Showing papers by "Barry R. Davis published in 1992"

Effect of captopril on mortality and morbidity in patients with left ventricular dysfunction after myocardial infarction. results of the survival and ventricular enlargement trial

Abstract: Background. Left ventricular dilatation and dysfunction after myocardial infarction are major predictors of death. In experimental and clinical studies, long-term therapy with the angiotensin-converting—enzyme inhibitor captopril attenuated ventricular dilatation and remodeling. We investigated whether captopril could reduce morbidity and mortality in patients with left ventricular dysfunction after a myocardial infarction. Methods. Within 3 to 16 days after myocardial infarction, 2231 patients with ejection fractions of 40 percent or less but without overt heart failure or symptoms of myocardial ischemia were randomly assigned to receive double-blind treatment with either placebo (1116 patients) or captopril (1115 patients) and were followed for an average of 42 months. Results. Mortality from all causes was significantly reduced in the captopril group (228 deaths, or 20 percent) as compared with the placebo group (275 deaths, or 25 percent); the reduction in risk was 19 percent (95 percent conf...

The Trial of Antihypertensive Interventions and Management (TAIM) Study: Adequate Weight Loss, Alone and Combined With Drug Therapy in the Treatment of Mild Hypertension

Abstract: This report examines the effect of weight loss, alone and in combination with drugs, on diastolic blood pressure change in the Trial of Antihypertensive Interventions and Management (TAIM), which is a randomized, multicenter, placebo-controlled clinical trial of drug and diet combinations in the treatment of mild hypertension among 787 patients. Diastolic blood pressure drop (11.6 mm Hg) at 6 months among those patients who were randomized to weight reduction and placebo drug treatment was greater among those who lost 4.5 kg or more, than the 7—mm Hg drop for those who lost less than 2.25 kg or for the placebotreated control group, and it was statistically equivalent to the reduction achieved by 25 mg of chlorthalidone or 50 mg of atenolol (11.1— and 12.4—mm Hg drop, respectively). Weight loss potentiated effects of drugs, with reductions of 18.4 mm Hg, for those patients who were taking atenolol and had a 4.5-kg or more weight loss, and of 15.4 mm Hg, for those patients who were taking chlorthalidone and had at least a 2.25-kg weight loss. We concluded that effective weight loss ( ≥4.5 kg) lowers blood pressure similarly to low-dose drug therapy and potentiates drug effects, with the apparent 4.5-kg threshold being lowered to 2.25 kg for those patients who receive chlorthalidone. (Arch Intern Med. 1992;152:131-136)

Effect of antihypertensive therapy on weight loss. The Trial of Antihypertensive Interventions and Management Research Group.

Abstract: We report the effect of weight changes of the type of antihypertensive medication prescribed in a trial of the relative efficacy of drug and dietary measures in mild hypertension. The Trial of Antihypertensive Interventions and Management studied 878 mildly hypertensive individuals randomly assigned, in a 3 x 3 design, to no diet change, weight loss, or a low sodium-high potassium diet and to placebo, 25 mg chlorthalidone, or 50 mg atenolol. The type of drug prescribed affected weight change with all diets. The drug effect on weight change, present in all groups at 6 months, was most pronounced in those randomly assigned to the weight loss diet, where the placebo group lost 4.4 kg, the atenolol group lost 3.0 kg, and the chlorthalidone group lost 6.9 kg. The group differences were attenuated but persisted at 24 months. We suggest that the antihypertensive drug prescribed affects the success of a conjoint weight loss program and speculate that the difference between the drugs may be due to their intrinsic effects on the sympathetic nervous system and related metabolic changes.

Coping With Cancer During the First Year After Diagnosis

Abstract: patients newly diagnosed with cancer was evaluated every 4 months during a 1- year period. Patients received a psychosocial interven- tion either immediately (early intervention, EI), or after a 4-month delay (later intervention, LI). No significant dif- ferences were found between the two groups, except at 8 months, when the LI group was significantly less de- pressed, anxious, and worried, and felt more in control than the EI group. The LI group continued to have less worry related to illness at

Analysis of a clinical trial involving a combined mortality and adherence dependent interval censored endpoint.

Abstract: Clinical trials often involve a variety of clinical and laboratory measures that are used as endpoints and sometimes two of these measures are combined in one endpoint. When the individual components of such a combined endpoint are 'time to event' measurements, the analysis is straightforward if each of the components is measured frequently and regularly over time. However, the analysis of the combined endpoint is more difficult when one component of the endpoint is right censored and the other is interval censored. This paper describes a statistic, based on a rank ordering of events for such a combined measure. The power of the test statistic is explored.

Renin Predicts Diastolic Blood Pressure Response to Nonpharmacologic and Pharmacologic Therapy

Abstract: Objective. —Plasma renin activity was measured at baseline and 6 months in a trial of nonpharmacologic therapy of mild hypertension to determine whether plasma renin activity predicts the diastolic blood pressure (DBP) response to nonpharmacologic therapy. Design, Setting, and Participants. —Randomized controlled trial of volunteers from the general community with mild hypertension (DBP between 90 and 100 mm Hg), off all antihypertensive therapy at baseline, treated in special research clinics (n=593). Interventions. —Subjects were randomly assigned to usual, weight loss, or low sodium/high potassium diet and then randomly assigned to receive placebo, chlorthalidone, or atenolol. Main Outcome Measures. —Renin was analyzed as plasma renin activity and as a renin index (logarithm of 24-hour urinary sodium excretion times logarithm of plasma renin activity) (593 patients at baseline and 6 months) to correct for varied sodium intakes. The DBP was measured using the random zero device. Results. —Change in DBP at 6 months could be predicted from baseline plasma renin activity or renin index. The DBP was decreased after 6 months of therapy by 2 mm Hg for each unit increase in baseline plasma renin activity and by 0.16 mm Hg for each unit increase in baseline renin index. Patients in the highest renin index quartile had a greater DBP response to atenolol therapy, and patients in the lowest renin index quartile had a greater DBP response to chlorthalidone therapy. Weight loss diet achieved a greater reduction in DBP in patients with higher baseline renin index and had an additive effect on DBP response in both of the drug groups. Patients on a weight loss diet receiving placebo in the highest baseline renin index quartile had a reduction in DBP of 12.4 mm Hg, compared with 4.4 mm Hg in the lowest baseline renin index quartile ( P =.009). A low sodium/high potassium diet had a lesser effect than a weight loss diet on pharmacologic therapy. As with the weight loss diet, patients on a low sodium/high potassium diet in the highest baseline renin index quartile had a greater reduction in DBP than patients in the lowest baseline renin index quartile. Conclusions. —These data suggest a significant relationship between baseline levels of plasma renin index and the likelihood of success of nonpharmacologic treatment of hypertension. ( JAMA . 1992;267:1221-1225)

Statistical methods that distinguish between attributes of assessment: prolongation of life versus quality of life.

Abstract: The authors propose a method to generate information relevant to the decision tree that adds addibonal perspective to the characterization of health quality during survival. Their approach uses survival data to distinguish two attributes of utility. prolongation of life and quality of life (QOL) Health-state transition probabilities correspond to the prolongation of life and are modeled in a discrete-time transient semi-Markov process. Quality-of-life-state transition probabilities are derived from the assumptions of a simple recurrent Markov proc ess They reflect events within the health-state sojourn time that differentiate perceptions of pain and suffering over a short fixed time period. Outcomes for these two dimensions of utility are highly relevant to the assessment of medical technology that might prolong life at the cost of increased pain and suffering, implying a reduced QOL The methods are dem onstrated on a subset of follow-up data from the Beta-Blocker Heart Attack Trial (BHAT). Key words: occ...

Repeated confidence intervals and prediction intervals using stochastic curtailment

Abstract: Jennlson and Turnbull (1984,1989) proposed procedures for repeated confidence intervals for parameters of interest In a clinical trial monitored with group sequential methods. These methods are extended for use with stochastic curtailment procedures for two samples in the estimation of differences of means, differences of proportions, odds ratios, and hazard ratios. Methods are described for constructing 1) confidence intervals for these estimates at repeated times In the course of a trial, and 2) prediction intervals for predicted estimates at the end of a trial. Specific examples from several clinical trials are presented.

An experimental model for the study of thermochemotherapy in vivo.

Abstract: Human melanomas serially passaged in nude mice as xenotransplants were used as models for the study of the effects of thermochemotherapy of human malignant tumours in vivo. Three such melanomas, one (BRO) fast-growing, one (SCH) slow-growing, and one (BEL) of intermediate growth rate, were chosen. One group was left untreated as a control, one received chemotherapy (cyclophosphamide), one received hyperthermia, and one a combination of both treatments. In all three tumours, the best results were obtained associating chemotherapy with hyperthermia. The fastest growing tumor responded more than the slower, which responded better than the slowest. This model should prove useful in testing the effectiveness of anticancer agents used in association with hyperthermia.

Successful treatment of medically refractory ventricular fibrillation with emergency cardiopulmonary bypass in an adolescent with corrected complex congenital heart disease.

Abstract: Whereas emergency cardiopulmonary bypass has become widely used in the adult population for refractory cardiac arrest,1 there are no reported cases of its use in a pediatric patient. We report a case of an adolescent with corrected complex congenital heart disease who survived medically refractory ventricular arrhythmias by being placed on cardiopulmonary bypass.