Evidence Check 2: Homeopathy - Homeowatch

Evidence Check 2: Homeopathy 9• analysis of the results of included studies, with statistical analysis (meta-analysis) ifappropriate; and• a critical summary of the systematic review, including identification of the“confidence intervals” 28 and “statistical significance” 29 of any findings.25. We expect the conclusions on the evidence for the efficacy of homeopathy to giveparticular weight to properly conducted meta-analyses and systematic reviews of RCTs.The distinction between efficacy and effectiveness26. It has been suggested that it is useful to draw a distinction between efficacy andeffectiveness. 30 Dr Peter Fisher, Director of the Royal London Homeopathic Hospital,explained the difference:In simple terms the distinction is between ideal conditions and real worldconditions—efficacy being ideal conditions and effectiveness being real worldconditions. 3127. Professor Edzard Ernst, Director of the Peninsula Medical School, gave the followingexample:Efficacy tests whether treatment works under ideal conditions; for instance, ahypertensive agent may well be effective under ideal conditions and then will notwork in the real world because people experience side-effects. 3228. The opposite might also occur: a product might not work in “ideal” conditions, butmay appear effective in “the real world”. In the case of homeopathy, arguments havepredominantly centred around whether or not it is a placebo treatment. If homeopathy wasbetter than a placebo treatment, one would expect tests of efficacy to show that it isefficacious; and “real world” tests of effectiveness to show that it may or may not beeffective. If homeopathy was a placebo treatment, it would fail tests of efficacy, but withtests of effectiveness it would appear to be effective for some conditions and some patients,but not for others.A summary of the logical outcomes depending on whether homeopathy is or is not a placeboEfficacyEffectivenessHomeopathy is not a placeboPASSHomeopathy is a placeboFAILEITHER PASS OR FAIL29. The answer to why a medicine can be effective without being efficacious lies with aphenomenon known as the placebo effect.28 A confidence interval helps assess the likelihood of a result occurring by chance. A confidence interval represents arange of values that is believed to encompass the “true” value with high probability (usually 95%).29 A result is defined as statistically significant if it is unlikely to have occurred by chance, typically when the probabilityof obtaining that result by chance is less than 5%.30 Ev 162 [Dr Relton]31 Q 11632 As above