Frederick Wolfe, et al. - Since no studies have examined which definitions of fibromyalgia (FM) and widespread pain (WSP) associated with mortality, nor of FM mortality in other diseases, experts evaluated these issues and the meaning of mortality in patients with FM. A Cox regression was applied to examine 35,248 rheumatic disease individuals with up to 16 years of mortality follow-up in all individuals and separately in those with diagnoses of rheumatoid arthritis (RA) (N=26,458), non-inflammatory rheumatic disorders (NIRMD) (N=5,167) and clinically diagnosed FM (N=3,659). In this study, the 2016 FM criteria and other FM and WSP criteria were used to models adjusted for age and gender as well as to models that included a full range of covariates, including comorbid disease and functional status. They further calculated the degree of explained variance (R2) as a measure of predictive ability. The results showed that FM is weakly correlated with mortality within all criteria definitions of FM and WSP examined (3.4% of explained variance), and across all diseases (RA, NIRMD, clinical FM) equally. Furthermore, it was reported that clinical and criteria-defined FM had different mortality results. There was no evidence for a positive association of cancer and FM or WSP.