Pain and osteoarthritis in primary care: factors associated with pain perception in a sample of 1,021 patients.

OBJECTIVE: Pain represents one of the most important predictors of quality of life in patients with osteoarthritis (OA). Prior studies were conducted in hospital settings and/or failed to control important factors such as depression, obesity, or physical activity. Therefore, the aim of the study was to determine factors associated with pain intensity in a large sample of OA patients in primary care.
DESIGN: Cross-sectional survey with a questionnaire containing sociodemographic data, the short form of the Arthritis Impact Measurement Scale (AIMS2-SF), and the Patient Health questionnaire, to assess concomitant depression. A hierarchical stepwise multiple regression analysis with the AIMS2-SF dimension "symptom" reflecting patients' pain intensity as the dependent variable was performed. PATIENTS: 1,021 patients form 75 primary care practices.
RESULTS: In the regression model four factors remained, explaining 46.5% of the variation in the dependent variable (P < 0.001): Severity of depression reflected in the PHQ-9 score showed the strongest association with pain intensity (beta = 0.459, P < 0.001). Functional disability of the lower limb achieved a beta of 0.427 (P = 0.003). A low educational level was associated with increased pain scores (beta = -0.321; P = 0.034), as well as a weak social network, (beta = 0.211; P = 0.042).
CONCLUSIONS: A variety of physical and psychological factors were associated with pain intensity. Appropriate pain treatment of OA patients in primary care should consider as many of these factors as possible. Further research is needed to assess if a more comprehensive and proactive approach will result in less pain and in increased quality of life.