Assessment of Quality of Life (AQoL)

Abstract

The Assessment of Quality of Life (AQoL) is a widely utilized Multi-Attribute Utility Instrument (MAUI) developed for measuring Health-Related Quality of Life (HRQoL). Specifically, the AQoL-8D version, an advanced iteration of the original AQoL-4D and AQoL-6D scales, incorporates eight distinct dimensions of functioning and well-being. This instrument is highly valued in cost-utility analysis, as its structure permits the calculation of preference-based utility scores, which are essential for determining Quality Adjusted Life Years (QALYs) in health economic evaluations.

The AQoL-8D addresses known limitations in older MAUIs by enhancing coverage of psychosocial and mental health domains, making it particularly sensitive to health states affecting emotional and social well-being. It consists of 35 items that generate scores across eight domains, which are then aggregated into a single utility index score.

Keywords

Quality of Life, AQoL-8D, Health Economics, Utility Score, HRQoL, Multi-Attribute Utility Instrument, Psychometrics, Health Status Measurement, QALYs, Monash University.

Authors

Jeff Richardson, Angelo Iezzi, Kim Dalziel.

Purpose

The primary purpose of the AQoL-8D is to generate comprehensive, preference-based measures of health status suitable for rigorous economic evaluation and resource allocation decisions in healthcare. The scale is designed to quantify the value (utility) that society places on different health states.

Beyond economic modeling, the AQoL-8D serves a crucial descriptive function, offering detailed insights into a patient’s self-reported functioning across eight key dimensions, thus supporting clinical evaluation and monitoring the effectiveness of health interventions across diverse patient populations.

Construct

The AQoL-8D measures the construct of Health-Related Quality of Life (HRQoL), viewed as a multi-dimensional concept. Unlike purely descriptive scales, the AQoL-8D is rooted in welfare economics, utilizing community-derived preferences to assign utility weights to the health states described by the scale items. The eight dimensions measured by the AQoL-8D are:

• Independent Living
• Senses
• Pain
• Mental Health
• Coping
• Relationships
• Self-Worth
• Life Satisfaction

Validity

The AQoL-8D demonstrates strong empirical validity across multiple criteria. Its content validity is high, stemming from the exhaustive coverage of both physical and complex psychological and social dimensions, which often go uncaptured by simpler utility instruments. Construct validity has been established through comparisons with benchmark instruments (such as the EQ-5D and SF-36), consistently showing that the AQoL-8D is more sensitive and responsive, particularly to changes in mental health and psychosocial functioning.

Furthermore, the scale exhibits robust known-groups validity, successfully distinguishing between patients suffering from different chronic conditions or varying levels of severity, confirming its ability to accurately reflect true differences in health status and quality of life.

Reliability

Reliability analyses confirm the high internal consistency and stability of the AQoL-8D instrument. Studies show high internal consistency across all eight domains, typically indicated by Cronbach’s alpha coefficients exceeding 0.80, suggesting strong homogeneity among the items within each dimension. This robust psychometrics ensures that the instrument provides stable and dependable measurement over time, a vital characteristic for longitudinal studies and clinical trials assessing treatment efficacy.

Factor Analysis

The structural integrity of the AQoL-8D was meticulously confirmed using advanced multivariate statistical techniques, primarily Confirmatory Factor Analysis (CFA) and Item Response Theory (IRT). These analyses supported the hypothesized eight-factor structure, affirming that the instrument successfully measures eight distinct and largely independent health dimensions. This multi-dimensional structure is fundamental to the scale’s design, enabling the derivation of a comprehensive multi-attribute utility function that translates the eight domain scores into a single, preference-weighted utility index.

Instrument

Test Type: Preference-Based MAUI (Multi-Attribute Utility Instrument)

Format: Self-administered questionnaire, typically requiring 5–10 minutes to complete.

Language Available: Primarily English (Australian), with validated translations available in several European and Asian languages.

Population Group: General adult population and clinical populations across various disease states.

Age Group: Adolescents (14 years and older) and adults.

Population Details: Utility weights for the AQoL-8D were derived from Australian community samples using the Time Trade-Off (TTO) method.

Test Methodology: The scale uses 5- or 6-level response categories for its items. These responses are used to define 35 items across 8 dimensions. A multi-attribute utility function converts these responses into a single utility score anchored between 0 (death) and 1 (full health).

Keywords

QALYs, Health Status Measurement, Monash University, Time Trade-Off, Psychosocial Functioning, Health Utility, Economic Evaluation, HRQoL.

Authors

Author ORCID Identifier: Information varies by author; specific ORCID identifiers should be sought from relevant academic profiles.

Affiliation Email addresses: [email protected] (Centre for Health Economics, Monash University)

Correspondence Address: Centre for Health Economics, Monash University, Melbourne, Australia.

Permissions & Fee and Test Year

The AQoL instruments are administered and licensed by the Centre for Health Economics (CHE) at Monash University. While the scales are often provided free of charge for non-commercial academic research, a licensing fee is typically required for commercial applications, including pharmaceutical trials and proprietary use.

The development and initial validation of the AQoL-8D instrument occurred between 2012 and 2015, representing the most recent and comprehensive version of the AQoL family of scales.

Reference’s

Richardson, J., Iezzi, A., Khan, M. A., & Chen, G. (2014). The Assessment of Quality of Life (AQoL)-8D instrument: a measure of quality of life with eight dimensions. Health Economics, 23(2), 213-226.

Iezzi, A., & Richardson, J. (2017). Measuring quality of life using the Assessment of Quality of Life (AQoL) instruments. Monash University.

Monash University Centre for Health Economics. (2023). AQoL Instruments Documentation. Further documentation and scale files are available directly from the Monash CHE website.

Items of the Assessment of Quality of Life (AQoL)

IMPORTANT: The following scale items must be preserved in their original language and must not be changed in any way.

AQoL-8D

INDEPENDENT LIVING

Q1 How much help do you need with jobs around the house [your place of residence] (e.g.‚ preparing food‚ cleaning the house‚ or gardening)?

• I can do all these tasks very quickly and efficiently without any help
• I can do these tasks relatively easily without help
• I can do these tasks only very slowly without help
• I cannot do most of these tasks unless I have help
• I can do none of these tasks by myself

Q2 Thinking about how easy or difficult it is for you to get around by yourself outside your house (e.g.‚ shopping‚ visiting):

• getting around is enjoyable and easy
• I have no difficulty getting around outside my house
• a little difficulty
• moderate difficulty
• a lot of difficulty
• I cannot get around unless somebody is there to help me

Q3 Thinking about your mobility‚ including using any aids or equipment such as wheelchairs‚ frames‚ and sticks: [How easy or difficult is it for you to move around (using any aids or equipment you need eg a wheelchair‚ frame or stick)?]

• I am very mobile
• I have no difficulty with mobility
• I have some difficulty with mobility (for example‚ going uphill)
• I have difficulty with mobility. I can go short distances only
• I have a lot of difficulty with mobility. I need someone to help me
• I am bedridden.

Q4 Thinking about washing yourself‚ toileting‚ dressing‚ eating‚ or looking after your appearance: [How difficult is it for you to wash‚ toilet‚ dress yourself‚ eat or care for your appearance?]

• these tasks are very easy for me
• I have no real difficulty in carrying out these tasks
• I find some of these tasks difficult‚ but I manage to do them on my own
• many of these tasks are difficult‚ and I need help to do them
• I cannot do these tasks by myself at all.

LIFE SATISFACTION

Q5 How content are you with your life?

• extremely
• mainly
• moderately
• slightly
• not at all

Q6 How enthusiastic do you feel?

• extremely
• very
• somewhat
• not much
• not at all

Q7 How often do you feel happy?

• all the time
• mostly
• sometimes
• almost never
• never

Q8 How often do you feel pleasure?

• always
• usually
• sometimes
• almost never
• never

MENTAL HEALTH

Q9 How often do you feel depressed?

• never
• almost never
• sometimes
• often
• very often
• all the time

Q10 How often do you have trouble sleeping?

• never
• almost never
• sometimes
• often
• all the time

Q11 How often do you feel angry?

• never
• almost never
• sometimes
• often
• all the time

Q12 Do you ever feel like hurting yourself?

• never
• rarely
• sometimes
• often
• all the time

Q13 How often did you feel in despair over the last seven days?

• never
• occasionally
• sometimes
• often
• all the time

Q14 And still thinking about the last seven days‚ how often did you feel worried? [How often did you feel worried in the last seven days?]

• never
• occasionally
• sometimes
• often
• all the time

Q15 How often do you feel sad?

• never
• rarely
• some of the time
• usually
• nearly all the time

Q16 When you think about whether you are calm and tranquil or agitated [Do you normally feel calm and tranquil or agitated?]: I am:

• always calm and tranquil
• usually calm and tranquil
• sometimes calm and tranquil‚ sometimes agitated
• usually agitated
• always agitated.

COPING

Q17 Thinking about how much energy you have to do the things you want to do [How much energy do you have to do the things you want to do?]: I am:

• always full of energy
• usually full of energy
• occasionally energetic
• usually tired and lacking energy
• always tired and lacking energy

Q18 How often do you feel in control of your life?

• always
• mostly
• sometimes
• only occasionally
• never

Q19 How much do you feel you can cope with life’s problems?

• completely
• mostly
• partly
• very little
• not at all

RELATIONSHIPS

Q20 How much do you enjoy your close relationships (family and friends)?

• immensely
• a lot
• a little
• not much
• I hate it

Q21 Your close relationships (family and friends) are: [How satisfying are your close relationships (family and friends)?]

• very satisfying
• satisfying
• neither satisfying nor dissatisfying
• dissatisfying
• unpleasant
• very unpleasant

Q22 How often do you feel socially isolated?

• never
• rarely
• sometimes
• often
• always

Q23 How often do you feel socially excluded or left out?

• never
• rarely
• sometimes
• often
• always

Q24 Your close and intimate relationships (including any sexual relationships) make you: [How happy are you with your close and intimate relationships?]

• very happy
• generally happy
• neither happy nor unhappy
• generally unhappy
• very unhappy

Q25 Thinking about your health and your relationship with your family: [Does your health affect your relationship with your family?]

• my role in the family is unaffected by my health
• there are some parts of my family role I cannot carry out
• there are many parts of my family role I cannot carry out
• I cannot carry out any part of my family role.

Q26 Thinking about your health and your role in your community (that is to say neighborhood‚ sporting‚ work‚ church‚ or cultural groups): [Does your health affect your role in your community (eg. residential‚ sporting‚ church or cultural activities)?]

• my role in the community is unaffected by my health
• there are some parts of my community role I cannot carry out
• there are many parts of my community role I cannot carry out
• I cannot carry out any part of my community role.

SELF-WORTH

Q27 How much of a burden do you feel you are to other people?

• not at all
• a little
• a moderate amount
• a lot
• totally

Q28 How often do you feel worthless?

• never
• almost never
• sometimes
• usually
• always

Q29 How much confidence do you have in yourself?

• complete confidence
• a lot
• a moderate amount
• a little
• none at all

PAIN

Q30 Thinking about how often you experience serious pain: [How often do you experience serious pain?]

I experience it: