Fibromyalgia revisited: do latent class analyses of symptom profiles in the general population confirm 2016 fibromyalgia diagnostic criteria?

Objectives: The definition of the 2016 diagnostic criteria of fibromyalgia (FM) syndrome and of FM severities was based on studies with clinical samples. We tested if somatic symptom profiles consistent with the symptom pattern of the FM 2016 diagnostic criteria and of severities of FM can be found in the general population.

Methods: Somatic symptom burden was measured by the Somatic Symptom Scale - 8 in 2,531 persons aged ≥14 years representative for the general German population. We used latent class analysis of SSS-8 items to identify somatic symptom profiles. The profiles were described by their association with age, gender, self-reported disabling somatic disease, psychological symptom burden, illness worries and self-perceived health.

Results: We identified five somatic symptom profiles. The majority of the population (40.9%) had a profile characterised by the absence of bothering symptoms. 5.9% had a profile defined by "considerable bothering" back and extremities pains, fatigue and sleep problems. This symptom profile was associated with older age, self-reported somatic diseases, psychological symptom burden and fair to poor general health. 63.2% of persons meeting FM 2016 criteria belonged to this profile. 17.8% of the sample were characterized by little perturbation by multiple somatic symptoms and good to fair general health. 36.8% of persons meeting FM 2016 criteria belonged to this profile.

Conclusions: Two somatic symptom profiles consistent with the 2016 FM diagnostic criteria were identified in the general German population. These symptom profiles differed in somatic and psychological symptom burden and general health supporting the distinction of FM severities.