Showing papers by "James F. Fries published in 2009"

Progress in Assessing Physical Function in Arthritis: PROMIS Short Forms and Computerized Adaptive Testing

Abstract: Objective. Assessing self-reported physical function/disability with the Health Assessment Questionnaire Disability Index (HAQ) and other instruments has become central in arthritis research. Item response theory (IRT) and computerized adaptive testing (CAT) techniques can increase reliability and statistical power. IRT-based instruments can improve measurement precision substantially over a wider range of disease severity. These modern methods were applied and the magnitude of improvement was estimated. Methods. A 199-item physical function/disability item bank was developed by distilling 1865 items to 124, including Legacy Health Assessment Questionnaire (HAQ) and Physical Function-10 items, and improving precision through qualitative and quantitative evaluation in over 21,000 subjects, which included about 1500 patients with rheumatoid arthritis and osteoarthritis. Four new instruments, (A) Patient-Reported Outcomes Measurement Information (PROMIS) HAQ, which evolved from the original (Legacy) HAQ; (B) “best” PROMIS 10; (C) 20-item static (short) forms; and (D) simulated PROMIS CAT, which sequentially selected the most informative item, were compared with the HAQ. Results. Online and mailed administration modes yielded similar item and domain scores. The HAQ and PROMIS HAQ 20-item scales yielded greater information content versus other scales in patients with more severe disease. The “best” PROMIS 20-item scale outperformed the other 20-item static forms over a broad range of 4 standard deviations. The 10-item simulated PROMIS CAT outperformed all other forms. Conclusion. Improved items and instruments yielded better information. The PROMIS HAQ is currently available and considered validated. The new PROMIS short forms, after validation, are likely to represent further improvement. CAT-based physical function/disability assessment offers superior performance over static forms of equal length.

Better assessment of physical function: item improvement is neglected but essential

Abstract: Physical function is a key component of patient-reported outcome (PRO) assessment in rheumatology. Modern psychometric methods, such as Item Response Theory (IRT) and Computerized Adaptive Testing, can materially improve measurement precision at the item level. We present the qualitative and quantitative item-evaluation process for developing the Patient Reported Outcomes Measurement Information System (PROMIS) Physical Function item bank. The process was stepwise: we searched extensively to identify extant Physical Function items and then classified and selectively reduced the item pool. We evaluated retained items for content, clarity, relevance and comprehension, reading level, and translation ease by experts and patient surveys, focus groups, and cognitive interviews. We then assessed items by using classic test theory and IRT, used confirmatory factor analyses to estimate item parameters, and graded response modeling for parameter estimation. We retained the 20 Legacy (original) Health Assessment Questionnaire Disability Index (HAQ-DI) and the 10 SF-36's PF-10 items for comparison. Subjects were from rheumatoid arthritis, osteoarthritis, and healthy aging cohorts (n = 1,100) and a national Internet sample of 21,133 subjects. We identified 1,860 items. After qualitative and quantitative evaluation, 124 newly developed PROMIS items composed the PROMIS item bank, which included revised Legacy items with good fit that met IRT model assumptions. Results showed that the clearest and best-understood items were simple, in the present tense, and straightforward. Basic tasks (like dressing) were more relevant and important versus complex ones (like dancing). Revised HAQ-DI and PF-10 items with five response options had higher item-information content than did comparable original Legacy items with fewer response options. IRT analyses showed that the Physical Function domain satisfied general criteria for unidimensionality with one-, two-, three-, and four-factor models having comparable model fits. Correlations between factors in the test data sets were > 0.90. Item improvement must underlie attempts to improve outcome assessment. The clear, personally important and relevant, ability-framed items in the PROMIS Physical Function item bank perform well in PRO assessment. They will benefit from further study and application in a wider variety of rheumatic diseases in diverse clinical groups, including those at the extremes of physical functioning, and in different administration modes.

Items, Instruments, Crosswalks, and PROMIS

Abstract: In the English language, there are 165 published questionnaire instruments intended to assess “disability” or “physical function” health outcomes, containing 1860 items1. If “health related quality of life” (HRQOL) questionnaires are included, the numbers are yet larger. With integration of the new sciences of Item Response Theory (IRT)2 and Computerized Adaptive Testing (CAT)3 into instrument development, the numbers of items and instruments could again grow larger. This unbounded proliferation of health status instruments is problematic and raises both serious issues and intriguing opportunities. For understanding these issues, some knowledge of IRT and CAT is required. IRT2,4 works at the level of the specific item, which has measurable characteristics such as information content, degree of difficulty, reliability, clarity, ease of translation, performance in different populations, importance to the subject, and others. IRT is sometimes termed “latent trait theory” as a major application of IRT is to estimate the value of a trait (or domain) such as “disability” or “quality of life,” where the trait itself cannot be directly observed. Two IRT requirements are that the items aggregated to estimate a trait are unidimensional in that they measure a single concept, and that they are not redundant (“locally dependent”) with other items in the group2. Given sufficient information about each item, one can predict the performance of one outcome assessment instrument compared with another. For example, one can quite readily, by selecting the better items from an item bank, create instruments that make more precise outcome assessments than the Health Assessment Questionnaire Disability Index (HAQ-DI)5 or the 6-item Short Form Health Survey (SF-6D) HRQOL6 instruments. In turn, this permits major increases in study statistical power or allows use …

How to ascertain drug safety in the context of benefit. Controversies and concerns.

Abstract: There is great concern about clearly defining benefit and risk in the context of both drug development and clinical practice. In view of this pressure, the OMERACT Executive identified the need to bring together clinical trialists, pharmacoepidemiologists, clinicians, clinical epidemiologists, statistical experts, and regulatory representatives to discuss different approaches to define risk and perhaps improved ways to express it. Each attendee spoke on a given topic and the group was charged to consider the issue of risk in the context of formally posed questions. This article provides a summary of the presentations and outlines the discussions that followed.

Rheumatologist perceptions of sources of health care disparities in minority rheumatoid arthritis patients.

Abstract: Disparities in health outcomes among minority patients persist and in some patients have worsened. A large body of evidence indicates minority differences in all-cause mortality, chronic disease prevalence, and poorer functional status. When compared with nonminority rheumatoid arthritis (RA) patients, minority counterparts have poorer health outcomes, including worse disability and pain and a poorer overall health perception. Genetics, socioeconomic, cultural, behavioral, and intraindividual factors, as well as their interactive effects, have been documented as potential contributors to inequities across numerous diseases and conditions between Whites and minority groups. The study of socioeconomic factors, such as education and income, has predominated, but independently has not completely explained the reasons for disparities, even after statistical adjustment. A patient’s mistrust of the physician or the health care system, inadequate access or use of the health care system, low health literacy, language barriers, and treatment refusal are also among possible forces. In addition, provider-patient factors, including prejudice, stereotyping, and ambiguity surrounding minority patient interactions have been posited as contributors to disparities in medical treatment and health outcomes. Reasons for these disparities among minority RA patients are largely unexplored, although substantial data demonstrate that minorities are disproportionately affected by the consequences of arthritis. Because arthritis and other rheumatic conditions are projected to increase to a quarter of the adult population by 2030, examination of relevant factors that contribute to health disparities is needed. The purpose of this exploratory study was to survey rheumatologist perceptions of behaviors, beliefs, and attitudes related to treatment and health outcomes of minority RA patients.