Question

give an example of a medical intervention that might be justified by a patient's subjective quality of life judgment. (philosophy/ethic answer please)

Answer 1

Subjective  quality of life (QOL) is becoming a standard health outcome measure especially for people with multiple, chronic, functional, psychological, or incurable illnesses. A good instrument is the pre-requisite of any measurement, which is in the form a questionnaire for QOL. This chapter reviews the concepts, principles, applications, scoring methods and selection criteria of subjective QOL measures to enable users to choose the most appropriate instruments for their purposes.

Quality of life (QOL) is a logical outcome measure of the effectiveness of modern health care much of which aims at relieving suffering and restoring normal living. The essential concepts of QOL measures are subjectivity, multi-dimensionality and well-being. Health-related quality of life (HRQOL) focuses on  dimensions that are modifiable by health. General health perception, psychological well-being and functioning are essential dimensions of HRQOL while symptoms and vitality are important causative variables.

Quality of life is a latent variable that cannot be directly measured. It needs to be converted to indicators of its component dimensions and domains to be quantified. To serve the purpose, the indicators must be valid, important, representative and adequate. A QOL measure presents the  indicators as items that can be rated on response  scales, which are then presented as a profile domain scores or a composite index of quality of life.

Hundreds of QOL measures have been developed mostly for the assessment of HRQOL. Generic measures that are applicable to people with different health status are more suitable for population and comparative studies. Disease specific measures tend to have high  sensitivity and are best used for evaluative purposes. Preference-based measures of health (PBMH) convert a multidimensional QOL state to a fractional index for the calculation of quality adjusted life years (QALYs) and cost-effectiveness. A critical appraisal of the nature and psychometric properties of a QOL measure can assure that it will meet the needs of the user.

Abbreviations:

COOP/WONCA Charts

The Dartmouth Corporation Functional Health Assessment Charts/World Organization of Family Doctors

EQ-5D

European Quality of Life-5 Dimension

HRQOL

Health-related quality of life

HUI-3

Health Utilities Index-Mark 3

ICC

intra-class correlation

MCID

minimal clinically important difference

MID

minimally important difference

PBMH

preference-based measures of health

PRO

patient reported outcome

QALYs

quality adjusted life years

QOL

quality of life

RS

rating scale

SD

standard deviation

SEM

standard error of measurement

SF-12

The Medical Outcomes Study 12-item Short-form Health Survey

SF-36

The Medical Outcomes Study 36-item Short-form Health Survey

SG

standard gamble

SIP

sickness impact profile

SRM

standardized response mean

TTO

time trade-off

VAS

visual analogue scale

WHOQOL

World Health Organization Quality of Life Assessment Instrument