Determination of fibromyalgia syndrome after whiplash injuries: methodologic issues.

Problems in diagnosing fibromyalgia syndrome (FM) among motor vehicle collision (MVC) patients with whiplash (WL) include the following: the predominance of tender points (TPs) in the neck/shoulder girdle region; the 3-month duration of widespread pain criterion; and, the stability of diagnosis. The present study examined the prevalence of FM in a cohort (N = 326) patients with persistent neck pain 3 months after WL injury who were enrolled in a treatment program. Physical examinations were performed at baseline and at the end of treatment. Results indicated that WL patients had a greater proportion of neck/shoulder girdle TPs, relative to distal TPs. Compared with a matched cohort of treatment-seeking FM patients, WL patients indicated less distal TPs (mean = 7.3 TPs vs. mean = 5.6 TPs, P < .001), but were equivalent on neck/shoulder girdle TPs (mean = 9.0 TPs vs. 9.2 TPs, NS). Baseline prevalence of FM for the WL cohort based on ACR criteria was 14% (95% CI = 10%-18%), adjusted TP criterion discounting for neck/shoulder tenderness indicated a prevalence of FM of 8% (95% CI = 5%-11%). Finally, 63% of patients meeting American College of Rheumatology FM criteria at baseline did not meet this criterion at post-treatment (∼6-months after an MVC). In conclusion, present criteria used in determining FM may result in spuriously inflated rates of diagnosis among WL patients because of persistent localized tenderness after an MVC. Furthermore, the transient nature of FM "symptoms" among WL patients should be taken into account before making a final diagnosis. The present criteria used in determining fibromyalgia may result in spuriously inflated rates of diagnosis among whiplash patients because of persistent localized tenderness after motor vehicle collisions.