Although preliminary studies suggest that non-Hodgkin's lymphoma (NHL) complicating rheumatoid arthritis (RA) may be a clinically distinct entity compared with that occurring in the general population, studies examining the impact of antecedent RA on survival are limited. In this prospective study, we examined the association of RA with survival in patients with NHL.
Using two large lymphoma registries, we identified patients with evidence of RA preceding NHL. Survival in RA patients was compared with that of controls using proportional hazards regression, adjusting for the effects of age, sex, lymphoma diagnosis-to-treatment lag time, calendar year, International Prognostic Index score, and NHL grade.
The frequency of NHL subtypes was similar in RA patients (n = 65) and controls (n = 1,530). Compared with controls, RA patients with NHL had similar overall survival (hazard ratio [HR] = 0.95; 95% CI, 0.70 to 1.30) but were at lower risk of lymphoma progression or relapse (HR = 0.41; 95% CI, 0.25 to 0.68) or death related to lymphoma or its treatment (HR = 0.60; 95% CI, 0.37 to 0.98), but were more than twice as likely to die from causes unrelated to lymphoma (HR = 2.16; 95% CI, 1.33 to 3.50).
RA is associated with improved NHL-related outcomes, including a 40% reduced risk of death occurring as a result of lymphoma or its treatment and approximately a 60% lower risk of lymphoma relapse or progression compared with non-RA controls. However, the survival advantage gained in RA from the acquisition of lymphomas with favorable prognoses is negated through an increased mortality from other comorbid conditions.