New Diagnostic Criteria for Fibromyalgia: Here to Stay?

Abstract

Objectives

To assess the percentage of patients who fulfill the American College of Rheumatology (ACR) 1990 as well as the ACR 2010 classification criteria, to evaluate whether there is a correlation between tender points and the Widespread Pain Index (WPI) as well as signs and symptoms that predict a fibromyalgia (FM) subtype and to identify those which have greater impact on functioning.

Materials and methods

We performed a cross-sectional comparative study of 206 patients with previous clinical diagnosis of FM. The studied variables were age, sex, years of disease, tender points, control points, WPI, Symptom Severity Score, subtype of FM, presence of other rheumatic disorders and the Fibromyalgia Impact Questionnaire (FIQ) score.

Results

The new diagnostic criteria of FM correctly classified 87.03% of patients who satisfied the ACR 1990 criteria. Both criteria were equally effective in assessing the impact of the disease. FM had a severe impact on the quality of life in 74.87% of patients. Somatoform disorder was the predominant subtype. Hyperalgesic FM had a significantly lower FIQ score than the somatoform disorder and depressive subtypes.

Conclusion

The ACR 2010 criteria are a simple evaluation tool to use in the primary care setting, that incorporate both peripheral pain and somatic symptoms. New and old criteria should coexist; they enable a major comprehension and ease the management of this prevalent disease.

Resumen

Objetivos

Evaluar el grado de concordancia entre los criterios antiguos de fibromialgia (FM) y los criterios del American College of Rheumatology (ACR) 2010, valorar si hay correlación entre puntos y áreas dolorosas, así como los signos y los síntomas que permitan predecir un tipo específico de FM (depresivo, hiperalgésico o somatizador) e identificar aquellos que presenten mayor correlación con la afectación vital de la enfermedad.

Materiales y métodos

Se realizó un estudio transversal comparativo en el que se incluyó a 206 pacientes con diagnóstico clínico previo de FM. Las variables evaluadas fueron: edad, sexo, años de evolución de la enfermedad, puntos dolorosos, puntos control, áreas dolorosas, presencia de fatiga, alteraciones del sueño y trastornos cognitivos, síntomas somáticos, tipo de FM, presencia de otras enfermedades reumatológicas y la puntuación promedio del cuestionario de impacto de la fibromialgia (FIQ).

Resultados

Los nuevos criterios diagnósticos clasificaron correctamente el 87,03% de los casos que cumplían con la antigua definición. Ningún criterio fue superior al otro para valorar el impacto de la enfermedad. El 74,87% de los pacientes presentó una afectación vital severa. Se evidenció un predominio del tipo de FM somatizador. El tipo hiperalgésico presentó un promedio de FIQ más bajo que los tipos depresivo y somatizador.

Conclusión

Los criterios del ACR 2010 constituyen una manera simple de evaluar pacientes con FM y tienen en cuenta las manifestaciones subjetivas de la enfermedad. Los nuevos criterios deberían convivir con los criterios antiguos; aportan una mayor comprensión y facilitan el manejo de esta patología tan prevalente.

Introduction

Fibromyalgia (FM) is a syndrome characterized by diffuse, chronic musculoskeletal pain, non-articular in origin, which is evidenced by palpation of tender points in specific anatomic areas and is usually accompanied by unrefreshing sleep, fatigue, morning stiffness and cognitive impairment. Fibromyalgia affects about 0.5%–5% of the population and is characterized by ambiguity in the diagnosis, uncertainty in the understanding of its pathophysiology and the difficulties of physicians to address it globally.¹

In 1990, the American College of Rheumatology (ACR) published classification criteria, based on an examination of tender points, requiring specialized evaluation.² The presence of chronic widespread (more than 3 months), generalized pain (in at least 3 of the 4 body quadrants), with 11 or more of 18 specific tender points was evaluated.

The impression that the FM was exclusively a musculo-skeletal disease was erroneously created. With the passage of time, there appeared a number of objections (practical and philosophical) to the 1990 ACR classification criteria. It first became increasingly evident that the tender point count was a barrier and was rarely performed in primary care, where most cases of FM were diagnosed, and when they did, these were often evaluated incorrectly. Many physicians were unaware of how to perform the examination of tender points, or simply omitted the procedure. Thus, in practice, the diagnosis of FM has been based primarily on the symptoms reported by patients.

Second, although the symptoms of fibromyalgia (fatigue, unrefreshing sleep, cognitive, etc.) were not considered by the ACR 1990, they have lately been recognized as having hierarchical importance. FM, then, is no longer considered a peripheral musculoskeletal disease and there has been a growing recognition of central sensitization of pain as the underlying neurobiological basis, which explains most of the systemic symptoms.

The new FM diagnostic criteria proposed in 2010 consist of a widespread pain index (Widespread Pain Index [WPI]) and a Symptom Severity Score [SS-Score]. According to the literature, this new method correctly classified 88.1% of cases diagnosed by the 1990 ACR criteria and, since it is essentially based on the information provided by patients, requires no physical examination nor requires specialized observer training, and is well suited to the field of Primary Health Care.³

On the other hand, the heterogeneity of the disease implies that not all patients with FM present and evolve in the same way; For these reasons, Giesecke et al. have issued a recommendation to classify FM into 3 groups, those associated with depression, those where there is an important functional or somatoform disorder or do not have psychopathology. This classification enables the homogenization of groups of patients with similar characteristics and potential common therapeutic approaches.4, 5

The primary objective of this study was to evaluate the degree of agreement between the old criteria for FM and the 2010 ACR criteria.

Secondary objectives were to assess whether there is a correlation between points and painful areas, and signs and symptoms that predict a specific type of FM (depressive, hyperalgesic or somatizing) and, secondly, to identify the signs and symptoms that exhibit a greater correlation with vital disease involvement, the impact of the disease for different types according to each criterion.