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STUDY DESIGN I
STUDY DESIGN II
RESULTS
STRENGTHS
LIMITATIONS
100
What was the study duration?
What is... 12 weeks.
100
How was the study blinded?
What is... double-blind.
100
What percent of participants sustained abstinence at 12 weeks in the placebo, 900 mg and 1800 mg groups.
What is... 4.1% (placebo), 11.1% (900 mg), and 17.0% (1800 mg).
100
Intention-to-treat analysis
Intention-to-treat analysis
100
Single-site study
Single-site study
200
How did the groups compare at baseline?
What is... The authors stated that “treatment groups did not differ on pretreatment demographic and clinical variables” as shown in the table. However, number of drinks per week was 17% greater in the placebo group (!)
200
What type of analysis was used?
What is... intention-to-treat.
200
What was the NNT and OR for no heavy drinking in the 1800 mg gabapentin group?
What is... NNT = 5 (95% CI, 3-78) & OR = 2.8 (95%, 1.1-7.5)
200
A novel study looking at the use of gabapentin for alcohol use disorder
A novel study looking at the use of gabapentin for alcohol use disorder
200
Significant drop-out rate
Significant drop-out rate
300
How were the subjects selected?
What is... Treatment-seeking volunteers with alcohol dependence were recruited primarily via IRB-approved print and Internet advertisements. April 2004 - February 2010. The Scripps Research Institute, La Jolla, California. 150 participants included
300
How was the study randomized?
What is... - Computer-generated randomization code provided by a laboratory biostatistician. The code was kept by the study pharmacist, who provided participants with weekly medication in a blister card package that was consecutively numbered for each participant and prepared according to the randomization schedule. - 1:1:1 ratio; 3 groups - placebo, 900 mg gabapentin and 1800 mg gabapentin
300
What is the NNT for the 1800mg group for sustained abstinence at 12 weeks?
TRICK QUESTION! -100 points if you answered 8!
300
Good background information
Good background information
300
Volunteer bias
Volunteer bias
400
What inclusion and exclusion criteria were applied?
What is... - To be eligible, men and women had to be older than 18 years; meet the DSM-IV citeria for current alcohol dependence; and be abstinent from alcohol at least 3 days prior to randomization. - Exclusion criteria were risk for significant withdrawal based on a CIWA-Ar score higher than 9; more than 1 month of abstinence; dependence on substances other than alcohol or nicotine; a urine drug screen that was positive for benzodiazepines, cocaine, methamphetamine, tetrahydrocannabinol, methadone, or opiates; clinically significant medical or psychiatric disorders; treatment with medications that could affect study outcomes; and treatment mandated by a legal authority.
400
What were the primary and secondary outcomes?
What is... - The authors modified their original analysis of mean abstinence duration to be a responder based on the rate of complete abstinence over the 12-week study. They also included the rate of no heavy drinking over the 12-week trial as a coprimary outcome, because this has become a standard outcome in alcoholism clinical trials. - Used a mixed-effect model of drinking quantity (number of drinks per week) and frequency (number of heavy drinking days per week) over the 12-week study period, as supportive primary outcomes. They also report changes in GGT as a supportive primary outcome. - Prespecified secondary outcomes were standardized measures of alcohol craving, sleep, and mood over the 12-week study period.
400
What trends were seen regarding secondary outcomes with gabapentin?
What is... significant linear dose effects.
400
Valuable primary and secondary outcomes
Valuable primary and secondary outcomes
400
Exclusion criteria included clinically significant medical or psychiatric disorders.
Exclusion criteria included clinically significant medical or psychiatric disorders.
500
How was the sample size calculation performed?
What is... The sample size estimation was derived from results of a prior trial that found an odds ratio (OR) of 2.96 for complete abstinence between drug and placebo, estimating a sample size of 150 would show a medium effect size for the difference between gabapentin and placebo in rate of complete abstinence with 80% power and an alpha level of 0.05.
500
What statistical tests/calculations were used?
What is... - Sample size calculation - Chi square analysis - Analysis of variance - All tests were 2-tailed, and an alpha < 0.05 was considered statistically significant - Linear dose effects for rates of complete abstinence and no heavy drinking over the 12-week study were assessed using the extended Mantel-Haenszel X^2 test for linear association. - Calculated the NNT and OR as estimates of effect size for each drug group relative to placebo to facilitate clinical interpretation of primary outcomes.
500
When the researchers checked in at 24 weeks, what were their findings?
What is... a sustained significant linear-dose effect for rate of complete abstinence, number of drinks per week, and number of heavy drinking days per week.
500
Procedure
Procedure
500
Would have been beneficial to compare with other approved therapies in a head-to-head trial (i.e. naltrexone)
Would have been beneficial to compare with other approved therapies in a head-to-head trial (i.e. naltrexone)