Predicting self-reported disability level by a number of pain sites marked on pain drawing.

To evaluate the connection between the number of pain sites (head and neck, upper extremities, trunk, and lower extremities) marked on pain drawing and general disability level measured by a 12-item WHO Disability Assessment Schedule 2.0 (WHODAS 2.0) score. A cross-sectional survey of 1988 patients with chronic musculoskeletal pain was conducted. Analysis of variance with contrasts was performed along with regression analysis. Despite the relatively mild median disability level measured as WHODAS 2.0 total score at 25%, the majority of the participants experienced, in the last month, severe pain with 8.1 points on a 0-10 numeric rating scale. Only 1% had left the pain drawing unmarked. Otherwise, 15% had marks in one area, 34% in two, 23% in three, and 27% in all four areas. The characteristics of those groups were similar except for disability. Disability level was 30-50% worse when pain was experienced in all four sites. The analysis of variance showed that both the number of pain sites and pain severity affected disability level (P<0.0001). There were differences in disability levels between each group pair. The regression analysis showed a linear relationship between disability and number of pain sites - marking one area more predicted increase in WHODAS 2.0 total score approximately by 5%. The number of sites marked on a pain drawing correlated with disability severity. Increase in this number may serve as an easy screening predictor of functional deterioration in people with chronic musculoskeletal pain.