Measuring Quality of Life through Validated Tools

Abstract

Quality of life needs to be considered in every patient clinical encounter and should be a vital component of wholistic care.  Its measurement will give a context and assess the impact of physical illness on patients’ daily life. This evaluation provides a preview of what it is like to be ill based on the individual’s unique personal experience that changes through time and disease course.¹

World Health Organization (WHO) has defined Quality of Life (QOL) as a “person’s perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards and concerns.”1 Health-related QOL, on the other hand, is a multidimensional consideration of how patients are affected by their illness diagnosis and management.²   There are tools available to determine QOL and can implicitly provide the impact of diseases on an individuals’ daily activities.  

Questionnaires currently available to measure quality of life can be divided into two categories: generic surveys intended for the general population and tools that are for disease-specific populations. Short form survey (SF-36) is the most widely known and used generic tool for QOL.³ Functional Assessment of Chronic Illness Therapy-Palliative (FACIT-PAL-14) Instrument for Filipino cancer patients in the article by Manalo and Nicolas-Casem is an example of a tool designed for a specific population.⁴

Palliative care patients are a vulnerable population with a wide range of difficulties, disabilities, and physical-mental fatigue. QOL is both an essential component of medical care and a significant outcome in cancer research. There is a need to measure QOL as it would assist health care providers to understand how the diagnosis of cancer, treatment or palliative care has affected daily life. This can lead to the recognition of the latest physical-emotional status, formulation of informed decisions, and evaluation of medical interventions. 

Tools that measure constructs such as quality of life need language translation and validation in the local setting, particularly if created using another language in a different culture.  However, validation of instruments to ensure that it will measure what it needs to evaluate is both a challenging and resource-intensive task. Challenges in health-related quality of life questionnaires include varying psychometric properties, different levels of validations, and patient compliance.³ The importance of suitable validation techniques should be underscored as research not suitably conducted according to standards yields invalid results.

There are several ways that will help establish validity and reliability of a tool to measure QOL.  The initial translation of an instrument into the local language should be substantiated with back-translation, engagement of several professional translators or addition of a committee tasked to compare the original to translated version.⁵ Construct validity can be established by comparing the new form to other tools that determine the same concepts and is typically evaluated by degree of agreement between the two measures.⁶ The last step in the process would include measurement of psychometric properties and pilot testing. Psychometric index such as Cronbach’s alpha is often reported as a validation measure to demonstrate internal reliability among questionnaire items.⁵

In the article by Manalo and Nicolas-Casem,⁴ they determined the psychometric property of a Tagalog version of FACITPAL-14. It was a cross-sectional study involving 500 cancer patients in an outpatient oncology clinic in the Ilocos Province. The tool had shown acceptable reliability and poor correlation with two instruments that measure performance status. There was, however, inadequate information on a local dialect version, sampling procedures, and on descriptions of the language translation status of the comparison tools.  

Measuring Quality of Life through validated tools is a vital part in the assessment of well-being, status, and perception of disability.  However, these instruments need to show validity and reliability. Tagalog-translated, validated, shortened questionnaires are needed for patients, not just for quality of life or palliative care, but also for individuals with chronic diseases, and conceivably in the assessment of family support, relationships, or function. Tool validation is not an easy undertaking, but it needs to be done, preferably with more culturally sensitive and accurately done validation studies.