Outcomes of Usual Chiropractic. The OUCH randomized controlled trial of adverse events

Abstract

Study Design: Blinded parallel group randomised controlled Objective: Establish the frequency and severity of adverse effects from short term usual chiropractic treatment of the spine when compared to a sham treatment group. Summary of Background Data: Previous studies have demonstrated that adverse events occur during chiropractic treatment. However, as a result of design limitations in previous studies, particularly the lack of sham-controlled randomised trials, understanding of these adverse events and their relation with chiropractic treatment, is suboptimal. Methods: We conducted a trial to examine the occurrence of adverse events resulting from chiropractic treatment. It was conducted across 12 chiropractic clinics in Perth, Western Australia. The participants comprised 183 adults, aged 20-85, with spinal pain. Ninety two participants received individualized care consistent with the chiropractors' usual treatment approach; 91 participants received a sham intervention. Each participant received two treatments. Results: Completed adverse questionnaires were returned by 94.5% of the participants after appointment one and 91.3% after appointment two. Thirty three per cent of the sham group and 42% of the usual care group reported at least one adverse event. Common adverse events were increased pain (sham 29%; usual care 36%), muscle stiffness (sham 29%; usual care 37%), headache (sham 17%; usual care 9%). The relative risk was not significant for either adverse event occurrence (RR = 1.24 95% CI 0.85 to 1.81); occurrence of severe adverse events (RR = 1.9; 95% CI 0.98 to 3.99); adverse event onset (RR = 0.16; 95% CI 0.02 to 1.34); or adverse event duration (RR = 1.13; 95% CI 0.59 to 2.18). No serious adverse events were reported. Conclusions: A substantial proportion of adverse events following chiropractic treatment may result from natural history variation and non-specific effects