Chou KL, Chow NW, Chi I Preventing economic hardship among Chinese elderly in Hong Kong. J Aging Soc Policy. 2004;16(4):79-97.
Conway Morris A, Caesar D, Gray S, Gray A TIMI risk score accurately risk stratifies patients with undifferentiated chest pain presenting to an emergency department. Heart. 2006 Sep;92(9):1333-4.
Kip KE, Hollabaugh K, Marroquin OC, Williams DO The problem with composite end points in cardiovascular studies: the story of major adverse cardiac events and percutaneous coronary intervention. J Am Coll Cardiol. 2008 Feb 19;51(7):701-7. doi: 10.1016/j.jacc.2007.10.034. Review.
Mettler FA Jr, Huda W, Yoshizumi TT, Mahesh M Effective doses in radiology and diagnostic nuclear medicine: a catalog. Radiology. 2008 Jul;248(1):254-63. doi: 10.1148/radiol.2481071451. Review.
Nabi F, Chang SM, Pratt CM, Paranilam J, Peterson LE, Frias ME, Mahmarian JJ Coronary artery calcium scoring in the emergency department: identifying which patients with chest pain can be safely discharged home. Ann Emerg Med. 2010 Sep;56(3):220-9. doi: 10.1016/j.annemergmed.2010.01.017. Epub 2010 Feb 6.
Rumberger JA, Brundage BH, Rader DJ, Kondos G Electron beam computed tomographic coronary calcium scanning: a review and guidelines for use in asymptomatic persons. Mayo Clin Proc. 1999 Mar;74(3):243-52. Review. Erratum in: Mayo Clin Proc 1999 May;74(5):538.
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.