Vascular Quality of Life Questionnaire

Abstract

The Vascular Quality of Life Questionnaire (Vascu-QoL) is a disease-specific, patient-reported outcome measure (PROM) developed by Morgan, Crayford, Murrin, and Fraser in 2001 to evaluate health-related quality of life (HRQoL) in individuals diagnosed with lower extremity peripheral artery disease (PAD), spanning intermittent claudication to chronic limb-threatening ischemia. Comprising 25 items, the instrument captures the multidimensional burden of peripheral arterial occlusive pathology across five distinct domains: Pain (4 items), Symptoms (4 items), Activities (8 items), Social (2 items), and Emotional (7 items). Each item is evaluated on an authentic 7-point Likert-type scale specific to each question, where a score of 1 represents the worst health state or greatest degree of functional impairment, and a score of 7 denotes the optimal health state or absence of limitation.

Psychometric evaluations across diverse international cohorts demonstrate that the Vascu-QoL possesses exceptional internal consistency reliability, with Cronbach’s alpha coefficients typically exceeding α = .90 for the overall scale and ranging between .70 and .92 across the subscales. Test-retest reliability intraclass correlation coefficients (ICC) consistently exceed .85 in clinically stable cohorts. Construct validity is supported by strong convergent associations with objective hemodynamic markers such as the ankle-brachial index (ABI), treadmill-determined pain-free and maximal walking distances, and established generic instruments such as the Short Form Health Survey (SF-36). Exploratory and confirmatory factor analyses validate its five-domain architecture while supporting an overarching unidimensional general HRQoL factor. Its documented responsiveness to conservative exercise programs, endovascular revascularization, and open surgical interventions positions the Vascu-QoL as an indispensable clinical and research instrument in vascular medicine, angiology, and vascular surgery.

Keywords

Vascular Quality of Life Questionnaire, Vascu-QoL, Peripheral Artery Disease, Health-Related Quality of Life, Intermittent Claudication, Chronic Limb-Threatening Ischemia, Patient-Reported Outcome Measure, Psychometrics, Factor Analysis, Construct Validity

Authors

The Vascular Quality of Life Questionnaire (Vascu-QoL) was developed and validated by a multidisciplinary team of clinicians, vascular surgeons, and health services researchers based in the United Kingdom:

• M. B. Morgan, Department of Vascular Surgery and Department of Public Health Medicine, King’s College London and St Thomas’ Hospital, London, United Kingdom.
• T. Crayford, Department of Public Health Medicine, King’s College London School of Medicine, London, United Kingdom.
• R. Murrin, Department of Vascular and Endovascular Surgery, Guy’s and St Thomas’ NHS Foundation Trust, London, United Kingdom.
• P. A. Fraser, Department of Vascular Surgery, King’s College Hospital, London, United Kingdom.

The primary validation study was conducted within the academic vascular units of King’s College Hospital and Guy’s and St Thomas’ Hospitals in London, addressing the need for a dedicated, sensitive, disease-specific psychometric questionnaire capable of reflecting subtle clinical changes in patients suffering from varying stages of peripheral arterial occlusive disease.

Purpose

Peripheral artery disease (PAD) is a chronic atherosclerotic condition characterized by progressive luminal narrowing of the lower limb arterial tree. While traditional clinical paradigms have prioritized objective hemodynamic parameters such as the ankle-brachial index (ABI), Doppler waveform morphology, absolute walking distances, and angiographic patency, these physiological measures correlate weakly with a patient’s personal perception of illness, physical impairment, and psychosocial suffering. Generic HRQoL instruments, such as the Medical Outcomes Study 36-Item Short Form Survey (SF-36) or the EuroQol 5-Dimension (EQ-5D), often lack the sensitivity required to detect the unique functional restrictions, microvascular pain syndromes, and limb-loss anxieties characteristic of lower extremity vascular compromise.

The primary purpose of the Vascu-QoL is to provide a standardized, psychometrically rigorous, disease-specific assessment tool designed to quantify the multidimensional impact of lower extremity ischemia on daily life. Clinically, the instrument fulfills three principal functions:

1. Baseline Disease Burden Stratification: It establishes the subjective severity of PAD across both symptomatic claudicants and patients with advanced chronic limb-threatening ischemia (CLTI), capturing symptom frequency, lifestyle restriction, and emotional distress.
2. Monitoring Therapeutic Response: The Vascu-QoL is responsive to clinical transitions, allowing clinicians and researchers to track therapeutic efficacy following structured supervised exercise therapy, pharmacological treatment (e.g., cilostazol), percutaneous transluminal angioplasty, stenting, or arterial bypass surgery.
3. Shared Decision-Making and Clinical Trials: In clinical trial designs, the scale serves as a standardized primary or secondary endpoint to benchmark patient-centered outcomes, aligning intervention success with meaningful improvements in functional autonomy, pain alleviation, and psychological well-being.

The theoretical rationale rests on the principle that the patient is the ultimate evaluator of therapeutic benefit. By translating physical pathology into quantifiable patient-reported domains, the Vascu-QoL ensures that vascular treatment strategies do not merely revascularize vessels on an angiogram, but tangibly enhance everyday functional capacity, sleep quality, psychological resilience, and social interaction.

Psychological Construct

The Vascu-QoL operationalizes health-related quality of life (HRQoL) as a hierarchical, multifaceted psychological and functional construct. Grounded in the World Health Organization’s (WHO) conceptualization of health as a state of complete physical, mental, and social well-being, the instrument disaggregates the overall disease experience into five primary dimensions:

1. Pain (4 Items)

Lower extremity arterial insufficiency induces profound ischemia-driven pain phenotypes. This domain evaluates the frequency, intensity, and disruptive reach of pain. It measures exercise-induced claudication distress (pain precipitated by walking) as well as the more severe nocturnal and resting ischemic manifestations that disrupt sleep architecture. The construct addresses not only the presence of pain, but also how recurrent nociceptive signaling causes sleep fragmentation and nocturnal awakening, producing chronic sleep deprivation and psychological distress.

2. Symptoms (4 Items)

Beyond macrovascular pain, PAD manifests through diverse neurovascular and microvascular sensations. The symptoms domain evaluates the severity of rest aching or cramping, distal extremity coldness, dependent swelling, ischemic paresthesias (burning sensations, numbness, or “pins and needles”), and the discomfort stemming from ischemic skin lesions, trophic skin changes, and foot ulcerations. This domain captures the physical sensory burdens that persist even when the patient is sedentary.

3. Activities (8 Items)

This subscale constitutes the largest functional domain within the instrument, capturing physical performance and mobility restrictions. Reflecting the International Classification of Functioning, Disability and Health (ICF) framework, it measures limitations in basic activities of daily living (ADLs) and instrumental activities of daily living (IADLs). Specific operationalized markers include level-ground walking tolerance, hill and stair climbing capacity, domestic chores (housework, yard work, shopping), prolonged standing, and general functional independence versus physical caregiver reliance.

4. Social (2 Items)

Vascular disease limits social mobility and interaction. The social domain assesses the degree to which arterial disease restricts the patient’s broader social life and their capacity to visit family, friends, and community venues. By capturing the contraction of the patient’s social radius, this construct reflects the risk of social isolation, diminished social support networks, and reduced participation in leisure activities directly attributable to restricted ambulatory range.

5. Emotional (7 Items)

The chronic, progressive, and limb-threatening nature of peripheral arterial disease imposes a significant psychological toll. The emotional domain quantifies illness-related affective and cognitive distress. It systematically assesses emotional frustration, health-related anxiety, depressive mood, feelings of being an interpersonal burden to family, loss of perceived personal autonomy, generalized irritability, and the existential fear of limb loss or major surgical amputation. This dimension acknowledges that the psychological sequelae of vascular disease are pervasive, often exacerbating perceived disability and lowering compliance with medical regimens.

Theoretical Framework

The construction and validation of the Vascu-QoL are anchored in prominent psychometric, medical-sociological, and cognitive-behavioral paradigms. Conceptually, the questionnaire integrates the Wilson and Cleary Model of Health-Related Quality of Life (Wilson & Cleary, 1995), which links biological and physiological variables, symptom status, functional status, general health perceptions, and overall quality of life into a causal continuum:

Biological / Vascular Pathology → Symptom Status → Functional Limitations → General Health Perceptions → Overall Quality of Life

Under this paradigm, arterial stenosis (a biological variable measured via angiography or ABI) leads to tissue hypoxia and claudication or rest pain (symptom status). These symptoms subsequently impede walking distance, climbing stairs, and carrying out domestic responsibilities (functional status). Over time, persistent functional impairment alters self-concept, fosters fear of amputation, and induces depressive affect (general health perceptions), culminating in diminished overall HRQoL.

Additionally, the scale draws upon Lazarus and Folkman’s Transactional Model of Stress and Coping. Living with a progressive circulatory disorder represents a chronic stressor characterized by unpredictable physical decline. The cognitive appraisals patients make regarding their somatic signals—such as interpreting leg fatigue as imminent gangrene or viewing reduced walking speed as personal helplessness—shape affective responses such as anxiety, depression, and social withdrawal. The Vascu-QoL measures both the somatic demand characteristics and the psychological appraisal processes (e.g., worry about worsening circulation, feeling like an interpersonal burden).

From a psychometric measurement theory perspective, the tool was conceptualized under Classical Test Theory (CTT), prioritizing domain-specific content validity, high item-total correlation, low measurement error, and linear score tractability, while subsequent cross-cultural adaptations have increasingly employed Item Response Theory (IRT) and Rasch modeling to confirm invariant measurement properties across demographic subgroups.

Validity

The Vascu-QoL has undergone rigorous psychometric validation across numerous observational cohorts, clinical trials, and international registries, demonstrating robust construct, convergent, discriminant, and criterion-related validity.

Construct and Convergent Validity

Construct validity was initially established by comparing Vascu-QoL domain and summary scores against established physiological markers and generic HRQoL instruments. Convergent validity is confirmed by moderate to strong, statistically significant correlations with the Medical Outcomes Study 36-Item Short Form Survey (SF-36). The Vascu-QoL Activities and Pain domains correlate strongly with the SF-36 Physical Functioning (PF) and Bodily Pain (BP) subscales (Pearson r values typically ranging between .65 and .82, p < .001). The Emotional domain shows high concordance with the SF-36 Mental Health (MH) and Role-Emotional (RE) scales (r = .60 to .75).

When evaluated against objective functional measures, Vascu-QoL total and activity scores correlate moderately with treadmill-based assessments: pain-free walking distance (PFWD: r = .45 to .62) and maximum walking distance (MWD: r = .48 to .67). Significant positive correlations are also observed with resting and post-exercise ankle-brachial index (ABI) measurements (r = .30 to .50), reflecting the expected moderate alignment between physiological perfusion deficits and experienced functional impairment.

Known-Groups (Discriminant) Validity

The questionnaire discriminates between clinical severity strata as categorized by the Fontaine classification (Stage I: asymptomatic; Stage IIa/IIb: mild-to-severe claudication; Stage III: ischemic rest pain; Stage IV: ulceration or gangrene) and the Rutherford categorization (Categories 0 through 6). Vascu-QoL summary scores decline monotonically from Fontaine Stage II (mean scores typically around 4.2 to 5.1) to Fontaine Stages III and IV (mean scores often falling below 2.5 to 3.2), confirming its ability to capture progressive disease severity (p < .001 across ANOVA cohorts).

Responsiveness and Longitudinal Validity

A primary psychometric strength of the Vascu-QoL is its longitudinal responsiveness to therapeutic interventions. In cohorts undergoing successful revascularization (angioplasty, stenting, or surgical bypass), effect sizes (Cohen’s d) and standardized response means (SRM) range from 0.80 to 1.45 at 3- and 6-month follow-up, indicating high sensitivity to clinical improvement. Conversely, patients with disease progression or failed interventions show corresponding declines in scores. The minimal clinically important difference (MCID) has been established in multiple validation studies as approximately 0.36 to 0.50 points on the 7-point summary scale, providing a benchmark for interpreting clinical meaningfulness in research trials.

Reliability

The reliability of the Vascu-QoL has been evaluated across multiple language translations (including British English, American English, Dutch, Swedish, German, Spanish, and Chinese) and clinical settings.

Internal Consistency

Internal consistency reliability, assessed via Cronbach’s alpha (α), exceeds standard psychometric thresholds (≥ .70 for research, ≥ .90 for individual clinical decision-making) across global studies:

• Total Instrument (25 Items): Cronbach’s alpha consistently ranges between α = .92 and .95, reflecting high scale homogeneity without redundancy.
• Activities Subscale: α = .88 to .93
• Pain Subscale: α = .78 to .86
• Emotional Subscale: α = .84 to .89
• Symptoms Subscale: α = .70 to .79
• Social Subscale: α = .72 to .81

Corrected item-total correlations for all individual items remain above .40, with the majority falling between .55 and .78.

Test-Retest Reliability

In stable clinical populations assessed across two- to four-week intervals without intervening surgical or medical changes, the Vascu-QoL demonstrates high test-retest reproducibility. Intraclass correlation coefficients (ICC, two-way mixed effects model) for the total score range from .86 to .94. Domain-specific ICC values remain robust: Activities (.88 to .92), Pain (.82 to .89), Emotional (.81 to .87), Symptoms (.76 to .83), and Social (.74 to .82). Bland-Altman limit-of-agreement analyses confirm the absence of systematic bias across repeated administrations.

Factor Analysis

The structural dimensionality of the Vascu-QoL has been confirmed using both exploratory factor analysis (EFA) and confirmatory factor analysis (CFA), supporting the original five-domain model proposed by Morgan et al. (2001).

Exploratory Factor Analysis (EFA)

In the original developmental cohort, principal components analysis (PCA) with varimax and oblimin rotations identified five distinct eigenvalues greater than 1.0, accounting for approximately 64% to 70% of the total variance across items. The factor loading matrix revealed strong clustering corresponding to:

• Factor 1 (Activities): Items 2, 4, 8, 11, 15, 17, 21, and 25 exhibited high primary loadings (range: .58 to .84) with minimal cross-loadings.
• Factor 2 (Emotional): Items 3, 10, 16, 18, 20, 22, and 24 loaded between .52 and .81.
• Factor 3 (Pain): Items 1, 6, 12, and 14 grouped together with loadings ranging from .61 to .85.
• Factor 4 (Symptoms): Items 7, 13, 19, and 23 formed an independent factor reflecting non-ambulatory sensory and trophic signs (loadings: .50 to .76).
• Factor 5 (Social): Items 5 and 9 loaded strongly (> .75) onto a dedicated interpersonal/social dimension.

Confirmatory Factor Analysis (CFA)

Subsequent psychometric investigations evaluating the latent structure in large multi-center cohorts using structural equation modeling have verified acceptable fit indices for the hypothesized 5-factor correlated model. Goodness-of-fit statistics across representative validation studies yield:

• Root Mean Square Error of Approximation (RMSEA): .048 to .062 (indicating close approximate fit).
• Comparative Fit Index (CFI): .92 to .96 (exceeding the standard .90 threshold).
• Tucker-Lewis Index (TLI): .91 to .95.
• Standardized Root Mean Square Residual (SRMR): .045 to .058.

Bifactor modeling and second-order CFA models also demonstrate that while the five individual domains have distinct construct identity, their moderate inter-correlations (r = .45 to .72) justify the calculation and clinical interpretation of a single, overarching total HRQoL score.

Instrument / Measurement Tool

The operational characteristics, administration requirements, and structural parameters of the Vascu-QoL are detailed below:

• Test Type: Disease-specific patient-reported outcome measure (PROM) / Self-administered psychometric questionnaire (also administrable via structured face-to-face or telephone interview).
• Format: Paper-and-pencil or secure electronic/digital assessment interface.
• Item Count: 25 items.
• Target Population: Adult and elderly individuals diagnosed with peripheral artery disease (Fontaine Stages I–IV; Rutherford Categories 0–6).
• Recall Period: Past two weeks (“In the past two weeks…”).
• Domain Allocations:
  • Pain (4 items): Items 1, 6, 12, 14
  • Symptoms (4 items): Items 7, 13, 19, 23
  • Activities (8 items): Items 2, 4, 8, 11, 15, 17, 21, 25
  • Social (2 items): Items 5, 9
  • Emotional (7 items): Items 3, 10, 16, 18, 20, 22, 24
• Response Format: Authentic 7-point Likert-type scale specific to each question (ranging from 1 = worst health state/greatest impairment to 7 = best health state/no impairment).
• Scoring Algorithm:
  • Each item is scored from 1 (poorest health status / maximum restriction) to 7 (best health status / no restriction).
  • Subscale Scores: Calculated as the arithmetic mean of the completed items within each respective domain (Sum of domain item scores divided by the number of items in that domain). Subscale scores range from 1.0 to 7.0.
  • Total Score: Calculated as the overall arithmetic mean across all 25 items (Sum of all completed items divided by 25). The total score ranges from 1.0 to 7.0.
  • Handling Missing Data: If no more than one item is missing within a specific domain (or ≤ 2 items missing across the entire instrument), the mean of the completed domain items can be imputed for the missing values. If more than 20% of items are missing, the protocol suggests invalidating that administration.
• Completion Time: Approximately 8 to 12 minutes.

Permissions & Fee and Test Year

The Vascular Quality of Life Questionnaire (Vascu-QoL) was originally published in 2001 by M. B. Morgan and colleagues. The scale was established as an academic instrument intended to advance clinical research, surgical outcome tracking, and quality improvement initiatives in vascular medicine. In general academic and non-commercial clinical trial environments, the questionnaire has been widely accessible without prohibitive fees, subject to proper academic citation and compliance with the authors’ copyright conditions. Institutional researchers, clinical registries, and commercial trial sponsors seeking to use the instrument, its validated foreign-language translations, or digital adaptations should contact the copyright holders, original development team at King’s College London / Guy’s and St Thomas’ NHS Foundation Trust, or authorized licensing management organizations to secure formal user agreements and scoring documentation.

References

• Morgan, M. B., Crayford, T., Murrin, R., & Fraser, P. A. (2001). Developing the Vascular Quality of Life Questionnaire: A new disease-specific measure for lower limb ischaemia. Journal of Vascular Surgery, 33(4), 679–687. https://doi.org/10.1067/mva.2001.112326
• de Vries, M., Ouwendijk, R., Kessels, A. G., de Haan, M. W., Flobbe, K., Hunink, M. G., van der Wilt, G. J., & Nelemans, P. J. (2005). Comparison of generic and disease-specific health-related quality of life measures in patients with peripheral arterial disease. Journal of Vascular Surgery, 41(2), 261–268. https://doi.org/10.1016/j.jvs.2004.11.021
• Nordanstig, J., Karlsson, J., & Hensater, M. (2012). Validation of the Swedish version of the Vascular Quality of Life Questionnaire (VascuQol) in patients with intermittent claudication and critical limb ischaemia. Health and Quality of Life Outcomes, 10, 112. https://doi.org/10.1186/1477-7525-10-112
• Abaraogu, U. O., Ezenwankwo, E. F., Dall, P. M., & Seenan, C. A. (2018). Living a life of restrictions: A qualitative systematic review of the experiences of individuals with intermittent claudication. Disability and Rehabilitation, 40(18), 2111–2122. https://doi.org/10.1080/09638288.2017.1334837
• 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

Items of the Scale