The phenome-wide relationship studies (PheWAS) in rheumatoid arthritis (RA) patients identifies a strong link between seronegativity and fibromyalgia, according to a recent study. Researchers performed electronic health record (EHR)-based PheWAS to identify disease links in seropositive and seronegative RA. They found:

• There were 2,199 individuals identified with RA and either rheumatoid factor (RF) or anti-cyclic citrullinated peptide antibody (ACPA).

• Of these, 1,382 (63%) were seropositive.

• Seronegative RA was linked with myalgia and myositis, and back pain.

• A manual record review showed 80% of myalgia and myositis codes were used for fibromyalgia, and follow-up with a specific EHR algorithm for fibromyalgia confirmed that seronegative RA was linked with fibromyalgia.

• Seropositive RA was linked with chronic airway obstruction and tobacco use.

Citation: Doss J, Mo H, Carroll RJ, Crofford RJ, Crofford LJ, Denny JC. Phenome-wide association study of rheumatoid arthritis subgroups identified association between seronegative disease and fibromyalgia. [Published online ahead of print September 2, 2016]. Arthritis Rheumatol. doi:10.1002/art.39851.