Elderly patients (aged ≥60 years) with rheumatoid arthritis (RA) may be less likely to receive treatment with tumor necrosis factor (TNF) inhibitors than younger patients with RA because of concerns about comorbidities and adverse events. However, a new study by Soo-Kyung Cho, MD, PhD, Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases, Seoul, South Korea, and colleagues shows that elderly patients who are prescribed these drugs have retention rates comparable to those of younger patients (Cho SK, et al. BMC Musculoskelet Disord. 2016;17:333).
A second finding of this study was that causes for discontinuation of anti-TNF drugs differed by age-group. Specifically, older patients were more likely to discontinue TNF inhibitors because of adverse events, whereas younger patients discontinued these drugs more frequently because of ineffectiveness.
Predictors of TNF inhibitor discontinuation also differed among age-groups. In elderly patients, predictors were glucocorticoid use and older age, whereas in younger patients, predictors included first use of a TNF inhibitor and short disease duration.
The retrospective study was based on data from 429 Korean patients with RA (totaling 838 patient-years) treated with TNF inhibitors who were enrolled in a biologic disease-modifying antirheumatic drug (DMARD) registry. Patients aged <60 years were categorized as younger (n = 322), and those aged ≥60 years were deemed elderly (n = 107). Elderly patients were more likely to be receiving lower doses of methotrexate and higher doses of glucocorticoids than younger patients, but these differences were not significant.
In the elderly cohort, the mean number of previous nonbiologic DMARDs used was significantly higher than in the younger group (4.4 vs 3.9; P = .01). The mean observational period was approximately 24 months for both groups. Observation began with the first dose of a TNF inhibitor, and stopped when the patient discontinued treatment, switched to another DMARD, was lost to follow-up, or died.
Elderly patients had a higher number of comorbid conditions than their younger counterparts, including cardiovascular disease (7.5% vs 1.2%, respectively); pulmonary disease, including interstitial lung disease, asthma, and chronic obstructive pulmonary disease (15.9% vs 1.9%, respectively); diabetes mellitus (18.7% vs 6.5%, respectively); and hypertension (46.7% vs 14.0%, respectively). The mean Disease Activity Scores at baseline did not differ between elderly and younger patients.
The TNF inhibitor retention rate did not differ significantly between age-groups over 3 years (59.0% for the elderly group vs 50.8% for the younger group). The median treatment period was 2.0 years for the elderly patients compared with 1.9 years for the younger cohort.
During the observation period, rates of TNF inhibitor discontinuation for any reason were 32.7% for the elderly group and 41.0% for the younger group. Reasons for discontinuation differed by age-group: development of adverse events was the most common reason for discontinuation in the elderly cohort (34.3%), whereas ineffectiveness was the most common reason for discontinuation among younger patients (41.7%). However, these differences were not significant.
During the observation period, 13 serious adverse events were reported in elderly patients, and 32 were reported in the younger group. Common serious adverse events in the elderly cohort included infection (n = 5), injury (n = 2), and malignancy (n = 2), whereas common serious adverse events in younger patients included infection (n = 15) and malignancy (n = 6). The overall incidence rate of serious adverse events was slightly higher in elderly patients compared with their younger counterparts (6.13 per 100 patient-years vs 5.11 per 100 patient-years, respectively). Higher rates of injury and respiratory disorder were also seen in elderly patients compared with younger patients.
Regarding retention rates observed in this retrospective study, the presence of comorbidities showed a protective effect against TNF inhibitor discontinuation in elderly patients. Ms Cho and colleagues speculated that patients with RA and comorbidities who receive TNF inhibitors may be able to keep receiving treatment with biologics more easily because of the reduced need for medications such as glucocorticoids and immunosuppressive agents.
“Although this encouraging result is from a small number of elderly patients and a relatively short observation period, we could insist that certain selection criteria for TNF inhibitors in elderly RA patients are reasonable in real-world clinical practice,” the investigators stated.
“Further effort should [be] invested in identifying a strategy for appropriate selection of biological DMARDs for elderly RA patients,” they added.
Limitations of the study include the small number of elderly patients, omission of elderly patients with recent- onset RA, and the inability to evaluate retention rates for each TNF inhibitor because of the small number of patients taking each drug. Ms Cho and colleagues suggested that further study should focus on finding optimal ways to tailor the selection of existing biologics to elderly patients with RA, because there are now many TNF inhibitors available, including biologics and biosimilars.