Chang PH, Chiang CH, Ho WC, Wu PZ, Tsai JS, Guo FR Combination therapy of varenicline with nicotine replacement therapy is better than varenicline alone: a systematic review and meta-analysis of randomized controlled trials. BMC Public Health. 2015 Jul 22;15:689. doi: 10.1186/s12889-015-2055-0.
Chiang CH, Huang KC Association between metabolic factors and chronic hepatitis B virus infection. World J Gastroenterol. 2014 Jun 21;20(23):7213-6. doi: 10.3748/wjg.v20.i23.7213.
Chiang CH, Huang KC Reply: To PMID 24425422. Hepatology. 2015 May;61(5):1763-4. doi: 10.1002/hep.27427. Epub 2015 Mar 23. No abstract available.
Chiang CH, Lai JS, Hung SH, Lee LT, Sheu JC, Huang KC Serum adiponectin levels are associated with hepatitis B viral load in overweight to obese hepatitis B virus carriers. Obesity (Silver Spring). 2013 Feb;21(2):291-6. doi: 10.1002/oby.20000.
Heatherton TF, Kozlowski LT, Frecker RC, Fagerstrom KO The Fagerstrom Test for Nicotine Dependence: a revision of the Fagerstrom Tolerance Questionnaire. Br J Addict. 1991 Sep;86(9):1119-27. doi: 10.1111/j.1360-0443.1991.tb01879.x.
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.