In fibromyalgia, a high predominance of small fiber pathology (SFP) was noted by the researchers. Also, the evidence of distinct phenotype involving SFP in fibromyalgia was provided by the study. Moreover, this is probably the first study to collate data on the overall prevalence of SFP in fibromyalgia.

Fibromyalgia involves extensive chronic pain along with features of neuropathic pain. It considerably affects quality of life people suffering from it. There is a lack of clarity on the pathophysiology of fibromyalgia, but current data suggest the participation of the peripheral nervous system with an increased incidence of SFP. The researchers conducted this systematic literature review was to confirm the incidence of SFP in fibromyalgia.

PubMed, CINAHL, MEDLINE, Web of Science, EMBASE and the Cochrane Library databases were used to search the electronic literature. For evaluation, English language articles published as full-text that give the prevalence of SFP in fibromyalgia studies in patients over 18 years were taken into account. Critical appraisal tool devised by Munn et al. was used to examine the risk of bias and methodological quality. Random-effects meta-analysis was used to evaluate the overall and subgroup pooled prevalence with 95% CI.

The database searches found a total of 935 studies. Screening of 45 articles was done and the inclusion criterion was met by 8 full-text articles, keeping in view the data from 222 individuals. As per meta-analysis, the pooled prevalence of SFP in fibromyalgia was observed to be 49% (95% CI: 38–60%) with an average degree of heterogeneity, (I2= 68%). The prevalence estimate for corneal confocal microscopy, was 59% (95% CI: 40–78%, I2= 51% and skin biopsy was 45% (95% CI: 32–59%, I2= 70%).

SFP is highly common in fibromyalgia. Strong evidence about the presence of distinct phenotype comprising SFP in fibromyalgia, finds the authors of the study. Recognising SFP may prove beneficial in estimating the relationship of SFP with pain. It may also aid in the development of future treatment therapies.