Assessment of craving in opioid use disorder: Psychometric evaluation and predictive validity of the opioid craving VAS.

BACKGROUND: This work evaluated the psychometric properties of the single-item Opioid Craving Visual Analog Scale (OC-VAS) for opioid use disorder (OUD). METHODS: Psychometric evaluation of the OC-VAS (range: 0-100 mm) was supported by Subjective Opiate Withdrawal Scale (SOWS) item 16 and total score, Clinical Opiate Withdrawal Scale (COWS) scores, and the 36-Item Short-Form Health Survey, using data from phase 3 study (NCT02357901; N = 487) participants who received randomized treatment and completed the OC-VAS at screening. Descriptive properties, test-retest reliability, construct validity, known-groups validity, and responsiveness were assessed. Interpretation of meaningful change and predictive validity were also explored. RESULTS: Descriptive properties for the OC-VAS at screening did not provide evidence of problematic floor/ceiling effects or missingness. The test-retest reliability was established by weekly intraclass correlations >0.70. At the screening and end of the study, the strong positive correlations between OC-VAS and SOWS Total/Item 16 score and the significant OC-VAS differences among COWS severity groups supported construct validity and known-groups (discriminating ability) validity, respectively. The associations between the changes in OC-VAS and in supporting measures/opioid use from screening to the end of the study demonstrated responsiveness and the ability to detect change in clinical status. During the induction and randomization treatment periods, significant relationships were identified between OC-VAS score and subsequent opioid use. CONCLUSIONS: This psychometric evaluation of the OC-VAS performed on a large OUD patient population provides evidence to support its use to measure the severity of opioid craving and its ability to predict opioid use.

State of the psychometric methods: patient-reported outcome measure development and refinement using item response theory.

BACKGROUND: This paper is part of a series comparing different psychometric approaches to evaluate patient-reported outcome (PRO) measures using the same items and dataset. We provide an overview and example application to demonstrate 1) using item response theory (IRT) to identify poor and well performing items; 2) testing if items perform differently based on demographic characteristics (differential item functioning, DIF); and 3) balancing IRT and content validity considerations to select items for short forms. METHODS: Model fit, local dependence, and DIF were examined for 51 items initially considered for the Patient-Reported Outcomes Measurement Information System® (PROMIS®) Depression item bank. Samejima's graded response model was used to examine how well each item measured severity levels of depression and how well it distinguished between individuals with high and low levels of depression. Two short forms were constructed based on psychometric properties and consensus discussions with instrument developers, including psychometricians and content experts. Calibrations presented here are for didactic purposes and are not intended to replace official PROMIS parameters or to be used for research. RESULTS: Of the 51 depression items, 14 exhibited local dependence, 3 exhibited DIF for gender, and 9 exhibited misfit, and these items were removed from consideration for short forms. Short form 1 prioritized content, and thus items were chosen to meet DSM-V criteria rather than being discarded for lower discrimination parameters. Short form 2 prioritized well performing items, and thus fewer DSM-V criteria were satisfied. Short forms 1-2 performed similarly for model fit statistics, but short form 2 provided greater item precision. CONCLUSIONS: IRT is a family of flexible models providing item- and scale-level information, making it a powerful tool for scale construction and refinement. Strengths of IRT models include placing respondents and items on the same metric, testing DIF across demographic or clinical subgroups, and facilitating creation of targeted short forms. Limitations include large sample sizes to obtain stable item parameters, and necessary familiarity with measurement methods to interpret results. Combining psychometric data with stakeholder input (including people with lived experiences of the health condition and clinicians) is highly recommended for scale development and evaluation.

Economic burden of advanced melanoma in France, Germany and the UK: a retrospective observational study (Melanoma Burden-of-Illness Study).

The aim of this study was to estimate the cost-of-illness associated with completely resected stage IIIB/IIIC melanoma with macroscopic lymph node involvement, overall and by disease phase, in France, Germany and the UK. This retrospective observational study included patients aged older than or equal to 18 years first diagnosed with stage IIIB/IIIC cutaneous melanoma between 1 January 2009 and 31 December 2011. Data were obtained from medical records and a patient survey. Direct costs, indirect costs and patient out-of-pocket expenses were estimated in euros (€) (and British pounds, £) by collecting resource use and multiplying by country-specific unit costs. National annual costs were estimated using national disease prevalence from the European cancer registry and other published data. Forty-nine centres provided data on 558 patients (58.2% aged <65 years, 53.6% stage IIIB disease at diagnosis). The mean follow-up duration was 27 months (France), 26 months (Germany) and 22 months (UK). The mean total direct cost per patient during follow-up was €23 582 in France, €32 058 in Germany and €37 970 (£31 123) in the UK. The largest cost drivers were melanoma drugs [mean €14 004, €21 269, €29 750 (£24 385), respectively] and hospitalization/emergency treatment [mean: €6634, €6950, €3449 (£2827), respectively]. The total mean indirect costs per patient were €129 (France), €4,441 (Germany) and €1712 (£1427) (UK). Estimates for annual national direct cost were €13.1 million (France), €30.2 million (Germany) and €27.8 (£22.8) million (UK). The economic burden of stage IIIB/IIIC melanoma with macroscopic lymph node involvement was substantial in all three countries. Total direct costs were the highest during the period with distant metastasis/terminal illness.

Best (but oft-forgotten) practices: expressing and interpreting associations and effect sizes in clinical outcome assessments.

This article reviews methods used to facilitate the interpretation and evaluation of group-level differences in clinical outcome assessments. These methods complement and supplement tests of statistical significance. Examples, including studies in nutrition, are used to illustrate the application of the interpretation methods for group-level comparisons from experimental or observational studies. In addition, specific pitfalls of evaluating change in meta-analysis studies are described. A set of recommendations is provided. This review is intended as an introduction for the novice and as a refresher for the experienced researcher.

Secukinumab improves patient-reported psoriasis symptoms of itching, pain, and scaling: results of two phase 3, randomized, placebo-controlled clinical trials.

BACKGROUND: Secukinumab is a human interleukin-17A antagonist indicated for the treatment of moderate to severe plaque psoriasis in adults who are candidates for systemic therapy or phototherapy. The objective of this analysis was to measure the treatment response on psoriasis-related itching, pain, and scaling via the Psoriasis Symptom Diary (PSD)(©). METHODS: ERASURE (n = 738) and FIXTURE (n = 1306) were double-blind, multicenter phase 3 studies in adults randomized to secukinumab (300, 150 mg, n = 1144) or placebo (n = 574) (administered at Weeks 0, 1, 2, 3, and 4, followed by dosing every 4 weeks) or a biologic active control (FIXTURE only). Patient-reported itching, pain, and scaling were assessed during the first 12 weeks of treatment using the PSD. The results reported here are limited to subjects in the secukinumab and placebo treatment groups who completed the PSD. The proportions of subjects achieving prespecified responses (improvement:reduction of at least 2.2 points for itching, 2.2 points for pain, or 2.3 points for scaling) were compared for secukinumab versus placebo. RESULTS: Overall, 39% of subjects completed the PSD at baseline and Week 12 (n = 453 secukinumab; 225 placebo). Subjects treated with secukinumab achieved significantly greater improvements in itching, pain, and scaling at Week 12 versus placebo (all P < 0.0001) and had significantly greater proportions of itching, pain, and scaling responders at Week 12 versus placebo (all P < 0.05). CONCLUSION: Secukinumab significantly improves patient-reported itching, pain, and scaling in adults with moderate to severe psoriasis compared with placebo.

Psychometric validation of the Psoriasis Symptom Diary using Phase III study data from patients with chronic plaque psoriasis.

OBJECTIVES: This analysis aimed to confirm the reliability, validity, and responsiveness of the Psoriasis Symptom Diary (PSD) using data from two Phase III studies in patients with moderate to severe chronic plaque psoriasis. METHODS: Data from two randomized, double-blind, double-dummy, placebo-controlled, multicenter Phase III studies (n = 820) assessing the efficacy and safety of secukinumab were used. The PSD (24-h recall; 0-10 numeric rating scale) was electronically administered each evening. Test-retest reliability was determined using intraclass correlations. Construct validity hypotheses were evaluated via correlations with the Psoriasis Area and Severity Index (PASI), Investigator's Global Assessment (IGA), Dermatology Life Quality Index (DLQI), EuroQoL 5-Dimension Health Status Questionnaire, and Patient Global Impression of Change (PGIC). Discriminating ability and responsiveness were evaluated by estimating mean differences and effect sizes between known groups (using the PASI and IGA). Phase II-derived, anchor-based PGIC thresholds and cumulative distribution function (CDF) plots described meaningful change. RESULTS: Items on the PSD yielded high intraclass coefficients (>0.90). Correlations were in the anticipated direction and by week 12 were moderate to strong (0.41-0.73) in magnitude, demonstrating construct validity. Average PSD item scores differed predictably and significantly between known groups. Responsiveness effect size estimates were moderate to large (0.6-1.5), and CDF plots showed the percentage of responders to be consistently higher in treatment than in placebo arms across the range of change in PSD scores. CONCLUSIONS: The PSD is reliable, valid, and responsive, and represents a valid tool to enhance treatment decisions in patients with moderate to severe plaque psoriasis.

Using classical test theory, item response theory, and Rasch measurement theory to evaluate patient-reported outcome measures: a comparison of worked examples.

OBJECTIVE: To provide comparisons and a worked example of item- and scale-level evaluations based on three psychometric methods used in patient-reported outcome development-classical test theory (CTT), item response theory (IRT), and Rasch measurement theory (RMT)-in an analysis of the National Eye Institute Visual Functioning Questionnaire (VFQ-25). METHODS: Baseline VFQ-25 data from 240 participants with diabetic macular edema from a randomized, double-masked, multicenter clinical trial were used to evaluate the VFQ at the total score level. CTT, RMT, and IRT evaluations were conducted, and results were assessed in a head-to-head comparison. RESULTS: Results were similar across the three methods, with IRT and RMT providing more detailed diagnostic information on how to improve the scale. CTT led to the identification of two problematic items that threaten the validity of the overall scale score, sets of redundant items, and skewed response categories. IRT and RMT additionally identified poor fit for one item, many locally dependent items, poor targeting, and disordering of over half the response categories. CONCLUSIONS: Selection of a psychometric approach depends on many factors. Researchers should justify their evaluation method and consider the intended audience. If the instrument is being developed for descriptive purposes and on a restricted budget, a cursory examination of the CTT-based psychometric properties may be all that is possible. In a high-stakes situation, such as the development of a patient-reported outcome instrument for consideration in pharmaceutical labeling, however, a thorough psychometric evaluation including IRT or RMT should be considered, with final item-level decisions made on the basis of both quantitative and qualitative results.

Quantitative challenges facing patient-centered outcomes research.

Patient-centered outcomes research collects and analyzes data from patients and other stakeholders to improve health care delivery and outcomes and guide health care decisions. However, there are a number of challenges in conducting quantitative analyses of patient-centered data. This article provides an overview of the analytical challenges and describes approaches to consider to overcome the challenges, as well as directions for future development.

Evaluation of the fibromyalgia diagnostic screen in clinical practice.

RATIONALE, AIMS AND OBJECTIVES: Fibromyalgia (FM) is challenging to diagnose, especially in primary care settings. The Fibromyalgia Diagnostic Screen was developed to facilitate the diagnosis of FM in clinical practice. The objectives of this study were to assess the performance of the Fibromyalgia Diagnostic Screen in primary care and specialty clinics, using the 1990 American College of Rheumatology (ACR) diagnostic criteria as the gold standard, and comparing the Fibromyalgia Diagnostic Screen with the London Fibromyalgia Epidemiology Study Screening Questionnaire (LFESSQ) and the modified 2010 ACR Fibromyalgia Diagnostic Criteria (ACR-FDC). METHODS: This multicenter, cross-sectional study included 150 adult chronic pain patients who underwent a physician-administered structured history and physical exam and completed the Fibromyalgia Diagnostic Screen, the LFESSQ and the modified ACR-FDC. The analyses determined the predictive ability of the Fibromyalgia Diagnostic Screen for FM. RESULTS: Item-level analyses provided support for the response categories and predictive ability of most of the Fibromyalgia Diagnostic Screen items. Additionally, the evaluation of the Fibromyalgia Diagnostic Screen scoring models demonstrated the greatest accuracy in predicting an FM diagnosis with a combination of patient items and clinician items that included an abbreviated tender point exam (sensitivity 0.68, specificity, 0.82). Sensitivity of the modified ACR-FDC and the LFESSQ was 0.87 and 0.86, respectively, with specificity 0.62 and 0.49, respectively. CONCLUSIONS: The Fibromyalgia Diagnostic Screen is a useful new clinical tool to aid in the evaluation of FM in clinical practice.

ISOQOL recommends minimum standards for patient-reported outcome measures used in patient-centered outcomes and comparative effectiveness research.

PURPOSE: An essential aspect of patient-centered outcomes research (PCOR) and comparative effectiveness research (CER) is the integration of patient perspectives and experiences with clinical data to evaluate interventions. Thus, PCOR and CER require capturing patient-reported outcome (PRO) data appropriately to inform research, healthcare delivery, and policy. This initiative's goal was to identify minimum standards for the design and selection of a PRO measure for use in PCOR and CER. METHODS: We performed a literature review to find existing guidelines for the selection of PRO measures. We also conducted an online survey of the International Society for Quality of Life Research (ISOQOL) membership to solicit input on PRO standards. A standard was designated as "recommended" when >50 % respondents endorsed it as "required as a minimum standard." RESULTS: The literature review identified 387 articles. Survey response rate was 120 of 506 ISOQOL members. The respondents had an average of 15 years experience in PRO research, and 89 % felt competent or very competent providing feedback. Final recommendations for PRO measure standards included: documentation of the conceptual and measurement model; evidence for reliability, validity (content validity, construct validity, responsiveness); interpretability of scores; quality translation, and acceptable patient and investigator burden. CONCLUSION: The development of these minimum measurement standards is intended to promote the appropriate use of PRO measures to inform PCOR and CER, which in turn can improve the effectiveness and efficiency of healthcare delivery. A next step is to expand these minimum standards to identify best practices for selecting decision-relevant PRO measures.

The development and initial assessment of the strategy and leadership systems capability evaluation survey.

Hospital management and leadership systems are associated with organizational success and quality care. The Strategy and Leadership Systems Capability Evaluation (CE) survey was developed by GE Healthcare to assess management and leadership systems at health care institutions, serve as a benchmark for improvement, and measure progress. To assess the psychometric properties of the 29-item CE survey, including the factor structure, scoring algorithm, reliability, and discriminant validity, an online survey was completed by 3450 employees at 15 US hospitals. Of these employees, 609 worked at a hospital where a leadership and management intervention occurred after the initial survey administration. Data were also collected on job level, number of hospital beds, hospital ownership, location, community type, and the implementation of hospital interventions. Item response frequencies showed no floor or ceiling effects and limited missing data. Interitem correlations were strong without obvious redundancies, and factor analysis suggested a unidimensional scale. The resulting scale had strong internal consistency and was able to discriminate among known groups. The CE survey was developed to evaluate management and leadership systems at health care institutions. This study provides psychometric evidence in support of the reliability, validity, and scoring structure of this survey.

Sphygmomanometry-evoked allodynia in chronic pain patients with and without fibromyalgia.

BACKGROUND: Fibromyalgia is a chronic pain syndrome that affects about 2% of the U.S. general population, with greater prevalence among women (3.5%) than men (0.5%). Previous research results suggest that the experience of pain (allodynia) upon sphygmomanometry may indicate the presence of fibromyalgia. OBJECTIVE: The aim of this study was to confirm these findings in patients with fibromyalgia and other chronic pain conditions and evaluate the use of sphygmomanometry as a potential screening tool for the identification of patients with fibromyalgia. METHODS: A total of 150 people participated in this multicenter, cross-sectional observational study. The study included a physician-conducted evaluation to determine if the participant met the American College of Rheumatology (ACR) 1990 diagnostic criteria for fibromyalgia. The presence of sphygmomanometry-evoked allodynia was assessed during a seated cuff pressure inflation that was repeated three times on each arm. Each site was provided a sphygmomanometer to ensure standardization, and the pressure of the cuff at the moment of pain initiation was recorded. If the patient did not indicate pain prior to 180 mmHg, then the inflation was stopped, a notation of no pain was made, and a cuff pressure of 180 mmHg was recorded. The mean of the six cuff pressure measurements was used for the analyses. Logistic regression was performed to analyze the relationship between sphygmomanometry-evoked allodynia and fibromyalgia. RESULTS: The evaluable sample was 148 (one participant had too large an arm circumference for the sphygmomanometer and another did not receive the clinician evaluation of ACR-determined fibromyalgia diagnosis). Over half of the participants were determined to have an ACR diagnosis of fibromyalgia. Of these, 71 (91%) were women and had an average age of 54 years. Of the 70 participants with no fibromyalgia diagnosis, 42 (60%) were women and also had an average age of 54 years. Sixty-one (78%) of the fibromyalgia participants, compared with 25 (36%) of those with no fibromyalgia diagnosis, reported sphygmomanometry-evoked allodynia. The participants with fibromyalgia reported pain ata lower cuff pressure compared with those without fibromyalgia (132 mmHg vs. 166 mmHg, p < .01). The logistic regression showed that sphygmomanometry-evoked allodynia predicted an ACR-determined FM diagnosis (χ(2) = 19.4, p < .01). DISCUSSION: These findings support previous research suggesting that patients who report pain upon sphygmomanometry may warrant further evaluation for the presence of fibromyalgia.

Prevalence of airway obstruction assessed by lung function questionnaire.

OBJECTIVE: To estimate the prevalence of unidentified chronic obstructive pulmonary disease (COPD) and determine the screening accuracy of the Lung Function Questionnaire (LFQ). PATIENTS AND METHODS: Cigarette smokers who had a smoking history of 10 or more pack-years and were aged 30 years or older were recruited from 36 centers from February 18, 2009, to May 29, 2009. A total of 1575 patients completed a Web-based survey including the 5-item LFQ. Spirometry was performed on patients with an LFQ total score of 18 or less and on a subset scoring more than 18. The primary outcome was the proportion of patients at risk of airflow obstruction as measured by the LFQ (score, ≤ 18) in whom an airflow obstruction was confirmed by spirometry. RESULTS: Of the patients who completed the LFQ, 849 (54%) had standardized spirometry data available. On the basis of LFQ and spirometry results, the estimated prevalence of possible COPD was 17.9% (95% confidence interval, 15.3%-20.6%). At a cut point of 18 or less, sensitivity, specificity, positive predictive value, and negative predictive value of the LFQ were 88%, 25%, 21%, and 90%, respectively. Approximately 1 in 5 patients (21%) aged 30 years or older and 1 in 4 (26%) aged 50 years or older scored 18 or less on the LFQ and had a ratio of forced expiratory volume in the first second of expiration to forced vital capacity less than 0.70. CONCLUSION: On the basis of postbronchodilator spirometry results using weighted estimates, approximately 1 in 5 patients (21%) aged 30 years or older with a smoking history of 10 or more pack-years seen in a primary care setting is likely to have COPD. The LFQ could be a helpful COPD case-finding tool for clinicians to identify patients who need further evaluation. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01013948.

Interpreting patient-reported outcome results: US FDA guidance and emerging methods.

In recent years, the US FDA has become more critical of instruments used to measure patient-reported outcomes (PROs) in clinical trials. To facilitate decisions related to the approval of drugs, labels and promotional claims based on PROs, the FDA created the Study Endpoints and Label Development (SEALD) group. SEALD has developed a PRO guidance related to the use of PRO measures used to support drug approvals and label claims, including recommendations for establishing thresholds for meaningful change at the individual level (i.e., defining a responder). This article examines in detail the FDA-recommended methodology for defining a responder and analyzing responder-based PRO measure results. We also present other responder analysis approaches for consideration in furthering the precision and interpretation of this methodology.

Development and psychometric evaluation of a new patient-reported outcome instrument measuring the functional impact of insomnia.

PURPOSE: The objective of this study was to develop and validate a patient-reported outcome instrument to comprehensively assess the consequences of inadequate sleep for use in insomnia-related studies. METHODS: To inform item development, relevant constructs were identified through patient focus groups, literature review, and expert input. Following a translatability assessment for United States (US) English, US Spanish, and French, the draft items were refined through iterative sets of patient interviews in the United States and France. Psychometric properties were evaluated using patient responses from a validation study including 432 participants with either a diagnosis of primary insomnia or no history of insomnia. RESULTS: Psychometric analyses supported item reduction from 38 to 26 items, yielding a unidimensional scale and preserving the original content (mood, tiredness/energy, memory/concentration, motivation, daily performance, social interaction, sexual functioning). Evidence of internal consistency (coefficient α = 0.97), convergent validity, and known-groups validity also was documented. CONCLUSIONS: The Sleep Functional Impact Scale (SFIS) is a psychometrically sound measure targeting the impact of insomnia on patient functioning. When administered with a sleep diary, this instrument has the ability to provide a more comprehensive assessment of treatment response in clinical studies.

Effects of insulin initiation on patient-reported outcomes in patients with type 2 diabetes: results from the durable trial.

AIM: To examine changes in patient-reported outcome (PRO) measures in patients with type 2 diabetes (T2DM) on oral agents who initiated insulin (insulin lispro mix 25/75 [LM25] or insulin glargine) in the DURABLE trial (n=580). METHODS: Subjects completed generic and diabetes-specific health-related quality-of-life measures (RAND-36 and Diabetes-39) and a symptom assessment measure (DSC-Revised) at baseline and 6 months post insulin initiation. Mean score change was evaluated. Effect size (ES; Cohen's d) and analysis of covariance were used to examine extent and significance of change both within and between treatment groups. RESULTS: Subject characteristics were mean age 57 years, males 59%, duration of diabetes 9.6 years, and baseline HbA1c 8.9%. In the total sample, significant (P<0.01) improvements (with small ES) were observed in four of eight RAND-36 subscales (ES range: 0.13-0.24), three of five Diabetes-39 subscales (ES range: 0.09-0.34), and five of eight DSC-Revised subscales (ES range: 0.15-0.38). While significance of within-group changes varied by treatment, only one subscale (physical functioning for LM25) showed deterioration. The changes were not significantly different (P>0.01) between regimens for any subscales. CONCLUSIONS: Our findings suggest that insulin initiation improves selective PRO in patients with poorly controlled T2DM.

Development and psychometric evaluation of the Bipolar Functional Status Questionnaire (BFSQ).

OBJECTIVES: Persistently impaired psychosocial functioning has been recognized in many individuals with bipolar disorder. However, existing measures of functional disability have been adapted for use in bipolar disorder based mainly on those developed for use in other conditions. The present study involved the development and validation of a new patient self-report measure specific to bipolar disorder, the Bipolar Functional Status Questionnaire (BFSQ). METHODS: Relevant constructs were identified, evaluated, and refined through an expert advisory panel in conjunction with patient interviews. Questionnaire items were vetted through iterative patient interviews. Psychometric properties were determined based on patient responses from implementation of the proposed 33-item questionnaire in an 11-site study of 596 patients with bipolar disorder across varied phases of illness. RESULTS: Eight constructs were identified as fundamental to functional status in bipolar disorder: cognitive function, sleep, role functioning, emotional functioning, energy/vitality, social functioning, personal management, and sexual functioning. Psychometric validation supported item reduction to a 24-item unidimensional scale, with high internal consistency (coefficient alpha's = 0.93-0.95), high test-retest reliability (intraclass correlation coefficient = 0.86, 95% confidence interval = 0.82-0.89), strong convergent validity with other functional disability measures (r's > 0.70), and highly significant discriminant validity across illness phases, with large effect sizes (Cohen's d > 0.70). CONCLUSIONS: The BFSQ is a psychometrically sound self-report measure that can be used to effectively quantify functional status across different clinical states in patients with bipolar disorder.

Responsiveness and minimum important differences for the erection quality scale.

PURPOSE: We evaluated the responsiveness and treatment sensitivity of the Erection Quality Scale, and provided further psychometric validation of this scale. MATERIALS AND METHODS: An 8-week, placebo controlled, randomized clinical trial investigating the efficacy and safety of vardenafil in patients with erectile dysfunction was performed. The Erection Quality Scale, together with a number of other patient and partner questionnaires, was administered at a screening visit, at baseline, and weeks 4 and 8 of treatment. Erection Quality Scale responsiveness was investigated by evaluating treatment induced changes and modeling using ANCOVA. Internal consistency, convergent and discriminant validity, and minimum important difference of the Erection Quality Scale were also assessed. RESULTS: Efficacy evaluations demonstrated that the Erection Quality Scale was sufficiently responsive to differentiate the treatment benefits of vardenafil compared with placebo. Internal consistency for the Erection Quality Scale total score was similar across visits, with values high enough to suggest reliability of items included in the scale. Discriminant validity of the Erection Quality Scale total score was demonstrated, with a high correlation with the erectile function domain of the International Index of Erectile Function (0.88, p <0.0001) and negligible correlations with clinical measures assumed to be unrelated to erection quality. All Erection Quality Scale total score comparisons substantially exceeded the 5-point minimum important difference estimate. CONCLUSIONS: The Erection Quality Scale was responsive and internally consistent, and demonstrated convergent and discriminant validity. Furthermore, this instrument provided a unique contribution to the measurement of erection quality compared to the International Index of Erectile Function. This study provides strong evidence supporting the use of the Erection Quality Scale in clinical trials.