FRI0113 COMPARISON OF INFECTION-RELATED HOSPITALIZATION COSTS IN PATIENTS WITH RHEUMATOID ARTHRITIS (RA) TREATED WITH ABATACEPT OR OTHER TARGETED DISEASE-MODIFYING ANTI-RHEUMATIC DRUGS (TDMARDS)
Authors: Damemarie Paul, Francis Lobo, Vardhaman Patel, Dhaval Patil
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background:</h3> Costs due to differences in risk of hospitalized infection associated with targeted disease-modifying anti-rheumatic drugs (tDMARDs) in patients with RA have not been evaluated. <h3>Objectives:</h3> Compare the risk and cost of infection-related hospitalizations in tumor necrosis factor inhibitor (TNFi)-experienced RA patients subsequently receiving tDMARDs in the US. <h3>Methods:</h3> A retrospective, observational study was conducted with 2 insurance claims databases (MarketScan and PharMetrics; January 1, 2009- June 30, 2017). Analyses were conducted in both datasets individually and in aggregate. The study population was adult TNFi-experienced RA patients initiating a subsequent tDMARD (date of tDMARD therapy=index date). Patients had 12 months of continuous enrollment prior to the index date (baseline period), and were required to have ≥1 inpatient claim or ≥2 outpatient medical claims on 2 different dates with a diagnosis code for RA. Patients with other autoimmune conditions were excluded. Follow-up began with the index date and included ≥12 months ending with the earliest of (1) end of insurance enrollment; (2) end of study period; (3) end of index treatment. Cohorts included (1) abatacept; (2) TNFi: adalimumab, certolizumab pegol, etanercept, golimumab, and infliximab; and (3) other non-TNFi: tocilizumab, rituximab, and tofacitinib. Hospitalized infection costs were measured on a per-patient-per-month (PPPM) basis (2016 USD). Two-part multivariable generalized linear models (GLMs) examined differences in costs. Baseline comorbidities, infection incidence, healthcare costs, payer type, age, gender, and geographic region were used as regression covariates. Log transformation and gamma distribution were applied in GLMs. <h3>Results:</h3> Overall, most patients were female (79%) with an average age of 52 years. Although a higher percentage (4.5%) of patients in the abatacept cohort had a hospital visit for infection in the baseline period compared to TNFi (2.0%, P&lt;0.0001) and other non-TNFi (3.6%, P=0.2619), the trend reversed in the follow-up period (2.8% for abatacept vs 3.7% for TNFi and 5.2% for other non-TNFi; P&lt;0.05). Regression results indicated a significantly higher risk for hospitalized infection for patients receiving a TNFi [HR: 1.6 (95% CI: 1.1, 2.2)] or other non-TNFi [HR: 1.9 (95%: 1.3, 2.8)] vs abatacept. Mean PPPM (95% CI) inpatient costs in the follow-up were $73 ($17-$158) for abatacept, $115 ($27-$224) for TNFi, and $125 ($29-$264) for other non-TNFi. Difference from baseline to follow-up PPPM inpatient costs was significantly lower for abatacept (difference of $42 for TNFi and $52 for other non-TNFi, P&lt;0.05). <h3>Conclusion:</h3> There were significantly lower infection-related hospitalizations and associated costs for TNFi-experienced RA patients who were switched to abatacept compared to patients switched to other therapies. <h3> Disclosure of Interests:</h3> Damemarie Paul Shareholder of: Bristol-Myers Squibb, Employee of: Damemarie Paul is an employee of Bristol-Myers Squibb., Francis Lobo Shareholder of: Bristol-Myers Squibb, Employee of: Bristol-Myers Squibb, Vardhaman PATEL Employee of: Bristol-Myers Squibb, Dhaval Patil Shareholder of: Bristol-Myers Squibb, Employee of: Bristol-Myers Squibb