Associations of Circulating Cytokines and Chemokines With Cancer Mortality in Men With Rheumatoid Arthritis.

OBJECTIVE: To examine the potential of circulating cytokines and chemokines as biomarkers of cancer mortality risk in patients with rheumatoid arthritis (RA). METHODS: Male participants in the Veterans Affairs RA registry were followed up from the time of enrollment until death or December 2013. Cytokines and chemokines were measured in banked serum obtained at the time of enrollment, using a bead-based multiplex assay, and a previously developed cytokine score was calculated. Vital status and cause of death were determined through the National Death Index. Associations of cytokines with cancer mortality were examined using multivariable competing-risks regression. RESULTS: Among 1,190 men with RA, 60 cancer deaths (30 of which were attributable to lung cancer) occurred over 5,307 patient-years of follow-up. The patients had a mean age of 64.5 years, had established disease (median duration 8.7 years), were seropositive for rheumatoid factor (81%) or anti-cyclic citrullinated peptide antibody (77%), and frequently had a history of smoking (82% current or former). Seven of 17 analytes examined were individually associated with cancer mortality. The cytokine score was associated with overall cancer (subhazard ratio [SHR] 1.42, 95% confidence interval [95% CI] 1.08-1.85) and lung cancer (SHR 1.86, 95% CI 1.57-2.19) mortality in multivariable analyses. Those in the highest quartile of cytokine scores had a >2-fold increased risk of overall cancer mortality (P = 0.039) and a 6-fold increased risk of lung cancer mortality (P = 0.028) relative to the lowest quartile. A synergistic interaction between current smoking and high cytokine score was observed. CONCLUSION: Serum cytokines and chemokines are associated with cancer and lung cancer mortality in men with RA, independent of multiple factors including age, smoking status, and prevalent cancer.

Cause-Specific Mortality in Male US Veterans With Rheumatoid Arthritis.

OBJECTIVE: There has been limited investigation into cause-specific mortality and the associated risk factors in men with rheumatoid arthritis (RA). We investigated all-cause and cause-specific mortality in men with RA, examining determinants of survival. METHODS: Men from a longitudinal RA registry were followed from enrollment until death or through 2013. Vital status and cause of death were determined using the National Death Index. Crude mortality rates and standardized mortality ratios (SMRs) were calculated for all-cause, cardiovascular disease (CVD), cancer, and respiratory mortality. Associations with all-cause and cause-specific mortality were examined using multivariable Cox proportional hazards and competing-risks regression. RESULTS: There were 1,652 men with RA and 332 deaths. The leading causes of death were CVD (31.6%; SMR 1.77 [95% confidence interval (95% CI) 1.46-2.14]), cancer (22.9%; SMR 1.50 [95% CI 1.20-1.89]), and respiratory disease (15.1%; SMR 2.90 [95% CI 2.20-3.83]). Factors associated with all-cause mortality included older age, white race, smoking, low body weight, comorbidity, disease activity, and prednisone use. Rheumatoid factor concentration and nodules were associated with CVD mortality. There were no associations of methotrexate or biologic agent use with all-cause or cause-specific mortality. CONCLUSION: Men in this RA cohort experienced increased all-cause and cause-specific mortality, with a 3-fold risk of respiratory-related deaths compared to age-matched men in the general population. Further studies are needed in order to examine whether interventions targeting potentially modifiable correlates of mortality might lead to improved long-term survival in men with RA.