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Background: Recently, it has been recognized that frailty and pre-frailty are common in patients with rheumatoid arthritis (RA) [1]. Whether frailty status portends an increased risk of adverse outcomes in patients with RA on biologic or targeted synthetic disease modifying anti-rheumatic drugs (b- or tsDMARDs) remains unknown.
Objectives: To evaluate the association between frailty and adverse outcomes in patients with RA exposed to b- or tsDMARDs.
Methods: Using the IBM/Watson MarketScan Commercial Claims and Encounters Databases, we identified all patients with RA who filled new prescriptions (or received infusions) for TNFα antagonists (TNFi), non-TNFi biologics (rituximab, abatacept, tocilizumab) or Janus Kinase inhibitors (JAKi) between 2008-2019. We used a 1-year lookback period without the use of these drugs to identify new users. The date of the first prescription within these three drug categories was the index date. Patients’ frailty risk score was calculated using the Claims-Based Frailty Index (CFI) [2], which estimates a deficit-accumulation frailty index using International Classification of Diseases codes, Current Procedural Terminology codes, and Healthcare Common Procedure Coding System codes in administrative claims data in the 1-year baseline period. The index ranges from 0 (not at all frail) to 1 (severely frail). The primary outcome was time to serious infections (those requiring hospitalization); secondary outcomes: any infection (outpatient or inpatient encounters) and all-cause hospitalizations.
Patients were followed until 1) outcome occurrence; 2) disenrollment; 3) >90 days elapsed (or >180 days for rituximab) without further fills of the first drug categories; 4) they filled/received infusions of b-/tsDMARDs from a different drug category; or 5) 2 years after index. Cox proportional hazards adjusting for demographics, calendar year, serious and/or opportunistic infections in the 12-months prior to index were used to estimate the adjusted hazard ratios (aHR) and 95% confidence intervals (CIs) for each outcome. In separate model, we additionally adjusted for comorbidity burden, and health care utilization (HCU).
Results: A total of 62,246 patients with RA met our inclusion criteria of whom 50,910 (82%) started TNFi as their first biologic, 9525 (15%) non-TNFi biologics, and 1811 (3%) JAKi. Among these, 3928 (6%) were considered frail. In multivariable analyses, frail patients had higher risk of serious infections compared to non-frail patients (aHR 2.37, 95% CI 2.05-2.74) which decreased to aHR 1.34, 95% CI 1.13-1.58 (
Multivariable models evaluating the association between frailty status and inpatient infections as the outcome
| Variable | #Hazard Ratio (95% Confidence Interval) | @Hazard Ratio (95% Confidence Interval) |
|---|---|---|
| Frail | 2.37 (2.05, 2.74 ) | 1.34 (1.13, 1.58 ) |
#Model adjusts for age, sex, major infection requiring inpatient admission in 12 months prior, concomitant baseline drugs such as csDMARDs, glucocorticoids, NSAIDs and opioids
@Model additionally adjusts for Chalrson comorbidy score and healthcare utilization
Conclusion: Frailty is an important predictor for the risk of adverse outcomes among patients with RA treated with b- or tsDMARDs. Our findings underscore the need for considering this parameter in patient evaluations (even among younger patients) in the clinic.
REFERENCES:
[1]Salaffi F et al: Prevalence of frailty and its associated factors in patients with rheumatoid arthritis: a cross-sectional analysis . Clin Rheumatol 2019
[2]Kim DH et al. Validation of a Claims-Based Frailty Index Against Physical Performance and Adverse Health Outcomes in the Health and Retirement Study . J Gerontol A Biol Sci Med Sci 2019
Acknowledgements: I have no acknowledgements to declare.
Disclosure of Interests: None declared