Czech version of OPQOL-35 questionnaire: the evaluation of the psychometric properties

Both prognoses and actual demographic trends in developed countries point to the increasing proportion in the population of people above 65 years of age. While seniors over 65 made up 11 % of the population of the European Union in the year 1960, an increase to 22 % is expected in 2020, and the number will keep on rising in following years [1]. The middle age of both males and females becomes longer, and this leads to thinking how far the “added years” of seniors will be spent in relative comfort, how far their needs will be met.

The ageing society itself should provide an opportunity to work for all seniors who want to lead an active way of life. Health care must be designed so as to prevent long-term dependence on institutional care of the elderly in dealing with their health problems. Seniors should be given the option of an active and independent life in old age, not only be provided with an expanding network of residential facilities [2]. Hence, one of the important themes of care for seniors is their quality of life.

Main domains characterizing the quality of human life that now appear in the literature are common for adults of different ages. According to Arnold they include: the cognitive, emotional, social, sexual, and behavioural functioning as well as perceived social support, life satisfaction, assessment of one’s own health, assessment of one’s own economic situation, the level of satisfaction of interests, one’s energy and vitality [3]. Experts add that in adulthood the areas are the same, nevertheless at different stages of life the emphasis is shifting to other areas, the priorities are different. What does it look like in old age?

The key factor in our further considerations is the fact that quality of life is understood as a matter of subjective and not objective data. In other words, it depends on the individual’s own unique perception, experience and evaluation of individual domains of quality of life, not on “what they are objectively like”, as they appear to outside observers. For the quality of life in old age the following domains are particularly important: health condition and functional ability of the senior, sense of being useful/useless for other people, network of social relationships, perceived level of social support, financial situation, and the quality of housing [4].

Why do we encounter different domains of quality of life in various papers on the elderly? It turns out that there are various models of quality of life used by different authors. In the very profound survey work [4], we counted ten of them, but the ways of sorting them intersect (according to the nature of indicators, to scientific discipline or according to methodological approaches). In principle it is possible to distinguish four groups of models: 1st psychological, 2nd sociological, 3rd medical, 4th integrated. These models were developed and validated by experts and professionals.

The afore-mentioned models therefore represent the view of professionals on what constitutes the quality of life. Equally important, however, is the view from the other side, the view of laymen. Seniors especially view themselves according to what constitutes the quality of life to them, and what their priorities are. Bowling and Gabriel carried out an investigation of a representative sample of 999 British seniors aged 65 and more [5]. They used a mixed approach. At first they used the personalized questionnaire SEIQOL-Schedule for the Evaluation of Individual Quality of Life [6]. In it, the individuals have the option to choose five themes of life, life goals, on which their life depends the most and then evaluate how much they succeed in fulfilling them. The questionnaire was supplemented with in-depth interviews with 80 senior citizens, which were recorded and then analyzed. In the cited British research the following life themes from the perspective of seniors appeared: social relationships and close interpersonal relationships (81 %); social roles and social activities (60 %); leisure activities that make the individuals happy (48 %); health (44 %); positive attitude to life and feeling of well-being, good mental functioning (38 %); home and neighbours (37 %); financial situation (33 %); autonomy and independence from other people (27 %).

One of the paradoxes of diagnosing the quality of life in old age is – as mentioned by [3]– that quality of life is intuitively understood as a positive or at least neutral phenomenon, but routine diagnostic procedures in the elderly are built mainly on negative indicators: on inability, not being self-reliant, on disease, depression, loneliness etc. Only the movement called “positive psychology” drew attention of researchers also to a thorough scientific investigation of the positive aspects of ageing, for example wisdom [7] humour and life satisfaction [8], and others.

Diagnosing the quality of life of elderly people serves primarily five purposes [9]. It allows you:

Usually, diagnosing the quality of life is characterized according to applied methods as qualitative, quantitative or mixed approaches. We have concentrated on the quantitative approach, which is based on questionnaires that are filled by seniors themselves. We have left aside the generic questionnaire SF-36 or EuroQol Five-Dimension Questionnaire [10], which are not aimed only at seniors, we were interested in questionnaires designed primarily for seniors. There are six of them. If we sort them by the year of their origin, we get this order: CASP-19 – Control, Autonomy, Self-Regulation, Pleasure [11], WHOQOL-OLD – World Health Organization Quality of Life – Old [12], QUAL-E – Quality of Life at the End of Life [13], EQOLI – Elderly Quality of Life Index [14, 15], OPOQOL - Older People’s Quality of Life Questionnaire [16], ASCOT – Adult Social Care Outcomes Toolkit [17]. When considering which one to choose, we have ruled out three of them at once: ASCOT questionnaire because it is designed primarily to assess the social, not medical care; EQOLI questionnaire, the development of which has not yet been completed and the questionnaire QUAL-E, because it focuses on specific period - the quality of life at the end of life. Of the three remaining, i.e. CASP-19, WHOQOL-OLD and OPQOL, the best results in the scientific comparison were reached by the last one [18].

In the questionnaire OPQOL-35 we appreciated that it helps evaluate the quality of life of seniors in general, regardless of their health condition. The OPQOL has excellent applicability to cognitively normal subjects, and it proved to be applicable to people suffering from mild to moderate dementia [19]. It investigates eight domains, thus allowing deliberate intervention with proper knowledge of the facts. We were pleased that OPQOL-35 had acceptable levels of reliability and validity in British population samples of older people, more modest in the ethnically diverse population sample. The questionnaire has potential for use as a multidimensional population survey instrument for use with older populations or as an outcome measure of multisector policy [16].

As a matter of fact, we need to assess the quality of life of both the relatively (for their age) healthy elderly and of those treated on an outpatient basis, but also of the elderly hospitalized at various clinics in the University Hospital. We are interested in the quality of life of seniors, who are living in different social conditions: at home, with family members, in a nursing home, and living in a home for the elderly.

The OPQOL-35 questionnaire was developed by Ann Bowling of University College London, London, Great Britain. The full name of the questionnaire reads: Older People’s Quality of Life Questionnaire [5, 16, 18, 20]. The questionnaire is designed to diagnose the quality of life of seniors. In 2008 it was verified in a group of 987 English seniors aged 65 plus. The questionnaire is based on the assumption that quality of life is a multidimensional concept and in the original version allows the evaluation of the quality of life related to eight domains: 1 life overall (4 items), 2 health (4 items), 3 social relationships and participation (8 items), 4 independence, control over life and freedom (5 items), 5 home and neighbourhood (4 items), 6 psychological and emotional well-being (4 items), 7 financial circumstances (4 items), 8 culture and religion (2 items).

The assumption of eight-factor structure is based on seniors’ responses to a short survey with open-ended questions about quality of their life [21]. Responses were coded to eight dimensions and then examined independently by two researchers to inform the inclusion of the items within subscales. The initial pool of 100 items was based on these responses. The selected 49 items were administered to 179 seniors and following analyses reduced their number to 32. Three items (focused on religion and children) were additionally added after a pilot test on a different culture [21].

Nevertheless, factor structure is unclear. Actual authors of OPQOL reported mostly two [22], four [22] or nine-factor solutions [18] based on principal component analysis (PCA). Other authors reported different number of factors, Chen extracted eight factors using PCA, which were similar to the original version [23]; but in our opinion, this solution had methodological lack. No other factor analyses are available. We agree with Ann Bowling [18], author of OPQOL, that a more detailed examination of the factor structure (probably confirmatory) is needed.

The OPQOL questionnaire consisted of 35 statements, with the participants being asked to indicate the extent to which they agree with each statement by selecting one of five possible options (“strongly disagree”, “disagree”, “neither agree nor disagree”, “agree”and “strongly agree”). The range in the original version is based on the principle of point allocation (1–5). Thus – the higher the score, the better the quality of life.

Cronbach’s alphas for the OPQOL-35 in all three samples satisfied the .70–.90 threshold for internal consistency [24]: Cronbach’s alpha .748 (British Ethnibus survey), alpha .876 (British ONS Omnibus survey), alpha .901 (Quality of life follow-up survey).

With the consent of Ms. Ann Bowling, the author of the original version, the OPQOL-35 questionnaire has been translated into Czech by E. Vachkova and J. Mares. The first step was a literal translation, in the second step the formulations were adjusted to reflect Czech socio-cultural traditions, and each item to be clearly related to its domain at the same time. In the third step, we submitted the text of the questionnaire to 15 seniors and asked them to mark words and formulations that were unclear to them, or could be understood in several ways, or the idea was expressed in a too complicated way. Based on their comments, we modified the text of the questionnaire so that it might be understandable for any elderly person. In the Czech version, we have reversed the five grade scale. We found that our seniors would prefer to evaluate statements using the Czech school grading, because in elementary and secondary schools one is the best mark and five the worst one. The original questionnaire used the principle of point allocation, where five points mean “strongly agree” and one means “strongly disagree”, which confused our seniors.

As we declared earlier, the structure of the original version of OPQOL is unclear, with no reliable factor analysis. The structural equivalence cannot be tested; however, we used a confirmatory factor analysis to verify the original eight-factor model. As the model did not fit (which we expected due to other PCA analyses with different results, [18, 21‐23]), we used the ordinal exploratory factor analysis. We consider our approach superior compared to the original PCA. It could help us better understand the factor structure of the OPQOL questionnaire.

Population sample and methods of its selection: We have set the following criteria for the selection of people – aged sixty years or more, good cognitive abilities, seniors of both sexes. The selection was determined by the availability of older people and their willingness to cooperate. They were seniors who, at the time of the research, were hospitalized in the University Hospital in Hradec Kralove (Departments of Cardiology and Angiology, Gastroenterology and Gerontology and Metabolic Diseases) or in smaller urban hospitals, or hospitals for long-term care, or patients treated on an outpatient basis at the general practitioners. Regarding the type of housing, there were the following categories: senior lives alone in his/her apartment and does not need the help of others; senior lives alone, but is occasionally helped by relatives; senior lives with the family; senior lives in sheltered housing or in a nursing home.

Data were collected by selected and instructed sisters of the medical devices.

The complete sample size was 478 people, 192 men (39.8 %) and 246 women (59.3 %); Age: 212 respondents (44.4 %) were aged 60–69 years, 165 (34.5 %) 70–79 years, and 101 (21.1 %) were older than 80.

Though men and women did not differ in their median age, Mann–Whitney U = 27350.0, p = .994, they differed in their marital status, χ ²(4, N = 478) = 19.31, p < .001. Using post-hoc Z-test we discovered that men were more often married, z = 5.85, p < .001, and women were more often widowed, z = -4.23, p < .001, see the Table 1 (both tests were significant after Bonferroni’s correction).

Two hundred fifty-six respondents (53.1 %) were living alone at home, 86 (17.8 %) at home but with other people’s help, 36 (7.5 %) were living with their family out of their own household. Only 16 respondents (3.3 %) were living in a nursing home and 88 (18.3 %) in a retirement home or residential care home. The differences between men and women in the way of living tested by chi-square were not significant, χ ²(4, N = 478) = 3.82, p = .43.

Only 56 respondents (11.6 %) considered themselves healthy, 319 (66.2 %) had age-appropriate diseases and 107 (22.2 %) were “fairly ill”. Differences between men and women were not significant, χ ²(2, N = 478) = 3.56, p = .17.

At the end of the questionnaire, respondents could assess their overall quality of life using the five-point Likert scale from 1 (very good) to 5 (very bad). The mean score was 1.46, the differences between men and women were not significant, Mann–Whitney U = 27023.0, p = .832.