Karon Cook | University of Washington (original) (raw)

Papers by Karon Cook

Value in Health, 2019

Background: There is a need for valid self-report measures of core health-related quality of life... more Background: There is a need for valid self-report measures of core health-related quality of life (HRQoL) domains. Objective: To derive brief, reliable and valid health profile measures from the Patient Reported Outcomes Measurement Information System ® (PROMIS ®) item banks. Methods: Literature review, investigator consensus process, item response theory (IRT) analysis, and expert review of scaling results from multiple PROMIS data sets. We developed 3 profile measures ranging in length from 29 to 57 questions. These profiles assess important HRQoL domains with highly informative subsets of items from respective item banks and yield reliable information across mild-to-severe levels of HRQoL experiences. Each instrument assesses the domains of pain interference, fatigue, depression, anxiety, sleep disturbance, physical function, and social function using 4-, 6-, and 8-item short forms for each domain, and an average pain intensity domain score, using a 0-10 numeric rating scale. Results: With few exceptions, all domain short forms within the profile measures were highly reliable across at least 3 standard deviation (30 T-score) units and were strongly correlated with the full bank scores. Construct validity with ratings of general health and quality of life was demonstrated. Information to inform statistical power for clinical and general population samples is also provided. Conclusions: Although these profile measures have been used widely, with summary scoring routines published, description of their development, reliability, and initial validity has not been published until this article. Further evaluation of these measures and clinical applications are encouraged.

Trials, Jan 6, 2018

The Institute of Medicine (IOM) reported that chronic pain affects about 100 million U.S. adults,... more The Institute of Medicine (IOM) reported that chronic pain affects about 100 million U.S. adults, with chronic low back pain (CLBP) cited as the most prevalent type. Pain catastrophizing is a psychological construct shown to predict the development and trajectory of chronic pain and patient response to pain treatments. While effective treatment for pain catastrophizing typically includes eight-session groups of cognitive behavioral therapy (CBT), a single-session targeted treatment class yielded promising results which, if replicated and extended, could prove to efficiently and cost-effectively reduce pain catastrophizing. In this trial, we seek to determine the comparative efficacy of this novel single-session pain catastrophizing class to an eight-session course of pain CBT and a single-session back pain health education class. We will also explore the psychosocial mechanisms and outcomes of pain catastrophizing treatment. In this trial we will randomize 231 individuals with CLBP ...

Pain, Jul 1, 2017

Pain behaviors are important indicators of functioning in chronic pain; however, no self-reported... more Pain behaviors are important indicators of functioning in chronic pain; however, no self-reported pain behavior instrument has been developed for pediatric populations. The purpose of this study was to create a brief pediatric measure of patient-reported pain behaviors as part of the Patient-Reported Outcome Measurement Information System (PROMIS). A pool of 47 candidate items for this measure had been previously developed through qualitative research. In this study, youth with chronic pain associated with juvenile fibromyalgia, juvenile idiopathic arthritis, or sickle cell disease (ages 8-18 years) from 3 pediatric centers completed all 47 candidate items for development of the pain behavior item bank along with established measures of pain interference, depressive symptoms, fatigue, average pain intensity, and pain catastrophizing. Caregivers reported on sociodemographic information and health history. Psychometric properties of the pain behavior items were examined using an item ...

Journal of clinical epidemiology, Jan 28, 2017

The objective of this study was to assess the psychometric properties of the Dutch-Flemish Patien... more The objective of this study was to assess the psychometric properties of the Dutch-Flemish Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function item bank in Dutch patients with chronic pain. A bank of 121 items was administered to 1,247 Dutch patients with chronic pain. Unidimensionality was assessed by fitting a one-factor confirmatory factor analysis and evaluating resulting fit statistics. Items were calibrated with the graded response model and its fit was evaluated. Cross-cultural validity was assessed by testing items for differential item functioning (DIF) based on language (Dutch vs. English). Construct validity was evaluated by calculation correlations between scores on the Dutch-Flemish PROMIS Physical Function measure and scores on generic and disease-specific measures. Results supported the Dutch-Flemish PROMIS Physical Function item bank's unidimensionality (Comparative Fit Index = 0.976, Tucker Lewis Index = 0.976) and model fit. Item...

The journal of pain : official journal of the American Pain Society, Jan 18, 2017

To date, there is no validated measure for pain catastrophizing at the daily level. The Pain Cata... more To date, there is no validated measure for pain catastrophizing at the daily level. The Pain Catastrophizing Scale (PCS) is widely used to measure trait pain catastrophizing. We sought to develop and validate a brief, daily version of the PCS for use in daily diary studies in order to facilitate research on mechanisms of catastrophizing treatment, individual differences in self-regulation, and to reveal the nuanced relationships between catastrophizing, correlates, and pain outcomes. After adapting the PCS for daily use, we evaluated the resulting 14 items using 3 rounds of cognitive interviews with 30 adults with chronic pain. We refined and tested the final Daily PCS in 3 independent, prospective, cross-sectional, observational validation studies conducted in a combined total of 519 adults with chronic pain who completed online measures daily for 14 consecutive days. For Study 1 (N=131), exploratory factor analysis revealed adequate fit and--unexpectedly--unidimensionality for ite...

Journal of pain research, 2016

The minimally important difference (MID) refers to the smallest change that is sufficiently meani... more The minimally important difference (MID) refers to the smallest change that is sufficiently meaningful to carry implications for patients' care. MIDs are necessary to guide the interpretation of scores. This study estimated MID for the Patient Reported Outcomes Measurement Information System (PROMIS) pain interference (PI). Study instruments were administered to 414 people who participated in two studies that included treatment with low back pain (LBP; n=218) or depression (n=196). Participants with LBP received epidural steroid injections and participants with depression received antidepressants, psychotherapy, or both. MIDs were estimated for the changes in LBP. MIDs were included only if a priori criteria were met (ie, sample size ≥10, Spearman correlation ≥0.3 between anchor measures and PROMIS-PI scores, and effect size range =0.2-0.8). The interquartile range (IQR) of MID estimates was calculated. The IQR ranged from 3.5 to 5.5 points. The lower bound estimate of the IQR (...

Value in Health, 2016

Objectives: Neuropathic pain (NP) is a consequence of many chronic conditions. This study aimed t... more Objectives: Neuropathic pain (NP) is a consequence of many chronic conditions. This study aimed to develop an unidimensional NP scale with scores that represent levels of NP and distinguish between individuals with NP and non-NP conditions. Methods: A candidate item pool of 42 pain quality descriptors was administered to participants with osteoarthritis, rheumatoid arthritis, diabetic neuropathy, and cancer chemotherapy-induced peripheral neuropathy. A subset of pain quality descriptors (items) that best distinguished between participants with and those without NP conditions were identified. Dimensionality of pain descriptors was evaluated in a development sample and cross-validated in a holdout sample. Item responses were calibrated using an item response theory model, and scores were generated on a T-score metric. NP scale scores were evaluated in terms of the reliability, validity, and ability to distinguish between participants with and without conditions typically associated with NP. Results: Of the 42 initial items, 5 were identified for the Patient-Reported Outcome Measurement Information System (PROMIS) Neuropathic Pain Quality Scale. T scores exhibited good discriminatory ability on the basis of receiver-operator characteristic analysis. Score thresholds that optimize sensitivity and specificity were identified. Construct, criterion, and discriminant validity, and reliability of scale scores were supported. Conclusions: The five-item Patient-Reported Outcome Measurement Information System (PROMIS PQ-Neuro) Neuropathic Pain Quality Scale is a short and practical measure that can be used to identify patients more likely to have NP and to distinguish levels of NP. The data collected will support future research that targets other unidimensional pain quality domains (e.g., nociceptive pain).

Journal of clinical epidemiology, May 27, 2016

To evaluate clinical validity, including responsiveness, of Patient-Reported Outcomes Measurement... more To evaluate clinical validity, including responsiveness, of Patient-Reported Outcomes Measurement Information System (PROMIS) pain interference (PROMIS-PI) and pain behavior (PROMIS-PB) T-scores. Data were aggregated from longitudinal studies of cancer, chronic low back pain (cLBP), rheumatoid arthritis, chronic obstructive pulmonary disease (COPD), and major depressive disorder (MDD). Linear mixed-effects models were used to compare baseline score differences and score changes over time. We calculated standardized response means (SRMs) for subgroups defined by self-reported change in general health and pain. A total of 1,357 individuals participated at baseline and 1,225 at follow-up. Hypotheses of significant change in PROMIS-PI and PROMIS-PB scores were supported in the intervention groups (cLBP and MDD). Differences in baseline scores for COPD exacerbators compared to stable COPD patients were in the hypothesized direction but were not statistically significant. Subgroups report...

Journal of Clinical Epidemiology, 2016

Objective-To present an overview of a series of studies in which the clinical validity of the Nat... more Objective-To present an overview of a series of studies in which the clinical validity of the National Institutes of Health's Patient Reported Outcome Measurement Information System (NIH; PROMIS) measures was evaluated, by domain, across six clinical populations. Study Design and Setting-Approximately 1,500 individuals at baseline and 1,300 at followup completed PROMIS measures. The analyses reported in this issue were conducted post hoc, pooling data across six previous studies, and accommodating the different designs of the six, within-condition, parent studies. Changes in T-scores, standardized response means, and effect sizes were calculated in each study. When a parent study design allowed, known groups validity was calculated using a linear mixed model. Results-The results provide substantial support for the clinical validity of nine PROMIS measures in a range of chronic conditions. Conclusion-The cross-condition focus of the analyses provided a unique and multifaceted perspective on how PROMIS measures function in "real-world" clinical settings and provides external anchors that can support comparative effectiveness research. The current body of clinical validity evidence for the nine PROMIS measures indicates the success of NIH PROMIS in developing measures that are effective across a range of chronic conditions.

PloS one, 2015

The Dutch-Flemish PROMIS Group translated the adult PROMIS Pain Interference item bank into Dutch... more The Dutch-Flemish PROMIS Group translated the adult PROMIS Pain Interference item bank into Dutch-Flemish. The aims of the current study were to calibrate the parameters of these items using an item response theory (IRT) model, to evaluate the cross-cultural validity of the Dutch-Flemish translations compared to the original English items, and to evaluate their reliability and construct validity. The 40 items in the bank were completed by 1085 Dutch chronic pain patients. Before calibrating the items, IRT model assumptions were evaluated using confirmatory factor analysis (CFA). Items were calibrated using the graded response model (GRM), an IRT model appropriate for items with more than two response options. To evaluate cross-cultural validity, differential item functioning (DIF) for language (Dutch vs. English) was examined. Reliability was evaluated based on standard errors and Cronbach's alpha. To evaluate construct validity correlations with scores on legacy instruments (e....

Journal of general internal medicine, Jan 20, 2015

Physical function (PF) is a common health concept measured in clinical trials and clinical care. ... more Physical function (PF) is a common health concept measured in clinical trials and clinical care. It is measured with different instruments that are not directly comparable, making comparative effectiveness research (CER) challenging when PF is the outcome of interest. Our goal was to establish a common reporting metric, so that scores on commonly used physical function measures can be converted into PROMIS scores. Following a single-sample linking design, all participants completed items from the NIH Patient Reported Outcomes Measurement Information System (PROMIS®) Physical Function (PROMIS PF) item bank and at least one other commonly used "legacy" measure: the Health Assessment Questionnaire (HAQ) or the Short Form-36 physical function ten-item PF scale (SF-36 PF). A common metric was created using analyses based on item response theory (IRT), producing score cross-walk tables. Participants (N = 733) were part of an internet panel, many of whom reported one or more chro...

Physical Medicine and Rehabilitation Clinics of North America, 2013

Quality of Life Research, 2014

Background-Although the use of patient-reported outcome measures (PROs) has increased markedly, c... more Background-Although the use of patient-reported outcome measures (PROs) has increased markedly, clinical interpretation of scores remains lacking. We developed a method to identify clinical severity thresholds for pain, fatigue, depression, and anxiety in people with cancer. Methods-Using available Patient-Reported Outcomes Measurement Information System (PROMIS) item bank response data collected on 840 cancer patients, symptom vignettes across a range of symptom severity were developed and placed on index cards. Cards represented symptom

Spine, 2008

Study Design-A post-hoc simulation of a computer adaptive administration of the items of a modifi... more Study Design-A post-hoc simulation of a computer adaptive administration of the items of a modified version of the Roland Morris Disability Questionnaire. Objective-To evaluate the effectiveness of adaptive administration of back pain-related disability items compared to a fixed 11-item short form. Summary of Background Data-Short form versions of the Roland Morris Disability Questionnaire have been developed. An alternative to paper-and-pencil short forms is to administer items adaptively so that items are presented based on a person's responses to previous items. Theoretically, this allows precise estimation of back pain disability with administration of only a few items. Materials and Methods-Data were gathered from two previously conducted studies of persons with back pain. An item response theory model was used to calibrate scores based on all items, items of a paper-and-pencil short form, and several computer adaptive tests (CATs). Results-Correlations between each CAT condition and scores based on a 23-item version of the Roland Morris Disability Questionnaire ranged from 0.93 to 0.98. Compared to an 11-item short form, an 11-item CAT produced scores that were significantly more highly correlated with scores based on the 23-item scale. CATs with even fewer items also produced scores that were highly correlated with scores based on all items. For example, scores from a five-item CAT had a correlation of 0.93 with full scale scores. Seven-and nine-item CATs correlated at 0.95 and 0.97, respectively. A CAT with a standard-error-based stopping rule produced scores that correlated at 0.95 with full scale scores. Conclusions-A CAT-based back pain-related disability measure may be a valuable tool for use in clinical and research contexts. Use of CAT for other common measures in back pain research, such as other functional scales or measures of psychological distress, may offer similar advantages.

Rehabilitation Psychology, 2014

Purpose-This study evaluated psychometric properties of the Patient Health Questionnaire-9 (PHQ-9... more Purpose-This study evaluated psychometric properties of the Patient Health Questionnaire-9 (PHQ-9), the Center for Epidemiological Studies Depression Scale-10 (CESD-10), and the eightitem PROMIS Depression Short Form (PROMIS-D-8; 8b short form) in a sample of individuals living with multiple sclerosis (MS). Research Method-Data were collected by a self-reported mailed survey of a community sample of people living with MS (n=455). Factor structure, inter-item reliability, convergent/ discriminant validity and assignment to categories of depression severity were examined. Results-A one factor, confirmatory factor analytic model had adequate fit for all instruments. Scores on the depression scales were more highly correlated with one another than with scores on measures of pain, sleep disturbance, and fatigue. The CESD-10 categorized about 37% of participants as having significant depressive symptoms. At least moderate depression was

Rehabilitation Psychology, 2012

Objective-To compare psychometric functioning of the Fatigue Severity Scale (FSS) and the Modifie... more Objective-To compare psychometric functioning of the Fatigue Severity Scale (FSS) and the Modified Fatigue Impact Scale (MFIS) in a community sample of persons with multiple sclerosis (MS). Research Method-A self-report survey including the FSS, MFIS, demographic and other health measures was completed by 1271 individuals with MS. Analyses evaluated the reliability and validity of the scales, assessed their dimensional structures, and estimated levels of floor and ceiling effects. Item response theory (IRT) was used to evaluate the precision of the MFIS and FSS at different levels of fatigue. Results-Participants had a mean score on the FSS of 5.1 and of 44.2 on the MFIS. Cronbach's alpha values for FSS and MFIS were all 0.93 or greater. Known-groups and discriminant validity of MFIS and FSS scores were supported by the analyses. The MFIS had low floor and ceiling effects, while the FSS had low floor and moderate ceiling effects. Unidimensionality was supported for both scales. IRT analyses indicate the FSS is less precise in measuring both low and high levels of fatigue compared to the MFIS.

Quality of Life Research, 2012

Purpose-This study examined the measurement invariance of responses to the patient-reported outco... more Purpose-This study examined the measurement invariance of responses to the patient-reported outcomes measurement information system (PROMIS) pain interference (PI) item bank. The original PROMIS calibration sample (Wave I) was augmented with a sample of persons recruited from the American Chronic Pain Association (ACPA) to increase the number of participants reporting higher levels of pain. Establishing measurement invariance of an item bank is essential for the valid interpretation of group differences in the latent concept being measured. Methods-Multi-group confirmatory factor analysis (MG-CFA) was used to evaluate successive levels of measurement invariance: configural, metric, and scalar invariance. Results-Support was found for configural and metric invariance of the PROMIS-PI, but not for scalar invariance. Conclusions and recommendations-Based on our results of MG-CFA, we recommend retaining the original parameter estimates obtained by combining the community sample of Wave I and ACPA participants. Future studies should extend this study by examining measurement equivalence in an item response theory framework such as differential item functioning analysis.

Quality of Life Research, 2011

Purpose-To derive from the Patient Reported Outcomes Measurement Information System (PROMIS) fati... more Purpose-To derive from the Patient Reported Outcomes Measurement Information System (PROMIS) fatigue item bank, a short form for individuals with multiple sclerosis (MS), the PROMIS-Fatigue MS. Methods-A panel of 37 clinicians and 46 individuals with MS ranked the relevance of PROMIS fatigue items to persons with MS. Eight items were selected for the PROMIS-Fatigue MS that maximized relevance rankings, content coverage, and item discrimination. The PROMIS-Fatigue MS and an existing, 7-item PROMIS fatigue short form (PROMIS-Fatigue SFv1.0) were administered to a new sample of 231 individuals with MS. Known groups and content validity were assessed. Results-Scores from the short forms were highly correlated (r = 0.92). Discriminant validity of the PROMIS-Fatigue MS scores was supported in known groups comparisons. Scores of neither short form exhibited an advantage in quantitative analyses. The PROMIS-Fatigue MS targeted more of the content included in participants' responses to open-ended questions than did the PROMIS-Fatigue SFv1.0. Conclusions-The PROMIS-Fatigue MS was derived to have content validity in MS samples. The validity of the measure was further supported by the ability of PROMIS-Fatigue MS items to discriminate among groups expected to differ in levels of fatigue. We recommend its use in measuring the fatigue of individuals with MS.

Quality of Life Research, 2009

Purpose-The primary objective of this study was to inform the development of measures of pain imp... more Purpose-The primary objective of this study was to inform the development of measures of pain impact appropriate for all respondents, including homeless individuals, so that they can be used in clinical research and practice. The secondary objective was to increase understanding about the unique experience of homeless people with pain. Methods-Seventeen homeless individuals with chronic health conditions (often associated with pain) participated in cognitive interviews to test the functioning of 56 pain measurement items and provided information about their experience living with and accessing treatment for pain. Results-The most common problems identified with items were that they lacked clarity or were irrelevant in the context of homelessness. Items that were unclear, irrelevant and/or had other identified problems made it difficult for participants to respond. Participants also described multiple ways in which their pain was exacerbated by conditions of homelessness and identified barriers to accessing appropriate treatment. Conclusions-Results suggested that the majority of items were problematic for the homeless and require substantial modifications to make the pain impact bank relevant to this population. Additional recommendations include involving homeless in future item bank development, conducting research on the topic of pain and homelessness, and using cognitive interviewing in other types of health disparities research.

Quality of Life Research, 2013

Purpose-In order to test the difference between group means, the construct measured must have the... more Purpose-In order to test the difference between group means, the construct measured must have the same meaning for all groups under investigation. This study examined the measurement invariance of responses to the patient-reported outcomes measurement information system (PROMIS) pain behavior (PB) item bank in two samples: the PROMIS calibration sample (Wave 1, N = 426) and a sample recruited from the American Chronic Pain Association (ACPA, N = 750). The ACPA data were collected to increase the number of participants with higher levels of pain. Methods-Multi-group confirmatory factor analysis (MG-CFA) and two item response theory (IRT)-based differential item functioning (DIF) approaches were employed to evaluate the existence of measurement invariance. Results-MG-CFA results supported metric invariance of the PROMIS-PB, indicating unstandardized factor loadings with equal across samples. DIF analyses revealed that impact of 6 DIF items was negligible.