1 Dialysis and Transplantation Center, C. I. Parhon University Hospital, Iasi, Romania, 2 Al. I. Cuza University, Department of Psychology, Iasi, Romania and 3 Renal Unit, Guy's Hospital, London, UK
Correspondence and offprint requests to: Dr Adrian Covic MD, PhD, Associate Professor of Nephrology, Director, Dialysis and Transplantation Center, Parhon Hospital, 50 Carol 1st Blvd, Iasi 6600, Romania. Email: acovic{at}xnet.ro
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Abstract |
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Methods. Eighty-two clinically stable HD patients completed the Short Form-36 Health Survey (mean age 47.9±12.1, mean treatment duration 72±50.6, 53.6% males). Illness representations were assessed by a structured interview containing questions derived from The Revised Illness Perception Questionnaire.
Results. Our results indicate a relatively low QoL of HD patients, with an important proportion of patients scoring less than 43 for the physical component summary (65.9%) and less than 51 for the mental component summary (58.5%). HD patients consider their illness as having a chronic course, which they understand and control quite well. A higher personal control is associated with a lower emotional response and a better understanding of the disease. However, the perceived negative consequences of the disease upon patients personal lives are considerable, as is their emotional response. Four of the six components of illness representations were strongly related to QoL parameters. On multiple regression analysis, between 15 and 31% in the variance of the physical and mental component of QoL was explained by three dimensions of illness representations: the perceived course of the disease, personal control and emotional response. Only the emotional response dimension of the illness representations is related to treatment duration (r = 0.48, P<0.01).
Conclusion. Our study demonstrates important relationships between illness representations and QoL in end-stage renal disease patients treated by HD. Future research will have to plan for interventions that could alter illness representations in order to confirm the real impact of illness representations upon patients QoL.
Keywords: end-stage renal disease; haemodialysis; illness representations; quality of life
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Introduction |
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Recent studies in chronic diseases suggest that QoL may be related to patient cognitive representations of illness and treatment, according to a theoretical self-regulation model of illness appraisal and behaviour [4]. This self-regulation model involves a central stage of cognitive representation of the health threat. The illness representation derives from prior experiences in the medical domain and guides the processing of information in a fashion consistent with prior knowledge [5,6]. The second stage is coping, which involves the selection and performance of a plan to deal with various/changing disease threats. Illness representations are multi-dimensional: disease identity (labeling the disease and understanding the disease symptoms), cause, consequences (perceived physical, psychological, social and economic impact of the disease), time-line (perceived course of the disease) and controllability (perceived management of the disease).
A direct influence of illness representations on QoL has been demonstrated in various chronic conditions: diabetes [7], chronic fatigue sindrome [8,9], Addison disease [10] and multiple sclerosis [11]. Unfortunately, since illness representations may vary widely across different chronic diseases and even among patients who suffer from the same medical condition [12], their relationship with QoL cannot be extrapolated to end-stage renal disease (ESRD). There are no previous published data concerning illness representations assessment in ESRD patients.
Given the importance of health-related QoL measures in predicting patients outcome and the modifiable nature of illness representations held by patients we aimed to determine the relationship between HD patients beliefs about disease and treatment and their QoL. Do illness representations predict QoL of HD patients? And if so, does treatment duration play a role in this association?
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Subjects and methods |
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Instruments
The Short Form Health Survey Questionnaire (SF-36) adapted for Romanian population [13] was used to assess eight dimensions of the QoL: physical functioning, social functioning, role-functioning emotional, role-functioning physical, vitality, bodily pain, mental health and general health perceptions. Two summary scores were obtained: one for the physical component (assessing physical functioning, role-functioning physical, vitality, bodily pain and general health perceptions) and one for the mental component (assessing social functioning, role-functioning emotional, mental health, vitality and general health perceptions). Scores range from 0 to 100, a higher score indicating a better QoL.
Illness representations were assessed with the well-validated Revised Illness Perception Questionnaire, a recently developed and widely used quantitative measure of the five components of illness representations in Leventhal's self-regulatory model [4]. Furthermore this instrument had been successful in predicting different aspects of adaptation and recovery in chronic illness [14]. Through a number of structured questions the following six components of illness representations were evaluated: time-line, consequences, personal control, treatment control, coherence and emotional response (see below for details). The patients rated the items on a four-point scale, ranging from strongly disagree to strongly agree. The reliability scores (Chronbach's alpha) for the six components of illness representation were comparable with those found in other studies assessing dimensions of illness representations [8,10].
The time-line dimension was assessed by six items ( = 0.62); e.g. I expect to have this illness for the rest of my life. A higher score on this dimension indicates the perception of a chronic course of the disease.
The consequences dimension was assessed by six items ( = 0.64), a higher score indicating that the patient considered their disease as having serious consequences upon their life (e.g. My illness strongly affects the way others see me).
Personal control dimension comprised five items ( = 0.70); e.g. My actions will have no effect on the outcome of my illness. In this case, a higher score indicates the perception of a better personal control of the disease.
Treatment control was assessed by five items ( = 0.68), a higher score indicating that the patient considers HD efficient in controlling ESRD (e.g. There is nothing which can help my condition).
Coherence is a measure of how well the patient understands his illness. It was evaluated by five items ( = 0.63); a higher score on this dimension indicating that patient considers to understand ESRD (e.g. My illness doesnt make any sense to me).
The last dimension assessedemotional responsehad six items ( = 0.74); a higher score on this dimension indicates a more intense emotional reaction to the disease (anxiety, depression); e.g. My illness makes me feel angry.
The study was approved by the Hospital's Ethical Committee and was performed in agreement with Helsinki's declaration of human rights.
Statistical analysis was performed using SPSS 7.5 for Windows. Correlation analysis was performed using Spearman's rho. Comparisons were made using the 2 test. Multiple stepwise regression analysis was used to predict independent variables affecting QoL. Initially simple correlations were examined between age, gender, treatment duration and PCS and MCS as dependent variables. As none of these independent variables were significantly related to QoL scores they were excluded as predictors from the final regression analysis. A model was constructed using PCS and MCS as dependent variables and the dimensions of illness representations as independent variables. A P value of 0.05 or less was considered to indicate statistical significance.
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Results |
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Discussion |
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HD patients consider their illness as having a chronic course, which they understand quite well and are able to control. A better understanding of the illness is associated with a lower emotional response and higher personal control of the disease. At the same time, the perception of a chronic course of the disease is associated with better personal control. However, the perceived negative consequences of the disease upon patients personal lives are considerable, as is their emotional response.
According to Leventhal and colleagues [16] the illness representation dimensions are interrelated. They function as groups of beliefs instead of single cognitions. Our results confirm this statement for ESRD patients on HD, demonstrating significant correlations between five of the six components of illness representations assessed. The fact that the treatment control dimension was not associated with any other dimension may be due to the cross-sectional design of our study.
It is important to discuss here the implications of a chronic illness schema held by dialysis patients. Previous research in non-renal populations indicates that patients who consider their illness as having a chronic course are more disabled in daily functioning [17] and show little inclination to engage in activities designed to control their illness [18]. This, however, is not true in HD patients. In fact, our study suggests that an increased perception of the disease chronicity is positively and significantly associated with better personal control and physical functioning. This contradiction may lie in the conceptualization of chronicity as a function of how much the disease interferes with daily life [17]. In well-dialysed patients without important co-morbidities the only interference of the disease with their lives is the fact that they have to come to treatment, in some cases for a long time. On the other hand a non-negligeable proportion of patients fail to comply with the prescribed medical regimens just because they think and hope that: my kidneys will regain functions one day. A patient admitted that he held this wrong belief for no <9 years. This is why we consider that holding a chronic illness schema is essential for the adaptation of our patients. This assumption was confirmed by multiple regression analysis.
Consistent with the self-regulation model [4] the adaptive outcome depends on coping, which in turn depends on illness representations. Our study demonstrates that three illness representation dimensionsthe chronicity perception (see above), personal control and the emotional responsehave the potential to be powerful predictors of QoL in ESRD patients. Future prospective analysis will have to reinforce this important finding. The role of copinga much weaker predictor of QoL in non-renal populations [9,10]remains also to be ascertained in a prospective design. Finally, future research will have to plan for interventions that could alter illness representationsfor example fostering patients understanding of ESRD and reducing the emotional response to their illness and treatment modalityin order to confirm the real impact of illness representations upon patients QoL.
Our findings are consistent with those obtained in other chronic but non-renal diseases. Particularly, emotional response and personal control also predicted the QoL of patients with chronic fatigue syndrome, Addison disease and multiple sclerosis [8,9,11]. Moreover, a study in type 1 and type 2 diabetes patients showed that understanding the nature of the diabetic disease and a superior perceived control of diabetes were significant predictors of engagement in diabetes-specific health behaviours and positive perceptions of QoL [7]. All these findings suggest a common mechanism of adaptation to chronic illnesses [9].
Our data suggest that time on HD has a minor influence on illness representations and QoL of our patients. There was no significant difference between illness representations held by new HD patients vs patients with a longer treatment history. Treatment duration seems to be associated only with a lower emotional response to disease. Although these findings are consistent with some recent studies including a small number of patients [19], we acknowledge the inherent limitations of a cross-sectional analysis and the requirement of a longitudinal testing of this important point.
Our findings confirm in ESRD the central assumption of the self-regulation theory [4], which states that in order to adapt to an illness, a patient behaves rationally, according to his personal model of disease and treatment. Illness representations held by HD patients are particular and therefore important to be recognized and assessed for optimal patient care. This is further supported by the described link between cognitive representations and QoL. Given the potential critical role of illness representations and the fact that adaptation to a chronic illness is a continuous process we advocate the initiation of a prospective trial assessing the QoL and the patients personal models of illness and treatment.
Conflict of interest statement. None declared.
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References |
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