Predictors of Adherence and Costs in First and Second Years after Biologic Initiation in Patients with Rheumatoid Arthritis (RA)

Bradley S. Stolshek¹, Sally W. Wade², Ajita De³, Ron L. Wade³ and Jason Yeaw³, ¹Amgen, Thousand Oaks, CA, ²Wade Outcomes Research and Consulting, Salt Lake City, UT, ³IMS Health, Plymouth Meeting, PA

Meeting: 2016 ACR/ARHP Annual Meeting

Date of first publication: September 28, 2016

Keywords: administrative databases and rheumatoid arthritis, Biologic agents, treatment

Session Information

Date: Tuesday, November 15, 2016

Title: Health Services Research - Poster III

Session Type: ACR Poster Session C

Session Time: 9:00AM-11:00AM

Background/Purpose: Rheumatoid arthritis (RA) is a chronic disease requiring continuous therapy to reach low disease activity targets and to delay its long-term health effects. We investigated predictors of adherence with biologic therapy and healthcare costs among patients with RA in the first and second year after first biologic initiation.

Methods: <span”>Patients with RA initiating a first (index) biologic between January 1, 2009 and December 31, 2012 and with 2 years of continuous enrollment were identified in the IMS PharMetrics Plus commercial claims database.Based on Year 1 data, we classified patients as ‘effectively’ or ‘non-effectively’ treated using a validated algorithm that considers six criteria of adherence, treatment changes, or steroid use. Adherence on index agent was defined by proportion of days covered (PDC) >80%. Logistic regression models assessed predictors of adherence at Years 1 and 2 using demographic, clinical and pre-index cost characteristics that were statistically significant in univariate analysis. Inverse probability of treatment weighted structural models were used to estimate total and RA-related healthcare costs in Year 2, controlling for baseline characteristics and effective/non-effective treatment in Year 1.

Results: <span”>Of the 10,374 eligible patients, 76.1% were female, median age was 51 years, and 77.9% used a non-biologic disease-modifying antirheumatic drug (DMARD) in 12 months pre-index. In Year 1, 29.7% were considered effectively treated.Among all patients, 46.0% and 33.6% were adherent over the entire one and two year periods, respectively. Patients using the infused agents, infliximab and abatacept, had the highest adherence (63.7%, 48.0) in Year 1, with infliximab users more adherent (47.0%) over 2 years. Adherence across the four subcutaneous agents was highest for adalimumab and etanercept. Adherence was more likely in older patients, males, and those with prior DMARD use over both time periods (Table). Additional predictors of adherence in both years were index drug, region and payer type. Higher total healthcare costs during Year 2 were predicted by effective treatment in Year 1, choice of index drug, greater patient age at index, prior use of glucocorticoids, and greater comorbidity burden (p<0.05). Effective treatment in Year 1, patient age at index, geographic region, and index year were significant predictors (p<0.05) of RA-related healthcare costs in Year 2.

Conclusion: <span”>Adherence in both time periods varied by drug, prior DMARD use, and demographic factors with several of these being significant predictors in Year 1 and 2.Year 2 total and RA-related health care costs were predicted by common variables of older age and effective treatment in Year 1. <span”>

Table. Predictors of 1- and 2-Year Adherence (PDC > 80%) With Biologic Therapy

Independent Variable

1 Year Adherence

OR (95% CI)

2 Year Adherence

OR (95% CI)

Index Biologic (reference etanercept, n = 4,426))

Abatacept (n = 487)

1.3 (1.1, 1.6)

1.0 (0.8, 1.2)

Adalimumab (n = 3,926)

1.1 (1.0, 1.2)

1.0 (0.9, 1.1)

Certolizumab (n = 255)

0.9 (0.7, 1.2)

1.0 (0.7, 1.3)

Golimumab (n = 369)

0.7 (0.6, 0.9)

0.8 (0.6, 1.0)

Infliximab (n = 911)

2.4 (2.0, 2.7)

1.9 (1.6, 2.2)

Age Group (reference 18-34 years)

35-44 years

1.1 (0.9, 1.3)

1.1 (1.0, 1.4)

45-54 years

1.3 (1.1, 1.5)

1.6 (1.3, 1.9)

55-64 years

1.6 (1.4, 1.9)

2.0 (1.7, 2.3)

Male (reference female)

1.3 (1.2, 1.5)

1.4 (1.2, 1.5)

Region (versus Northeast)

Midwest

1.0 (0.9, 1.1)

South

0.8 (0.7, 0.8)

0.8 (0.7, 0.9)

West

0.9 (0.7, 1.0)

0.9 (0.7, 1.1)

Payer Type (reference Commercial)

Self-insured

0.9 (0.9, 1.0)

Other/Unknown

0.5 (0.4, 0.8)

0.5 (0.3, 0.8)

Prior DMARD Use (reference no use)

1.5 (1.4, 1.7)

1.5 (1.3, 1.6)

Index Year (reference 2009)¹

2010

1.2 (1.1, 1.3)

—

2011

1.1 (1.0, 1.3)

—

2012

1.1 (1.0, 1.2)

—

Log (Pre-index Total Healthcare Costs)

0.9 (0.9, 1.0)

0.9 (0.9, 0.9)

¹Index year did not meet selection criteria for inclusion in 2-year model. OR=odds ratio

Disclosure: B. S. Stolshek, Amgen, 1,Amgen, 3; S. W. Wade, Amgen, 5; A. De, Amgen, Inc., 5; R. L. Wade, Amgen, Inc., 5; J. Yeaw, Amgen, Inc., 5.

To cite this abstract in AMA style:

Stolshek BS, Wade SW, De A, Wade RL, Yeaw J. Predictors of Adherence and Costs in First and Second Years after Biologic Initiation in Patients with Rheumatoid Arthritis (RA) [abstract]. Arthritis Rheumatol. 2016; 68 (suppl 10). https://acrabstracts.org/abstract/predictors-of-adherence-and-costs-in-first-and-second-years-after-biologic-initiation-in-patients-with-rheumatoid-arthritis-ra/. Accessed .

« Back to 2016 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/predictors-of-adherence-and-costs-in-first-and-second-years-after-biologic-initiation-in-patients-with-rheumatoid-arthritis-ra/