Health Assessment Questionnaire-Disability Index Improvement Research Articles

Minimally Important Difference of Health Assessment Questionnaire in Psoriatic Arthritis: Relating Thresholds of Improvement in Functional Ability to Patient-rated Importance and Satisfaction

To evaluate changes in function as measured by Health Assessment Questionnaire Disability Index (HAQ-DI) and the meaningfulness of the changes, in importance and satisfaction, in patients with psoriatic arthritis (PsA). HAQ-DI was assessed at baseline and at Weeks 4, 12, and 24 in a randomized double-blind study of 205 patients with active PsA receiving etanercept 25 mg twice weekly or placebo. Concurrently, patients rated the importance of and satisfaction with their change in function on a 7-point scale (1 = not at all important/satisfied; 7 = extremely important/satisfied). Mean HAQ-DI improvement corresponding to ratings of minimally (2-3) or very (6-7) important or satisfied was determined using a posthoc linear mixed-model analysis. Patient importance ratings were used as an anchor to estimate minimally important difference (MID) for HAQ-DI; distribution-based estimates were also calculated. A total of 161 patients (69 placebo; 92 etanercept) had ≥ 1 HAQ-DI scores showing improvement from baseline and a corresponding importance or satisfaction rating. HAQ-DI improvements corresponding to importance scale ratings of 2 or 3 were 0.335 (95% CI 0.214, 0.455) and 0.360 (95% CI 0.263, 0.456), respectively, suggesting an MID of about 0.35. HAQ-DI improvements corresponding to satisfaction scale ratings of 2 and 3 were 0.293 (95% CI 0.230, 0.357) and 0.360 (95% CI 0.307, 0.413). For a given change in HAQ-DI, nearly two-thirds of patients indicated a lower rating for satisfaction than for importance. This trial was registered in the ClinicalTrials.gov registry (NCT00317499). Our study suggests the MID for HAQ-DI in PsA is about 0.35. The results may also provide insight into patient satisfaction with changes in function and expectations for therapy.

Biologic Therapy for Systemic Sclerosis: A Systematic Review

Biologic agents are increasingly used in the rheumatic diseases. Their role in patients with systemic sclerosis (SSc) is uncertain. Our aim was to evaluate the effectiveness and safety of biologic agents in SSc. We review the evidence for the use of biologic agents to improve inflammatory arthritis, disability, and skin score, and we review adverse effects with biologic agents in patients with SSc. A systematic literature review was performed to identify studies evaluating the use of biologic agents in SSc. Medline, Embase, CINAHL, and Cochrane Database of Systematic Reviews were searched. A standardized abstraction form was used to extract biologic agent, study design, sample size, treatment effect, and adverse effects. A total of 23 studies from 1413 citations were evaluated. Three studies evaluated infliximab, 3 evaluated etanercept, 3 evaluated antithymocyte globulin, 3 evaluated imatinib, 6 evaluated rituximab, and 1 study each evaluated interferon-γ (IFN-γ), IFN-α, relaxin, delipidated, deglycolipidated Mycobacterium vaccae, human anti-transforming growth factor ß1 antibody, and oral type I collagen. Studies of etanercept and infliximab suggest improvements in inflammatory arthritis and Health Assessment Questionnaire Disability Index (HAQ-DI). None of the other biologic agents demonstrated reproducible, statistically significant improvements in joint count, HAQ-DI, or skin score. Anti-tumor necrosis factor-α agents may improve inflammatory arthritis and disability in SSc. The effect on skin score is uncertain. Adequately powered trials are needed to evaluate efficacy, and longitudinal studies are needed to evaluate longterm safety of these agents in SSc.

Equivalent Responses to Disease-modifying Antirheumatic Drugs Initiated at Any Time During the First 15 Months After Symptom Onset in Patients with Seropositive Rheumatoid Arthritis

To evaluate responses by time to initiation of nonbiologic disease-modifying antirheumatic drugs (DMARD) in a DMARD-naive cohort of patients with early seropositive rheumatoid arthritis (RA). Subjects were categorized by the time from symptom onset to the first DMARD use (median 5.7 months, range 0.6-15.9). Subjects who started their first DMARD within 5 months of symptom onset were compared to subjects who started after 5 months. Disease Activity Scores (DAS-44) and total Sharp Score (TSS) progression rates were analyzed using Wilcoxon rank-sum and chi-square tests; multiple linear regression analysis adjusted for potential covariates. The slope of the least-squares regression line was calculated to estimate the annualized TSS progression rates. Of 233 RA patients, 76% were female and mean age was 50 (SD 13) years. At DMARD start, DAS-44 was similar in all subsets within the 0.6 to 15 months' duration between symptom onset and DMARD initiation. Erosion scores tended to be higher in those who started DMARD later, but Health Assessment Questionnaire-Disability Index (HAQ-DI) scores were higher in those who started DMARD earlier. During the 2 years after DMARD initiation, improvements in HAQ-DI and DAS-44 were similar in the various duration subsets, with about 25% ever achieving DAS remission (DAS < 1.6). Radiographic progression tended to be numerically but not statistically more rapid in the earlier subsets. Following initiation of nonbiologic DMARD therapy at various times within 15 months of symptom onset, improvements of DAS-44, HAQ-DI, remission rate, and radiographic progression rate were similar, although higher baseline erosion scores were present in those with later initiation of DMARD.

Indirect cost-effectiveness analyses of abatacept and rituximab in patients with moderate-to-severe rheumatoid arthritis in the United States

Objective: To estimate the incremental cost per quality-adjusted life-years (QALYs) for abatacept and rituximab, in combination with methotrexate, relative to methotrexate alone in patients with active rheumatoid arthritis (RA).Methods: A patient-level simulation model was used to depict the progression of functional disability over the lifetimes of women aged 55–64 years with active RA and inadequate response to a tumor necrosis factor (TNF)-α antagonist therapy. Future health-state utilities and medical care costs were based on projected values of the Health Assessment Questionnaire Disability Index (HAQ-DI). Patients were assumed to receive abatacept or rituximab in combination with methotrexate until death or therapy discontinuation due to lack of efficacy or adverse events. HAQ-DI improvement at month 6, after adjustments for control drug (methotrexate) response, was derived from two clinical trials. Costs of medical care and biologic drugs, discounted at 3% annually, were from the perspective of a US third-party payer and expressed in 2007 US dollars.Results: Relative to methotrexate alone, abatacept/methotrexate and rituximab/methotrexate therapies were estimated to yield an average of 1.25 and 1.10 additional QALYs per patient, at mean incremental costs of $58,989 and $60,380, respectively. The incremental cost-utility ratio relative to methotrexate was $47,191 (95% CI $44,810–49,920) per QALY gained for abatacept/methotrexate and $54,891 (95% CI $52,274–58,073) per QALY gained for rituximab/methotrexate. At an acceptability threshold of $50,000 per QALY, the probability of cost effectiveness was 90% for abatacept and 0.0% for rituximab.Conclusion: Abatacept was estimated to be more cost effective than rituximab for use in RA from a US third-party payer perspective. However, head-to-head clinical trials and long-term observational data are needed to confirm these findings.