The placebo response rate in pharmacological trials in patients with irritable bowel syndrome: a systematic review and meta-analysis
Review (73 RCTs) found over a quarter of patients with IBS had a placebo response in terms of global improvement (27.3%); researchers recommend that future trials apply a run-in period of ≥2 weeks and once or twice daily dose schedule to minimise placebo response rate.
Source:
Lancet Gastroenterology and Hepatology
SPS commentary:
According to a commentary, as recently as 10 years ago, the basic question of whether a patient achieved adequate or global relief of symptoms was the most common (and most sensible) endpoint trials. Yet this endpoint yielded placebo response rates reaching around 40%. It notes that active placebo (with informed consent) has even shown promise as an IBS treatment, highlighting challenges in evaluating investigational IBS treatments in randomised, placebo-controlled trials.