Trials in functional dyspepsia report placebo response rates of 30% to 40%.
Dr Talley and colleagues identified predictors of the placebo response.
The researchers enrolled patients from primary, secondary and tertiary practices with functional dyspepsia defined by Rome II criteria into 1 of 4 clinical trials.
Scintigraphic assessment of gastric emptying at baseline was repeated at the end of the treatment in those with delayed emptying.
After a 2 week run-in period, patients were followed for 8 weeks on placebo.
Response was assessed on a weekly basis.
|The predominant symptom was an unstable measure over the trial|
|Alimentary Pharmacology & Therapeutics|
The investigators defined a responder as satisfactory relief of meal-related symptoms on at least 50% of weeks.
The mean age of patients was 44 years, 74% were female, and 35% were placebo responders.
The investigative team found that the predominant symptom was an unstable measure over the trial.
Independent predictors of a lower placebo response were lower body mass index and a more consistent predominant symptom pattern.
No association was seen with age, gender, centre type, baseline symptom score, baseline or change in gastric emptying, or baseline quality of life.
Dr Talley's team commented, “In functional dyspepsia, a consistent predominant symptom pattern and lower body mass index may be associated with a lower placebo response rate.”