The authors have declared that no competing interests exist.
Emotional deterioration is frequently found in patients with chronic kidney disease, but some patients are affected by depressed mood without fulfilling the criteria of a depressive disorder. Those patients might rather suffer from an apathy symptom. Apathy as a symptom of a medical disease is accompanied by loss of motivation and interest, cognitive impairments, and emotional distress. Our study tested how groups of apathetic and depressed chronic kidney disease patients responded to a single haemodialysis session on measures of mood.
21 haemodialysis patients were assigned to subgroups (depressed, apathetic only, without depression and apathy) according to clinical relevant cut-offs. Sensitive questionnaires were administered to monitor mood state in general and mood changes before and after a single haemodialysis session in the chronic kidney disease patients. The results were compared to 20 age-matched healthy controls receiving no treatment.
Fortheen dialysis patients had eighter apathy or depressen and seven had neighter apathy nor depression
The absence of a short-term mood change in apathetic dialysis patients makes them comparable to dialysis patients with depression. We argue that apathetic patients lack the probable mood brightening effect of the haemodialysis. The lack of emotional improvement by dialysis sessions could also lead to decreased adherence of the patients. Hence, apathy seems to be a serious symptom in chronic kidney disease that is worth to be considered at least in the diagnostic process. Accompanying psychotherapeutic care for these patients would be desirable
Depression has been identified with a prevalence of 21% and as the most common psychiatric disorder in chronic kidney disease (CKD)
Beside depressive symptoms in CKD patients the clinical impression is often marked by loss of motivation and interest and emotional distress. A simultaneous depletion of behaviour, cognition, and emotion is observed although no pronounced depression exists in these patients. We argue that apathy can describe this state of non-depressed but affective impaired CKD patients. Apathy has received different definitions in the literature. Marin defined apathy as loss of motivation and interest and differentiated between apathy as a syndrome and apathy as symptom of diseases and disorders associated with cognitive impairment, diminished level of consciousness, or disturbance of emotion
Whereas the occurrence of depression in CKD and its negative impact on cognition and quality of life has been widely studied, symptomatic apathy has never been considered so far. It remains unclear whether apathy and depression could be differentiated also in CKD patients. We assume that apathetic and depressed patients independently exist among the CKD population. Apathy and depression should have different effects on the quality of life, in particular on the long-term mood state of the patients. Furthermore, symptoms of apathy and symptoms of depression should moderate the emotional reactivity to the haemodialysis treatment to a different extent. The hypothesis was tested by means of a pre-post control group design evaluating changes of mood before and after a single dialysis session.
This is a secondary analysis of a study that had been published previously
All participants were tested twice within a 24-hour retest interval. CKD patients were tested at two time points, immediately before dialysis as well as 24 hours after dialysis to assess the potential effect of dialysis avoiding circadian changes. Tests were performed in a quiet room. Controls were tested in their home settings. Demographic data, depression and apathy were assessed from all participants. From dialysis patients, specific medical history, routine laboratory tests and a complete list of medication were obtained.
The study was approved by the local Ethics Committee (reference #2012-30) and conducted according to the ethical principles regarding human experimentation as laid down in the Declaration of Helsinki. After all participants were provided with detailed information about the purpose, course, and possible risks of the study, they gave their writtenconsent.
Apathy was assessed with a German version of the Apathy Evaluation Scale (AES). The AES is a self-assessment syndrome-independent scale to evaluate symptoms of a lack of motivation in several disorders and diseases
The Beck Depression Inventory (BDI) was used to assess the severity of a probable mood disorder
To assess persistent deteriorations in mood a questionnaire of a German health survey of Quality of Life was administered
In order to measure short-term changes in mood we needed a method that is sensitive enough to detect subtle differences within a very narrow time interval (24h retest interval). The multi-dimensional state questionnaire is a standardized instrument which is available in two forms (A and B) and met our requirements of short retest intervals
First, BDI and AES scores were computed for each participant and compared with the cut-offs. Based on this decision CKD patients were assigned into three subgroups: patients without apathy and depression (CKD─), patients with apathy only (CKD+A), and patients with depression (CKD+D). Healthy controls who meet the apathy or depression criteria were excluded from further analyses. The control group and the three CKD subgroups form the independent variable.
Second, descriptive statistics (group means, standard deviations, standard error of means, or frequencies) were computed for each dependent variable. Hypotheses’ testing was performed as group mean testing and relies on one-way ANOVAs and orthogonal linear contrast in case of comparing healthy controls and CKD patients. Comparisons of CKD patients only rely on one-way non-parametric ANOVAs by Ranks (H test), because of low group numbers. The general level of significance was set to p<0.05. Measurements of effect size were Cohen’s d for between-group comparisons and Hedges g for pre-post comparisons. Both are comparable in its possible size. A general guideline for interpretation of effect sizes is small (0.3), moderate (0.5), and large (0.8). Statistical calculations were performed with SPSS 20 software.
Seven CKD patients were identified with clinical relevant symptoms of depression (BDI≥15). Clinically relevant symptoms of apathy were detected in eleven out of 21 CKD patients and one control person (AES≥34). The diagnosis of apathy overlapped with the diagnosis of depression in four CKD patients. Seven CKD patients did show neither depression nor apathy symptoms.
Nine of the CKD patients were under medications with psychopharmacological effect: antidepressant and anticonvulsant drugs were most frequently used in the CKD+D group. Sedatives and analgesics were more frequent in CKD with apathy further indicating the subtle complaints in this group of patients.
Apathy and depression symptoms were further characterized by means of an analysis of the BDI and AES subscales, respectively. Somatic and cognitive-emotional symptoms and the BDI sum score were significantly increased in CKD patients compared to healthy controls. CKD+D patients differed significantly to the CKD+A and the CKD─ patients in these scores. However, an average BDI score of 17.4 in CKD+D patients indicated no more than a mild depression. CKD+A and CKD─ showed small but no significant differences compared to healthy controls. The subscale suicidal thoughts could not differentiate the CKD groups.
Behavioural and cognitive-emotional symptoms of apathy and the AES sum score were significantly increased in the CKD+A as well as in the CKD+D group compared to healthy controls, indicating that depression shares nearly all symptoms of apathy. CKD─ patients obtained an AES profile that was comparable to those of the control group.
Controls | CKD─ | CKD+A | CKD+D | P-values | ||
N=20 | N=7 | N=7 | N=7 | Controls vs. CKD |
CKD only |
|
Mean age in yrs. (SD) | 56.6 (12.7) {33-80} | 56.9 (18.3) | 57.3 (7.9) | 54.4 (2.8) | 0.925 | 0.833 |
range | {37-79} | {48-68} | {51-59} | |||
No. of females | 13 (65%) | 2 (29%) | 1 (14%) | 6 (86%) | 0.155 | 0.042 |
Employed | 11 (55%) | 3 (43%) | 0 (0%) | 0 (0%) | 0.001 | 0.079 |
High degree of formal education | 9 (45%) | 4 (57%) | 0 (0%) | 2 (29%) | 0.275 | 0.098 |
Mean dialysis vintage in month (SD) | - | 35 (36) | 58 (60) | 61 (65) | - | 0.808 |
range | {1-88} | {4-184} | {3-196} | |||
Psychopharmacological medication | ||||||
Antidepressant | 0 (0%) | 0 (0%) | 2 (29%) | 3 (43%) | 0.020 | 0.292 |
Anticonvulsive | 0 (0%) | 1 (14%) | 0 (0%) | 2 (29%) | 0.079 | 0.742 |
Sedative, analgesic | 0 (0%) | 0 (0%) | 3 (43%) | 1 (14%) | 0.040 | 0.263 |
Symptoms of depression (BDI) | ||||||
Somatic symptoms | 3.5 (2.6) | 4.4 (2.1) | 4.4 (0.8) | 8.0 (2.2) | 0.005 | 0.004 |
Cognitive-emotional symptoms | 0.4 (0.6) | 0.9 (1.1) | 0.7 (1.5) | 3.3 (1.6) | 0.001 | 0.009 |
Suicidal thoughts | 0.1 (0.3) | 0.1 (0.4) | 0.1 (0.4) | 0.3 (0.5) | 0.433 | 0.745 |
Sum score | 5.7 (3.5) | 7.6 (3.7) | 8.0 (2.5) | 17.4 (1.7) | <0.001 | 0.001 |
Symptoms of apathy (AES) | ||||||
Behavioural symptoms | 13.0 (2.8) | 13.4 (1.8) | 19.4 (2.1) | 18.9 (5.5) | <0.001 | 0.01 |
Cognitive-emotional symptoms | 6.5 (1.2) | 6.6 (1.5) | 9.4 (1.1) | 8.4 (2.7) | 0.002 | 0.037 |
Sum score | 25.5 (4.5) | 26.0 (4.7) | 38.0 (3.8) | 36.1 (10.1) | <0.001 | 0.018 |
CKD─ : without apathy and depression CKD+A: with apathy only CKD+D: with depression and probable apathy
: ANOVA contrast controls vs. all CKD groups : non-parametric omnibus test CKD groups only
Next we tested changes in mood related to the dialysis treatment.
In this study we tested how three different groups of CKD patients responded on a measure of short-term mood after a single session of haemodialysis. First, our findings suggest a high rate of apathetic patients (approx. two-third) among the CKD population. Second, a dichotomous distinction between patients with and without clinical relevant depression led to a sub group with symptoms of apathy only. These apathetic CKD patients showed the behavioural and cognitive-emotional symptoms of apathy, but lacked the somatic and cognitive-emotional symptoms of a prevailing depression, which clearly shows that patients were able to differentiate apathy and depression symptoms by means of self-report scales. Depressed mood (cognitive-emotional symptoms) turned out to be the best discriminator between patients with and without a depression. Suicidal thoughts, which were also suggested by former studies
Clearly, our sample size is small and not reliable to derive a prevalence rate in general. The study relied on CKD patients receiving haemodialysis treatment only. No conclusions can be thrown on CKD patients receiving other treatments like peritoneal dialysis, which is not limited to a 4-5 hour treatement thrice weekly but is usually done daily over many hours. Symptoms of depression were reported as less frequent and less severe in these patients
To further explore apathy in CKD we focused on the differential effect of apathy and depression on the sustained mood state. CKDs’ quality of life was often reported as severely affected by an additional depression
Apathetic CKD patients did not turn out to be at a higher risk than patients without apathy to develop further deteriorations in their prevailing mood state. Hence, in the second part of our study we tried to evaluate this outcome in terms of short-term mood changes. The momentary mood was assessed immediately before a dialysis session and 24 hours later after approximately one day of recovery. Here apathetic CKD patients showed a pattern comparable to that observed in patients with a clinical relevant depression. We could not show a short-term improvement in mood that was associated with the dialysis treatment in the apathetic CKD patients. In CKD patients without apathy we could demonstrated this possible effect. The mood of patients without apathy and depression improved nearly to the level of healthy controls. The effect size (within-subject d=1.3) indicated a large effect on our short-term mood measure.
The latter observation after all indicated apathetic patients as restricted as depressed patients. We argue that apathetic CKD patients are on risk to develop depressions later in the disease process. The absence of a (previously perceived) brightening effect could also mean a loss of positive reinforcement. Loss of positive reinforcement could negatively influence patients’ compliance and is a main factor in the aetiology of a major depression
Chronic kidney disease patients undergoing haemodialysis frequently show loss of motivation, cognitive impairments, and emotional distress without suffering from a depression. Apathy as a symptom of the renal disease seems to be attributable to this state. Patients with apathy are less impaired in quality of life than patients with depression, but lack a positive emotional reactivity to the dialyses treatment, which was observable in patients without apathy and depression. The clinical practice could consider apathy as a severe symptom in patients with end-stage renal failure. It is possible to discriminate between depression and apathy in those patients with the self-report questionnaires BDI and AES. Treating apathy in CKD could improve the adherence to the requirements of the dialysis treatment and omit the progression of the disease, probable cognitive impairments and an emotional distress.