What use are fibromyalgia (FM) control points?

OBJECTIVE: To investigate the relationship between control

points and symptom and distress severity in fibromyalgia (FM).

METHODS: Eighty- four new patients with FM seen at an

outpatient rheumatology center from December 1994 through

August 1996 underwent tender point and dolorimetry

examinations at 18 active and 4 control sites. All completed

the assessment scales for fatigue, sleep disturbance, anxiety,

depression, global severity, pain, and functional disability,

and a composite measure of distress constructed from scores of

sleep disturbance, fatigue, anxiety, depression, and global

severity — the Rheumatology Distress Index (RDI).

RESULTS:

Control point positivity was common in FM (63.1%) and was

associated with somewhat more severe FM symptoms and general

distress, yielding an increase in the RDI of 9.2 units or 0.55

standard deviation units. There was no evidence of

particularly worse disease in patients with high counts of

control tender points, and increasing numbers of tender points

beyond the first positive control point were generally not

associated with, or were only weakly associated with,

increasing symptom severity. Many patients with positive

control points had only mild levels of symptom severity.

Finally, we found no clusters of patients with very severe

symptoms associated with control points, or with dolorimetry

scores, or with ratios of dolorimetry scores from different

body regions of varying pain thresholds.

CONCLUSION: Positive

control points are a common feature (63%) in FM, and appear to

be a marker for a generally low pain threshold rather than a

disproportionate increase in severe symptoms or distress.

Control point positivity should not be used to disqualify a

diagnosis of FM. Control point measurements do not add much to

FM diagnosis or assessment and, perhaps, should be abandoned.

At the least, they should be designated “high threshold”

points rather than control points. Dolorimetry is considerably

less useful in FM assessment than the manual tender point

examination.