Trends in the Incidence of SOLID Tumors in Patients with Rheumatoid Arthritis in Spain. a National Observational Cohort Study

Background During the last 20 years, the rheumatoid arthritis (RA) treatment has changed. Considering the increasing use of biological immunomodulators to treat this desease and the concern that immunomodulation may alter cancer risk, it’s important to know the tumors incidence in RA. Objectives To analyze the incidence and trend of hospital admissions for solid tumors in patients with RA in Spain during the period between 1999 and 2015. Methods This is a retrospective population based study. We analized a national administrative database that includes a Minimum Basic Data Set (MBDS) of all hospital admissions of RA patients. Period: 1999 to 2015. We selected the MBDS for solid tumors. Cases were identified by the presence in primary and secondary diagnosis of ICD 9 codes. The population at risk was estimated through the population census of the National Institute of Statistics, with an estimated prevalence of RA of 0,5% (women: 0,8%, men:0,2%). Crude and adjusted rates of the solid tumors were calculated. The trend was analyzed by Generalized Linear Model (GLM). Results 338.343 RA hospital admissions were detected in the study period, being 18.401 (5,4%) due to solid tumors. The main clinical-demographic characteristics are shown in the next table. The solid tumor adjusted rate during the study period was 647,53/105 inhabitants/yr (366,97/105 in women and 1792,99/105 in men; relative risk men:women =4,8). This rate increased from 305,65/105 in 1999 to 993,19/105 inhabitants/yr in 2015 (from 814,06/105 in 1999 to 2535,5/105 in 2015 in men; from 181,68/105 in 1999 to 607,71/105 in 2015 in women). The annual age-adjusted rate increased significantly: 7,37% (6,52% in men and 8,02% in women; p≤0,001). figure1 Conclusions There was an increasing incidence of hospital admissions due to solid tumors in RA in Spain during the period 1999-2015. An annual rate increase of 7.37%, is estimated. Disclosure of Interest: None declared