Impact of age on the appearance of adverse eventsat the beginning of biological treatment: data from the BIOBADASER 3.0 registry

Abstract

Background: Currents medical advances are allowing patients with chronic arthritis to live to advanced ages. Although the risks of biological therapies in elderly patients have been previously evaluated, data are scarce since they are mainly derived from clinical trials, in which elderly populations are often underrepresented or event excluded (patients up to 75 years old). In addition, comparisons between such studies are difficult in the absence of a consensus in defining the groups’ age.

Objectives: To evaluate the impact of age on the appearance of adverse events (AE) in patients with rheumatic diseases (rheumatoid arthritis -RA-, ankylosing spondylitis -AS- and psoriatic arthritis -PsA) at the start of biological treatment.

Methods: Multicenter prospective study in a real-world setting. Information was obtained from BIOBADASER, a national safety registry of patients with rheumatic diseases treated with biologics or targeted synthetic disease modifying anti-rheumatic drugs. For this analysis, all patients included in this registry since 2000 and diagnosed with RA, AS or PsA were included, and classified into four categories according to age at initiation of biologic treatment: young (< 25 years-old), adults (25-64 years-old), elderly (65-75 years-old) and very elderly (> 75 years-old). Data collected included: 1) patient’s data 2) data on treatment and 3) data on AE. Proportions, means and standard deviations were used to describe the population. Poisson regression model was carried out to explore factors associated with the appearance of AEs. Crude and adjusted incidence rate ratios (IRRs) were calculated.

Results: A total of 2531 patients were included: 1154 RA (45.59%), 680 PsA (26.87%), and 697 AS (27.54%). Age groups: there were 64 young patients (2.52%), 2166 adults (85.57%), 243 elderly adults (9.6%), and 58 very elderly adults (2.29%). Comorbidities increased with age, while smoking rates decreased. Methotrexate use was similar in all age groups (53.99% in the total sample), but corticosteroid treatment increased with age (young 27.7%, adults 47%, elderly adults 64.36% and the very elderly 70.21%). 77.87% received anti-TNF treatment, and 22.13% other biological drugs. Poisson regression model showed an increased probability of suffering a first adverse event with increasing age regardless of the disease (IRR for AS: 1.04 (0.87-1.26); IRR for PsA: 1.08 (0.92-1.28)). Other factors associated with higher IRR were sex (being woman), type of biological treatment (TNF inhibitors), concomitant therapy (methotrexate), smoking, comorbidities (Charlson Index) and time of evolution of rheumatic disease. No differences were found between pathologies.

Conclusion: A mix of clinical and patient factors seem to explain the appearance of a first AE after biological therapy initiation, with age being one of those explanatory variables.