Proarrhythmic Medicines and Primary Cardiac Arrest

This study has been completed.
Sponsor:
Information provided by:
National Heart, Lung, and Blood Institute (NHLBI)
ClinicalTrials.gov Identifier:
NCT00005253
First received: May 25, 2000
Last updated: January 27, 2006
Last verified: January 2006
  Purpose

To determine whether treatment with antidepressant, anticonvulsant, and antiarrhythmic drug therapies having the potential for proarrhythmia increased the risk of primary cardiac arrest. The aim of the original grant, starting in 1990 and ending in 1994, was to determine whether use of diuretics for hypertension increased the risk of primary cardiac arrest compared to the use of other antihypertensive agents.


Condition
Cardiovascular Diseases
Heart Diseases
Heart Arrest
Hypertension
Arrhythmia

Study Type: Observational

Resource links provided by NLM:


Further study details as provided by National Heart, Lung, and Blood Institute (NHLBI):

Study Start Date: January 1990
Estimated Study Completion Date: January 2000
Detailed Description:

BACKGROUND:

The original grant from 1990 to 1995 was funded because analyses of clinical trial subgroups had raised the concern that, in patients with high blood pressure, diuretic therapy may increase the risk of sudden cardiac death. Given the size of the hypertensive population in the United States, the prevalence of diuretic therapy for hypertension, and the persistent concerns regarding the relation of diuretic therapy to the risk of primary cardiac arrest (PCA), the study proved to be of particular interest to clinicians, epidemiologists, public policy makers, and the general public.

Beginning in 1995 when the grant was renewed, unexpected findings from the Cardiac Arrhythmia Suppression Trial--an adverse effect on mortality of two antiarrhythmic drug therapies--had heightened concerns that drug therapies other than diuretics may increase the risk of primary cardiac arrest.

DESIGN NARRATIVE:

The original study beginning in 1990 was population-based with a case-control design. Using the community-based surveillance system for out-of-hospital primary cardiac arrest in Seattle and King County, Washington, all cases of primary cardiac arrest (PCA) were identified which had occurred among 18,000 pharmacologically-treated hypertensive patients receiving care at Group Health Cooperative (GHC) from 1977-1993. Approximately 180 cases were identified. Controls were obtained from a random sample of GHC enrollees with pharmacologically-treated hypertension, matched to cases at a ratio of 3 to 1, according to age, gender, and year of occurrence of PCA. The computerized pharmacy data base of GHC allowed ascertainment of patterns of exposure to specific antihypertensive drug therapy in an identical fashion for both cases and controls. Medical records were reviewed to gather information about potential confounding factors and effect modifiers, such as severity of hypertension. Data analysis, using stratification and logistic regression, determined whether use of diuretics increased the risk of PCA compared to use of other antihypertensive agents; whether the risk of PCA depended upon the dose of diuretic therapy; and whether electrocardiographic abnormalities modified the risk of PCA associated with diuretics.

The study was renewed in 1995 to determine whether treatment with antidepressant, anticonvulsant, and antiarrhythmic drug therapies having the potential for proarrhythmia increased the risk of primary cardiac arrest. The study was a population-based case-control study nested within a cohort of patients who received medical care at a large pre-paid Health Care Plan in Seattle, Washington. Cases were patients who had a primary cardiac arrest between 1977 to 1994. Controls were a stratified random sample of patients, frequency-matched to cases by age, gender, calendar-year, and known heart disease. Treatment with drugs was assessed through a computerized pharmacy database. Ambulatory-care medical records were reviewed to assess clinical characteristics, including the indication for therapy, the severity of heart disease, co-existing morbidity, and other risk factors. For both antidepressant and anticonvulsant drugs, analyses were stratified by known heart disease, because the risk of treatment might be particularly large among patients with known heart disease. For antiarrhythmic drugs, analyses were restricted by a single, current indication for the therapy--maintenance of sinus rhythm among patients with chronic atrial fibrillation; and, by the availability of a prior echocardiogram, in order to control for the type and severity of underlying heart disease. After adjustment for potential confounders, the investigators estimated the relative safety of: 1) drugs within the same therapeutic class; and, 2) the dosage schedule for specific drugs. In addition, they determined if concurrent treatment with other drugs that altered cardiac conduction or morbidity that altered drug disposition influenced the risk among patients treated with a drug therapy.

  Eligibility

Genders Eligible for Study:   Male
Accepts Healthy Volunteers:   No
Criteria

No eligibility criteria

  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00005253

Sponsors and Collaborators
Investigators
Investigator: David Siscovick University of Washington
  More Information

Publications:
ClinicalTrials.gov Identifier: NCT00005253     History of Changes
Other Study ID Numbers: 1135
Study First Received: May 25, 2000
Last Updated: January 27, 2006
Health Authority: United States: Federal Government

Additional relevant MeSH terms:
Arrhythmias, Cardiac
Cardiovascular Diseases
Heart Arrest
Heart Diseases
Hypertension
Pathologic Processes
Vascular Diseases

ClinicalTrials.gov processed this record on August 18, 2014