Dennis A. Revicki

Recommended methods for determining responsiveness and minimally important differences for patient-reported outcomes

OBJECTIVE The objective of this review is to summarize recommendations on methods for evaluating responsiveness and minimal important difference (MID) for patient-reported outcome (PRO) measures. STUDY DESIGN AND SETTING We review, summarize, and integrate information on issues and methods for evaluating responsiveness and determining MID estimates for PRO measures. Recommendations are made on best-practice methods for evaluating responsiveness and MID. RESULTS The MID for a PRO instrument is not an immutable characteristic, but may vary by population and context, and no one MID may be valid for all study applications. MID estimates should be based on multiple approaches and triangulation of methods. Anchor-based methods applying various relevant patient-rated, clinician-rated, and disease-specific variables provide primary and meaningful estimates of an instruments MID. Results for the PRO measures from clinical trials can also provide insight into observed effects based on treatment comparisons and should be used to help determine MID. Distribution-based methods can support estimates from anchor-based approaches and can be used in situations where anchor-based estimates are unavailable. CONCLUSION We recommend that the MID is based primarily on relevant patient-based and clinical anchors, with clinical trial experience used to further inform understanding of MID.

Psychometric evaluation and calibration of health-related quality of life item banks: Plans for the Patient-Reported Outcomes Measurement Information System (PROMIS)

Background:The construction and evaluation of item banks to measure unidimensional constructs of health-related quality of life (HRQOL) is a fundamental objective of the Patient-Reported Outcomes Measurement Information System (PROMIS) project. Objectives:Item banks will be used as the foundation for developing short-form instruments and enabling computerized adaptive testing. The PROMIS Steering Committee selected 5 HRQOL domains for initial focus: physical functioning, fatigue, pain, emotional distress, and social role participation. This report provides an overview of the methods used in the PROMIS item analyses and proposed calibration of item banks. Analyses:Analyses include evaluation of data quality (eg, logic and range checking, spread of response distribution within an item), descriptive statistics (eg, frequencies, means), item response theory model assumptions (unidimensionality, local independence, monotonicity), model fit, differential item functioning, and item calibration for banking. Recommendations:Summarized are key analytic issues; recommendations are provided for future evaluations of item banks in HRQOL assessment.

Reporting of Patient-Reported Outcomes in Randomized Trials: The CONSORT PRO Extension

The CONSORT (Consolidated Standards of Reporting Trials) Statement aims to improve the reporting of randomized controlled trials (RCTs); however, it lacks guidance on the reporting of patient-reported outcomes (PROs), which are often inadequately reported in trials, thus limiting the value of these data. In this article, we describe the development of the CONSORT PRO extension based on the methodological framework for guideline development proposed by the Enhancing the Quality and Transparency of Health Research (EQUATOR) Network. Five CONSORT PRO checklist items are recommended for RCTs in which PROs are primary or important secondary end points. These recommendations urge that the PROs be identified as a primary or secondary outcome in the abstract, that a description of the hypothesis of the PROs and relevant domains be provided (ie, if a multidimensional PRO tool has been used), that evidence of the PRO instruments validity and reliability be provided or cited, that the statistical approaches for dealing with missing data be explicitly stated, and that PRO-specific limitations of study findings and generalizability of results to other populations and clinical practice be discussed. Examples and an updated CONSORT flow diagram with PRO items are provided. It is recommended that the CONSORT PRO guidance supplement the standard CONSORT guidelines for reporting RCTs with PROs as primary or secondary outcomes. Improved reporting of PRO data should facilitate robust interpretation of the results from RCTs and inform patient care.

Evidence for reliability, validity and usefulness of the Medical Outcomes Study HIV Health Survey (MOS-HIV)

The Medical Outcomes Study HIV Health Survey (MOS-HIV) is a brief, comprehensive measure of health-related quality of life (HRQoL) used extensively in human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS). The 35-item questionnaire includes ten dimensions (health perceptions, pain, physical, role, social and cognitive functioning, mental health, energy, health distress and quality of life (QoL)) and takes approximately 5 minutes to complete. Subscales are scored on a 0–100 scale (a higher score indicates better health) and physical and mental health summary scores can be generated. The MOS-HIV has been shown to be internally consistent, correlate with concurrent measures of health, discriminate between distinct groups, predict future outcomes and be responsive to changes over time. Limited experience suggests acceptable reliability and validity in women, injecting drug users and African–American and lower socioeconomic status patients. The MOS-HIV is available in 14 languages and has been included as a secondary outcome measure in numerous clinical trials for all stages of disease. In several studies it has detected significant differences between treatments; in some cases concordant with conventional end-points and, in others, discordant. The interpretation of scores is facilitated by an explanation in terms meaningful to the intended audience. Research is needed to compare the MOS-HIV to other strategies for HRQoL assessment in early HIV disease.

Recommendations on health-related quality of life research to support labeling and promotional claims in the United States

Health-related quality of life (HRQL) outcomes evaluation is becoming an important component of clinical trials of new pharmaceuticals and medical devices. HRQL research provides patients, providers, and decision makers with important information on the impact of disease and treatment on physical, psychological, and social functioning and well-being. These outcomes are also useful to the pharmaceutical and device industries as they attempt to understand and communicate product value to physicians, patients, health insurers and others. HRQL labeling and promotional claims in the US are likely to increase over the next few years. The evidentiary requirements to make such a claim should be based on accepted scientific standards of HRQL evaluation and consistent with the regulatory requirements for clinical efficacy. This report outlines the scientific practices that should be considered in the evaluation of evidence for an HRQL claim, including the selection of appropriate domains, evidence to support the reliability and validity of HRQL measurement, considerations in research design and statistical analyses, and the issue of clinical significance. Representatives from the pharmaceutical and device industries, regulatory agencies, and the HRQL scientific community should work together to make certain the use of HRQL in labeling and promotion are based on sound scientific evidence, and that these messages are clearly and accurately reported to the consumers.

Psychometric considerations in evaluating health-related quality of life measures.

How does one determine if a measure of health-related quality of life (HRQL) is adequate for clinical trials? Psychometric methods are frequently used to answer this question. What is psychometrics all about? In this paper we address these questions, discussing common psychometric evaluation procedures applied to HRQL measures. Specifically, we discuss issues regarding the evaluation of reliability and validity (including responsiveness).

RELIABILITY AND VALIDITY OF THE GASTROINTESTINAL SYMPTOM RATING SCALE IN PATIENTS WITH GASTROESOPHAGEAL REFLUX DISEASE

The objective of this study was to evaluate the reliability and validity of the Gastrointestinal Symptom Rating Scale (GSRS) in US patients with gastroesophageal reflux disease (GERD). Five hundred and sixteen adults with predominant heartburn symptoms of GERD were recruited from gastroenterologist and family physician practices and treated with 6 weeks of 150mg ranitidine twice daily to identify poorly responsive symptomatic GERD. The GSRS, the Medical Outcomes Study Short Form-36 (SF-36) Health Survey and the Psychological General Well-being (PGWB) scale were administered at baseline and after 6 weeks of treatment. Reported ratings of GERD-related symptoms from physician and patient diaries were measured. The GSRS contains five scales: reflux syndrome, abdominal pain, constipation syndrome, diarrhoea syndrome and indigestion syndrome. The internal consistency reliabilities for the GSRS scales ranged from 0.61 to 0.83 and the intraclass correlation coefficients ranged from 0.42 to 0.60. The GSRS scale scores were correlated with the SF-36 and PGWB scales and with the number and severity of heartburn symptoms. Patients with two or three clinician-rated GERD-related symptoms reported worse GSRS scale scores compared with patients with fewer symptoms (p < 0.0001). Statistically significant differences in the mean GSRS scale scores were observed between treatment responders and non-responders (p < 0.0001) and patients showing a response to treatment had larger mean changes in their GSRS scales than patients not showing a response to treatment (p < 0.0001). The standardized response means ranged from 0.42 to 1.43 for the GSRS scale scores. It was concluded that the GSRS is a brief, fairly comprehensive assessment of common gastrointestinal symptoms. The GSRS has good reliability and construct validity and the GSRS scales discriminate by GERD symptom severity and are responsive to treatment. The GSRS is a useful patient-rated symptom scale for evaluating the outcomes of treatment for GERD.

The impact of measuring patient-reported outcomes in clinical practice: a systematic review of the literature

ObjectiveThe purpose of this paper is to summarize the best evidence regarding the impact of providing patient-reported outcomes (PRO) information to health care professionals in daily clinical practice.MethodsSystematic review of randomized clinical trials (Medline, Cochrane Library; reference lists of previous systematic reviews; and requests to authors and experts in the field).ResultsOut of 1,861 identified references published between 1978 and 2007, 34 articles corresponding to 28 original studies proved eligible. Most trials (19) were conducted in primary care settings performed in the USA (21) and assessed adult patients (25). Information provided to professionals included generic health status (10), mental health (14), and other (6). Most studies suffered from methodologic limitations, including analysis that did not correspond with the unit of allocation. In most trials, the impact of PRO was limited. Fifteen of 23 studies (65%) measuring process of care observed at least one significant result favoring the intervention, as did eight of 17 (47%) that measured outcomes of care.ConclusionsMethodological concerns limit the strength of inference regarding the impact of providing PRO information to clinicians. Results suggest great heterogeneity of impact; contexts and interventions that will yield important benefits remain to be clearly defined.

Impact of hepatitis C on health related quality of life: a systematic review and quantitative assessment.

Hepatitis C virus (HCV) diminishes health related quality of life (HRQOL), and it is now common to measure HRQOL in clinical trials. We sought to summarize the HRQOL data in HCV, and to establish the minimally clinically important difference (MCID) in HRQOL scores in HCV. We performed a systematic review to identify relevant studies, and converted HRQOL data from each study into clinically interpretable statistics. An expert panel used a modified Delphi technique to estimate the MCID in HCV. We found that patients with HCV scored lower than controls across all scales of the SF‐36. Patients achieving sustained virological response (SVR) scored higher across all scales versus patients without SVR, especially in the physical health domains. HRQOL differences did not correspond with differences in liver histology or ALT levels. Based upon the published data, the expert panel concluded that the SF‐36 vitality scale was most relevant in patients with HCV, and generated a mean MCID of 4.2 points on this scale. In conclusion, patients with HCV have a clinically significant decrement in HRQOL versus controls, and physical HRQOL improves in patients achieving SVR but not in those without SVR. The data further suggest that traditional outcomes fail to capture the full spectrum of illness related to chronic HCV. A difference of 4.2 points on the SF‐36 vitality scale can be used as an estimate of the MCID in HCV, and this value may be used as the basis for power calculations in clinical trials evaluating HRQOL. Supplementary material for this article can be found on the HEPATOLOGY website (http://www.interscience.wiley.com/jpages/0270‐9139/suppmat/index.html). (HEPATOLOGY 2005;41:790–800.)

Development of a PROMIS item bank to measure pain interference

&NA; This paper describes the psychometric properties of the PROMIS‐pain interference (PROMIS‐PI) bank. An initial candidate item pool (n = 644) was developed and evaluated based on the review of existing instruments, interviews with patients, and consultation with pain experts. From this pool, a candidate item bank of 56 items was selected and responses to the items were collected from large community and clinical samples. A total of 14,848 participants responded to all or a subset of candidate items. The responses were calibrated using an item response theory (IRT) model. A final 41‐item bank was evaluated with respect to IRT assumptions, model fit, differential item function (DIF), precision, and construct and concurrent validity. Items of the revised bank had good fit to the IRT model (CFI and NNFI/TLI ranged from 0.974 to 0.997), and the data were strongly unidimensional (e.g., ratio of first and second eigenvalue = 35). Nine items exhibited statistically significant DIF. However, adjusting for DIF had little practical impact on score estimates and the items were retained without modifying scoring. Scores provided substantial information across levels of pain; for scores in the T‐score range 50–80, the reliability was equivalent to 0.96–0.99. Patterns of correlations with other health outcomes supported the construct validity of the item bank. The scores discriminated among persons with different numbers of chronic conditions, disabling conditions, levels of self‐reported health, and pain intensity (p < 0.0001). The results indicated that the PROMIS‐PI items constitute a psychometrically sound bank. Computerized adaptive testing and short forms are available.