The association between clinical findings on physical examination and self-reported severity in back pain - Results of a population-based study

Study design. A cross-sectional population-based study of back pain. Objective. To evaluate the association between clinical findings on physical examination and subjective severity in nonspecific back pain. Summary of background data. Assessment of severity of back pain always has been controversial. Most studies evaluating the role of clinical findings in back pain have been hospital- or clinic-based, often representing a highly select population. This selection is avoided in the population-based approach of the present study. Methods. Approximately 4,000 German inhabitants of Lubeck, aged 25-74, were selected randomly from the local population registry and received a postal questionnaire. Those who reported ''back pain today'' (n = 1200) or ''back pain within the past 12 months but no back pain before'' (n = 75) were invited to come in for a clinical examination. Thirty-four physical measurements were taken. They were divided into four groups: static measurements, dynamic measurements, neurologic findings, and non-organic physical signs. Self-reported severity of back pain was measured by a pain questionnaire and a 12-item activities of daily living list to assess functional disability. Results. Within each of the four groups of physical measurements, those that corresponded best with the subjective severity of back pain could be identified (e.g., rotation, lateral flexion, and fingertip-floor distance; scoliosis, the position of the side plumb line, and pain on percussion of the spine; pseudo-Lasegue and hand muscle strength). Those that corresponded best could be differentiated statistically from less correlative measurements such as kyphosis and lordosis; flexion of the lumbar, thoracic, or cervical spine; abdominal muscle strength; and axial loading. The agreement between the classification of back pain severity based on clinical findings and the classification based on self-reports was moderate (kappa = 0.47). Conclusions. Assessment of severity in back pain can only partly be based on the clinical findings of a physical examination. There is a relatively weak agreement between the results of physical examination and the subjective reporting of pain and disability.