Asthma — Clinical Epidemiology of Asthma in An HMO
Citation(s)
Osborne ML, Vollmer WM, Buist AS Diagnostic accuracy of asthma within a health maintenance organization. J Clin Epidemiol. 1992 Apr;45(4):403-11.
Osborne ML, Vollmer WM, Buist AS Periodicity of asthma, emphysema, and chronic bronchitis in a northwest health maintenance organization. Chest. 1996 Dec;110(6):1458-62.
Vollmer WM, Buist AS, Osborne ML Twenty year trends in hospital discharges for asthma among members of a health maintenance organization. J Clin Epidemiol. 1992 Sep;45(9):999-1006.
Vollmer WM, Osborne ML, Buist AS 20-year trends in the prevalence of asthma and chronic airflow obstruction in an HMO. Am J Respir Crit Care Med. 1998 Apr;157(4 Pt 1):1079-84.
Vollmer WM, Osborne ML, Buist AS Temporal trends in hospital-based episodes of asthma care in a health maintenance organization. Am Rev Respir Dis. 1993 Feb;147(2):347-53.
Interventional studies are often prospective and are specifically tailored to evaluate direct impacts of treatment or preventive measures on disease.
Observational studies are often retrospective and are used to assess potential causation in exposure-outcome relationships and therefore influence preventive methods.
Expanded access is a means by which manufacturers make investigational new drugs available, under certain circumstances, to treat a patient(s) with a serious disease or condition who cannot participate in a controlled clinical trial.
Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.
Phase 1: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase 2: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
Phase 3: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase 4: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.
