In many studies of osteoarthritis treatment, there is an improvement in pain relief when a dummy ‘placebo’ treatment is compared to no treatment at all, but there is very little extra improvement when the real treatment is compared to placebo. This response to placebo varies greatly from patient to patient. Identifying the characteristics of a person whom will best respond to placebo treatment, along with the factors that will predict a beneficial placebo response, will help maximise treatment effect and design future pain relief studies.
We are going to analyse individual patient data collected from trials that have compared a treatment for osteoarthritis pain alongside a placebo. These include using non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen applied to the skin as a patch, cream or gel; or capsaicin (the spicy substance in chillies) also applied to the skin; steroid injections and glucosamine tablets. The data from all these studies will be combined and analysed. We will compare the characteristics of those people who responded to the placebo treatment compared to those who did not. We hope to be able to identify a subgroup of people with osteoarthritis who are most likely to respond to placebo and to be able to identify factors that will predict a response.
Placebo data of 945 subjects from 11 studies has been collected and is now being analysed.