Psychometric Evaluation of Joint-Specific Patient-Reported Outcome Measures Before and After Total Knee Replacement: A Dissertation

Background: Patient reports of pain and function are used to inform the need for and timing of total knee replacement (TKR) and evaluate TKR outcomes. This dissertation compared measurement properties of commonly-used patient surveys in TKR and explored ways to develop more efficient knee-specific function measures. Methods: 1,179 FORCE-TJR patients (mean age=66.1, 61% female) completed questionnaires before and 6 months after TKR. Patient surveys included the knee-specific Knee injury and Osteoarthritis Outcome Score (KOOS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and generic SF-36 Health Survey. Tests of KOOS and WOMAC measurement properties included evaluations of scaling assumptions and reliability. Item response theory methods were used to calibrate 22 KOOS function items in one item bank; simulated computerized adaptive tests (CAT) then were used to evaluate shorter function scores customized for each patient. Validity and responsiveness of measures varying in attributes (knee-specific versus generic, longer versus shorter, CAT versus fixed-length) were compared. Results: KOOS and WOMAC scales generally met tests of scaling assumptions, although many pain items were equally strong measures of pain and physical function. Internal consistency reliability of KOOS and WOMAC scales exceeded minimum levels of 0.70 recommended for group-level comparisons across sociodemographic and clinical subgroups. Function items could be calibrated in one item bank. CAT simulations indicated that reliable knee-specific function scores could be estimated for most patients with a 55-86% reduction in respondent burden, but one-third could not achieve a reliable (≥ 0.95) CAT score post-TKR because the item bank did not include enough items vi measuring high function levels. KOOS and WOMAC scales were valid and responsive. Short function scales and CATs were as valid and responsive as longer KOOS and WOMAC function scales. The KOOS Quality of Life (QOL) scale and SF-36 Physical Component Summary discriminated best among groups evaluating themselves as improved, same or worse at 6 months. Conclusions: Results support use of the KOOS and WOMAC in TKR. Improved knee-specific function measures require new items that measure higher function levels. TKR outcomes should be evaluated with a knee-specific quality of life scale such as KOOS QOL, as well as knee-specific measures of pain and function and generic health measures

Evaluation of smoking-specific and generic quality of life measures in current and former smokers in Germany and the United States

BACKGROUND: Health-related quality of life (QOL) surveys include generic measures that enable comparisons across conditions and measures that focus more specifically on one disease or condition. We evaluated the psychometric properties of German- and English-language versions of survey scales representing both types of measures in samples of current and former smokers. METHODS: TQOLITv1 integrates new measures of smoking-specific symptoms and QOL impact attributed to smoking with generic SF-36 Health Survey measures. For purposes of evaluation, cross-sectional data were analyzed for two independent samples. Disease-free (otherwise healthy) adults ages 23-55 used a tablet to complete surveys in a clinical trial in Germany (125 current and 54 former smokers). Online general population surveys were completed in the US by otherwise healthy current and former smokers (N = 149 and 110, respectively). Evaluations included psychometric tests of assumptions underlying scale construction and scoring, score distributions, and reliability. Tests of validity included cross-sectional correlations and analyses of variance based on a conceptual framework and hypotheses for groups differing in self-reported smoking behavior (current versus former smoker, cigarettes per day (CPD)) and severity of smoking symptoms in both samples and, in the German trial only, clinical parameters of biomarkers of exposure. RESULTS: Tests of scaling assumptions and internal consistency reliability (alpha = 0.71-0.79) of the smoking-specific measures were satisfactory, although ceiling effects attenuated correlations for former smokers in both samples. Correlational evidence supporting validity of smoking-specific symptom and impact measures included their substantial inter-correlation and higher correlations (than generic measures) with smoking behavior (favoring former over current groups) and CPD in both samples. In the German trial, both smoking-specific measures correlated significantly (p \u3c 0.05) with all four biomarkers. QOL impact attributed to smoking correlated with the SF-36 mental but not physical summary measures in both samples. CONCLUSIONS: German- and English-language TQOLITv1 surveys have comparable and satisfactory psychometric properties. Cross-sectional tests, including correlations with four biomarkers, support the validity of the new smoking-specific measures for use in studies of otherwise healthy smokers. Smoking-specific measures consistently performed better than generic QOL measures in all tests of validity

Varying the item format improved the range of measurement in patient-reported outcome measures assessing physical function

BACKGROUND: Physical function (PF) is a core patient-reported outcome domain in clinical trials in rheumatic diseases. Frequently used PF measures have ceiling effects, leading to large sample size requirements and low sensitivity to change. In most of these instruments, the response category that indicates the highest PF level is the statement that one is able to perform a given physical activity without any limitations or difficulty. This study investigates whether using an item format with an extended response scale, allowing respondents to state that the performance of an activity is easy or very easy, increases the range of precise measurement of self-reported PF. METHODS: Three five-item PF short forms were constructed from the Patient-Reported Outcomes Measurement Information System (PROMIS(R)) wave 1 data. All forms included the same physical activities but varied in item stem and response scale: format A ( Are you able to ... ; without any difficulty / unable to do ); format B ( Does your health now limit you ... ; not at all / cannot do ); format C ( How difficult is it for you to ... ; very easy / impossible ). Each short-form item was answered by 2217-2835 subjects. We evaluated unidimensionality and estimated a graded response model for the 15 short-form items and remaining 119 items of the PROMIS PF bank to compare item and test information for the short forms along the PF continuum. We then used simulated data for five groups with different PF levels to illustrate differences in scoring precision between the short forms using different item formats. RESULTS: Sufficient unidimensionality of all short-form items and the original PF item bank was supported. Compared to formats A and B, format C increased the range of reliable measurement by about 0.5 standard deviations on the positive side of the PF continuum of the sample, provided more item information, and was more useful in distinguishing known groups with above-average functioning. CONCLUSIONS: Using an item format with an extended response scale is an efficient option to increase the measurement range of self-reported physical function without changing the content of the measure or affecting the latent construct of the instrument

Survivors of an Acute Coronary Syndrome with Lower Patient Activation Are More Likely to Experience Declines in Health-Related Quality of Life

Background: Patient activation comprises the knowledge, skills, and confidence for self-care, and may lead to better health outcomes. Objectives: We examined the relationship between patient activation and changes in health-related quality of life (HRQOL) following hospitalization for an acute coronary syndrome (ACS). Methods: We studied patients from 6 medical centers in central Massachusetts and Georgia who had been hospitalized for an ACS between 2011 and 2013. At 1 month after hospital discharge, patients completed the 6-item Patient Activation Measure and were categorized into 4 levels of activation. Multinomial logistic regression analyses compared activation level with clinically meaningful changes (≥ 3.0 points generic, ≥10.0 points disease-specific) in generic physical (SF-36 PCS), generic mental (SF-36 MCS), and disease-specific (Seattle Angina Questionnaire, SAQ) HRQOL from 1 to 3 and 1 to 6 months after hospitalization, adjusting for potential sociodemographic and clinical confounders. Results: Patients (n=1,042) were on average 62 years old, 34% female, and 87% non-Hispanic white. Overall, 10% were in the lowest level of activation. Patients with the lowest activation had 1.95 (95% CI: 1.05, 3.62) and 2.18 (95% CI: 1.17, 4.05) times the odds of experiencing clinically significant declines in MCS and SAQ QOL scores, respectively, between 1 and 6 months than the most activated patients. Patient activation level was not associated with meaningful changes in PCS scores. Conclusions: Hospital survivors of an ACS with lower activation may be more likely to experience declines in mental and disease-specific HRQOL than more activated patients, identifying a group at risk of poor outcomes

Measurement properties of the Western Ontario and McMaster Universities Osteoarthritis Index: a systematic review

OBJECTIVE: To conduct a systematic review of the measurement properties of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and to evaluate the quality of WOMAC measurement studies using COSMIN (Consensus-Based Standards for the Selection of Health Measurement Instruments) criteria. METHODS: A search was conducted in the MEDLINE, CINAHL, Embase, PsycINFO, Scopus, and SPORTDiscus databases through September 2013. Data that assessed the WOMAC measurement model, reliability, validity, respondent burden, and equivalence across methods of administration were extracted. Overall study quality was rated following COSMIN criteria. RESULTS: A total of 76 articles from 22 countries were included. Internal consistency reliability was consistently high (≥0.90) for the function scale and acceptable (≥0.70) for the pain and stiffness scales. Test-retest reliability was acceptable. Score equivalence was demonstrated across paper and electronic methods of data collection. Floor and ceiling effects were low except for notable (24-38%) proportions of patients achieving the best possible scores on the pain and stiffness scales 1-23 years after arthroplasty. Five exploratory factor analyses did not support a measurement model in which the pain and function items were distinct. Correlations between the WOMAC pain and function scales were high (median 0.79). The WOMAC pain and function scales had similar correlations with other pain measures, and therefore the WOMAC pain scale did not show divergent validity. COSMIN criteria were not fully met in most studies. CONCLUSION: The WOMAC scales were reliable, but its pain scale was highly related to physical function. Further research into joint-specific pain measures that have broader content validity is needed

Validity and Responsiveness of the Knee Injury and Osteoarthritis Outcome Score: A Comparative Study Among Total Knee Replacement Patients

OBJECTIVE: To evaluate validity and responsiveness of the Knee Injury and Osteoarthritis Outcome Score (KOOS) in relation to other patient-reported outcome measures before and after total knee replacement (TKR). METHODS: Pre-TKR and 6-month post-TKR data from 1,143 patients in a US joint replacement cohort were used to compare the KOOS, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the SF-36 Health Survey (SF-36). Validity was evaluated with multiple methods, including correlations of pre-TKR scale scores and analysis of variance models that used pre-TKR data to compare the relative validity of scales in discriminating between groups differing in assistive walking device use and number of comorbid conditions. Validity was also evaluated by using post-TKR minus pre-TKR change scores to assess relative validity of scales in discriminating between groups rating themselves as better, same, or worse (BSW) in their capability to do activities at 6 months. Responsiveness also was described using effect sizes and standardized response means. RESULTS: In support of convergent and discriminant validity, KOOS scale scores were worse for patients using an assistive device but only declined weakly with increasing comorbid conditions. While all knee-specific scales discriminated between BSW groups, the KOOS quality of life (QOL) scale was significantly better (P \u3c 0.05) than all measures except the SF-36 physical component summary. KOOS QOL also had the highest effect size, while SF-36 measures had lower effect sizes and standardized response means. KOOS pain and symptoms scales discriminated better than WOMAC pain and stiffness scales among BSW groups. CONCLUSION: KOOS scales were valid and responsive in this cohort of US TKR patients. KOOS QOL performed particularly well in capturing aggregate knee-specific outcomes

The Validity of Disease-specific Quality of Life Attributions Among Adults with Multiple Chronic Conditions

BACKGROUND: A crucial assumption underlying all disease-specific quality of life (QOL) measures, that patients can validly differentiate a specific disease in the presence of multiple chronic conditions, has not been tested using multiple methods. Our objective was to evaluate the convergent and discriminant validity of QOL attributions to specific diseases among adults with multiple chronic conditions (MCC). METHODS: Adults age 18 and older (N=4,480) sampled from eight pre-identified condition groups (asthma, COPD, angina/MI with angina, congestive heart failure, diabetes, chronic kidney disease, osteoarthritis, rheumatoid arthritis) completed an Internet survey. Comorbid conditions were determined using a 35-condition checklist. Product-moment correlations were analyzed separately by pre-identified condition group using the multitrait-multimethod of construct validation, where traits were defined by 9-26 conditions and each condition was measured by two methods: disease severity rating and Disease-specific Quality of Life Impact Scale (QDIS) global rating. A third method (symptom or clinical marker) was available for the eight pre-identified conditions. Convergent validity was supported when correlations among different methods of measuring the same condition (trait) were substantial (r \u3e /=0.40). Discriminant validity was supported when correlations between the same and different methods of measuring different conditions were significantly lower than corresponding convergent correlations. RESULTS: In support of convergent validity, 22 of 24 convergent correlations were substantial (r=0.38-0.84, median=0.53). In support of discriminant validity, 833 of 924 tests (90.2%) yielded significantly higher convergent than discriminant correlations across the eight pre-identified conditions. Exceptions to this pattern of results were most often observed for comorbid conditions within the same clinical area. CONCLUSIONS: Collectively, convergent and discriminant test results support the construct validity of disease-specific QOL impact attributions across MCC within the eight pre-identified conditions. Noteworthy exceptions should be considered when interpreting some specific QOL impact attributions and warrant further study. Pursuit of a summary disease-specific QOL impact score standardized across MCC is recommended

A 12-item short form of the Knee injury and Osteoarthritis Outcome Score (KOOS-12): tests of reliability, validity and responsiveness

OBJECTIVE: To evaluate reliability, validity and responsiveness of KOOS-12, a 12-item short form of the 42-item Knee injury and Osteoarthritis Outcome Score (KOOS) that provides Pain, Function and Quality of Life (QOL) scale scores and a summary knee impact score. DESIGN: Data from 1,392 knee osteoarthritis (OA) patients from the FORCE-TJR research cohort who completed KOOS before and 6 and 12 months after total knee replacement (TKR) were analyzed. KOOS-12 includes a pain frequency item and three items measuring pain during increasingly difficult (sitting/lying, walking, stairs) activities; function items about standing, rising from sitting, getting in/out of a car, and twisting/pivoting; and the 4-item KOOS QOL scale. Percent computable scale scores, floor and ceiling effects, internal consistency reliability, validity (scale correlations, tests of known groups validity using one-way analysis of variance (ANOVA)) and responsiveness (effect sizes, standardized response means) were compared for the KOOS-12, full-length KOOS, KOOS-PS and KOOS, JR. RESULTS: Internal consistency reliability was above 0.70 for all KOOS-12 scales and \u3e /=0.90 for the KOOS-12 Summary score. Validity and responsiveness of KOOS-12 Pain, Function and QOL scales was satisfactory and reached similar conclusions as comparable full-length KOOS scales. The KOOS-12 Summary score was most responsive in discriminating between groups who differed in global ratings of post-TKR change in physical capabilities and had the highest effect sizes and standardized response means. CONCLUSIONS: KOOS-12 was a reliable and valid alternative to KOOS in TKR patients with moderate to severe OA and provided three domain-specific and summary knee impact scores with substantially reduced respondent burden

Item selection for 12-item short forms of the knee injury and Osteoarthritis Outcome Score (KOOS-12) and hip disability and Osteoarthritis Outcome Score (HOOS-12)

OBJECTIVE: To develop 12-item short forms (KOOS-12, Hip disability and Osteoarthritis Outcome Score (HOOS)-12) of the 42-item Knee injury and Osteoarthritis Outcome Score (KOOS) and 40-item HOOS that represent the full-length instruments sufficiently to provide joint-specific pain, function and quality of life (QOL) domain and summary joint impact scores. This paper describes KOOS-12 and HOOS-12 item selection. Subsequent papers will examine KOOS-12 and HOOS-12 reliability, validity and responsiveness. DESIGN: Items were selected based on qualitative information from patients, clinicians and KOOS/HOOS translators and analysis of data from 1,395 knee osteoarthritis (OA) and 1,281 hip OA patients from the FORCE-TJR cohort who completed KOOS or HOOS before and after total joint replacement (TJR). Item response theory models and computerized adaptive test (CAT) simulations were used to identify items that best measured patients\u27 levels of pain and function pre- and post-TJR. KOOS-12/HOOS-12 items were selected based on content, coverage of a wide measurement range, high item information, item usage in computerized adaptive testing (CAT) simulations, scale-level properties (reliability, validity, responsiveness), and qualitative information. RESULTS: KOOS-12 and HOOS-12 each included a pain frequency item and three items measuring pain during increasingly difficult activities (sitting/lying, walking, up/down stairs); function items about standing, rising from sitting, getting in/out of a car, and twisting/pivoting (KOOS-12) or walking on an uneven surface (HOOS-12); and the original 4-item QOL scale. CONCLUSIONS: This study demonstrated the benefits of examining patient-reported outcome measures using modern psychometric methods, to create short forms with diverse content that provide domain-specific and summary joint impact scores

A 12-item short form of the Hip disability and Osteoarthritis Outcome Score (HOOS-12): tests of reliability, validity and responsiveness

OBJECTIVE: To evaluate reliability, validity and responsiveness of Hip disability and Osteoarthritis Outcome Score (HOOS)-12, a 12-item short form of the 40-item HOOS. HOOS-12 provides Pain, Function and Quality of Life (QOL) scale scores and a summary hip impact score. DESIGN: Data from 1,273 FORCE-TJR hip osteoarthritis (OA) patients who completed HOOS before and six and 12 months after total hip replacement (THR) were analyzed. HOOS-12 includes a pain frequency item and three items measuring pain during increasingly difficult (sitting/lying, walking, stairs) activities; function items about standing, rising from sitting, getting in/out of a car, and walking on an uneven surface; and the 4-item HOOS QOL scale. Percent computable scale scores, floor and ceiling effects, internal consistency reliability, validity (scale correlations, tests of known groups validity using one-way analysis of variance (ANOVA)) and responsiveness (effect sizes, standardized response means) were compared for HOOS-12, full-length HOOS, HOOS-PS and HOOS, JR. RESULTS: Internal consistency reliability was above 0.70 for all HOOS-12 scales and above 0.90 for the HOOS-12 Summary score. Validity and responsiveness of HOOS-12 Pain, Function and QOL scales were satisfactory and reached similar conclusions as comparable full-length HOOS scales. The HOOS-12 Summary score was highly responsive in discriminating between groups who differed in global ratings of post-THR change in physical capabilities and had high effect sizes and standardized response means (SRM). CONCLUSIONS: HOOS-12 was a reliable and valid alternative to HOOS in THR patients with moderate to severe OA and provided three domain-specific and summary hip impact scores with substantially reduced respondent burden