Related Experiment Video
Updated: May 3, 2026

A Clinical Trial Assessing the Safety, Efficacy, and Delivery of Olive-Oil-Based Three-Chamber Bags for Parenteral Nutrition
Published on: September 20, 2019
How conducting a clinical trial affects physicians' guideline adherence and drug preferences
Morten Andersen1, Jakob Kragstrup, Jens Søndergaard
1Research Unit for General Practice, University of Southern Denmark, Odense, Denmark. mandersen@health.sdu.dk
Context:
General practitioners are frequently involved in clinical trials sponsored by pharmaceutical companies but the effects of participation on their prescribing patterns have not been evaluated.
Objective:
To determine how conducting a company-sponsored clinical trial influenced physicians' adherence to international treatment recommendations and their prescribing of the pharmaceutical company's drugs.
Design, Setting, And Patients:
Observational cohort study in Funen County, Denmark, comparing 10 practices that were conducting a trial on asthma medicine with 165 control (non-trial-conducting) practices. The study population included 5439 patients treated with asthma drugs from the trial-conducting practices and 59,574 patients from the control practices. Practices conducted the trial between April 26, 2001, and October 7, 2002.
Main Outcome Measures:
Adherence to guidelines measured as use of inhaled corticosteroids among asthma patients. Prevalence of use of the company's drugs and the trial sponsor's share of the total volume of asthma drugs prescribed.
Results:
The baseline proportion of asthma patients using inhaled corticosteroids was 68.5% in trial-conducting and 69.1% in control practices. Conducting the trial did not influence guideline adherence (odds ratio [OR] after 2 years, 1.00; 95% confidence interval [CI], 0.84-1.19). In trial-conducting practices, the sponsoring company's share of the total prescribed volume of asthma drugs increased compared with control practices (6.7%; 95% CI, 3.0%-11.7%). This could be attributed to a significantly higher preference for the company's inhaled corticosteroids (OR, 1.26; 95% CI, 1.04-1.54) and trends toward increased prescribing of the company's other asthma drugs.
Conclusion:
Conducting a trial sponsored by a pharmaceutical company had no significant impact on physicians' adherence to international treatment recommendations but increased their use of the trial sponsor's drugs.
More Related Videos
06:28E-Patient Counseling Trial E-PACO: Computer Based Education versus Nurse Counseling for Patients to Prepare for Colonoscopy
Published on: August 1, 2019
07:40Preparation of Peripheral Blood Mononuclear Cell Pellets and Plasma from a Single Blood Draw at Clinical Trial Sites for Biomarker Analysis
Published on: March 20, 2021
Related Concept Videos
Clinical Trials
There are four phases in a clinical trial. A phase one...
Blinding
Clinical Trials: Overview
Types of Biopharmaceutical Studies: Controlled and Non-Controlled Approaches
Non-controlled studies, commonly employed for initial exploration, lack a control group, rendering them susceptible to biases and external influences. In contrast,...
Bioavailability Study Design: Healthy Subjects Versus Patients
Therapeutic Drug Monitoring: Affecting Factors