The prediction of self-care behaviors in end-stage renal disease patients using Leventhal's Self-Regulatory Model

Abstract

Objective

To assess the utility of Leventhal's Self-Regulatory Model (SRM) to predict self-care behavior with regard to dietary, medication, and fluid regimes in end-stage renal disease (ESRD) patients.

Methods

In a prospective study, ESRD patients treated via hospital-based haemodialysis (N=73) were screened for cognitive deficits and completed questionnaires that enquired about illness perceptions, coping strategies, knowledge of kidney disease, and psychological distress at Time 1. Physiological proxy measures of self-care behaviors regarding diet (serum potassium levels), fluid intake (mean and standard deviation of interdialytic weight gain), and medication (serum phosphate levels) regimes were collected 3 weeks later at Time 2.

Results

Illness representations (emotional and timeline perceptions) predicted self-care behaviors with regard to diet and medication. Emotion-focused coping strategies predicted higher levels of variation in adherence to fluid restrictions. Younger males were less likely to adhere to the fluid restrictions.

Conclusions

The SRM has predictive utility. Psychological interventions should focus on alleviating disease-specific distress and challenging erroneous timeline perceptions in order to increase adherence to dietary and medication regimes in ESRD patients. A more specific measure of coping for ESRD is required to clarify the role of coping strategies in this population. Younger, male patients should be targeted for extra support with fluid restrictions.

Introduction

The majority of patients who experience end-stage renal disease (ESRD) are treated via hospital-based haemodialysis [1]. Haemodialysis removes water, waste, and salt by passing the patient's blood through a semi-permeable membrane within a dialysis machine. It is usually conducted 3 days per week for approximately 4 h per session. Haemodialysis patients should attend for dialysis, remain for the entire period, and take prescribed medications. Foods that are high in protein, sodium, and potassium should be restricted because overconsumption can lead to cardiovascular complications and cardiac arrest [2]. Fluid intake should also be limited due to ESRD patients' inability to excrete fluids. Excessive fluid consumption can lead to muscle cramping, congestive heart failure, oedema, vomiting, and death [3]. ESRD treatment is compromised by a lack of engagement in self-care behavior that reduces therapeutic benefits to the patient and increases substantially the cost of treatment [4].

Enhanced knowledge of the factors that predict self-care behaviors is potentially important given the serious consequences of nonadherence for patient well-being. One approach that has been fruitful in the prediction of self-care behavior in chronic illness is Leventhal's Self-Regulatory Model (SRM) [5], [6], [7]. The SRM states that an individual processes the health threat presented by an illness via two parallel pathways that interact as the individual adapts to the illness. The first pathway involves a cognitive representation of the illness and its associated coping strategies. The second pathway comprises an emotional representation of the illness and corresponding coping strategies. Feedback loops allow for the appraisal of coping effectiveness to influence the cognitive and emotional representations which, in turn, influence future coping responses. In this manner, the SRM describes a dynamic, self-regulatory system for representing, processing, and coping with a health threat. The model can be used to explain self-care behaviors, such as adhering to dietary recommendations, which can be viewed as problem-focused coping responses or nonadherence to dietary recommendations that could be viewed as emotion-focused coping responses (e.g., comfort eating to deal with distress).

There are five main components of the illness representation: identity (symptoms), cause (attribution), timeline (belief about the likely duration of the illness), consequences, and controllability/curability. These components were originally operationalized in the Illness Perception Questionnaire (IPQ) [8]. However, the IPQ has been revised recently to include three further subscales to assess cyclical timeline perceptions (a belief that symptoms remit and recur), illness coherence (understanding of the illness), and emotional representations (emotional distress specific to the illness) (IPQ-R) [9], [10]. Given its enhanced psychometric properties, the IPQ-R was employed in the present study.

Within the SRM, self-care behavior is viewed as a problem-focused coping response that is influenced by illness representations [5]. However, the coping strategies that individuals employ to help them to adhere to medical advice (the coping behavior) have been shown to mediate the relationship between illness representations and self-care behavior in previous studies (e.g., Ref. [11]). In this way, measurement of coping strategies could enhance the predictive utility of illness representations. The effect of coping strategies has not, to our knowledge, been investigated in relation to self-care behavior in ESRD patients undergoing haemodialysis.

Process models of coping posit that individuals develop coping strategies to deal with ongoing stressful situations [12], [13], [14]. Lazarus and Folkman [12] have outlined two conceptually separate types of coping, which could be used simultaneously and both of which could lower psychological distress. Problem-focused coping refers to efforts to change the situation, whereas emotion-focused coping strategies are thought to moderate the emotional distress associated with the stressful situation. A third type of coping response, maladaptive coping, refers to less helpful coping strategies such as behavioral disengagement or self-blame [13].

Haemodialysis is a relatively passive medical procedure where individuals with ESRD are required to relinquish control of their treatment to medical staff [15]. In these circumstances, research suggests that emotion-focused coping strategies would be more adaptive [16], whereas other aspects of the treatment may require more active coping responses, i.e., dietary and fluid restrictions and taking prescribed medication. A meta-analytic study of coping strategies and health outcomes suggested that adherence to these elements of treatment would probably be enhanced through the adoption of problem-focused coping strategies and that maladaptive coping strategies would be associated with poor or nonadoption of medical advice [17] Consistent with this position, Whitmarsh et al. [11] found that the high use of problem-focused coping and the low use of maladaptive coping predicted attendance at cardiac rehabilitation.

The SRM, in conjunction with coping strategies, has been applied successfully, within prospective designs, to the prediction of self-care behavior in patients with diabetes [18], [19] and heart disease [11], [20], [21]. The SRM has also predicted nonadherence to immunosuppressant medication in renal transplant recipients [22] and has been related, within a cross-sectional design, to quality of life in ESRD patients undergoing dialysis [23]. However, to the best of our knowledge this model has not been applied, prospectively, to the prediction of self-care behaviors in ESRD patients who are treated via haemodialysis.

A number of factors complicate the study of self-care behavior in ESRD and these should be controlled [24]: dialysis adequacy, disease severity, age, gender, knowledge about kidney disease and its treatment, and psychological distress were operationalized and included as control variables in the present study. Additionally, concerns have been raised about the levels of cognitive impairment in ESRD patients [25]. It is reasonable to assume that such cognitive impairments, if they exist, could impede the completion of self-report measures. Accordingly, a brief cognitive screening interview was conducted with each participant. Finally, most previous studies of self-care behaviors in ESRD have employed arbitrary cut-off values to determine nonadherence and this has impeded the cross-study comparison of results. The present study employed continuous outcome variables, analysed via multiple regression procedures to address this issue [24].

Based on the previous research we formulated three hypotheses: (1) that the illness representations would predict physiological proxy measures of self-care behaviors over and above clinical and medical factors; (2) that the relationship would be mediated by coping strategies as predicted by the SRM; and (3) that problem-focused coping would be associated with higher rates of self-care, and emotion-focused and maladaptive coping strategies would be associated with lower levels of self-care.