Background: With an aging population we are now faced with an increasing number of older people with immune-mediated inflammatory rheumatic diseases (IMID) which require immunosuppression despite limited evidence for their safety in this age group. Real world data is lacking due to high withdrawal rates from clinical trials from therapy-related complications as well as age over 65 in itself being an exclusion criteria in many studies. Advanced age is a risk factor for infection, cancer and cardiovascular disease. There is a need to investigate the efficacy and safety profile of biologic therapy in the elderly population to better inform future practice.

Objectives: To establish the rates of infection, malignancy and cardiovascular events in rheumatology patients aged >75 and compare such events in a cohort starting biologic therapy versus Methotrexate monotherapy.

Methods: Retrospective chart and electronic record review, using the database DAWN, of all patients attending the Rheumatology Department in Beaumont Hospital. Inclusion criteria was applied to include all patients aged 75 or over who were on a biologic therapy for a confirmed rheumatological condition on a specified date (21 ^st November 2024). People aged 74 or under and all patients with missing data were excluded. A control group including patients aged 75 or over on Methotrexate was recruited. Data collection included age, rheumatological diagnosis, duration of disease, comorbidities, regular medications, nbDMARD and biologic use (both current and previous), length of biologic use, age at which biologic was commenced, hospital presentations, rates of infections were recorded.

Results: A total of 166 patients (83 on biologic therapy, either mono or combination therapy and 83 on Methotrexate monotherapy) were recruited. Average follow up for the biologic group was 5 years with the Methotrexate group followed for 6 years. The average age in the biologic and control group at analysis was 79 years and 81 years respectively. The most common diagnosis in both groups was seropositive rheumatoid arthritis [Biologic 42/83 (51%), MTX 40/83 (48%), followed by seronegative RA [Biologic 16/83 (19%), MTX 26/83 (31%)] and Psoriatic Arthritis (PsA) [Biologic 8/83 (9%), MTX 10/83 (12%)]. The majority of patients in both groups were multi-morbid (Biologic 78/83 (94%), MTX 75/83 (90%)]. The prevalence of comorbidities is shown in Table 1. The majority of patients were on 5 or more medications [Biologic 52/83 (63%) vs MTX 48/83 (58%)]. Over an average follow up of 5.7 years, the total number of hospital admissions/presentations in the entire cohort was 55% (92/166) – 9.7 admissions/100 years of patient follow up. Biologic treated patients were more likely to be hospitalised over the follow up period with a rate of hospitalisation/100 years of patient follow up of 11.9 vs 8 in the Methotrexate arm. The overall number of patients requiring admission for serious infection was low albeit higher in the biologic treated patients - Biologic vs MTX - 5.2 vs 3.2/100 patient years follow up. There was no major difference in type of infections requiring admission between groups (Biologic vs MTX - Pneumonia 8/83 vs 10/83, p=0.61, UTI 7/83 v 5/83 p=0.55 and skin/ joint infections 4/83 vs 2/83 p=0.69). Within the biologic cohort infections occurred significantly more often in anti-TNF vs non-anti- TNF treated patients (18/50 vs 4/33 respectively, p=0.015). Cardiovascular events and incident malignancy occurred at similar rates also – CVS events 3/83 vs 4/83 p=0.7, Malignancy 2/83 vs 2/83 p = 1. 80% of biologic treated patients remained on their first biologic at 5 years indicating acceptable disease response. The commonest reason for biologic withdrawal or change was disease flare rather than complication of treatment (10/83 vs 9/83 respectively, p=0.8).

Conclusion: Our study identified high rates of multimorbidity and polypharmacy in elderly patients commencing immunosuppression. Whilst overall rates of hospitalisation were low, biologic treated patients suffered more serious infections resulting in hospital admission. Anti-TNF therapy may be associated with an increased risk of infection in this patient cohort as observation that warrants investigation in a larger prospective cohort.

REFERENCES: NIL.

Acknowledgements: Rheumatology Department in Beaumont Hospital.

Disclosure of Interests: None declared.

© The Authors 2025. This abstract is an open access article published in Annals of Rheumatic Diseases under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ). Neither EULAR nor the publisher make any representation as to the accuracy of the content. The authors are solely responsible for the content in their abstract including accuracy of the facts, statements, results, conclusion, citing resources etc.