Psychological variables associated with foot function and foot pain in patients with plantar heel pain.

It is widely accepted that psychological variables are associated with self-reported pain and self-reported physical function in patients with musculoskeletal pain. However, the relationship between psychological variables and foot pain and foot function has not been evaluated in people with plantar heel pain. Eighty-four participants with plantar heel pain completed the Depression, Anxiety and Stress Scale short version (DASS-21) and Foot Health Status Questionnaire. Using a hierarchical regression analysis, a baseline model with age, sex and BMI explained 10 % of the variability in foot function. The addition of depression and stress in separate models explained an additional 7.3 % and 8.1 % of foot function scores, respectively. In the respective models, depression was a significant predictor (β = -0.28; p = 0.009) as was stress (β = -0.29; p = 0.006). Females drove the effect between stress and foot function (β = -0.50; p = 0.001) and depression and foot function (β = -0.53; p < 0.001). In regression models for foot pain, depression, anxiety and stress did not contribute significantly to pain scores. When the data was stratified by sex, stress (β = -0.36; p = 0.024) and depression (β = -0.41; p = 0.013) were significantly associated with foot pain in females but not in males. For participants with plantar heel pain, stress and depression scores were significantly associated with foot function but not foot pain. When the data was stratified by sex, stress and depression were significant predictors of foot pain and function in females.