Arthritis & Rheumatism, Volume 60,
October 2009 Abstract Supplement

The 2009 ACR/ARHP Annual Scientific Meeting
Philadelphia October 16-21, 2009.


Utilization of VA Pharmacy Benefits Management Data and the VA Rheumatoid Arthritis Database to Demonstrate Reduced Disease Activity in Rheumatoid Arthritis Patients Adherent with Methotrexate

Cannon1,  G. W., Sauer1,  BC, Hayden1,  CL, Reimold2,  A.M., Hooker3,  R.S., Kerr4,  G.S., Richards4,  J.S.

VA and University of Utah. Salt Lake City, UT
VA and UTSouthwestern Medical Center. Dallas, TX
VA, Dallas, TX
VA and Georgetown University. Washington, DC
VA and University of Colorado. Aurora, CO
VA and University of Mississippi. Jackson, MS
U Nebraska, Omaha, NE

Purpose:

The linkage of pharmacy databases with objective clinical outcome measures provides an opportunity to evaluate rheumatoid arthritis (RA) therapies in real world clinical settings. This work merges information from the Veterans Affairs Rheumatoid Arthritis (VARA) registry initiated in 2003 and the VA Pharmacy Benefits Management (PBM) database with data from 1998 to determine if adherence with prescribed methotrexate (MTX) for the treatment of RA is associated with a reduction in RA disease activity.

Methods:

VARA routinely collects 28 joint disease activity score (DAS28) on RA patients as part of this prospective multicenter observation cohort study. PBM data on these subjects were obtained during this observation period. For each MTX prescription, the estimated duration of the prescription, total dose of MTX dispensed, and anticipated date for refill of medication was recorded. The time gap between anticipated refill and actual refill of the next MTX prescription was calculated. MTX treatment course duration was defined as the time from the initial MTX prescription until the expected refill date for the last MTX prescription before a 90 day gap or discontinuation. The medication possession ratio (MPR), a measure of adherence, was calculated as the proportion of treatment time that the patient had drug available. Adherence was defined as an MPR >= 0.80. For each patient the average DAS28 over the course of therapy, prescribed MTX dose, and observed MTX dose were calculated. Patients included in this analysis were RA subjects who had at least one DAS28 score measured during their initial course of MTX therapy that was greater than 12 weeks in duration.

Results:

Compared to non-adherent (MPR < 0.80) patients (n = 61), MTX adherent patients (n=329) had lower mean DAS28 score and ESR despite similar prescribed dose of MTX (Table). Other clinical chacteristics for these two groups were similar.

 AgeDisease Duration (yr)RF (+)aCCP (+)Prescribed MTX dose (mg/wk)Observed MTX dose (mg/wk)DAS 28ESR
MPR<80% (n=61)65 ± 119 ± 1082%70%16 ± 411 ± 34.1 ± 1.430 ± 25
MPR>=80% (n=329)67 ± 1210 ± 1184%74%16 ± 415 ± 43.6 ± 1.223 ± 17
p-valueN.S.N.S.N.S.N.S.N.S.<0.001<0.02<0.01

The impact of adherence on DAS28 was more pronounced after adjusting for weekly observed MTX dose. The results were unchanged after adjustment for age, disease duration, prescribed duration, and prescribed MTX dose.

The impact of adherence on DAS28 was more pronounced after adjusting for weekly observed MTX dose. The results were unchanged after adjustment for age, disease duration, prescribed duration, and prescribed MTX dose.

Conclusion:

RA patients in the VARA registry who were adherent with MTX therapy had significantly lower disease activity over follow-up in comparison to similar patients who were not adherent with therapy. This analysis demonstrates the potential for the use of data from these databases to evaluate clinical effectiveness of RA therapies in real world practice.

To cite this abstract, please use the following information:
Cannon, G. W., Sauer, BC, Hayden, CL, Reimold, A.M., Hooker, R.S., Kerr, G.S., et al; Utilization of VA Pharmacy Benefits Management Data and the VA Rheumatoid Arthritis Database to Demonstrate Reduced Disease Activity in Rheumatoid Arthritis Patients Adherent with Methotrexate [abstract]. Arthritis Rheum 2009;60 Suppl 10 :1398
DOI: 10.1002/art.26472

Abstract Supplement

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