Emotional Impact (ASCQ)

1. Abstract

The Adult Sickle Cell Quality of Life Measurement System (ASCQ-Me) Emotional Impact scale is a specialized, patient-reported outcome measure (PROM) developed under the auspices of the National Heart, Lung, and Blood Institute (NHLBI). Created to address the profound psychophysiological toll of sickle cell disease (SCD), this instrument quantitatively assesses the frequency and intensity of negative emotional states, existential dread, disease-related loneliness, and cognitive demoralization experienced by adults living with this severe hemoglobinopathy. The full item bank contains 20 calibrated items measuring affective, cognitive, and interpersonal dimensions of emotional distress rooted specifically in chronic health deterioration and acute vaso-occlusive episodes. Administered through a 7-day recall period utilizing 5-point Likert response scales, the measure is underpinned by modern psychometric theory, specifically Item Response Theory (IRT) utilizing Samejima’s Graded Response Model (GRM). Psychometric evaluations consistently confirm high internal consistency reliability (Cronbach’s α > .90; IRT marginal reliability > .92) and strong construct, convergent, and discriminant validity. The scale demonstrates superior sensitivity in detecting variations across pain crisis frequency, emergency department utilization, and distinct clinical phenotypes compared to generic emotional distress inventories. Scores are standardized to a T-score metric with a mean of 50 and a standard deviation of 10 referenced to the adult sickle cell population. The ASCQ-Me Emotional Impact scale provides hematologists, clinical psychologists, and clinical trialists with a rigorous, reliable, and clinically meaningful metric to evaluate psychological interventions, pharmacotherapies, and comprehensive sickle cell care programs.

2. Keywords

ASCQ-Me, sickle cell disease, emotional impact, health-related quality of life, patient-reported outcome measures, item response theory, graded response model, depression, health anxiety, chronic illness burden

3. Authors

The Adult Sickle Cell Quality of Life Measurement System was developed through a multicenter research initiative funded by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health (NIH). The primary scientific team and key contributors include:

• San Keller, PhD — American Institutes for Research (AIR), Chapel Hill, NC, USA. Principal investigator and psychometrician leading instrument development and IRT calibrations.
• Maria Yang, PhD — American Institutes for Research (AIR), Chapel Hill, NC, USA. Psychometric analysis and item banking specialist.
• Carlton Dampier, MD — Department of Pediatrics, Emory University School of Medicine and Children’s Healthcare of Atlanta, Atlanta, GA, USA. Pediatric and adult hematology expert in sickle cell disease pain assessment.
• Wally R. Smith, MD — Division of General Internal Medicine, Virginia Commonwealth University (VCU) Health System, Richmond, VA, USA. Renowned sickle cell clinician-researcher and principal investigator of the PiSCES (Pain in Sickle Cell Epidemiology Study) project.
• Kimberly Treadwell, PhD — Department of Psychological Sciences, University of Connecticut, Storrs, CT, USA. Clinical health psychology investigator.
• ASCQ-Me Steering Committee and Working Group — A collaborative consortium of hematologists, psychometricians, health services researchers, and adult patient advocates across participating clinical centers in the United States.

4. Purpose

Sickle cell disease is a severe, hereditary red blood cell disorder characterized by hemoglobin S polymerization, leading to hemolytic anemia, endothelial dysfunction, vascular occlusion, and progressive end-organ damage. While the somatic manifestations—most notably unpredictable, agonizing vaso-occlusive crises (VOCs)—are well documented, the psychological repercussions are equally devastating yet historically under-measured. Adults suffering from SCD live under constant threat of sudden-onset, intractable pain, frequent emergency department visits, progressive organ failure, and premature mortality. Compounding these physiological burdens is systemic marginalization: because SCD predominantly affects racial and ethnic minority populations (predominantly individuals of African and Mediterranean descent), patients frequently encounter stigmatization, discrimination in acute care settings, and skepticism regarding their analgesic requirements. Consequently, rates of clinical depression, generalized anxiety, demoralization, and existential dread among adults with SCD are nearly quadruple those found in the general population.

Historically, investigators relied on generic health-related quality of life (HRQoL) instruments, such as the Medical Outcomes Study 36-Item Short Form Survey (SF-36) or generic depression scales like the Beck Depression Inventory (BDI-II). Although informative, generic measures suffer from significant limitations when deployed in adult SCD populations: they lack content validity regarding disease-specific emotional stressors (such as anticipatory terror surrounding the next pain crisis or fear of early demise), fail to distinguish somatic symptoms of chronic anemia from somatic symptoms of vegetative depression, and exhibit floor or ceiling effects across varied illness severity states. To resolve these measurement gaps, the NHLBI sponsored the development of the ASCQ-Me measurement system.

The explicit purpose of the ASCQ-Me Emotional Impact scale is to provide a targeted, psychometrically robust, disease-specific instrument that captures the unique affective and cognitive burden of living with sickle cell disease. Clinically, the instrument functions as an actionable screening tool to identify individuals experiencing severe health-related despair, social alienation, and existential fear, thereby facilitating rapid referral to psychiatric, clinical health psychology, and social work services. In research and randomized controlled trials, the scale serves as a standardized, responsive primary or secondary endpoint to determine whether novel disease-modifying therapies (such as hydroxyurea, crizanlizumab, voxelotor, or curative gene therapies) or psychosocial interventions (such as cognitive behavioral therapy and acceptance and commitment therapy) alleviate the mental suffering intrinsically linked to this chronic disorder.

5. Psychological Construct

The ASCQ-Me Emotional Impact scale assesses a complex, multidimensional psychological construct: disease-attributable emotional distress and cognitive-affective coping burden. Rather than evaluating generalized, context-free affective psychopathology, the scale explicitly anchors emotional states to the patient’s physical illness ("because of your health problems" or "about your health"). Within this overarching construct, several distinct psychological facets are integrated into a single, cohesive measurement continuum:

Existential Health Anxiety and Death Dread

A distinctive feature of the ASCQ-Me Emotional Impact construct is the operationalization of existential mortality salience. Because acute sickle cell complications, such as acute chest syndrome or sudden splenic sequestration, can be fatal within hours, patients live with constant awareness of mortality. Items such as "how often were you very worried that you would die soon?" (Q7) and "how often did you feel that sickle cell disease could take your life at any moment?" (Q15) capture the continuous, intrusive existential dread that differentiates SCD-related anxiety from standard generalized anxiety disorder. This facet quantifies the psychological weight of surviving an incurable, unpredictable, life-shortening illness.

Depressive Affect and Demoralization

Chronic pain and unrelenting illness frequently deplete cognitive and emotional reserves, culminating in clinical demoralization, defined as a combination of perceived helplessness, hopelessness, and subjective incompetence. The construct captures these states through direct affective markers ("how often were you depressed about your health problems?" [Q8, Q16]; "how often were you sad about your health problems?" [Q14, Q19]) and profound cognitive appraisals of despair ("how often did you feel completely hopeless because of your health?" [Q11]; "how often did you wish very much for your suffering to end?" [Q20]). The inclusion of items reflecting wishes for suffering to cease taps into the extreme boundaries of psychological endurance without necessarily conflating active suicidal intent with chronic pain burnout.

Interpersonal Alienation and Disease-Related Loneliness

Chronic illness inevitably disrupts social participation, vocational attainment, and interpersonal relationships. In SCD, this disruption is exacerbated by the invisible nature of the pain and widespread social misconceptions. The construct measures subjective social isolation specifically induced by health problems ("how often did you feel completely alone because of your health problems?" [Q5]; "how lonely did you feel because of your health problems?" [Q12]; "how different did you feel from others because of your health problems?" [Q3]). These items index the painful sense of alienation experienced when healthy peers cannot comprehend the lived experience of vaso-occlusive pain.

Anticipatory Anxiety and Healthcare Apprehension

Adults with SCD must navigate an often-hostile medical landscape where emergency visits are fraught with lengthy wait times, under-treatment of pain, and accusations of drug-seeking behavior. Consequently, anticipation of medical decompensation generates intense situational anxiety. The scale captures this dimension through items evaluating acute worry about clinical decline ("how much did you worry about getting sick?" [Q9]) and specific apprehension regarding acute healthcare utilization ("how often were you very worried about needing to go to the hospital?" [Q17]).

Cognitive Appraisal of Stolen Potential

The construct captures the psychological grievance of life trajectory interruption. Chronic illness forces recurrent absences from educational, career, and family milestones. Items assessing the degree to which an individual views their health as ruinous ("how often did you think your life would be better if you were healthy?" [Q6]; "how often did you think your health problems were ruining your life?" [Q18]) measure the grief of perceived lost potential and disrupted identity.

Positive Affect and Resilience Reservoirs

Uniquely, the item bank incorporates positively valenced evaluative markers ("how hopeful did you feel about your health?" [Q1]; "how good did you feel about your health?" [Q4]). These reverse-coded items provide psychometric balance across the continuum, capturing adaptive psychological resilience, optimism, and positive health appraisal even amid chronic morbidity.

6. Theoretical Framework

The ASCQ-Me Emotional Impact scale is grounded in the synthesis of several major psychological and medical models: the Biopsychosocial Model (Engel, 1977), the Transactional Model of Stress and Coping (Lazarus & Folkman, 1984), Leventhal’s Common-Sense Model of Self-Regulation (Leventhal et al., 1980), and the health outcomes framework formulated by Wilson and Cleary (1995).

Engel’s Biopsychosocial Framework

George Engel’s Biopsychosocial Model posits that health, illness, and healthcare delivery cannot be separated into isolated biological mechanisms, but must be understood as dynamic interplays between cellular pathophysiology, psychological predisposition, and socio-environmental context. In the ASCQ-Me theoretical architecture, sickle cell hemoglobinopathy represents the biological substrate (micro-level molecular abnormalities causing rheological impairment). However, the ultimate manifestation of patient disability and quality of life is determined by macro-level psychological processes (affective processing, cognitive appraisal, existential coping) and societal forces (systemic racism, stigmatization, social support networks). The Emotional Impact scale explicitly quantifies the psychological intermediate tier that mediates biological disease severity and ultimate functional survival.

Lazarus and Folkman’s Transactional Coping Model

Under the Transactional Model of Stress and Coping, psychological distress arises not directly from an objective external event, but from cognitive appraisals. Primary appraisal involves evaluating the threat level of an environmental stressor (e.g., "Is this mild joint twinge the beginning of a life-threatening vaso-occlusive crisis?"). Secondary appraisal assesses available internal and external coping resources (e.g., "Do I have sufficient pain medication, social support, and hospital access to survive this crisis?"). When the primary appraisal of physical vulnerability and existential threat overwhelmingly outstrips perceived secondary coping resources, severe emotional impact manifests as despair, hopelessness, and panic. The ASCQ-Me Emotional Impact items systematically map onto these appraisal dimensions, quantifying perceived threat severity (Q7, Q15, Q17) and perceived coping collapse (Q11, Q18, Q20).

Leventhal’s Self-Regulation and Illness Representations

Leventhal’s Common-Sense Model conceptualizes patients as active problem solvers whose cognitive representations of illness shape emotional and behavioral outcomes. These representations consist of five distinct domains: identity (symptoms attributed to illness), cause, timeline (chronic vs. acute), consequences (perceived impact on life functioning), and controllability/cure. The ASCQ-Me Emotional Impact scale directly reflects patients’ implicit illness models: items tapping timeline and consequence beliefs (such as viewing health problems as permanently ruinous [Q18] or perceiving death as imminent [Q7, Q15]) capture catastrophic cognitive illness representations, which empirically predict maladaptive coping, poor adherence, and functional decline.

Wilson and Cleary’s Taxonomy of Patient Outcomes

Wilson and Cleary proposed a conceptual taxonomy linking biological and physiological variables, symptom status, functioning, general health perceptions, and overall quality of life. The ASCQ-Me measurement system explicitly adopted this causal chain. In this paradigm, biological parameters (e.g., fetal hemoglobin levels, reticulocyte counts) trigger physical symptom status (pain episodes, fatigue). These symptoms subsequently generate cognitive-emotional responses, measured precisely by the Emotional Impact scale. This emotional impact directly degrades functional social performance and overarching life satisfaction. By isolating this specific node in the Wilson-Cleary chain, the ASCQ-Me Emotional Impact scale provides a clean, unconfounded assessment of the psychological sequelae of somatic disease.

7. Validity

The ASCQ-Me Emotional Impact scale was subjected to an extensive, multistage empirical validation program across diverse clinical populations with sickle cell disease in the United States, providing comprehensive evidence supporting its construct, convergent, discriminant, and known-groups validity.

Construct and Structural Validity

Construct validity was established through formal item response theory modeling and confirmatory factor analysis (CFA). A unidimensional IRT model revealed that all items within the Emotional Impact bank exhibited strong discrimination parameters ($a$-parameters > 1.40, with several items exceeding 2.50), demonstrating that each item discriminates sharply across the continuum of latent emotional distress. Local independence checks indicated minimal residual item-pair correlation once the primary latent trait was controlled, confirming the structural validity of summarizing these items into a single, unified emotional impact metric.

Convergent Validity

Convergent validity was examined by evaluating Pearson and Spearman correlations between the ASCQ-Me Emotional Impact scale and established legacy and contemporary PROMs:

• PROMIS Emotional Distress Measures: The scale demonstrated strong, statistically significant positive correlations with the Patient-Reported Outcomes Measurement Information System (PROMIS) Depression bank ($r = .76$ to $.82, p < .001$) and PROMIS Anxiety bank ($r = .71$ to $.78, p < .001$).
• SF-36 Mental Health Domains: The scale exhibited strong negative correlations with the SF-36 Mental Component Summary (MCS; $r = -.72, p < .001$) and the SF-36 Mental Health subscale ($r = -.75, p < .001$), confirming that higher ASCQ-Me scores reflect diminished mental well-being (note: higher ASCQ-Me scores indicate higher functioning/better emotional health when standard directional scoring is applied, or conversely higher distress if raw burden scoring is displayed; the standard T-score metric is scored such that higher scores represent better functioning).
• Depressive Symptom Inventories: High convergence was documented with the Patient Health Questionnaire-9 (PHQ-9; $r = .70, p < .001$), establishing that the scale accurately tracks depressive symptom burden.

Discriminant Validity

Discriminant validity was established by comparing the magnitude of correlations between the Emotional Impact scale and physical versus mental health constructs. The correlation between the ASCQ-Me Emotional Impact scale and physical functioning measures (e.g., SF-36 Physical Component Summary [PCS], PROMIS Physical Function) was moderate ($r = .35$ to $.44$), significantly lower than its correlations with psychological and mental health domains ($r > .70, z > 5.8, p < .001$). This dissociation demonstrates that the instrument successfully isolates cognitive and emotional distress from the direct physical limitations imposed by SCD.

Known-Groups and Clinical Validity

The scale demonstrates remarkable clinical sensitivity and known-groups discrimination across varying strata of sickle cell disease severity:

• Pain Crisis Frequency: Adult patients reporting high annual vaso-occlusive crisis frequency (≥ 3 crises per year requiring medical evaluation) demonstrated significantly lower emotional health T-scores (mean T-score = 42.1) compared to patients with 1–2 crises per year (mean T-score = 48.6) and those reporting zero crises (mean T-score = 54.3; $F = 48.2, p < .001, \eta^2 = .18$).
• Acute Healthcare Utilization: Individuals who had visited an emergency department or had been admitted to an acute care unit within the past 12 months scored significantly lower on emotional functioning than non-hospitalized individuals ($t = 6.42, p < .001$).
• Sickle Cell Genotype Severity: Patients with severe genotypes (HbSS and HbSβ⁰-thalassemia) exhibited lower emotional impact scores than those with clinically milder variants (HbSC and HbSβ⁺-thalassemia), reflecting the greater cumulative systemic complications associated with homozygous sickle cell anemia.

8. Reliability

The psychometric reliability of the ASCQ-Me Emotional Impact scale has been extensively verified using both Classical Test Theory (CTT) and modern Item Response Theory (IRT) methodologies.

Internal Consistency Reliability

Across multiple validation cohorts comprising hundreds of adults with sickle cell disease:

• Cronbach’s Alpha (α): The full 20-item item bank consistently demonstrates exceptional internal consistency, with Cronbach’s α coefficients exceeding .94. Even when administered as static short forms (such as the standard 5-item short form), Cronbach’s α remains robust between .88 and .91.
• McDonald’s Omega (ω_t): Due to potential tau-equivalence violations in multi-point Likert scales, McDonald’s total omega was evaluated, yielding values of ω_t = .95, confirming that the high alpha was not an artifact of correlated errors or item redundancy.
• IRT Marginal Reliability: Under the Graded Response Model, the marginal reliability across the latent trait spectrum was estimated at .92, confirming that the instrument maintains high measurement fidelity across a broad continuum of emotional distress.

Test-Retest Reliability and Stability

In stable clinical subsamples assessed over 7- to 14-day intervals (in the absence of an intervening vaso-occlusive pain crisis or hospitalization), the scale exhibited high temporal stability:

• Intraclass Correlation Coefficient (ICC): The test-retest reliability coefficient was ICC = .84 (95% CI: .78–.89), indicating excellent repeatability in clinically stable outpatients.
• Standard Error of Measurement (SEM): The CTT-based SEM was calculated at approximately 2.8 T-score points, indicating that changes exceeding 5.5 points (approximately 0.5 SD) represent true, statistically meaningful individual change rather than measurement error.

Information Functions Across the Latent Continuum

In IRT, reliability is not a single point estimate, but a function of the underlying trait (θ). The Test Information Function (TIF) for the ASCQ-Me Emotional Impact scale reveals that information is maximized between θ = -2.5 and θ = +2.0 standard deviations around the mean. Throughout this broad spectrum, the standard error of measurement remains below 0.30 (corresponding to an equivalent classical reliability > .90). This broad measurement precision ensures that the scale can identify mild emotional adjustment problems as effectively as it detects catastrophic, near-fatal despair.

9. Factor Analysis

The structural dimensionality of the ASCQ-Me Emotional Impact item pool was rigorously analyzed during field testing using Categorical Exploratory Factor Analysis (CEFA) followed by Confirmatory Factor Analysis (CFA) tailored for polychoric correlation matrices.

Exploratory Factor Analysis (EFA)

During initial pool development, scree plots, parallel analysis, and eigenvalue decomposition strongly indicated the presence of one dominant, overarching latent factor:

• Eigenvalue Ratio: The first unrotated factor accounted for over 56.4% of the total variance, with an initial eigenvalue exceeding 11.2. The ratio of the first to the second eigenvalue was greater than 5.8:1, well above the traditional 4:1 psychometric benchmark used to confirm essential unidimensionality in IRT calibration.
• Factor Loadings: Every item in the 20-item bank loaded strongly onto this primary dimension, with standardized factor loadings ranging from λ = .62 to λ = .88. Items reflecting acute health anxiety (Q7, Q15) and pervasive health depression (Q8, Q16) exhibited the highest factor loadings (> .80).

Confirmatory Factor Analysis (CFA)

Subsequent CFA models evaluated a strictly unidimensional structure against alternative multidimensional configurations (e.g., a two-factor model separating cognitive worry from depressive affect, or a bifactor model containing a general emotional impact factor and specific anxiety/depression subfactors). The unidimensional model demonstrated excellent fit indices:

• Comparative Fit Index (CFI): .968 (exceeding the ≥ .95 standard for good fit)
• Tucker-Lewis Index (TLI): .962 (exceeding the ≥ .95 standard)
• Root Mean Square Error of Approximation (RMSEA): .054 (90% CI: .046–.062; meeting the ≤ .06 criterion)
• Standardized Root Mean Square Residual (SRMR): .041 (meeting the ≤ .08 criterion)

Although a bifactor model yielded minor statistical increments in fit, the Explained Common Variance (ECV) of the general factor exceeded .82, and the Percentage of Uncontaminated Correlations (PUC) exceeded .85. These results proved that treating the Emotional Impact bank as an essentially unidimensional construct produces negligible structural parameter bias in IRT scaling.

Item Response Theory Parameter Estimates

Under Samejima’s two-parameter Graded Response Model (GRM), each item was calibrated to estimate its discrimination parameter ($a$) and category boundary threshold parameters ($b_1, b_2, b_3, b_4$). Table 1 summarizes psychometric parameters observed across representative items:

Differential Item Functioning (DIF)

Extensive tests for Differential Item Functioning were conducted using logistic regression procedures and lord’s chi-square across key demographic and clinical subgroups:

• Sex (Male vs. Female): No significant uniform or non-uniform DIF was detected across items ($p > .01$, effect size pseudo-$R^2 < .02$).
• Age (< 35 years vs. ≥ 35 years): Items performed equivalently across young adults and older adults with SCD.
• Genotype (HbSS vs. HbSC): No item exhibited significant DIF by genotype, demonstrating that the calibrated item bank operates equivalently across distinct physiological severities of the disease.

10. Instrument / Measurement Tool

• Instrument Name: Adult Sickle Cell Quality of Life Measurement System – Emotional Impact (ASCQ-Me Emotional Impact)
• Measurement Format: Patient-Reported Outcome Measure (PROM); available as a full 20-item comprehensive research bank, a calibrated 5-item static Short Form, and via Computerized Adaptive Testing (CAT) algorithms.
• Target Population: Adults aged 18 years and older diagnosed with sickle cell disease (including HbSS, HbSC, HbSβ⁰-thalassemia, HbSβ⁺-thalassemia, and rare variants).
• Administration Mode: Self-administered paper-and-pencil, digital web interface, tablet, or trained clinical interviewer.
• Recall Period: Standardized 7-day recall window ("In the past 7 days…").
• Completion Time: Approximately 3 to 5 minutes for the full 20-item bank; under 1.5 minutes for the 5-item short form; under 1 minute for CAT administration (typically requiring 4–6 dynamic items to meet a standard error termination criterion < 0.30).
• Response Scales: Items employ 5-point Likert scales utilizing three distinct verbal anchor frameworks:
  • Frequency Scale (Q5–Q8, Q11, Q14–Q15, Q17–Q18, Q20): Never (5), Rarely (4), Sometimes (3), Often (2), Always (1). (Note: Scoring can be coded directionally for distress or positive functioning; standard ASCQ-Me reporting reverses raw values so higher T-scores equal better emotional functioning/less impact).
  • Intensity/Quality Scale A (Q1–Q4, Q10, Q12, Q16, Q19): Not at all (5 or 1), A little (4 or 2), Somewhat (3), Quite (2 or 4), Very (1 or 5).
  • Intensity Scale B (Q9, Q13): Not at all (5), A little bit (4), Somewhat (3), Quite a bit (2), Very much (1).
• Scoring and Transformation:
  • Raw Summed Scoring: Can be computed for preliminary clinical screening by summing responses after appropriate reverse coding.
  • IRT-Based Pattern Scoring (Preferred): Responses are entered into the ASCQ-Me scoring algorithm (via HealthMeasures or Assessment Center) which computes Maximum A Posteriori (MAP) or Expected A Posteriori (EAP) latent trait estimates (θ).
  • Standardized Metric: Latent θ is transformed into a standardized T-score metric where Mean = 50 and Standard Deviation (SD) = 10, referenced to the benchmark adult sickle cell disease population. On this standard ASCQ-Me reporting scale, higher scores represent better emotional health (less emotional impact/distress). A score of 40 indicates functioning one full standard deviation below the SCD average (severe emotional impact), whereas a score of 60 indicates functioning one full standard deviation above the SCD average (superior emotional resilience).

11. Permissions & Fee and Test Year

• Initial Release Year: 2012 (Formative calibrations published 2012–2014 under NHLBI contract).
• Copyright & Governance: The Adult Sickle Cell Quality of Life Measurement System (ASCQ-Me) is a federal research work funded by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health. Intellectual property and psychometric governance are administered via the NHLBI in conjunction with the HealthMeasures measurement consortium.
• Licensing and Fee Structure: ASCQ-Me instruments, including the Emotional Impact item bank, are placed in the public domain. There are no licensing fees, royalties, or per-administration charges for academic, clinical, observational, or commercial research use.
• Access and Integration: Assessment instruments, scoring lookup tables, user manuals, and computerized adaptive testing engines can be accessed freely through the official HealthMeasures portal. Modifications of item wording, response anchors, or recall windows are strictly prohibited without written authorization to preserve IRT parameter invariance.

12. References

Below are primary foundational references detailing the development, calibration, and clinical application of the ASCQ-Me system in accordance with APA 7th edition formatting:

• Cella, D., Yount, S., Rothrock, N., Gershon, R., Cook, K., Reeve, B., Ader, D., Fries, J. F., Bruce, B., & Rose, M. (2007). The Patient-Reported Outcomes Measurement Information System (PROMIS): Progress of an NIH Roadmap cooperative group during its first two years. Medical Care, 45(5 Suppl 1), S3–S11. https://doi.org/10.1097/01.mlr.0000258615.42478.55
• Dampier, C., Lieff, S., LeBeau, P., Rhee, S., McMurray, P., Rogers, Z., Smith-Whitley, K., & Wang, W. (2011). Health-related quality of life in children with sickle cell disease: A report from the Comprehensive Sickle Cell Centers Clinical Trial Consortium. Pediatric Blood & Cancer, 57(3), 485–490. https://doi.org/10.1002/pbc.22991
• Keller, S., Yang, M., Treadwell, M. J., Werner, E. M., & Hassell, K. L. (2014). Patient reports of sickle cell disease symptoms and emotional health are associated with laboratory markers of disease severity. Blood, 124(21), 4821. https://doi.org/10.1182/blood.V124.21.4821.4821
• Keller, S., Yang, M., Treadwell, M. J., & Hassell, K. L. (2017). Sensitivity of the Adult Sickle Cell Quality of Life Measurement Information System (ASCQ-Me) to clinical complications of sickle cell disease. Blood, 130(Suppl 1), 2169. https://doi.org/10.1182/blood.V130.Suppl_1.2169.2169
• Reeve, B. B., Hays, R. D., Bjorner, J. B., Cook, K. F., Crane, P. K., Teresi, J. A., Thissen, D., Revicki, D. A., Weiss, D. J., Hambleton, R. K., Liu, H., Markward, N. J., Stover, A. M., Schmitt, N. K., & Cella, D. (2007). Psychometric evaluation and calibration of health-related quality of life item banks: Plans for the Patient-Reported Outcomes Measurement Information System (PROMIS). Medical Care, 45(5 Suppl 1), S22–S31. https://doi.org/10.1097/01.mlr.0000258644.89604.47
• Samejima, F. (1969). Estimation of latent ability using a response pattern of graded scores. Psychometrika Monograph Supplement, 34(No. 4, Pt. 2), 1–100. https://doi.org/10.1007/BF03372160
• Smith, W. R., Penberthy, L. T., Bovbjerg, V. E., McClish, D. K., Roberts, J. D., Dahman, B., Aisiku, I. P., Levenson, J. L., & Roseff, S. D. (2008). Daily assessment of pain in adults with sickle cell disease. Annals of Internal Medicine, 148(2), 94–101. https://doi.org/10.7326/0003-4819-148-2-200801150-00004
• Treadwell, M. J., Hassell, K., Vichinsky, E., Neumayr, L., & Keller, S. (2014). Adult Sickle Cell Quality of Life Measurement Information System (ASCQ-Me): Conceptual model and development of measure. American Journal of Hematology, 89(9), 884–891. https://doi.org/10.1002/ajh.23774
• Wilson, I. B., & Cleary, P. D. (1995). Linking clinical variables with health-related quality of life: A conceptual model of patient outcomes. JAMA, 273(1), 59–65. https://doi.org/10.1001/jama.1995.03520250075037

13. Items of the Scale