Health-Related Quality of life in chronic kidney disease
Health-Related Quality of Life (HRQoL) refers to the dimensions of functioning that are affected by one’s disease and/or treatment, including physical (the ability to perform activities of daily living, as well as physical symptoms resulting from the disease or treatment), psychological (ranging from severe psychological distress to a positive sense of well-being and cognitive functioning), and social functioning (quantitative and qualitative aspects of social relationships and societal integration) [1].
Chronic diseases (e.g., cancer, heart diseases, stroke, diabetes, bowel diseases, renal disease, and psychiatric diseases) have the potential of affecting and worsening the overall health of patients by limiting their capacity to have a good functional status and reducing the positive reinforcing outcomes of participating in valued activities and feelings of personal control [2,3,4,5,6,7].
Chronic kidney disease (CKD) is defined by indicators of kidney damage—imaging or proteinuria (i.e., albumin to creatinine ratio)—and decreased renal function—below thresholds of glomerular filtration rate (GFR) estimated from serum creatinine concentration—for at least three months [8].
The current recommendations by the Kidney Outcomes Quality Initiative [9] and National Institute for Health Excellence [10] are to use serum creatinine concentration to estimate glomerular filtration rate and transform it using the Chronic Kidney Disease Epidemiology Collaboration equation.
CKD compromises the physical—complications include anaemia, reduced red blood cell survival, iron deficiency, and mineral bone disease—and psychological health of patients, daily functioning, general wellbeing, and social functioning [11].
With a prevalence in the general population around 13% [12] CKD is associated with HRQoL across all the stages [13,14,15]. Poorer HRQoL is also related to a higher risk of developing end-stage kidney disease, which in turn predicts hospitalization and mortality, and falls as GFR declines [16]. The more the kidney function worsens, the more the risk of death increases, and it’s largely attributable to death form cardiovascular disease and cancer [17].
Big-Five personality traits in CKD
The Big-Five model of personality integrates most of the evidence in personality psychology [18, 19] and assumes that individual differences in personality characteristics can be organised into five broad trait domains: extraversion (extravert people experience high levels of happiness and life satisfaction), agreeableness (individuals high in this trait are helpful, warm and emphatic), conscientiousness (persons high in this trait tend to be well-organised, goal-directed and persistent), neuroticism (persons high in this trait tend to experience strong levels of distress) and openness (people high in openness have broad interests and seek experiences).
Big-Five personality traits can affect HRQoL of different disorders because they could influence patients’ willingness to take treatment options, predispose to neuropsychiatric symptoms and affect coping strategies [11]. Overall, conscientiousness was connected to higher compliance to treatments and indications of doctors, better physical and mental HRQoL, whereas neuroticism was linked to lower HRQoL [20,21,22,23,24,25,26].
Schoormans et al. [27] also showed that this adverse personality effect was limited to older men, suggesting that age should also be considered when exploring the relationship between personality traits and HRQoL in patients with other chronic diseases.
A similar type of inverse association between neuroticism and perceived health, showing how CKD patients with higher traits of neuroticism prove to be more preoccupied with their health symptoms, complaining about them more and consequently perceived poorer HRQoL [28].
Another relevant contribution by Poppe et al. [29] showed that CKD patients with neurotic personality tend to be less accepting of the disease and to endorse more denial. In support of this, the authors explain that high levels of neuroticism are usually associated with specific attitudes (inflexibility, withdrawal, passivity, wishful thinking, negative emotion focus, and less adaptive coping).
Beside this, the authors also hypothesised that the mental HRQoL of CKD patients can be directly explained by the relationship between neuroticism and the perception of health, as this association has been proven by many studies: neuroticism being associated with a worse perception of mental HRQoL [11, 24]. The authors explain that this negative association can probably be explained by the negative tendency of neurotic patients to be hyper-vigilant regarding the negative stimuli they encounter and excessively inattentive to the positive ones.
In addition, Ibrahim et al. [11] showed a positive association between extraversion and mental HRQoL, which is aligned with findings of other studies not strictly related to CKD patients [26]. The explanation given by the author is that extraverted people are more likely to be easily distracted away from their disabilities.
Moreover, conscientiousness, agreeableness and openness were not associated with HRQoL. However, since conscientiousness in other studies proved to be predictive of higher treatment adherence [24] and conscientiousness and agreeableness were associated with higher self-rated health [26].
Illness denial in CKD
The concept of denial as recurrent defence mechanism in human experience was firstly introduced by Sigmund Freud (as cited in Rossi Ferrario et al. [30]) and subsequently refined by Anna Freud (as cited in Gagani et al. [31]) as an unintentional process which comes into play to reduce the anxiety caused by a specific threatening problem by preserving a person from something that he/she is not yet ready to face. For many years since this theorisation, denial has been considered mostly as uniquely pathological, but during the last times it has been recognised as playing a protective role in psychological functioning [32].
While generally considered as a unidimensional construct, other scholars suggested the complexity and fluctuation of denial and its negative and positive effects on HRQoL in chronic illness [33,34,35].
Nevertheless, a circular relationship was demonstrated between depression and negative self-care behaviours in CKD patients [30, 36], i.e., patients with depression are less likely to comply with medication, dialysis, and renal diet and more likely to have a sedentary lifestyle.
Recently, Rossi Ferrario et al. [30] proposed a new multidimensional model of denial and discussed its positive side as an effective strategy for facing the initial phases of an illness (i.e., invasive examinations or burdensome therapies), and the negative side when in its more severe, persistent forms, denial may lead to maladaptive behaviours and distress during the chronic course of the disease. The authors defined it as composed of two correlated components, namely denial of negative emotions (the emotional reactivity related to the individual’s emotional life and its regulation) and resistance to change (the behavioural efforts and life-style changes necessary to manage illness). The components represent a preliminary phase characterised by the removal of unpleasant material from consciousness. The authors also introduced a third independent component, the conscious avoidance, representing a later phase where awareness is present, but the individual voluntarily avoids facing the threatening situation.
In sum, following Gagani et al. [31], it is legitimate to assume that denial may be to some extent a functional strategy in the first phase of an illness, but it can prevent cure and control of chronic illness like CKD, particularly in the long run. Therefore, health professionals should verify whether CKD patients’ denial is adaptive or maladaptive so it can be addressed properly during treatment.
Rationale and hypotheses of the present study
Low attention has been dedicated to the personality profiles and illness denial in CKD patients and their relation with the domains of HRQoL. Poorer HRQoL can predict a higher risk of hospitalization and mortality, and broadly a worse adjustment to the dialytic therapy. Thus, a clearer knowledge of the psychological variables associated with a worse HRQoL in the predialysis stage might suggest specific interventions in this population, with the aim of improving their adjustment to the new therapeutic pathway [11, 16].
The aim of the present study was to investigate the association between illness denial and Big-Five personality traits and HRQoL dimensions beyond the effect of gender, age, medical comorbidity (cardiovascular respiratory diseases and dysmetabolism) and psychological distress (i.e., trait anxiety) in a group of patients with CKD in the predialysis stage. We hypothesised that conscientiousness, agreeableness and openness are related to better physical, mental and social dimensions of HRQoL, and that neuroticism is related to a worse HRQoL in all its dimensions.