Effects of Achieving Target Measures in Rheumatoid Arthritis on Functional Status, Quality of Life, and Resource Utilization: Analysis of Clinical Practice Data

Abstract

Objective: To evaluate associations between achieving guideline-recommended targets of disease activity, defined by the Disease Activity Score in 28 joints using C-reactive protein level (DAS28-CRP) <2.6, the Simplified Disease Activity Index (SDAI) ≤3.3, or the Clinical Disease Activity Index (CDAI) ≤2.8, and other health outcomes in a longitudinal observational study.

Methods: Other defined thresholds included low disease activity (LDA), moderate (MDA), or severe disease activity (SDA). To control for intraclass correlation and estimate effects of independent variables on outcomes of the modified Health Assessment Questionnaire (M-HAQ), the EuroQol 5-domain (EQ-5D; a quality-of-life measure), hospitalization, and durable medical equipment (DME) use, we employed mixed models for continuous outcomes and generalized estimating equations for binary outcomes.

Results: Among 1,297 subjects, achievement (versus nonachievement) of recommended disease targets was associated with enhanced physical functioning and lower health resource utilization. After controlling for baseline covariates, achievement of disease targets (versus LDA) was associated with significantly enhanced physical functioning based on SDAI ≤3.3 (ΔM-HAQ -0.047; P = 0.0100) and CDAI ≤2.8 (-0.073; P = 0.0003) but not DAS28-CRP <2.6 (-0.022; P = 0.1735). Target attainment was associated with significantly improved EQ-5D (0.022-0.096; P < 0.0030 versus LDA, MDA, or SDA). Patients achieving guideline-recommended disease targets were 36-45% less likely to be hospitalized (P < 0.0500) and 23-45% less likely to utilize DME (P < 0.0100).

Conclusion: Attaining recommended target disease-activity measures was associated with enhanced physical functioning and health-related quality of life. Some health outcomes were similar in subjects attaining guideline targets versus LDA. Achieving LDA is a worthy clinical objective in some patients.

Trial registration: ClinicalTrials.gov NCT01793103.

Figure 1

Mean modified Health Assessment Questionnaire (MHAQ) disability scores, EuroQol 5‐domain (EQ‐5D) health‐related quality of life scores, and durable medical equipment (DME) use among patients achieving targets (light bars) compared to those not achieving target measures (dark bars). Disease targets were Disease Activity Score in 28 joints using the C‐reactive protein level (DAS28‐CRP) <2.6, Simplified Disease Activity Index (SDAI) ≤3.3, or Clinical Disease Activity Index (CDAI) ≤2.8. For numbers of patients who achieved (or did not achieve) the target at each time point, see Supplementary Table 3, available on the Arthritis Care & Research web site at http://onlinelibrary.wiley.com/doi/10.1002/acr.22678/abstract.

Figure 2

Mean modified Health Assessment Questionnaire (MHAQ) disability scores, EuroQol 5‐domain (EQ‐5D) health‐related quality of life scores, and durable medical equipment (DME) use among patients with Disease Activity Score in 28 joints using the C‐reactive protein level (DAS28‐CRP) <2.6, Simplified Disease Activity Index (SDAI) ≤3.3, or Clinical Disease Activity Index (CDAI) ≤2.8 (light bars) compared to low disease activity (dark bars), moderate disease activity (black bars), and severe disease activity (striped bars). Low disease activity = 2.6 < DAS28‐CRP ≤3.2; 3.3 < SDAI ≤11.0; 2.8 < CDAI ≤10.0. Moderate disease activity = 3.2 < DAS28‐CRP ≤5.1; 11.0 < SDAI ≤26; 10.0 < CDAI ≤22.0. Severe disease activity = DAS28‐CRP >5.1; SDAI >26.0; CDAI >22.0.