Quantifying pain threshold and quality of life of fibromyalgia patients.

The most typical symptom of fibromyalgia (FM) is diffuse pain, and pain at specific points-tender points-is crucial for its diagnosis. By comparing healthy individuals and FM patients, this study was aimed at assessing pain and quality of life of Brazilian females with FM, while seeking for a correlation between pain threshold and quality of life. A total of 178 women were evaluated: 124 were FM patients and 54 were healthy women. Pain threshold at tender points was quantified by dolorimetry, and diffuse pain by means of the visual analogue scale (VAS); the Fibromyalgia Impact Questionnaire (FIQ) was used to evaluate quality of life. Statistical treatment of the data allowed for proposing two indexes: a pain threshold index (PT) and a quality of life one (QOL). PT is the lowest value among all pain thresholds measured at the 18 tender points; QOL is the mean of responses to the FIQ and VAS. Both indexes were tested and showed significant differences between the test and control groups. By pairing pain threshold values of each tender point in the test and control groups, it was found that the most sensitive points matched between the two groups, that is, the most sensitive anatomic spots in a healthy individual are also likely to be the most sensitive points in a person with FM. This suggests that a stimulus that provokes slight discomfort to a healthy person may produce more pain in FM patients--which may bear implications for FM clinical treatment. In this sample of Brazilian women, FM patients had both lower pain threshold and worse quality of life than healthy women.