Eisner MD, Katz PP, Yelin EH, Henke J, Smith S, Blanc PD Assessment of asthma severity in adults with asthma treated by family practitioners, allergists, and pulmonologists. Med Care. 1998 Nov;36(11):1567-77. Erratum in: Med Care 2000 Aug;38(8):880-5.
Eisner MD, Katz PP, Yelin EH, Shiboski SC, Blanc PD Risk factors for hospitalization among adults with asthma: the influence of sociodemographic factors and asthma severity. Respir Res. 2001;2(1):53-60. Epub 2000 Dec 29.
Eisner MD, Yelin EH, Henke J, Shiboski SC, Blanc PD Environmental tobacco smoke and adult asthma. The impact of changing exposure status on health outcomes. Am J Respir Crit Care Med. 1998 Jul;158(1):170-5. Retraction in: Eisner MD, Shiboski SC, Yelin EH, Blanc PD, Bainton DF. Am J Respir Crit Care Med. 2000 Sep;162(3 Pt 1):788.
Katz PP, Eisner MD, Henke J, Shiboski S, Yelin EH, Blanc PD The Marks Asthma Quality of Life Questionnaire: further validation and examination of responsiveness to change. J Clin Epidemiol. 1999 Jul;52(7):667-75. Erratum in: J Clin Epidemiol. 2001 Jan;54(1):106-7.
Katz PP, Yelin EH, Eisner MD, Blanc PD Perceived control of asthma and quality of life among adults with asthma. Ann Allergy Asthma Immunol. 2002 Sep;89(3):251-8.
Snyder L, Blanc PD, Katz PP, Yelin EH, Eisner MD Leukotriene modifier use and asthma severity: how is a new medication being used by adults with asthma? Arch Intern Med. 2004 Mar 22;164(6):617-22.
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.