Classifying fibromyalgia patients according to severity: the combined index of severity in fibromyalgia

Abstract

The aim of this study was to establish the cutoff points in the Combined Index of Fibromyalgia Severity (ICAF) questionnaire which allow classification of patients by severity and to evaluate its application in the clinical practice. The cutoff points were calculated using the area under the ROC curve in two cohorts of patients. Three visits, basal, fourth month and 15th month, were considered. The external criterion for grading severity was the number of drugs consumed by the patient. Sequential changes were calculated and compared. Correlations with drug consumption and comparisons of severity between patients with different types of coping were also calculated. Correlation between the number of drugs and the ICAF total score was significant. Three cutoff points were established: absence of Fibromyalgia (FM), <34; mild, 34–41; moderate, 41–50 and severe, >50, with the following distribution of severity: absence in 0.4 %, mild in 18.7 %, moderate in 32.5 % and severe in 48.4 % of the patients. There were significant differences between groups. The treatment under daily clinical conditions showed a significant improvement of the patients which was maintained at the end of follow-up. There was a 17 % reduction in the severe category. The patients with more passive coping factor showed highest punctuations in the remaining scores and were more prevalent in the severe category. The patients with a predominance of the emotional factor showed a better response at the end of follow-up. The established cutoff points allow the classification of FM patients by severity, to know the prognostic and to predict the response to the treatment.