At least 37 records · Page 2Linked to original sources
PubMed1999

Efficacy of treating hypertension in women.

OBJECTIVE: To assess whether the relative and absolute benefit of hypertension treatment in women varies with age or race. DESIGN: Systematic review of studies from 1966 to 1998 using MEDLINE, reviews, and consultation with experts. Eleven randomized controlled trials of pharmacologic treatment of prJgiary hypertension with cardiovascular morbidity and mortality outcomes were selected, with a pooled population of 23,000 women. Relative risks were combined for each end point to form a summary risk ratio using meta-analytic techniques based on a random-effects model. Summary risk ratios were converted to numbers needed to treat (NNTs). Data were dichotomized by age to approxJgiate menopausal status (30 to 54 years, and 55 years and older), and by race (white and African American). MAIN RESULTS: In women aged 55 years or older (90% white), hypertension treatment resulted in a 38% risk reduction in fatal and nonfatal cerebrovascular events (95% confidence interval [CI] 27%, 47%; 5-year NNT 78), a 25% reduction in fatal and nonfatal cardiovascular events (95% CI 17%, 33%; 5-year NNT 58), and a 17% reduction in cardiovascular mortality (95% CI 3%, 29%; 5-year NNT 282). In women aged 30 to 54 years (79% white), hypertension treatment resulted in a 41% risk reduction in fatal and nonfatal cerebrovascular events (95% CI 8%, 63%; 5-year NNT 264), and a 27% risk reduction in fatal and nonfatal cardiovascular events (95% CI 4%, 44%; 5-year NNT 259). Hypertension treatment in African-American women (mean age, 52 years) reduced the risk of fatal and nonfatal cerebrovascular events by 53% (95% CI 29%, 69%; 5-year NNT 39), fatal and nonfatal cardiovascular events by 45% (95% CI 18%, 63%; 5-year NNT 21), fatal and nonfatal coronary events by 33% (95% CI 6%, 52%; 5-year NNT 48), and all-cause mortality by 34% (95% CI 14%, 49%; 5-year NNT 32). Analyses in white women aged 30 to 54 years did not show any statistically significant treatment benefit or harm. CONCLUSIONS: Hypertension treatment lowers the relative and absolute risk of cardiovascular morbidity and mortality in women aged 55 years and older and in African-American women of all ages. A greater effort should be made to increase awareness and treatment in these groups of women. Although relative risk reductions for cerebrovascular and cardiovascular events are sJgiilar for younger and older women, the NNT of younger women is at least 4 tJgies higher. Decisions about treatment of hypertension in younger white women should be influenced by the individual patient's absolute risk of cardiovascular disease.

Adult↗
PubMed1999

[Prognostic importance of ambulatory arterial pressure monitoring in France. Initial results of the OCTAVE II study. OCTAVE II Research Group].

RATIONALE: Ambulatory blood pressure measurement (ABPM) is commonly used in clinical practice, whereas its added value to the management of hypertension is not definitely documented. OBJECTIVE: The OCTAVE II study was launched in 1991 to explore the prognostic value of ABPM, compared to that of the gold standard, the clinical blood pressure measurement. METHODS: Two hundred and six French cardiologists recruited 3569 participants over 18 years of age, provided they deemed ABPM was useful (mean age of 56 years, 52% of men, 65% already treated by antihypertensive drugs). The prognostic value of various blood pressure measurements, systolic or diastolic, clinical or ambulatory (diurnal, nocturnal or during 24 hours), has been assessed in multivariate models adjusted on the baseline characteristics associated with risk. The outcome was the occurrence of a major cardiovascular event, including stroke, myocardial infarction and cardiovascular death. RESULTS: After an average follow-up of five years, cardiovascular morbidity was known for 85% of the participants, and their vital status for 91%. On the whole population, the best prognostic indicators were systolic blood pressure compared with diastolic, ABPM compared with clinical blood pressure measurements, and nocturnal ABPM compared with diurnal ABPM. In the untreated participants at baseline, cardiovascular risk regularly increased among the four groups: normotensives, white-coat hypertensives, dippers, non-dippers. Between the extreme categories, the cardiovascular event rate was multiplied by 6.5. CONCLUSION: In this French population, ABPM and most of all its nocturnal component, was better correlated with cardiovascular prognosis. It remains to assess: 1) the general value of our findings, 2) the respective values of self blood pressure measurement versus ABPM, and 3) whether ABPM allows a better risk prevention.

Adult↗
PubMed1998

Assessing treatment-time interaction in clinical trials with time to event data: a meta-analysis of hypertension trials.

Exploration of the variation of treatment effect over time in randomized clinical trials with low event rates is limited by lack of power. A meta-analysis on individual patient data from such trials can partly solve the problem, but brings other computational difficulties. Using an example in hypertension, we describe appropriate methods for graphical description and statistical modelling of treatment-time interactions in large data sets. Also, a method is developed for determining the total number of events required to detect treatment-period interactions of plausible magnitude. We conclude that trialists tend to overinterpret the observed data when looking for potential treatment-time interactions by visual comparisons of survival curves, failing to realize the substantial amounts of data that are needed for their detection and estimation.

Humans↗
PubMed1998

The calculation of a confidence interval on the absolute estimated benefit for an individual patient.

Physicians need a method to predict the individualized absolute therapeutic benefit before deciding which therapy to prescribe to a given patient and the confidence intervals around this estimate. We have derived a method to predict the absolute individual therapeutic benefit in a previous work. In this paper, we present a Monte Carlo simulation to estimate the bias of prediction for an individual with certain characteristics and use a bootstrap method to compute its confidence intervals. Because the bootstrap approach does not depend upon the parametric assumption for the distribution of the prediction, it can be applied to situations where the parametric distribution is unknown. Over 35,000 cases of subjects at risk of cardiovascular events were available for analysis. Our results show the 95% confidence intervals for each individual. In a clinical setting, the use of this approach makes it possible to predict the absolute therapeutic benefit for each patient (the quantity of individual benefit) with sufficient precision.

Cardiovascular Diseases↗
PubMed1998

[Identification and prediction of responders to a therapy. A model and its preliminary application to hypertension].

The effect of a given treatment for a given disease may be estimated from randomized controlled clinical trials, expressed as a single treatment effect averaged over the trial population. However, in recent years there has been an increasing willingness to individualize therapeutic decisions. The method we report here identifies responders by assessing the individual probability of an event, according to the treatment group. We used a treatment-stratified Cox regression model including interaction between treatment and patient's covariates, with common regression coefficients for treated and untreated, except for the special case of a prognostic variable which has an interaction with treatment. Further, we used a discriminate function based on the final model, representing the absolute individual therapeutic effect, to identify the patients to be treated according to a given threshold of clinical efficacy. The model was explored on the INDANA database (which pools individual patient data from clinical trials of anti-hypertensive drug intervention). Data on 36,444 patients, from five randomized controlled trials were included. The results show the relationship between the proportion of avoided events among the avoidable ones, and the proportion of patients treated who were responders, as a function of the threshold of absolute benefit defining responders. The confidence intervals of the absolute therapeutic benefit for each individual were calculated, by using the Monte Carlo simulation method. A comparison of the survival of treated and controlled individuals, in both subgroups of responders and non responders, illustrated the relevance of the model. We conclude that the tools for predicting individual therapeutic benefit do exist. It will be important to assess the reproducibility of these results in other models or in other populations before widespread application. It will be necessary to have a properly computerized environment and to train doctors to use these tools.

Decision Support Techniques↗
PubMed1997

Effect of antihypertensive drug treatment on cardiovascular outcomes in women and men. A meta-analysis of individual patient data from randomized, controlled trials. The INDANA Investigators.

BACKGROUND: Trials of drug therapy for hypertension have shown that such therapy has a clear overall benefit in preventing cardiovascular disease. Although these trials have included slightly more women than men, it is still not clear whether treatment benefit is similar for both sexes. OBJECTIVE: To quantify the average treatment effect in both sexes and to determine whether available data show significant differences in treatment effect between women and men. DESIGN: Subgroup meta-analysis of individual patient data according to sex. Analysis was based on seven trials from the INDANA (INdividual Data ANalysis of Antihypertensive intervention trials) database and was adjusted for possible confounders. PATIENTS: 20,802 women and 19,975 men recruited between 1972 and 1990. INTERVENTIONS: Primarily beta-blockers and thiazide diuretics. RESULTS: In women, treatment effect was statistically significant for stroke (fatal strokes and all strokes) and for major cardiovascular events. In men, it was statistically significant for all categories of events (total and specific mortality, all coronary events, all strokes, and major cardiovascular events). The odds ratios for any category of event did not differ significantly between men and women. In absolute terms, the benefit in women was seen primarily for strokes; in men, treatment prevented as many coronary events as strokes. Graphical analyses suggest that these results could be completely explained by the difference in untreated risk. CONCLUSIONS: In terms of relative risk, treatment benefit did not differ between women and men. The absolute risk reduction attributable to treatment seemed to depend on untreated risk. These findings underline the need to predict accurately the untreated cardiovascular risk of an individual person in order to rationalize and individualize antihypertensive treatment.

Adrenergic beta-Antagonists↗
PubMed1997

[The Cochrane Collaboration, support of therapeutic information].

Today, prescribers need to distinguish between the clinical practices based on randomized clinical trialing information and those based on animal physiological data or theory. Now the information on therapeutics is becoming more dense, more complex and less available to the clinicians. Information sources are numerous and varied, including data whose quality differs. These data are unhierarchised in terms of methodological quality and clinical relevance. It will be optimal if each prescriber could himself collect and analyse scientific information. In fact this situation cannot be effective in private physician's practices. An international collaboration, the Cochrane Collaboration, including volunteers, university researchers, and clinical investigators has the following objective: to prepare, maintain and disseminate systematic reviews of the effects of health care. The Cochrane Collaboration is thus the most adapted intermediairy between scientifically actualized data and clinical practitioners.

France↗
PubMed1997

Effect of antihypertensive treatment in patients having already suffered from stroke. Gathering the evidence. The INDANA (INdividual Data ANalysis of Antihypertensive intervention trials) Project Collaborators.

BACKGROUND AND PURPOSE: Drug treatment of high blood pressure has been shown to reduce the associated cardiovascular risk. Stroke represents the type of event more strongly linked with high blood pressure, responsible for a high rate of death or invalidity, and with the highest proportion of events that can be avoided by treatment. Hypertensive patients with a history of cerebrovascular accident are at particularly high risk of recurrence. Specific trials of blood pressure lowering drugs in stroke survivors showed inconclusive results in the past. METHODS: We performed a meta-analysis using all available randomized controlled clinical trials assessing the effect of blood pressure lowering drugs on clinical outcomes (recurrence of stroke, coronary events, cause-specific, and overall mortality) in patients with prior stroke or transient ischemic attack. RESULTS: We identified 9 trials, including a total of 6752 patients: 2 trials included 551 hypertensive stroke survivors; 6 trials of hypertensive patients included a small proportion of stroke survivors (536 patients); 1 trial included stroke survivors, whether hypertensive or not (5665 patients). The recurrence of stroke, fatal and nonfatal, was significantly reduced in active groups compared with control groups consistently across the different sources of data (relative risk of 0.72, 95% confidence interval: 0.61 to 0.85). There was no evidence that this intervention induced serious adverse effect. CONCLUSIONS: Blood pressure lowering drug interventions reduced the risk of stroke recurrence in stroke survivors. Available data did not allow to verify whether such benefit depends on initial blood pressure level. More data are needed before considering antihypertensive therapy in normotensive patients at high cerebrovascular risk.

Aged↗
PubMed1997

[The Hypertension Cochrane Review Group. Presentation and user's guide].

Cochrane collaboration has been developing since 1992 as an international network aiming at performing systematic reviews of available data on therapeutic effectiveness. The fundamental principles of this organisation are trying to avoid duplication of efforts, seeking the best reliability, using reproducible and quantitative synthesis techniques, offering constantly updated results. All health domains are progressively covered. The production unit in one domain is the review group. The Hypertension Cochrane Review Group (HTN CRG) has been officially registered on May 15th 1996. Information and products from the group are available through its news letter, through the Cochrane Library CD-ROM, regularly updated, and on the Internet (http://merece.uthscsa.edu/htncrg). The Hypertension Cochrane Review Group includes an editorial board (with an administrator and three editors), the authors of systematic reviews, internal and external reviewers. The geographic link is the San Antonio Cochrane Centre (Texas, USA). Invitations to participate have been sent to people interested in hypertension and who where known to the Cochrane collaboration, and to authors of previous reviews in hypertension. It is possible to collaborate with the HTN CRG through: performing a systematic review; reviewing protocols and systematic reviews; hand-searching medical journals; being a member of the editorial team. The first protocol for a systematic review edited by the group concerns antihypertensive treatment in the elderly, and is available in the 1996 and subsequent editions of the Cochrane Library. The group welcomes other reviews from domains awaiting registration, and collaborates with related domains review groups such as Diabetes CRG, or Stroke CRG. The group contributes to the effort of hand-searching medical literature, Pr Plouin being responsible for the Archives des Maladies du Coeur et des Vaisseaux. The second edition in 1996 of the Cochrane Library included 114 systematic reviews and 131 protocols, being the only media with similar objectives.

Computer Communication Networks↗
PubMed1996

New meta-analysis of treatment trials of hypertension: improving the estimate of therapeutic benefit.

The objectives of this sub group meta-analysis on the treatment of hypertension was to: (1) high-light specific results of well-designed trials; (2) group trials according to their specific clinical context; (3) express results of the meta-analysis in absolute reduction terms; and (4) estimate the bias of withdrawal because of blood pressure increase. This meta-analysis is based on summarised published results from randomised controlled trials, comparing a drug treatment versus placebo or no treatment, with morbi-mortality as the principle outcome. The following data were analysed: (1) total mortality; (2) cardiovascular mortality; (3) stroke; (4) major coronary events; and (5) congestive heart failure. The treatment significantly reduced the incidence of all outcomes in trials involving older patients, avoiding up to nine strokes (OR = 0.66, 95% Cl: 0.56-0.77) and four major coronary events (OR = 0.79, 95% Cl: 0.68-0.92) every 1000 patient-years when the bias of withdrawal was taken into account. The only outcome significantly influenced by treatment in younger patients with mild-to-moderate hypertension was stroke, with one stroke avoided every 1000 patient-years (OR = 0.51, 95% Cl: 0.39-0.66). There was insufficient statistical power in the trials which enrolled patients with non-moderate hypertension to reach clinical significance, except for the reduction in the incidence of congestive heart failure. However, the results indicated a trend towards greater absolute benefit under treatment. Trials enrolling patients with post-stroke hypertension also had insufficient power, but suggested benefit by the reduction of the incidence of stroke recurrence and congestive heart failure under treatment. In conclusion, the most constant treatment benefit concerned stroke, although the absolute reduction was very modest in younger patients with mild-to-moderate hypertension. Only the results from trials in older patients showed a significant reduction of major coronary events. Such results need further analyses, ideally based on individual patient data.

Adult↗
PubMed1996

[Presentation of OCTAVE II. A current epidemiologic study in France of the added prognostic value of ambulatory blood pressure monitoring].

The diagnosis of "white coat" hypertension, the measurement of indices of 24 hour variability of the blood pressure and increased accuracy of blood pressure estimation are some of the advantages of ambulatory blood pressure monitoring. They are part of the reason why the method has been adopted by ambulatory blood pressure monitoring is really useful in the treatment of hypertension is fragile: although the correlation with target organ complications seems better than with conventional blood pressure measurement, it remains to be shown that this information helps to predict and then improve the prognosis of hypertension. With respect to this first stage of demonstration of the added prognostic value attributable to ambulatory blood pressure monitoring, several studies have been undertaken, one of which is OCTAVE II. The goals were to analyse the predictive values of the indices obtained by ambulatory blood pressure monitoring in terms of cardiovascular morbidity and mortality after having described the correlations between these indices and the characteristics of individual patients. Two hundred and sixty six cardiologists, members of the French College of Cardiology, included 3,569 patients in whom an indication for ambulatory blood pressure monitoring had been retained, over a period of 10 months in 1991. These patients were 56.4 year old on average, with 52.6% men, hypertensive or not. The 5 year follow-up should end at the beginning of 1997.

Blood Pressure↗
PubMed1991

[Value of a new fast CK-MB determination for the diagnosis of myocardial infarction during the 1st hours. Preliminary study].

This study evaluated the time for a new, rapid and reliable CK-MB analysis to become positive in myocardial infarction and compared it with classical total CK analyses. Serial analyses of total CK and CK-MB were performed in 49 consecutive patients referred to the Coronary Care Unit for suspected acute myocardial infarction. Twenty of these patients had myocardial infarction with rising enzyme levels, which enabled comparison of the precocity of one analysis compared to another. In these patients, the CK-MB analysis became positive on average 85 to 110 minutes before that of total CK. This result shows that CK-MB analysis can be a diagnostic sign of acute myocardial infarction at an earlier stage than the total CK analysis. The authors discuss the clinical value of this test in difficult indications of fibrinolytic therapy and underline that it enables a more objective assessment of the time of onset of necrosis than clinical data alone.

Creatine Kinase↗
PubMed1987

[Purulent pleurisy due to Legionella bozemanii].

Since the advent of antibiotics, the bacteriological profile of empyema has changed. It is necessary to recall the recently discovered organisms. Although rarely mentioned in the literature, the Legionnellas may be causative in an empyema. We report a case of empyema to Legionnella bozemanii proven seriologically.

Antibodies, Bacterial↗
PubMedDate not supplied

[The problem of therapeutic efficacy indices. 1. Elements of the problem].

Efficacy indices measure the efficacy of therapies. They derive, by definition, from two quantities, the basal or control risk of event, Rc, observed in the control group, and the on-treatment risk, Rt, observed in the treated group. In clinical trials and meta-analyses, each is an unbiased measure of efficacy. Although they are a combination of frequencies, these indices are used in clinical practice to predict the benefit in treated patients. Their relevance to express efficacy depends on the type of clinical condition, and is better for acute diseases than for chronic diseases. In order to be useful for prescribers, they should meet certain specifications. In addition, they should be considered in the more general framework of effect models.

Clinical Trials as Topic↗
PubMedDate not supplied

[The problem of therapeutic efficacy indices. 2. Description of the indices].

The four indices for a binary outcome or therapeutic objective are: the odds ratio, the relative risk, the absolute benefit and the number of patients to treat. For a continuous outcome, the effect size is the best choice. The odds ratio approximates the relative risk. The difference may be large in some instances. The number of patients to treat is the reciprocal of the absolute benefit. Although they are built on the same two quantities, they are not interchangeable and should not be considered in the same way. Moreover, their meaning is not straightforward and they can be misused.

Clinical Protocols↗
PubMedDate not supplied

Primary aldosteronism and adrenal incidentaloma.

Adrenal incidentaloma are usually found during the assessment of non adrenal disease. In this paper we report the association between a bilateral adrenal hyperplasia and a macronodule of adrenal cortex (adrenal incidentaloma) which is a rare and misleading cause of primary aldosteronism. In the light of this association even if it is likely to remain rare and of those previously published, its existence is an additional reason for suggesting surgical treatment of primary aldosteronism only to patients who satisfy the following criteria: 1) satisfactory control with spironolactone; 2) poor spironolactone tolerance and poor control with other drugs; 3) accept to be operated on and the risk of a possible error.

Adrenal Cortex↗