Symptoms patients receiving manual therapy experienced and perceived as adverse: a secondary analysis of a survey of patients' perceptions of what constitutes an adverse response.

: Previous qualitative studies demonstrated that the process by which patients determined whether a response to manual therapy is adverse is very complex. However, it remains unknown which responses to manual therapy patients perceived as adverse. : To describe symptoms patients experienced and perceived as adverse following manual therapy and to explore predictors of adverse responses (AR) for the body region with the greatest number of AR. We hypothesized that patients receiving manual therapy for neck conditions would present with more symptoms perceived as AR. : This was a secondary analysis of a previous cross-sectional survey of 324 patients receiving manual therapy from Canadian physiotherapists. It included questions regarding symptoms patients experienced after a treatment including manual therapy and perceived as adverse. Poisson and negative binomial regression were used to determine factors associated with the number of symptoms that patients experienced and perceived as adverse. : Symptoms that affected patient's functionality were most often perceived as AR. The neck region was the body part with the greatest number of perceived AR (n = 83). Patients with neck pain who agreed that education may change their experience with AR had a lower incidence rate of AR. : Findings indicate that communication regarding post-treatment symptoms between clinicians and patients is important and can potentially influence patients' perception of post-treatment symptoms.