Do placebo response rates from cessation trials inform on strength of addictions?

There is an implied assumption that addictions to different substances vary in strength from weak (easier to stop) to strong (harder to stop), though explicit definitions are lacking. Our hypothesis is that the strength of addictions can be measured by cessation rates found with placebo or no treatment controls, and that a weaker addiction would have a higher cessation rate than a stronger addiction. We report an overview of systematic reviews and meta-analyses of cessation trials, using randomised or quasi-randomised trials and reporting objectively-measured abstinence. The outcome for comparison was quit rates-typically the percentage of participants abstinent according to an objective test of abstinence at six months or longer. Twenty-eight cessation reviews (139,000 participants) were found. Most data came from reviews of smoking cessation in over 127,000 participants, and other reviews each covered a few thousand participants. Few reviews used data from studies shorter than three months, and almost all determined abstinence using objective measures. Cessation rates with placebo in randomised trials using objective measures of abstinence and typically over six months duration were 8% for nicotine, 18% for alcohol, 47% for cocaine, and 44% for opioids. Evidence from placebo cessation rates indicates that nicotine is more difficult to give up than alcohol, cocaine, and opioids. Tobacco is also a severe addiction, with a number of major deleterious health effects in a large number of people.

Mean analgesic consumption is inappropriate for testing analgesic efficacy in post-operative pain: analysis and alternative suggestion.

BACKGROUND AND OBJECTIVE: Post-operative analgesic consumption is often used as a surrogate measure for pain; analyses of mean data assume a Gaussian distribution and use parametric statistics to assess statistical differences, often in small samples. We used a large individual patient dataset to examine the distribution of analgesic consumption, the validity of such analyses and alternative dichotomous outcomes. METHODS: Analysis of individual patient data from 913 patients over 48 post-operative hours in five randomised trials. Patients had either epidural injection of placebo or morphine (as sulphate and extended release epidural morphine) and use of patient-controlled analgesia. Post-operative fentanyl consumption was calculated over 0-24, 24-48 and 0-48 h. RESULTS: The distribution of analgesic consumption for all patients over the periods 0-24, 24-48 and 0-48 h was exponential. Most patients used less than 750 µg fentanyl over 48 h; 34% used over 1000 µg fentanyl (100 mg morphine), 13% over 2000 µg and 5% over 3000 µg. Mean, median and mode were very different; 20% of patients consumed almost 60% of post-operative analgesic, and standard deviations were generally larger than means. A useful dichotomous outcome was less than 750 µg fentanyl consumed over 48 h, a level associated with very good or excellent patient pain rating. Use of very good or excellent patient pain rating differentiated between different doses of epidural morphine. CONCLUSION: Because of a highly skewed distribution, post-operative analgesic consumption is an uncertain method of measuring analgesic efficacy of an intervention designed to limit pain during and after surgery.

Pregabalin in fibromyalgia: meta-analysis of efficacy and safety from company clinical trial reports.

OBJECTIVES: Meta-analysis of pregabalin trials in FM using company trial reports, which provide more detailed information about trials than published papers. FM is a common condition with a significant impact on quality of life. METHODS: Reports of five high-quality randomized trials (3808 patients) of pregabalin in FM were obtained from Pfizer. Four trials (2754 patients) were of classical trial design and one was an enriched enrolment randomized withdrawal design. Outcomes for meta-analysis from the four trials with classical design were pooled in an intention-to-treat analysis. RESULTS: Significant benefit of pregabalin over placebo was seen for a variety of outcomes including mean pain and sleep scores, the proportion of patients achieving at least 50% pain relief and most of the individual domains of short-form 36. Only a minority of patients achieve moderate or substantial pain relief. The proportions of patients with any adverse event, somnolence or dizziness were also significantly greater with pregabalin than with placebo. There was no difference with regard to serious adverse events. A dose-response relationship was apparent for at least 50% pain relief and for adverse event outcomes. CONCLUSIONS: Pregabalin is effective in treating FM and is relatively safe. The size of therapeutic effect is similar to that with other recent interventions such as duloxetine and the combination of tramadol and paracetamol. Enriched enrolment randomized withdrawal design gives similar results to classical trial designs in FM.

Imiquimod for actinic keratosis: systematic review and meta-analysis.

Benefit and harm associated with treating actinic keratosis (AK) with the immune response modifier imiquimod was assessed using published randomized-controlled trials. Five randomized double-blind trials lasted 12-16 weeks and treated 1,293 patients. Complete clearance occurred in 50% of patients treated with imiquimod, compared to 5% treated with vehicle, and the number needed to treat (NNT) for one patient to have their keratosis completely cleared after 12-16 weeks was 2.2 (95% confidence interval 2.0-2.5). For partial (>/=75%) clearance the NNT was 1.8 (1.7-2.0). The proportion of patients with any adverse event, any local adverse event, or any treatment-related adverse event was substantially higher with imiquimod than with vehicle, and numbers needed to harm for one additional adverse event with imiquimod over 12-16 weeks ranged from 3.2 to 5.9. Particular local adverse events with imiquimod included erythema (27%), scabbing or crusting (21%), flaking (9%), erosion (6%), edema (4%), and weeping (3%). Imiquimod 5% cream was effective in the treatment of AK, preventing potential development of squamous cell carcinoma. Future investigation might be aimed at elucidating optimal dosing to minimize adverse events without detriment to efficacy, and evaluating long-term recurrence.