Background Structural damage and disease activity in RA patients may increase the risk of fall-related injuries (FRIs) due to limited mobility, impaired balance and postural instability.
Objectives To compare risks for FRIs between RA patients treated with anti-TNF therapies versus those treated with methotrexate (MTX) monotherapy in a real-world setting.
Methods Adults with ≥1 RA diagnosis (ICD-9 CM: 714.0) were identified in a large-scale U.S. claims database (OptumInsight, 1998-2011). Patients were stratified into treatment groups (anti-TNF and MTX group) based on their treatment history, irrespective of exposure to that treatment afterwards, similar to an intent-to-treat (ITT) approach. The anti-TNF group comprised new initiators with ≥1 claim for anti-TNFs, with or without MTX (index date defined as the date of the first anti-TNF claim). The MTX group comprised MTX users who were not eligible for the anti-TNF group and who filled ≥1 prescription for MTX (index date randomly selected). During the 6-month baseline period preceding the index date, patients in both groups were required to have continuous health plan enrollment and to be free of anti-TNF exposure. The primary study outcome was first hospitalization with FRI (ICD-9 CM: 800-829 and 850) after the index date. A secondary outcome was first use of any health care service (i.e. inpatient, out-patient, and emergency room) related to FRIs after the index date. Incidences for primary and secondary outcomes were described using Kaplan-Meier (KM) curves, and were compared between the treatment groups using multivariable Cox proportional hazard models adjusting for age, gender, Charlson comorbidity index, healthcare plan type, total RA-related costs and rates of FRIs during the baseline period.
Results A total of 11,894 patients were included in the anti-TNF group and 13,361 in the MTX group. Follow-up beyond 5 years was available for 2,011 and 1,104 patients, and median follow-up were 702 (1st quartile/Q1: 301, 3rd quartile/Q3: 1396) and 363 (Q1: 133, Q3: 882) days, respectively. The 5-year KM rates of hospitalizations with FRIs were 5.6% and 4.1% in the anti-TNF cohort and the MTX cohort, respectively. Based on the time-to-event analyses adjusting for baseline characteristics (including baseline FRIs), patients in the anti-TNF group were 21.3% less likely to incur a hospitalization with FRIs compared to patients in the MTX cohort (adjusted hazard ratio/HR: 0.79, 95% CI: 0.66–0.94, unadjusted HR: 0.69, 95% CI: 0.58–0.82). Moreover, patients in the anti-TNF cohort were 10.5% less likely to be diagnosed with FRIs at any place of service (adjusted HR: 0.90, 95% CI: 0.83–0.97, unadjusted HR: 0.84, 95% CI: 0.78–0.91) compared to patients in the MTX cohort.
Conclusions In this retrospective study of long-term, real-world outcomes, RA patients initiating anti-TNFs experienced a significantly lower risk of FRIs compared to patients receiving MTX.
Disclosure of Interest Y. Bao Shareholder of: AbbVie, Employee of: AbbVie, A. Ganguli Shareholder of: AbbVie, Employee of: AbbVie, G. De Employee of: Analysis Group, which has received consulting fee from AbbVie to partner on this research, S. Kelkar Employee of: Analysis Group, which has received consulting fee from AbbVie to partner on this research, J. Curtis Consultant for: AbbVie