Abstract
BACKGROUND: In epidemiological studies on neck-shoulder disorders, physical examination by health professionals, although more expensive, is usually considered a better method of data collection than self-administered questionnaires on symptoms. However, little is known on the comparison of these two methods of data collection. The agreement between self-administered questionnaires and the physical examination on the presence of neck-shoulders disorders was assessed in the present study. METHODS: This study was conducted among clerical workers using video display units. Prevalent cases were workers for whom neck-shoulder symptoms were present for at least 3 days during the previous 7 days and for whom pain intensity was greater than 50 mm on a 100 mm visual analogue scale. All 85 workers meeting this definition and a random sample of 102 workers who did not meet this definition were selected. Physical examination included measures of active range of motion and musculoskeletal strength. Cohen's kappa and global percent agreement were calculated to compare the two methods of data collection. The effect on the agreement of different question and physical examination definitions and the importance of the time interval elapsed between the administrations of the tests were also evaluated. RESULTS: Kappa coefficients ranged from 0.19 to 0.54 depending on the definitions used to ascertain disorders. The agreement was highest when the two instruments were administered 21 days apart or less (Kappa = 0.54, global agreement = 77%). It was not substantially improved by the addition of criteria related to functional limitations or when comparisons were made with alternative physical examination definitions. Pain intensity recorded during physical examination maneuvers was an important element of the agreement between questionnaire and physical examination findings. CONCLUSION: These results suggest a fair to good agreement between the presence of musculoskeletal disorders ascertained by self-administered questionnaire and physical examination that may reflect differences in the constructs measured. Shorter time lags result in better agreement. Investigators should consider these results before choosing a method to measure the presence of musculoskeletal disorders in the neck-shoulder region.