Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


Comparison of the Patient-Based Routine Assessment of Patient Index 3 in Usual Care of Rheumatoid Arthritis to the Physician-Based Disease Activity Score-28 Joint Count and Clinical Disease Activity Index.

Lupash1,  Daniel, Patel2,  Aarat M., Amity3,  Christine L., Frydrych3,  Lynne M., Sippel3,  Derek, Jones3,  Donald M., Goudeau3,  Danielle

University of Pittsburgh, Pittsburgh, PA
Univ of Pittsburgh Med Ctr / Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA
Univ of Pittsburgh Med Ctr, Pittsburgh, PA
Univ of Pittsburgh, Pittsburgh, PA
Brigham & Womens Hospital, Boston, MA

Background/Purpose:

Studies support using quantitative measures of disease activity in the care of RA patients to improve patient outcomes. In addition, quantitative measures will soon be required by payers for full reimbursement for RA patient care. Despite Disease Activity Score-28 joint count's (DAS28) widespread use in clinical trials, it is challenging to use in clinical care because it requires a complex calculation, a blood test result (CRP or ESR), and a 28 joint assessment. Clinical Disease Activity Index (CDAI) avoids a complex calculation and ESR/CRP but still requires a 28 joint assessment. The Routine Assessment of Patient Index 3 (RAPID3) avoids these obstacles by assessing disease activity based on 3 patient-reported outcomes: physical function, pain, and global health status. This study compared RAPID3 as a measure of disease activity in the usual care of RA patients to DAS28 and CDAI.

Methods:

725 subjects in the University of Pittsburgh's Rheumatoid Arthritis Comparative Effectiveness (RACER) registry were evaluated. DAS28 was calculated using CRP. Correlations between DAS28, CDAI, and RAPID3 at a single visit were calculated. Next, comparisons of subjects classified by disease activity were performed. Finally, for 313 RA patients with follow-up visits, correlations were calculated for the change in DAS28, CDAI, and RAPID3 between visits.

Results:

Spearman rank-order correlation results indicated that RAPID3 correlated with DAS28 (0.67, p<0.001) and CDAI (0.68, p<0.001) but not as strongly as CDAI correlated with DAS28 (0.93, p<0.001). RAPID3 and DAS28 categorization by disease activity were in agreement only 35% of the time, kappa score of 0.18. In contrast, CDAI and DAS28's categorization by disease activity were in agreement 54% of the time, kappa score of 0.41.

Table 1. DAS28 vs. RAPID3 Categorization of RACER Patients

 DAS28
RAPID3RemissionLowModerateHighTotal
Near Remission102 (36%)6 (6%)9 (3%)0 (0%)117
Low70 (24%)15 (15%)15 (6%)4 (6%)104
Moderate74 (26%)41 (42%)85 (31%)5 (7%)205
High41 (14%)35 (36%)161 (60%)62 (88%)299
Total2879727071725
Kappa (95% CI) = 0.18 (0.17–0.19) (slight agreement)

Table 2. DAS28 vs. CDAI Categorization of RACER Patients

 DAS28
CDAIRemissionLowModerateHighTotal
Remission96 (34%)1 (1%)0 (0%)097
Low174 (60%)63 (65%)27 (10%)0264
Moderate17 (6%)32 (33%)164 (61%)0213
High01 (1%)79 (29%)71 (100%)151
Total2879727071725
Kappa (95% CI) = 0.41 (0.37–0.44) (moderate agreement)

Of 287 subjects with a remission DAS28, only 102 had a near remission RAPID3 while 115 (40%) had a moderate or high RAPID3 (Table 1). When comparing these two groups, the 115 moderate to high RAPID3 patients had a higher Charlson Comorbidity Index (1.88 vs. 1.45, p=0.002) and lower SF-12 mental (47.38 vs. 52.03, p<0.001) and physical (34.5 vs. 49.1, p<0.001) health related quality of life than the 102 near remission RAPID3 patients; there were no differences in age, sex or disease duration between these groups. Pearson correlation results indicated that changes in RAPID3 between visits correlated significantly with changes in DAS28 (0.59, P<0.001) and CDAI (0.52, p<0.001) between visits, but not as strongly as changes in CDAI correlated with changes in DAS28 between visits (0.89, p<0.001).

Conclusion:

DAS28 and CDAI were more strongly correlated than RAPID3 was correlated to CDAI or DAS28. Among subjects in DAS28 remission, 40% of subjects had discrepant RAPID3 and DAS28 associated with lower quality of life and more comorbidities. This suggests RAPID3 may lack specificity in a subset of RA patients as a measure of RA disease activity.

To cite this abstract, please use the following information:
Lupash, Daniel, Patel, Aarat M., Amity, Christine L., Frydrych, Lynne M., Sippel, Derek, Jones, Donald M., et al; Comparison of the Patient-Based Routine Assessment of Patient Index 3 in Usual Care of Rheumatoid Arthritis to the Physician-Based Disease Activity Score-28 Joint Count and Clinical Disease Activity Index. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :2143
DOI:

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