Illness perception in Polish patients with chronic diseases: Psychometric properties of the Brief Illness Perception Questionnaire

Abstract

The study evaluates the psychometric properties of a Polish translation of the Brief Illness Perception Questionnaire. A total of 276 patients with chronic conditions (58.7% women) completed the Brief Illness Perception Questionnaire and the Hospital Anxiety and Depression Scale. The internal consistency of the Polish Brief Illness Perception Questionnaire measured with Cronbach’s alpha was satisfactory (α = 0.74). Structural validity was demonstrated by significant inter-correlations between the Brief Illness Perception Questionnaire components. Discriminant validity was supported by the fact that the Brief Illness Perception Questionnaire enables patients with various conditions to be differentiated. Significant correlations were found between Brief Illness Perception Questionnaire and depression and anxiety levels. The Polish Brief Illness Perception Questionnaire thus evaluated is a reliable and valid tool.

Keywords

Brief Illness Perception Questionnaire chronic illness health psychology illness perception methodology quantitative methods validation

Introduction

Illness perception is a psychological concept that has evolved as a basic construct of Leventhal’s common sense model (Diefenbach and Leventhal, 1996). According to this model, each patient facing illness creates an individual cognitive and emotional representation of their illness. The cognitive representation has five dimensions: identity (the symptoms believed to be part of the illness), timeline (how long the condition is expected to last), cure/control (the perceived controllability of the illness and the effectiveness of the treatment) and causation (factors believed to be the cause of the condition) (Hagger and Orbell, 2003). Studies of illness perception have revealed that this has affected patients’ involvement in care, compliance and health behaviours, their emotional response to illness, their coping behaviours and the strategies adopted while dealing with illness (Hagger and Orbell, 2003; Van Esch et al., 2014; Woith and Rappleyea, 2016). It is of even greater importance that illness perception is modifiable, and the ensuing changes may enable patients to cope better and produce more satisfactory illness outcomes (Bonsaksen et al., 2013; Hagger and Orbell, 2003; Juergens et al., 2010; Petrie et al., 2002; Rees et al., 2015; Wiborg and Lowe, 2015).

In recent years, there has been a significant increase in research concerning illness perception, especially since questionnaires assessing illness perception have become available. These have included the Illness Perception Questionnaire (IPQ) (Weinman et al., 1996), the revised version of the IPQ, known as the IPQ-R (Moss-Morris et al., 2002) and the Brief Illness Perception Questionnaire (B-IPQ) designed by Elizabeth Broadbent (Broadbent et al., 2006). Research has demonstrated that the original English version of the B-IPQ is acceptably reliable and has good concurrent, discriminant and predictive validity (Broadbent et al., 2006). However, the psychometric properties of other language versions of the questionnaire have as yet only been established in a few studies (Bazzazian and Besharat, 2010; Paheco-Huergo et al., 2012; Pain et al., 2006; Radat et al., 2008; Yaraghchi et al., 2012). New adaptations for other languages and modified versions for particular diseases are encouraged (Broadbent et al., 2006; Hvidberg et al., 2014; Moss-Morris et al., 2002).

No validation study has so far been published of the B-IPQ performed in the Polish population. This study aims to rectify this by evaluating the psychometric properties of a Polish translation of the B-IPQ.

Method

Measures

The B-IPQ consists of eight items scored on an 11-point Likert scale (range: 0–10). Each item reflects one of the following dimensions: consequences, timeline, personal control, treatment control, identity, concern, coherence/understanding and emotional response. The ninth question is open-ended and concerns patients’ beliefs about the causes of their illness (Broadbent et al., 2006). Quantitative analysis provides eight sub-scores, one for each B-IPQ item, which reflect aspects of illness perception, and a total score generated by summing up the scores for the B-IPQ items with a reverse scoring of items 3, 4 and 7. A higher total score reflects perception of an illness as being more threatening. The open-ended question asks the patients to list the three most important causes of their diseases. Categorical analysis of the answers received is carried out by grouping these into specific categories, such as hereditary factors, life-style, environment and stress. Analysis of the causal factors was not carried out for this study.

The Hospital Anxiety and Depression Scale (HADS) was used to assess levels of depression and anxiety (Zigmond and Snaith, 1983). Evaluation of distress forms an important component of studies among patients with a variety of medical conditions and also in the context of illness perception and its assessment and measurement (Bazzazian and Besharat, 2010; De Raaij et al., 2012). The scale consists of 14 items with responses on a 4-point Likert scale. Seven of the items measure depressive symptoms and the remaining 7 items anxiety symptoms. The maximum HADS score for each subscale is 21 points; scores below 8 indicate a normal result, 9–10 points demonstrate moderate anxiety or depression, while a score of 11 or more reflects severe depressive/anxiety symptoms. In this study, we used a Polish version of HADS. A validation study of the test revealed it to be of satisfactory reliability (Majkowicz, 2000).

Sociodemographic data were collected using a structured interview. All the patients were informed of the purpose of the study and agreed to participate in it. The research fulfilled the ethical requirements for each of the participating centres and received their approval.

Translation procedure

Research was conducted between 2006 and 2013. In the early stages, the Polish version of B-IPQ was unavailable. Once translation rights had been obtained, the first author of this article, a psychologist experienced in the field who is also a Polish native speaker fluent in English, translated the questionnaire into Polish. Next, an English speaker who did not know the original English version of the B-IPQ performed a back-translation into English. The latter was checked and approved by a second Polish native speaker fluent in English and then compared with the original by the whole translation team. The final version (see Appendix 1) was tested in a pilot study involving 30 patients with systemic lupus erythematosus (SLE). The aim was to obtain their opinions on the simplicity and comprehensibility of the test. The patients easily understood the questionnaire and filled it in without difficulty.

Participants

The study group consisted of 276 patients with medically confirmed diagnoses of various chronic conditions as follows: patients with myocardial infarction (MI) (N = 58) consecutively recruited from a cardiac rehabilitation setting; consecutive outpatients with rheumatoid arthritis (RA) (N = 50), SLE (N = 54) and mixed connective tissue disease (MCTD) (N = 19) recruited from rheumatology outpatient clinics; inpatients with neurological diseases (N = 24); internal medicine inpatients (N = 21) and young adult outpatients with minor chronic conditions (N = 50). Details of the study sample and characteristics of the patients are presented in Table 1.

Table 1.

Characteristics of the study sample (N = 276).

	N	Sex (% female)	Mean age (SD)	Mean duration of the disease (SD)
Myocardial infarction	58	19.0	60.2 (7.6)	5.1 (7.2)
Rheumatoid arthritis	50	76.0	52.0 (13.5)	13.8 (12.4)
Systemic lupus erythematosus	54	94.4	46.5 (11.9)	12.1 (7.6)
Mixed connective tissue disease	19	84.2	47.7 (11.3)	6.3 (5.0)
Neurology inpatients	24	25.0	59.7 (12.9)	4.7 (6.3)
Internal medicine inpatients	21	42.9	52.05 (13.5)	13.9 (7.6)
Young adult outpatients with minor chronic conditions	50	62	22.9 (1.5)	7.95 (8.4)

SD: standard deviation.

Examination procedure

Prior to the study, each researcher (psychologists and a nurse) participated in a lecture on Leventhal’s theory and was given detailed instructions concerning the B-IPQ. Patients were each given oral instruction during face-to-face interviews.

Statistical analysis

Descriptive statistics were used to show the characteristics of the study sample. Mean values were used with standard deviation (SD) in the case of quantitative variables and proportions in the case of categorical variables. The reliability of the B-IPQ was tested by examining the internal consistency using Cronbach’s alpha (α) coefficient. In order to assess the test’s structural validity, inter-correlations between the B-IPQ dimensions were calculated using Spearman’s correlation coefficient. Discriminant validity was assessed by using a series of one-way analysis of variance (ANOVA) with post hoc Scheffe tests to determine the differences between the groups of patients studied. Spearman’s correlation coefficient was used to assess concurrent validity by examining the correlations between levels of depression and anxiety measured by the HADS and B-IPQ dimensions and by the total B-IPQ score.

Results

Internal consistency

The internal consistency of the Polish version of B-IPQ evaluated was very good. Cronbach’s alpha coefficient for the total score was 0.74. The values of Cronbach’s alpha coefficient for the B-IPQ dimensions were in an acceptable range between 0.67 for consequences and identity and 0.74 for personal control and treatment control.

Inter-correlations between B-IPQ dimensions: structural validity

Table 2 provides Spearman’s correlation coefficients, computed to investigate the correlations between components of the B-IPQ. Observed inter-correlations between the test items were in accordance with expectations, demonstrating that the questionnaire items measured the illness perception as one construct (Table 2).

Table 2.

Correlations between B-IPQ illness perception dimensions.

	1.	2.	3.	4.	5.	6.	7.	8.
1. Consequences		.28*	.10	.10	.63*	.51*	.16*	.58*
2. Timeline	.28*		.21*	.08	.32*	.23*	.22*	.24*
3. Personal control	.10	.21*		.33*	.22*	.07	.32*	.04
4. Treatment control	.10	.08	.33*		.08	.04	.17*	.09
5. Identity	.06*	.32*	.22*	.08		.51*	.26*	.52*
6. Concern	.51*	.23*	.07	.04	.51*		.26*	.54*
7. Understanding	.16*	.22*	.32*	.17*	.26*	.26*		.14*
8. Emotional response	.58*	.24*	.04	.09	.52*	.54*	.14*

B-IPQ: Brief Illness Perception Questionnaire.

Statistically significant correlations; p < .05.

Discriminant validity

Table 3 presents significant differences found between the groups of patients. The results observed were in line with what was expected. Patients with SLE, RA and MCTD had the highest scores in the timeline dimension and differed significantly from the young adults. Significant differences were noted between all groups and the young adults in terms of treatment control, the highest scores being those of the hospitalised patients. Patients suffering from RA had higher results for identity than the young adults and the post-MI patients from a cardiac rehabilitation setting. These two groups also had significantly lower mean scores in concern and emotional response than those observed in patients with RA. In general, the lowest scores in all but one of the illness perception dimensions were observed in the young adults with minor chronic conditions (see Table 3).

Table 3.

Brief IPQ mean scores (SD) in patients with various chronic conditions.

	MI	RA	SLE	MCTD	N	INT	YA	Significant differences *	F
Consequences	6.10 (2.86)	7.02 (3.02)	5.94 (2.54)	5.0 (2.38)	6.71 (2.48)	6.67 (2.76)	4.22 (2.69)	YA vs RA	5.58*
								YA vs N
Timeline	8.00 (2.68)	9.0 (2.22)	9.11 (2.03)	8.79 (2.12)	7.79 (2.75)	7.38 (3.67)	6.44 (3.49)	YA vs RA	5.77*
								YA vs SLE
Personal control	6.66 (2.64)	7.22 (2.72)	6.48 (2.32)	6.79 (2.25)	6.38 (2.79)	6.38 (2.33)	5.56 (2.63)	–	1.88
Treatment control	8.16 (1.89)	8.06 (2.28)	7.85 (2.23)	7.95 (2.44)	8.29 (2.10)	8.48 (2.40)	5.42 (3.01)	YA vs MI, RA, SLE, MCTD, N and INT	9.01*
Identity	5.91 (2.78)	8.36 (2.03)	6.80 (2.64)	6.84 (2.71)	6.42 (2.41)	6.48 (2.82)	5.44 (2.79)	Article I. MI vs RA	6.26*
								Article II. MI vs YA
Concern	4.74 (3.50)	7.82 (2.56)	6.30 (2.70)	5.68 (2.02)	6.33 (2.88)	6.62 (3.96)	4.54 (2.87)	RA vs MI	5.31*
								RA vs YA
Understanding	6.03 (3.32)	8.30 (2.48)	6.83 (2.38)	7.26 (1.94)	8.58 (2.04)	8.19 (2.64)	6.82 (2.58)	MI vs RA	7.13*
								MI vs N
Emotional response	5.0 (2.81)	7.46 (2.68)	6.44 (2.83)	4.84 (2.52)	6.29 (3.10)	5.24 (3.81)	4.52 (3.12)	RA vs MI	5.94*
								RA vs YA

B-IPQ: Brief Illness Perception Questionnaire; SD: standard deviation; MI: myocardial infarction; RA: rheumatoid arthritis; SLE: systemic lupus erythematosus; MCTD: mixed connective tissue disease; N: neurology inpatients; INT: internal medicine inpatients; YA: young adults with minor chronic conditions.

Significant differences at .05 level Scheffe test between particular pairs of diagnostic groups.

Analysis of the differences between inpatients and outpatients revealed significantly higher scores in consequences, concern and treatment control among inpatients (see Table 4).

Table 4.

B-IPQ mean scores (SD) – differences between inpatients and outpatients.

	Inpatients (N = 103)	Outpatients (N = 173)	F
Consequences	6.58 (2.8)	5.10 (2.7)	19.37*
Timeline	8.21 (2.8)	7.00 (3.0)	0.45
Personal control	6.76 (2.7)	6.15 (2.5)	3.76
Treatment control	8.19 (2.1)	6.88 (2.9)	19.21*
Identity	6.87 (2.7)	6.25 (2.8)	3.48
Concern	6.25 (3.4)	5.49 (2.8)	3.01*
Understanding	7.47 (3.0)	6.89 (2.4)	4.04
Emotional response	6.04 (3.1)	5.41 (3.0)	2.79

B-IPQ: Brief Illness Perception Questionnaire; SD: standard deviation.

Statistically significant differences; p < .05.

Concurrent validity

To assess concurrent validity, analysis was performed of the correlations between anxiety and depression as measured by the HADS. Concern, emotional response and total B-IPQ scores correlated significantly with depression and anxiety. The results are shown in Table 5 (online supplement).

Discussion

Illness perception was postulated by Weinman and Petrie (1997) as a new paradigm for health psychology and psychosomatics. This approach still seems to have great potential for future research and valuable implications for clinical practice. The development of measures to assess illness perception and their wide use enables patients with chronic conditions to be understood better as more is learnt of their underlying coping mechanisms, health behaviours and treatment outcomes. These methods are vital and are especially valuable for clinical psychologists working with chronically ill patients, since they help identify patients with unrealistic and/or threatening illness perceptions that demand modification. Taking into account the fact that in most cases psychological examination requires assessment of many different aspects of the way patients function, our priority has been to obtain a reliable Polish version of a short measure of illness perception.

This study has confirmed that the evaluated Polish version of the B-IPQ (see Appendix 1) is a reliable tool useful for assessing illness perception in Polish patients. This conclusion was reached on the basis of the satisfactory results obtained from analyses of internal consistency and discriminant, structural and concurrent validity.

The results obtained in our study for the mean scores in the illness perception dimensions assessed by the B-IPQ are in accordance with those obtained by Broadbent in the original B-IPQ study (Broadbent et al., 2006) and by other researchers who have studied patients with chronic heart disease (Giardini et al., 2012; Yaraghchi et al., 2012). Agreement in the B-IPQ results was also observed between our groups of patients with SLE and RA and those studied, respectively, by Daleboudt et al. (2011) and Hyphantis et al. (2013). Illness perception has also been assessed in stroke patients, but no detailed data on the B-IPQ scores have been revealed (Sjölander et al., 2013). Young adults with minor chronic health problems obtained the lowest scores in our study in most of the B-IPQ dimensions. Similar results were observed in young patients with atopic dermatitis in a study by Wittkowski et al. (2008) and in the original B-IPQ study among young patients with minor conditions, namely, allergies and colds (Broadbent et al., 2006).

The present results have shown that the Polish version of the B-IPQ evaluated by us has good internal consistency. As has been suggested, a Cronbach’s alpha coefficient greater than 0.7 attests good reliability of the method undergoing testing (Nunnally, 1986). Thus, the alpha coefficient 0.74 obtained in our study demonstrates an adequate level of reliability for our version of the B-IPQ.

Discriminant validity was demonstrated in our study of a group of Polish patients by observing logical significant differences between subgroups with different chronic diseases and also between inpatients and outpatients. Patients with RA were significantly more concerned and emotionally preoccupied than young adults with minor conditions and patients undergoing cardiac rehabilitation and also experienced significantly more symptoms than these two groups of patients. In keeping with expectations, the lowest scores in all but one of the illness perception dimensions were observed in young adults with minor chronic conditions. As expected, the timeline was perceived to be longest by patients with SLE, RA and MCTD and shortest by the group with minor health problems. The highest perceived treatment control was noted in hospitalised patients (in internal medicine and neurology settings) who were receiving specific medical treatment and/or rehabilitation during the examination. The most concerned were patients with RA and SLE, both chronic disabling diseases, hospitalised patients with neurological diseases and internal medicine inpatients, whose concern may have been related to the hospitalisation per se and the experience of acuter and more severe symptoms. Inpatients were more concerned about their disease; their illness was more burdensome to them, but at the same time they felt that it was more controllable by treatment. These results demonstrated that the version of B-IPQ assessed is able to differentiate between various groups of patients, as did the original test (Broadbent et al., 2006).

Concurrent validity was approved by noted significant correlations between depression and anxiety and the B-IPQ total score. The B-IPQ score offers the possibility of assessing the extent to which illness perception is threatening for the patient. According to the authors of the original B-IPQ, the higher the test score, the more threatening the illness perception (Broadbent et al., 2006). Significant positive correlations between total B-IPQ score and depression and anxiety are in accordance with this relationship. Moreover, anxiety levels as well as depression were significantly correlated with concern and emotional response. In addition, depression was, as expected, related to perceived lower controllability and more burdensome consequences and identity. Similar results have been noted by other authors for depression (Grace et al., 2005; Groarke et al., 2005) and anxiety symptoms (De Raaij et al., 2012; Groarke et al., 2005) as correlates of B-IPQ dimensions.

The structural validity of the Polish version of the B-IPQ was demonstrated by inter-score correlation analyses. The observed correlations were in the expected direction: consequences, timeline and identity were positively correlated with each other as well as with concern and emotional response. The last two were also positively correlated with each other.

The lack of significant positive correlations observed between control and other dimensions was in keeping with expectations and the basic theory of illness perception. Other authors have communicated similar results for the control dimension (Broadbent et al., 2006; De Raaij et al., 2012; Giannousi et al., 2010; Hurt et al., 2015). Nevertheless, we agree with French and Weinman (2008) that this illness perception dimension demands further and more detailed investigation. According to our clinical experience, ‘controllability’ as a psychological construct appears to be the most complex and multifactorial of the dimensions and of greatest interest in the construct of illness perception, inviting further discussion. Similar conclusions were drawn by Rees et al. (2015) who found the control dimension to be, in fact, multidimensional.

The broad extent of self-perceived control over illness is apparent from the wide range of questionnaire scores and from clinical observations of patients with the same illness. These inter-patient differences, both in the type of controllable symptoms and the level of control, may be responsible for the complexity. A symptom associated with a specific disease may be perceived by one patient as somewhat controllable and by another as totally beyond control. Different patients can perceive different symptoms as controllable. Moreover, while the perceived control may be in accordance with objective knowledge about the specific disease, it may also be based on the very subjective experience of the patient. Differences can be even more evident when illness perception is compared between patients with different chronic diseases. Controllability may indeed be influenced by many overlapping factors, including the somatic, psychological and social. Since generic scales may miss some aspects of the perception of a particular illness, we strongly agree with other authors regarding the necessity of creating illness-specific measures (Anderson-Lister and Treharne, 2014; Hvidberg et al., 2014; McCorry et al., 2013; Rees et al., 2015).

The strength of our study is that it is, as far as we know, the first Polish study to assess illness perception using the B-IPQ with a number of groups of patients with various chronic diseases. Additionally, it is the first study to be aimed at evaluating the questionnaire’s psychometric properties. Also new was the use of the fact that a group of young adult patients with minor chronic problems was used to estimate discriminant validity instead of patients with acute health problems. Conscious of the need to be mindful of both linguistic and conceptual correctness in creating new language versions of psychometric tests (Broadbent et al., 2011; Paheco-Huergo et al., 2012), we followed a rigorous translation procedure with back-translation and a pilot study to identify potential problems that might make the B-IPQ less straightforward and understandable for the patient. Another advantage of our study was that assessment of illness perception was performed by clinical psychologists or a trained nurse at a psychological consultation or in a face-to-face interview.

Some limitations of the study should be noted. Since the majority of participants were outpatients, only a single assessment of illness perception was made using the B-IPQ. It was not subjected to the test–retest method, nor was it possible to evaluate the predictive validity of the method studied. No other Polish questionnaire measuring illness perception was available at the time of the study, and so it was not possible to compare the B-IPQ results with other methods of assessing this. Translation of the IPQ-R has been completed by the authors of this article (Nowicka-Sauer et al., 2014), and the research aimed at its validation is still in progress. Since the groups of neurological and internal medicine inpatients studied were not numerous, results from these patient groups should be analysed with caution.

Some researchers have pointed out the limitations of these methods of assessing illness perception (French and Weinman, 2008; Rees et al., 2015), and we acknowledge these, but both the research results and our clinical experience while studying them show their undeniable value in understanding patients’ cognitive picture of illness. This study provides a reliable and useful tool that is helpful in daily clinical practice and that may contribute to an increase in knowledge of illness perception.

Footnotes

Appendix 1

The Brief Illness Perception Questionnaire – evaluated Polish translation.

Acknowledgements

The authors thank all the patients who participated in the study.

Declaration of conflicting interests

None declared.

Funding

The study received no specific funding from any agency in the public, commercial or not-for-profit sectors.

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