**Abstract**

Healthcare workers, clinicians and/or researchers require information on the consequences of illness on their patients, as well as on the effects associated with treatments, when making decisions on recommended treatments and for follow-up evaluations of the same. Identifying health indicators which provide necessary and appropriate data for the evaluation of clinical outcomes in terms of Health-Related Quality of Life (HRQoL), as established by the WHO Biopsychosocial Model, and which provide appropriate and pertinent information on physical, mental and social factors in patients, can improve decision-making in relation to a comprehensive and global perspective of clinical outcomes of the various treatments and procedures given to patients. This chapter aims to provide an overview of the various tools for assessing Health-Related Quality of Life, as a growing number of clinicians, researchers and patient groups wish for comprehensive and not merely biological measures of health. This may be explained by the growing number of selfadministered or interview questionnaires which have the aim of measuring changes in health as well as the consequences of the various treatments used mainly on chronicity and chronic health conditions. During recent decades, numerous tools have been developed and applied to the measurement of the effects of Health-Related Quality of Life in patients based on biological or physical aspects, psychological or mental aspects, and social aspects. This chapter will review the most frequently-used tools for the measurement of Health-Related Quality of Life, and recommendations are made for their use in medical care according to psychometric characteristics and quality criteria, as a guide for use in the field of healthcare, in public health, or in outcomes research.

**Keywords:** Health-Related Quality of Life (HRQoL), health conditions, medical care

#### **1. Introduction**

The term "health indicator" refers to a characteristic associated to the health of an individual or a population. In Public Health and in Health Planning, population health indicators are used to show the magnitude of a medical problem, to reflect a change in the health status of a patient or a population over time, to compare and assess differences in health status among patients and populations, and to analyse and evaluate the extent to which treatment goals have been achieved in patients in order to recommend these treatments for use in clinical practice and research [1, 2].

Measurement of health and Health-Related Quality of Life (HRQoL) has acquired great importance in recent decades as a means of measuring clinical outcomes in patients and of monitoring the progress of various treatments along with their physical, psychological and social consequences [3]. Medical practitioners frequently must choose from among diverse tools with the aim of obtaining essential relevant information for decisions on treatment, with analysis and a multidimensional assessment of these treatments on patients.

Meanwhile, countries have health information systems which permit the development of a wide variety of health indicators, and thus allow periodic surveys of their healthcare situation. These indicators provide information on their change over time, which makes it possible to assess trends and geographical distributions. Likewise, the wide availability of these indicators allows comparison with other countries [4, 5].

Selection of indicator sets is commonly done in countries with well-developed health information systems with the aim of providing executive and multidimensional information. Among global health indicators are those whose objective is to assess the perception of improvement in patient functional capacity on a global scale, i.e. assessing subjective patient perception of the physical, mental and social components in a global and comprehensive fashion [6].

The concept of Quality of Life has undergone such rapid development that it is used very frequently and to such an extent that it has become a common expression in both professional settings and the general population. The healthcare sector is not immune to its influence and many professionals rely on it to assess the patient's psychosocial experience and the effects on the disease of medical and surgical interventions and procedures. This term originated in the USA after the end of World War II, during the development of the Welfare State.

The development of HRQoL research is linked to changes during recent decades in the concept of health, whose basis has shifted from a *biomedical* model to a *biopsychosocial* model [7]. This indicator began to be used extensively from the 1980s, especially in connection with the care of chronically ill patients. Patient health and ability to function depends on and is a consequence of several components: physical, mental and social. Therefore patients must be assessed globally and, consequently, the functioning of all three components must be taken into account for a patient to progress as a person and a social individual.

In this context, HRQoL estimates and measures living conditions of patients which are linked to health conditions and/or disease, and has become a fundamental *dependent or response variable* when assessing success of therapeutic or surgical aims in the medical field. In other words, the HRQoL indicator is currently a valuable tool for understanding circumstances linked to disease and medical care.

The first model or framework which was established to measure Quality of Care was described and proposed by *A. Donabedian* [8]. This author proposed a framework, now classic, which evaluates three components. Firstly, *structure,* the stable attributes required for care, i.e. the available resources: human, material, technological, financial, etc. This component has been used to accredit hospitals and health centres for teacher training, and to classify hospitals. Teaching posts which are made available for training resident interns are allotted based on this element of quality of care. Secondly, the model must assess and analyse the *process***,** the actions taken with the available resources; i.e. the use healthcare providers make of what they have in their clinics, clinical services, medico-surgical services, etc. Thirdly,

*Modifiers of Health-Related Quality of Life by Biological, Psychological and Social… DOI: http://dx.doi.org/10.5772/intechopen.97451*


#### **Table 1.**

*Classical model of quality of care.*

the model considers *outcome***,** i.e. the results in terms of improved health, lifestyle, quality of life and wellbeing (**Table 1**).

The **overall aim** of this chapter is to present the tools for measuring Health-Related Quality of Life (HRQoL) which allow a global, subjective evaluation of patients in connection to the various medical and or surgical procedures which they undergo. These tools should also provide the ability to follow up on the effects and consequences on patients of these procedures from a multidimensional perspective. The information obtained from these indicators enables professional decisionmaking based on relevant, personal and holistic information about patients. The goal of this chapter is also eminently practical: without entering into theoretical considerations, it will perform a methodological review of these tools to facilitate decision-making when choosing generic and/or specific surveys.

#### **2. Methodology**

In the field of health, HRQoL measurements are widely used, to the extent that specialist journals exist while non-specialist journals have also, in recent years, published editorials and articles on the subject. Available information on tools for the measurement of HRQoL has been subjected to a review process according to the following criteria: 1. - Adaptation to the objective. 2.-Psychometric criteria of *validity, reliability* and *discriminative power or sensitivity to change*. 3.- Practical utility for health workers, teachers and researchers in various settings and population groups, such as the general population or vulnerable groups (e.g. chronic patients, individuals with disabilities and dependent or frail persons). The measurement tools included in this chapter were chosen according to whether the questionnaires contain items which evaluate physical, psychological and social factors according to the biopsychosocial health model, which was proposed in the 1970s and adapted by the WHO [7] as a means of evaluating HRQoL and wellbeing in patients and across population groups [9–14]. And these have been selected based on metrical quality criteria of previously selected instruments such as:

#### **2.1 Validity**

In the measurement of HRQoL, no single method for assessing the validity of measuring instruments exists, as it is an indirect assessment through indicator systems. In other words, there is no single way for a tool to measure what it is intended to measure through *content validity* based on the analysis of the concept to be measured and with a definition of the dimensions covered such that the indicators represent the dimensions of health status to be analysed and evaluated. *Construct validity,* on the other hand, is the relationship between the variable to be measured and the concept indicator being measured, i.e. health [15–19].

#### **2.2 Reliability**

The reliability of an instrument is given by its stability or consistency in observations when the process of measurement is repeated under equal or similar conditions. Several types of reliability may be derived from this definition: *test–retest* (stability of the tool if measurement conditions and concept are unchanged), *interobserver* (if measurement is carried out by multiple observers and the concordance index, kappa, is between 0.8 and 1 [20]), and *internal consistency* (stability of scores among the various elements of the measuring tool) [21].

#### **2.3 Discriminatory power or sensitivity to change**

This property requires that small clinical variations due to a treatment or procedure are reflected in the scores given by patients. Evaluating this property is essential in instruments whose sole purpose is assessment. When a measuring tool is used to categorise patients with differing degrees of severity or disability, discriminatory power is vital. A recent study analysed and assessed the Nottingham Health Profile (NHP), the Short Form-36 (SF-36) survey, the Psychological General Well-Being Index (PGWB) and a single-item 0 to 100 Self-Rated Health Scale, evaluating psychometric properties such as internal consistency, construct validity and discriminatory power. The authors conclude that there is high concordance among the three HRQoL tools (PGWB, SF-36 and NHP) in all aspects but the social, and that these tools may identify the presence of self-assessed poor health. The quick, simple Self-Rated Health Scale was strongly correlated with the more time-consuming PGWB, SF-36 and NHP [21]. Reviews have also been published on tools for assessing the properties of instruments measuring quality of life [22].

#### **2.4 Internal consistency**

In questionnaires developed to measure different dimensions separately, as it happens when HRQoL is measured, each dimension's internal consistency must be evaluated using Cronbach's alpha. Its values range between 0 and 1 and indicate the degree of agreement between two quantitative variables, similar to the correlation coefficient.

#### **2.5 Strength of recommendation**

Following the above psychometric criteria and a qualitative SWOT analysis we identify those tools which meet the criteria of consistency, validity, and discriminative power and which have more strengths than weaknesses and, therefore, represent an opportunity for improving patient HRQoL. While the aim is to provide a quick, eminently practical guide for use in research on health and quality of life for instructors, health workers and researchers, tools must be adapted to socioclinical context and to specific patients.

In summary, generic measures of quality of life are proposed, contrasted against previous studies and other tools with clinical utility in highly prevalent diseases due to their importance and significance in both the general population and in vulnerable groups (such as elderly individuals with morbidity and multiple pathologies, and disabled and/or dependent individuals).

All these tools seek to convert Evidence-Based Medicine (EBM) into Results-Based Medicine (RBM), taking into account biological, physical, mental, emotional and social components in order to improve patient HRQoL and wellbeing. This evolution from EBM to RBM is very important for chronic patients, elderly

individuals, and individuals with disabilities, because those components which provide satisfaction in life are improved and thus improve quality of life and wellbeing.

### **3. Generic HRQoL tools**

#### **3.1 SF-36 survey**

One of the best-known and most widely used tools for the measurement of HRQoL internationally is the **SF-36 Survey** [23, 24]. This was developed in the US in the 1990s for use in analysis and assessment of clinical outcomes, based on questionnaires which included a variety of concepts related to health.

This tool consists of 36 questions, 35 of which assess health through eight dimensions covering two areas, Functional Status and Emotional Wellbeing. The functional area is represented by the following dimensions: Physical Function (10 items), Social Function (2 items), Role Limitations due to physical problems (4 items), Role Limitations due to emotional problems (3 items). Wellbeing includes the following dimensions: Mental Health (5 items), Vitality (4 items), Pain (2 items). Finally, overall assessment of health includes the dimension Perception of General Health (5 items) and Change in Health Status over time (1 item). Two versions exist: standard, with a 4-week recall period, and acute, with a 1-week recall period. The 36th question covers perceived changes in health in the year prior to the interview.

The SF-36 survey has good validity, reliability and sensitivity to change, giving this tool a Grade A recommendation, i.e. the survey meets sufficient quality criteria. Experts and practitioners who have employed the survey quote numerous reasons for its use, such as ease of use and interpretation, multidimensional assessment, comparability, and use in vulnerable groups [11–13]. Furthermore, the Short-Form survey has several versions according to number of items (36, 12, 8 or 6), enabling it to be generalised and used in multiple contexts and with diverse aims [25–27]. SF-12 was the most used for assessment of clinical outcomes. These diverse versions show good psychometric properties across different patients, population groups and countries. Therefore SF-36 is shown as an effective and reliable tool for the measurement of clinical outcomes in patients with various conditions and across various population groups such as persons with intellectual disabilities [11, 13]. It has been validated in numerous countries and therefore allows comparisons among patients with diverse health conditions, diseases and medical treatments, as well as comparison with a general reference population. **Table 2** shows the number of items for each component assessed by the survey. These items register both positive and negative changes in health (**Table 2**).

In a review of the survey's measuring ability, reliability, validity and responsiveness to instrument change, conducted on 17 chosen articles which assessed the psychometric characteristics of the questionnaire, the reliability of SF-36 scales was greater than the suggested standard (Cronbach's alpha) of 0.7 in 96% of evaluations. The pooled evaluations obtained by meta-analysis were higher than 0.7 in all cases. SF-36 showed good differentiation among groups of varying severity, moderate correlation with clinical indicators, and high correlation with other HRQoL instruments. In addition, the survey scores predict mortality. Therefore, SF-36 and its derivatives are an appropriate tool for use in medical research, as well as in clinical practice; in some countries attempts were made to add the survey to medical records, though this has been less successful [28].

Consequently, the SF-36 survey is a complete instrument which allows the assessment of generic HRQoL or health status in patients by analysing and


#### **Table 2.**

*Number of items for each component assessed by the survey.*

evaluating various aspects of the patients, and its clinical use is recommended in order to assess the outcomes of treatment or care based on the opinion of the patients, as a reliable, valid tool with sensitivity to change.

Above all, its use is recommended when cure and/or prognosis rates of two treatments are equal, but differences may be seen in the vital and social implications of each treatment (such as chemotherapy with profound side effects, in cases of cancer) or when limitations occur in the patient's life and wellbeing. It may also be used to assess patient satisfaction with the service provided and to assess reintegration to normal life in cases of disabling diseases and conditions or in persons with disabilities [11, 13]. In addition, the survey may be self-administered by patients or be given by an interviewer. According to experts [29], this tool has a Grade A recommendation for its psychometric criteria, for its generalisability for comparisons, and for its recent use in various cohorts such as the elderly and persons with Alzheimer's disease [11–13, 30–32], and in very diverse conditions and circumstances [33–40]. It can therefore be used to assess HRQoL of patients in general and of vulnerable population groups, alone or in combination with other tools. In summary, the SF-36 is a reproducible, short, valid and versatile survey which has even been proposed for use in economic measures of health [41].

#### **3.2 Nottingham health profile**

The Nottingham Health Profile was developed in the UK in the late 1970s with the aim of measuring the subjective perception of the impact of health problems. The authors state that it is appropriate for use in assessing medical and/or social interventions, in pre-post or quasi-experimental designs, as a measure of comparisons among cohorts, as a survey tool on selected populations, for long-term followup in patients with chronic disease, as a complement to medical history, and for clinical research in selected patient cohorts. In summary, experts state that it is most suitable for patients with significantly impaired health status, because the survey has the *weakness* of lacking items that track positive health [29].

It is a generic tool for measuring the *degree of physical, psychological and social suffering* associated with medical, social and emotional problems that affect the lives of patients.

The survey consists of two parts. The first has 38 questions with 6 dimensions: Energy (3 items), Pain (8 items), Physical Mobility (8 items), Emotional Reactions *Modifiers of Health-Related Quality of Life by Biological, Psychological and Social… DOI: http://dx.doi.org/10.5772/intechopen.97451*

(9 items), Sleep (5 items) and Social Isolation (5 items). These items aim to represent various states of health and record Yes/No responses from the patient. The second part consists of 7 questions on health-related limitations to 7 functional activities of daily living: paid employment, household chores, social life, family life, sex life, hobbies and interests, and free or leisure time. The score ranges from 0 to 100 depending on whether a patient's responses are all negative (0) or all positive (100) [42–44]. Six different scores are obtained for each of the dimensions, giving an estimated observation of the patient's perception of their state of health which may be used without staging of the items, simply by taking the number of positive responses divided by the number of items in that dimension and multiplied by 100 to obtain a range of results from 1 to 100 with the same interpretation as globally. The authors recommend the use of scores by dimension, rather than global scores. A short or reduced version exists, with 22 items. It may be self-administered (preferable) or with an interviewer or interviewers. It has been used in patients with coronary disease, lung cancer, undergoing addiction treatment with methadone, and fibromyalgia [45–48]. It is Grade A recommendation for its psychometric criteria, its generalisability for use in comparisons, and for utility in patient followup and in diverse conditions and patient cohorts.

#### **3.3 Sickness impact profile (SIP)**

The Sickness Impact Profile (SIP) was developed in the United States with the aim of providing a valid and sensitive measure of perceived health status in order to correctly appraise clinical outcomes during evaluation, planning and programming of health policies. It was designed for the assessment and measurement of dysfunction from in types and degrees of severity of patients and their conditions, although it is specifically designed for patients with moderate or severe deficiencies and dysfunctions [29]. The overall objective of the SIP is the measurement of *dysfunction caused by disease* in critical patients [49] and the assessment of quality of life in patients in need of surgical intervention for urinary diversions [50], defining "dysfunction" as an alteration in the manner of approaching and performing any given activity, with total cessation of the same or with total replacement by a novel activity. In other words, it is a useful tool for the evaluation of disability in the field of Occupational Health, which can improve the objectivity of the committees that assess disability and functional impairment. SIP also evaluates capability in activities of daily living such as resting, eating, household management, recreation, walking, personal hygiene and grooming, work, social integration, state of mind, emotional behaviour and ability to communicate [29].

The SIP is based on the patient's perception of their own illness and not on the professional and scientific concept of that illness. This instrument is based around changes in behaviour and activities of daily living (ADLs) as a result of negative effects of diseases and their consequences, on a simple generic HRQoL scale composed of 136 questions grouped into 12 categories. Of these twelve categories, seven can be grouped into two, Physical or Psychosocial, and five are independent. The physical dimension consists of mobility, ambulation, and body care and movement; the psychosocial dimension has four categories: social relationships, intellectual activity, emotional activity and communication. The five independent categories are sleep and rest, eating, hobbies and entertainment, work, and household tasks.

In this tool the patient must mark only the questions which describe their *circumstances and state of health* at the present moment, and those which are related and/or associated with the disease and its consequences. The result ranges from 0 to 100, where 0 is absence of dysfunction and 100 is maximum dysfunction. It is

obtained by summing the scalar values of items marked by patients divided by the sum of scalar values of all the SIP items and multiplying by 100. It may be selfadministered, which is preferable, or given by an interviewer. It is Grade A for its psychometric criteria [29, 51], for its generalisability for comparisons, and for utility in assessments of patient perception of their own health status and the consequences of various diseases such as incontinence, chronic pain and periodontal disease [52–55].
