International Journal of Behavioral Medicine

, Volume 21, Issue 2, pp 240–247

Decreased Physical Effort, Fatigue, and Mental Distress in Patients with Coronary Artery Disease: Importance of Personality-Related Differences

Authors

    • Behavioral Medicine InstituteLithuanian University of Health Sciences
    • CoRPS—Center of Research on Psychology in Somatic diseases, Department of Medical and Clinical PsychologyTilburg University
  • Julija Brozaitiene
    • Behavioral Medicine InstituteLithuanian University of Health Sciences
  • Margarita Staniute
    • Behavioral Medicine InstituteLithuanian University of Health Sciences
  • Vaidute Gelziniene
    • Behavioral Medicine InstituteLithuanian University of Health Sciences
  • Inga Duoneliene
    • Behavioral Medicine InstituteLithuanian University of Health Sciences
  • Victor J. M. Pop
    • CoRPS—Center of Research on Psychology in Somatic diseases, Department of Medical and Clinical PsychologyTilburg University
  • Robertas Bunevicius
    • Behavioral Medicine InstituteLithuanian University of Health Sciences
  • Johan Denollet
    • CoRPS—Center of Research on Psychology in Somatic diseases, Department of Medical and Clinical PsychologyTilburg University
Article

DOI: 10.1007/s12529-013-9299-9

Cite this article as:
Bunevicius, A., Brozaitiene, J., Staniute, M. et al. Int.J. Behav. Med. (2014) 21: 240. doi:10.1007/s12529-013-9299-9

Abstract

Background

Identification of cardio-toxic psychological symptoms in coronary artery disease (CAD) patients is important.

Purpose

We examined the association of negative affectivity (NA), social inhibition (SI), and their combination in the distressed (Type D) personality with functional status, fatigue, and mental distress in CAD patients.

Method

Following acute coronary syndrome, 690 consecutive CAD patients agreed to participate in this cross-sectional study and were evaluated for clinical characteristics, including left ventricular ejection fraction (LVEF), and for NA, SI, and Type D personality (i.e., NA and SI; DS14 scale) when they entered a cardiac rehabilitation program in Lithuania. Patient-centered outcomes included functional status (bicycle ergometer), symptoms of fatigue (Multidimensional Fatigue Inventory-20), and mental distress (Beck Depression Inventory–II and Hospital Anxiety and Depression Scale).

Results

The reference subgroup (neither NA nor SI) included 34 % of patients; 13 % had NA only, 19 % had SI only, and 34 % had Type D profile. Type D patients had worse functional status, and Type D patients and NA-only patients had higher symptom levels of fatigue and mental distress. In multivariate regression models that included LVEF, clinical characteristics, and depressive symptoms, Type D personality was an independent predictor of decreased exercise capacity (OR = 1.77, 95 % CI 1.06–2.95, p = .03) and decreased motivation for activity (OR = 3.14, 95 % CI 1.73–5.73, p < .001). Type D, NA, and SI were also independent predictors of mental distress.

Conclusions

Type D personality traits independently predicted poor functional status and worse patient-centered outcomes independently from LVEF and depression. Further studies exploring personality-related differences in cardiovascular outcomes are needed.

Keywords

Coronary artery diseaseType D personalityOutcomesFunctional status

Introduction

The patient perspective on functional and health status is considered to be an important outcome of effective treatment in cardiology, but relatively little is known about the determinants of these patient-centered outcomes [1, 2]. Apart from objective markers of disease severity, behavioral markers such as depression may be associated with diminished health status benefits [3]. However, the association between depression and functional status is complex. Others have reported that depression was associated with lower exercise capacity [4], but we could not replicate this association in a study of 1,470 coronary artery disease (CAD) patients [5]. These mixed findings suggest that other variables may partially explain substantial individual differences in patient-centered outcomes.

Individual differences in personality may have an adverse effect on these outcomes. Type D personality is characterized by the combination of negative affectivity (NA; the tendency to experience negative emotions) and social inhibition (SI; the tendency to inhibit self-expression), and has been associated with adverse clinical events, poor health status, symptoms of fatigue, and mental distress in cardiac patients [69]. Less is known about the association of Type D with functional status. One study found that Type D patients covered shorter distance on the 6-min walking test without substantial differences in heart rate [10]. Decreased functional status in Type D patients might be due to decreased effort to perform, but more research is needed to test this assumption.

Recently, it has been argued that further studies should be directed towards dismantling of depressive symptoms in order to identify the most cardio-toxic symptoms such as anhedonia [1113]. Hence, research needs to study the association of Type D with anhedonia, depressed mood, and suicide ideation as distinct depressive symptoms. To date, most studies evaluated the role of Type D personality using dichotomous categories (presence versus absence), but research should also focus on the outcome effects of the separate NA and SI components of Type D [14].

Therefore, in this study, we examined the association of NA alone, SI alone, and their combination (i.e., Type D) with functional status, symptoms of fatigue, and mental distress as important patient-centered outcomes in CAD patients who participated in cardiac rehabilitation.

Methods

Patients

From February 2007 until August 2011, a total of 1,800 consecutive CAD patients attending a rehabilitation program at the Cardiovascular Rehabilitation Clinic of the Behavioral Medicine Institute of the Lithuanian University of Health Sciences in Palanga, Lithuania, were considered for this study. All study patients were referred to the rehabilitation clinic within 1 week after discharge from the cardiac inpatient department following treatment for acute coronary syndromes. All patients were receiving standard treatment for secondary prevention of CAD according to the existing guidelines. Eight hundred and forty-three patients were not invited to participate in the study because they were older than 80 years of age (n = 216), had documented cognitive disorientation or communicative disabilities, or did not speak Lithuanian fluently (n = 90), had severe comorbidities (n = 303) or unstable cardiovascular status (n = 183), or were not invited due to logistic reasons (e.g., not referred by the clinician; n = 51). A total of 957 (53 %) patients met the inclusion criteria; however, 267 (28 %) patients refused to participate in the study. Thus, our final study sample consisted of 690 (74 % men and 26 % women; mean age, 58 ± 9 years) patients. The study and its consent procedures were approved by the Ethics Committee for Biomedical Research at the Lithuanian University of Health Sciences, Kaunas, Lithuania. A written informed consent was obtained from each study patient.

Study Design

Within 3 days of admission to the rehabilitation clinic, all patients were evaluated for demographic and clinical characteristics, including CAD diagnosis; New York Heart Association (NYHA) functional class [15]; previous revascularization procedures, CAD risk factors, including diabetes mellitus, smoking, hypertension, and body mass index (BMI); and psychiatric treatments. Hypertension was defined as diastolic pressure ≥90 mmHg and/or systolic pressure ≥140 mmHg, and obesity as BMI ≥30 kg/m2. During the same visit, all patients were evaluated for personality (DS14 scale) [6]; symptoms of fatigue (Multidimensional Fatigue Inventory or MFI-20) [16]; symptoms of depression, depressed mood, anhedonia, suicidal ideation, and worthlessness (the Beck Depression Inventory–II or BDI-II) [17]; and symptoms of anxiety and depression (Hospital Anxiety and Depression Scale or HADS) [18]. After the visit, questionnaires were checked for missing items, and patients were asked to complete the missing items. Total depressive symptom severity was evaluated using both the BDI-II and HADS, and different clusters of depressive symptoms were evaluated with the BDI-II in order to prevent an overlap between questions targeting depressive symptoms.

During the initiation of the rehabilitation program, 675 study patients underwent exercise capacity evaluation using a standard bicycle ergometer testing procedure, and left ventricular ejection fraction (LVEF) was evaluated quantitatively by a cardiologist in 651 patients by means of echocardiography. A total of 638 patients underwent bicycle ergometer testing procedure and echocardiography. Values of the LVEF were categorized into two groups: normal to mild systolic dysfunction (LVEF >40 %) and moderate to severe systolic dysfunction (LVEF ≤40 %).

Individual Differences in Type D Personality

The DS14 scale consists of two 7-item subscales of NA and SI that are designed to measure respective personality traits [6, 19]. Each item is rated on a five-point Likert-type scale from 0 (false) to 4 (true) with total scores ranging from 0 to 28 on each subscale. Scores ≥10 on the NA and SI subscales indicate respective personality traits, and scores ≥10 on both subscales indicate Type D personality. Lithuanian translation of the DS14 scale [20] was shown to be a highly reliable instrument for evaluation of Type D personality construct and for identification of Type D patients using cutoff scores ≥10 in both DS14 subscales [21]. In the current study, all patients were classified into one of four discrete personality subgroups: a reference subgroup with low NA and SI scores (both NA ≤9 and SI ≤9) and three potential risk subgroups: SI-only (SI ≥10 but NA ≤9), NA-only (NA ≥10 but SI ≤9), and Type D personality profile (both NA ≥10 and SI ≥10).

Functional Status

Exercise capacity was used as an objective measure of functional status and was evaluated using a standardized computer-driven bicycle ergometer with rising workload of 25 W every 3 min [22]. Patients were exercised to their self-determined maximal capacity or until the cardiologist stopped the test because of cardiovascular symptoms such as chest pain or dizziness, potentially dangerous arrhythmias or ST-segment deviations, or marked systolic hypotension or hypertension. The workload in watt at the time of the end of the exercise test was considered to reflect exercise capacity. Patients were considered to have a decreased exercise capacity if their exercise capacity was ≤50 W. A cutoff for exercise capacity of 50 W was chosen because it was shown that exercise capacity of ≤50 W on bicycle ergometer testing procedure is associated with moderate to severe functional impairment and cardiac symptoms for a 70-kg person [22].

Patient-Centered Outcomes

Different symptoms of fatigue, depressive manifestations, and mental distress were used as markers of patient-centered outcomes. Symptoms of fatigue were measured using the MFI-20, a 20-item measure comprised of five subscales of general fatigue, physical fatigue, reduced activity, reduced motivation, and mental fatigue [16, 23]. General fatigue refers to overall sensations of fatigue and decreased functioning, physical fatigue to physical sensations associated with fatigue, reduced activity to the possible consequence of fatigue, reduced motivation to decreased intent to start any activity, and mental fatigue to concentration difficulties. Patients rated these manifestations of fatigue during the past few days ranging from 1 (no fatigue) to 5 (very fatigued). Scores on MFI-20 subscales range from 4 to 20, and higher scores indicate higher levels of fatigue. Patients were considered to have significant levels of fatigue if they scored 1 SD above the mean scores on respective MFI-20 subscales. Lithuanian translation of the MFI-20 is widely used for research purposes in Lithuania [23, 24].

The BDI-II is a reliable 21-item self-rating questionnaire that evaluates for severity of depressive symptoms during the previous 2 weeks [17]. Each item is scored on a 0–3 scale with higher scores corresponding to more severe depressive symptoms. Patients were considered depressed if they scored ≥14 on the BDI-II, because it was originally suggested that scores ≥14 on the BDI-II suggest mild depression, and we have recently reported that a cutoff score of ≥14 of the BDI-II had optimal psychometric properties for screening for major depressive disorder in CAD patients [17, 25]. Furthermore, in line with previous research in CAD patients, depressed mood score was calculated by adding scores on the BDI-II items 1 (sadness) and 10 (crying), and anhedonia score was calculated by adding scores on the BDI-II items 4 (loss of enjoyment) and 12 (loss of interest in others) with higher scores indicating more severe depressed mood and anhedonia, respectively [13]. Patients were considered to have anhedonia and/or depressed mood if they scored 1 SD above the mean on respective subscales. Suicidal ideation was evaluated using the BDI-II item 9 (suicidal thoughts or wishes) and feeling of worthlessness using the BDI-II item 14 (worthlessness). Patients were considered to have suicide ideation and/or feeling of worthlessness if they scored ≥1 on the respective items.

The HADS is a 14-item self-rating instrument that consists of subscales of anxiety (HADS-A) and depression (HADS-D), which are designed to measure respective symptoms [18]. Possible scores in both subscales range from 0 to 21 with higher score indicating more severe symptoms. Scores on the HADS-D and HADS-A subscales ≥8 indicate possible clinical depression and possible clinical anxiety, respectively [18]. Lithuanian version of the HADS was shown to be a reliable screening instrument in CAD patients [25].

Statistical Analyses

Differences in gender, clinical characteristics (LVEF, BMI, prevalence of patients with NYHA functional class III, previous interventions for CAD, hypertension, and smoking), functional status (exercise capacity), fatigue (MFI-20 subscales), and mental distress (BDI-II and HADS) between the four subgroups of patients (NA only, SI only, Type D, and reference group) were analyzed using a one-way analysis of variance (ANOVA) for continuous variables and Pearson's χ2 test for categorical variables. Significant differences (p ≤ .05) were followed by post hoc analyses using Sheffe test for continuous variables and Pearson's χ2 test for categorical variables contrasting (a) patients with NA only versus reference subgroup, (b) Type D patients versus reference subgroup, and (c) Type D patients versus NA-only subgroup.

We employed multiple logistic regression analyses (enter method) to evaluate the independent risk for decreased exercise capacity and decreased motivation for activity associated with NA only, SI only, and Type D personality. Age, gender, systolic dysfunction (LVEF ≤40 %), history of MI and angina pectoris, obesity, and current depressive symptoms (BDI-II ≥14) were included as potential covariates in the regression model. Similarly, multiple logistic regression analyses (enter method) were used to evaluate the independent risk for decreased activity, mental fatigue, anhedonia, suicide ideation, worthlessness, and depressive symptoms (HADS-D ≥8) associated with NA only, SI only, and Type D personality, adjusting for age, BMI, and LVEF as continuous variables and for gender, history of MI, and history of angina pectoris as categorical variables. A probability of .05 or less was used as the criterion to include the independent variable in the multivariate models and a probability of .1 or more was used as the criterion to remove the independent variable from the models. Data are presented as odds ratio (95 % confidence interval).

Data were analyzed with the SPSS 17.0 for Windows (Chicago, IL). Data are presented as mean ± standard deviation for continuous variables and as the number (percent) for categorical variables.

Results

Baseline Characteristics

The majority of patients had previous MI (71 %), hypertension (79 %), and previous percutaneous coronary intervention procedure (77 %). Seventy-three, 19, and 8 % of patients were NYHA functional class II, III, and I, respectively. None were NYHA functional class IV. Ten percent of patients had diabetes, 14 % were smoking, and 46 % were obese. Eighteen percent of patients used benzodiazepines and 3 % used antidepressants. Twelve percent of patients had LVEF of ≤40 %, and 47 % of patients had decreased exercise capacity.

According to the scores of the DS14, 13 % of patients were classified in the NA-only subgroup, 19 % in the SI-only subgroup, 34 % in the Type D subgroup, and 34 % in the reference subgroup (neither NA nor SI). According to the HADS scores, 33 % of patients had symptoms of anxiety and 13 % had symptoms of depression. According to the BDI-II scale, 33 % of patients had depressive symptoms, 24 % had anhedonia, 6 % had suicide ideation, and 30 % had feelings of worthlessness.

Type D, Clinical Characteristics, Functional Status, and Patient-Centered Outcomes

ANOVA analyses revealed significant omnibus differences between NA-only patients, SI-only patients, Type D patients, and reference subgroup patients (Table 1). These differences were significant for gender, BMI, exercise capacity, general and physical fatigue, decreased activity and motivation for activity, mental fatigue, depression, and anxiety (all ps ≤.02). Regarding specific manifestations of depression, there were significant personality-related differences in anhedonia, depressed mood, suicide ideation, and worthlessness (all ps <.001). In contrast, personality was not associated with LVEF, NYHA functional class III, previous interventions, hypertension, and smoking (Table 2).
Table 1

Gender, clinical characteristics, functional status, fatigue, and mental distress as a function of four different Type D personality subgroups

 

Reference group

Only one component of Type D

Type D personality

F (p) or χ2 (p)

NA only versus reference, p

Type D versus reference, p

Type D versus NA only, p

(NA−/SI−)

(NA−/SI+)

(NA+/SI−)

(NA+/SI+)

    

Gender (n (%))

Men

199 (84 %)

111 (84 %)

50 (57 %)

150 (65 %)

42.36 (<.001)

<.001

<.001

.196

Women

38 (16 %)

22 (16 %)

38 (43 %)

82 (35 %)

Clinical characteristics

LVEF, % (mean ± SD)

51.2 ± 7.9

49.0 ± 8.9

51.0 ± 7.9

50.9 ± 9.1

1.8 (.14)

BMI, kg/m2 (mean ± SD)

29.6 ± 4.9

29.7 ± 4.5

31.4 ± 5.2

30.2 ± 4.8

3.2 (.02)

.035

.581

.305

NYHA class III (n (%))

38 (16)

27 (20)

11 (13)

55 (24)

7.26 (.06)

Previous interventions (n (%))

Percutaneous coronary intervention

171 (74)

61 (69)

110 (83)

187 (79)

10.19 (.12)

Coronary artery bypass grafting

61 (26)

27 (31)

23 (17)

50 (21)

Hypertension (n (%))

190 (82)

75 (85)

101 (76)

180 (76)

5.33 (.15)

Smoking (n (%))

32 (14 %)

16 (12 %)

12 (14 %)

34 (15 %)

.50 (.92)

Functional status (mean ± SD)

Exercise capacity, W

75.9 ± 30.5

68.7 ± 27.3

66.5 ± 28.8

62.0 ± 25.9

9.5 (<.001)

.075

<.001

.653

Fatigue (mean ± SD)

General fatigue

9.4 ± 3.6

10.7 ± 3.5

12.0 ± 3.8

12.4 ± 3.6

27.7 (< .001)

<.001

<.001

.926

Physical fatigue

10.5 ± 4.0

11.8 ± 4.2

12.5 ± 3.9

13.3 ± 3.8

19.4 (<.001)

.002

<.001

.442

Decreased activity

11.5 ± 3.9

12.5 ± 3.6

13.1 ± 3.5

13.8 ± 3.6

16.0 (<.001)

.005

<.001

.553

Decreased motivation

8.9 ± 3.2

10.1 ± 3.2

10.3 ± 3.3

11.8 ± 3.3

28.7 (<.001)

.017

<.001

.005

Mental fatigue

8.0 ± 3.79

9.3 ± 3.5

10.4 ± 4.0

11.7 ± 3.8

38.7 (<.001)

<.001

<.001

.057

Mental distress (mean ± SD)

BDI-II Anhedonia

.39 ± .68

.71 ± .90

1.01 ± 1.29

1.38 ± 1.23

39.0 (<.001)

<.001

<.001

.037

BDI-II Depressed mood

.17 ± .53

.30 ± 0.73

1.02 ± 1.12

1.21 ± 1.27

57.3 (<.001)

<.001

<.001

.492

BDI-II Suicide ideation

.02 ± .13

.04 ± .23

.08 ± .27

.13 ± .39

6.5 (<.001)

.350

<.001

.633

BDI-II worthlessness

.13 ± .33

.25 ± .51

.41 ± .62

.60 ± .68

32.2 (<.001)

<.001

<.001

.043

BDI-II total score

5.86 ± 4.81

8.49 ± 5.53

14.11 ± 7.99

16.73 ± 8.79

108.23 (<.001)

<.001

<.001

.028

HADS depression

2.3 ± 2.1

3.5 ± 2.4

4.2 ± 2.4

5.9 ± 3.4

69.3 (<.001)

<.001

<.001

<.001

HADS anxiety

4.0 ± 2.8

4.6 ± 2.7

7.8 ± 3.6

8.2 ± 3.5

83.8 (<.001)

<.001

<.001

.878

In bold, p < .05

BDI-II Beck Depression Inventory–II, BMI body mass index, HADS Hospital Anxiety and Depression Scale, LVEF left ventricular ejection fraction, NA negative affectivity, SI social inhibition, W watts

Table 2

Risk of decreased exercise capacity and decreased motivation associated with Type D personality (n = 638)

 

Decreased exercise capacitya

Decreased motivationb

ORc

95 % CI

p

ORa

95 % CI

p

Age

1.07

1.05–1.09

<.001

1.01

.99–1.04

.38

Female gender

5.54

3.43–8.96

<.001

3.72

2.32–5.96

<.001

LVEF ≤40 %

3.14

1.75–5.61

<.001

.97

.51–1.84

.92

History of MI

2.46

1.60–3.77

<.001

.98

.62–1.63

.98

Angina pectoris

1.09

.75–1.59

.64

.94

.60–1.48

.80

BMI ≥30 kg/m2

1.15

.79–1.67

.47

.95

.61–1.47

.81

Depressive symptoms d

1.49

.95–2.35

.08

2.33

1.39–3.90

.001

Social inhibition only

1.26

.75–2.12

.38

1.77

.87–3.62

.12

Negative affectivity only

.95

.51–1.80

.88

1.17

.52–2.61

.71

Type D personality

1.84

1.12–3.03

.02

2.48

1.31–4.70

.006

In bold, p < .05

BMI body mass index, LVEF left ventricular ejection fraction

a≤ 50 W on bicycle ergometer testing procedure

bScore equal to or greater than 1 standard deviation above the mean on the MFI-20 reduced motivation subscale

cOdds ratios of multiple logistic regression analyses with all variables entered into the model

dScore ≥14 on the Beck Depression Inventory–II

Post hoc analyses revealed that proportion of women was higher among Type D patients and NA-only patients when compared to the reference group. Type D patients had significantly lower exercise capacity when compared to the reference subgroup patients (p < .001), and NA-only patients had significantly higher BMI when compared to the reference subgroup patients (p = .035). As for fatigue, Type D patients (all ps <.001) and NA-only patients (ps range from .017 to <.001) scored higher on all MFI-20 subscales when compared to the reference subgroup patients. Similarly, Type D patients and NA-only patients when compared to the reference subgroup patients scored significantly higher on the BDI-II total scale, anhedonia, depressed mood, and worthlessness items and on the HADS-D and HADS-A (all ps <.001). Only Type D patients scored significantly higher on suicide ideation when compared to the reference subgroup (p < .001). Importantly, Type D patients were also significantly less motivated for activity (p = .005) and had significantly higher levels of anhedonia (p = .037), worthlessness (p = .043), and overall BDI-II and HADS-D depressive symptoms (p < .001) than NA-only patients.

Multiple Logistic Regression Models

In multiple logistic regression models containing age, gender, LVEF ≤40 %, histories of MI and angina pectoris, obesity, elevated depressive symptoms, SI only, and NA only, Type D personality was independently associated with increased risk for decreased exercise capacity (OR = 1.84, 95 % CI (1.12–3.03), p = .02) and decreased motivation (OR = 2.48, 95 % CI (1.31–4.70), p = .006) (see Table 2). Other significant predictors of decreased exercise capacity were female gender, LVEF ≤40 %, history of MI, and more advanced age. Female gender and depressive symptoms also independently predicted increased risk for decreased motivation. It is important to note that the use of the BDI-II cutoff value of ≥10 in the latter models yielded similar results.

After adjustment for age, gender, LVEF, cardiac diagnosis, and BMI, Type D personality remained independently associated with decreased activity (OR = 2.71, 95 % CI (1.51–4.87), p < .001), mental fatigue (OR = 3.36, 95 % CI (1.99–5.68), p < .001), anhedonia (OR = 6.67, 95 % CI (3.89–11.45), p < .001), suicide ideation (OR = 6.55, 95 % CI (2.21–19.43), p = .001), worthlessness (OR = 7.00, 95 % (4.34–11.31), p < .001), and depressive symptoms (OR = 17.80, 95 % (6.92–45.78), p < .001) (see Table 3). NA was independently associated with increased risk for anhedonia (OR = 3.57, 95 % CI (1.81–7.04), p < .001), suicide ideation (OR = 4.98, 95 % CI (1.39–17.90), p = .014), and worthlessness (OR = 3.91, 95 % CI (2.13–7.18), p < .001), and SI was independently associated with increased risk for anhedonia (OR = 2.52, 95 % CI (1.32–4.81), p = .005), worthlessness (OR = 1.89, 95 % CI (1.05–3.38), p = .03), and depressive symptoms (OR = 4.04, 95 % CI (1.34–12.20), p = .013).
Table 3

Association of social inhibition only, negative affectivity only, and Type D personality with fatigue and mental distress (n = 651)

 

N (%)

Social inhibition only (NA−/SI+)

Negative affectivity only (NA+/SI−)

Type D personality (NA+/SI+)

MFI-20 decreased activitya

103 (15 %)

OR = 1.87 (.93–3.75), p = .08

OR = 1.45 (.65–3.25), p = .37

OR = 2.71 (1.51–4.87),p = .001

MFI-20 Mental fatiguea

135 (20 %)

OR = 1.21 (.60–2.44), p = .59

OR = 1.90 (.95–3.79), p = .071

OR = 3.36 (1.99–5.68),p< .001

BDI-II anhedoniaa

165 (24 %)

OR = 2.52 (1.32–4.81),p= .005

OR = 3.57 (1.81–7.04),p< .001

OR = 6.67 (3.89–11.45),p< .001

BDI-II suicide ideationb

41 (6 %)

OR = 1.78 (.43–7.28), p = .42

OR = 4.98 (1.39–17.90),p= .014

OR = 6.55 (2.21–19.43),p= .001

BDI-II worthlessnessb

208 (30 %)

OR = 1.89 (1.05–3.38),p= .03

OR = 3.91 (2.13–7.18),p< .001

OR = 7.00 (4.34–11.31),p< .001

HADS depressionc

91 (13 %)

OR = 4.04 (1.34–12.20),p= .013

OR = 2.96 (.86–10.19), p = .09

OR = 17.80, (6.92–45.78),p< .001

Multiple logistic regression analyses with low negative affectivity/low social inhibition coded as 0, adjusted for age, gender, left ventricular ejection fraction, cardiac diagnosis (myocardial infarction or angina), and body mass index

In bold, p < .05

BDI-II Beck Depression Inventory–II, MFI-20 Multidimensional Fatigue Inventory-20, NA negative affectivity, SI social inhibition

aScore equal to or greater than 1 standard deviation above the mean

bScore equal to or greater than 1

cScore equal to or greater than 8

Discussion

In this cohort of Lithuanian patients with CAD, Type D personality was an independent predictor of poor functional status and decreased motivation for activity, after adjusting for LVEF, clinical characteristics, depressive symptoms, and the main effects of NA and SI. Type D personality, NA, and SI were also independent predictors of fatigue and depressive symptoms, adjusting for LVEF and clinical characteristics. Regarding mental distress, NA appeared to be the most toxic component of Type D personality construct.

A recent meta-analysis that included both negative and positive studies of Type D in cardiac patients showed that Type D personality was associated with a more than twofold adjusted risk of adverse outcomes, such as mortality and nonfatal MI [26]. These authors also recommended to employ robust statistical analyses adjusting for psychological, biological, and social factors in multivariate models. Importantly, in the present study, we adjusted for the main NA and SI effects, depressive symptoms, and disease severity. In these analyses, Type D personality was associated with twofold adjusted risk for poor exercise capacity and for decreased motivation for activity. A Hungarian study in 387 patients recovering from coronary artery bypass graft surgery also showed that Type D patients covered significantly shorter distance on the 6-min walking test than nontype D patients, without any substantial differences in heart rate or perceived exertion, suggesting that Type D was associated with inadequate effort during this exercise test [10]. Interestingly, a study in 110 mild traumatic brain injury patients reported poor effort on cognitive tests of Type D patients [27]. Our results in a larger sample of CAD patients showed that Type D personality is associated with decreased motivation to perform and with poor functional status, even after adjustment for disease severity and depression.

From a clinical perspective, these results suggest that Type D personality may partly account for false-positive test results on exercise stress tests as an important diagnostic tool in patients with CAD. Future research needs to explore whether it would be useful to account for Type D characteristics when interpreting exercise stress tests. Moreover, decreased motivation for activity and poor functional status can lead to physical inactivity in CAD patients with Type D personality, suggesting a potential behavioral pathway linking Type D with poor cardiovascular health [28]. This also suggests that assessment of Type D personality at the initiation of a cardiac rehabilitation program might be useful to identify a subgroup of patients less likely to comply with preventive exercise recommendations.

Decreased motivation (or apathy) is one of the key symptoms of depression; thus, depressed patients are difficult to motivate in general and difficult to motivate to change their lifestyle and behavior [29, 30]. In this context, it is important to note that in our study, both depressive symptoms and Type D personality were independently associated with decreased motivation. Hence, interventions targeting only depressive symptoms might be insufficient for improving motivation of CAD patients, and more extensive psychological assessment of CAD patients, including the evaluation for Type D personality, is needed in order to identify high-risk patients and to guide psychological interventions.

As expected, other independent predictors of decreased functional status were advanced age, female gender, systolic dysfunction, and a history of MI. However, depressive symptoms were not associated with functional status. We have reported previously that decreased exercise capacity was associated with CAD severity but not with depressive or anxiety symptoms in a study of 1,470 CAD patients [5]. Another study in 1,367 patients referred for exercise stress testing found that patients with major depressive disorder had poor exercise tolerance and performance after adjusting for age, gender, family history of CAD, smoking, and use of β-blockers [4]. It is possible that relevant predictors of exercise capacity were not included to multivariate models in the latter study or that major depression but not subclinical depressive symptoms can impact functional status. Overall, these findings suggest that in patients with CAD, Type D personality can exert similar negative effects on functional status as major depression and that this adverse effect of Type D is independent from depressive symptoms or systolic dysfunction. In the current study, Type D was not associated with LVEF which confirms previous findings in 1,205 post-MI patients and suggests that the association between Type D and health outcomes is not confounded by decreased LVEF [31].

After adjustment for LVEF, age, gender, cardiac diagnosis, and BMI, Type D personality was independently associated with reduced activity, mental fatigue, anhedonia, suicide ideation, and worthlessness. These findings are in line with previous studies demonstrating that in CAD patients, Type D personality is independently associated with poor patient-centered outcomes, including increased fatigue and mental distress [6, 8, 9]. Importantly, Type D personality and NA were associated with an increased risk for suicide ideation in the current study, which confirms the association between Type D personality and suicidal ideation observed in the German general population [32]. This further underscores the clinical significance of Type D personality for identifying high-risk patients because the suicide rate was reported to be twofold higher in in-hospital-treated CAD patients when compared to the general population [33].

In line with recent recommendations, we have evaluated the association of NA, SI, and their combined effect (i.e., Type D) with different symptoms of fatigue and depression [11, 14]. NA and SI were independently associated with anhedonia and worthlessness, and NA was independently associated with suicide ideation. However, compared to NA-only patients, Type D patients had even higher levels of deactivation, anhedonia, worthlessness, and total depressive symptoms, thereby supporting the notion that the combined effect of NA and SI within the Type D construct has incremental value above and beyond the effect of NA alone. Taken together, these findings suggest that looking at different NA, SI, and Type D subgroups can be a promising avenue for further research because it can improve our knowledge regarding mechanisms underlying the association of personality-related differences with CAD outcomes and more precisely define targets for possible interventions.

Some limitation of this study should be acknowledged. First, due to cross-sectional design, we were unable to address causality of the observed associations or to evaluate the relationship of personality variables with clinical outcomes. Second, the majority of patients had mild to moderate heart failure, and there were no patients with advanced heart failure; thus, studies in CAD patients with more advanced heart disease are needed. Third, this study did not include a structured psychiatric interview, but standard, well-validated questionnaires were used to assess for Type D personality, fatigue, and mental distress. Finally, 28 % of patients refused to participate in the study. Strengths of this study include the standard assessments of CAD severity (echocardiography) and functional status (bicycle stress testing), the relatively large sample size, and the cross-cultural confirmation of findings from previous reports on the role of Type D personality in Lithuanian CAD patients.

In sum, our findings showed that Type D personality was associated with poor functional status and decreased motivation for activity, after adjustment for systolic dysfunction and depressive symptoms. Type D personality and its two components, NA and SI, were also associated with more symptoms of fatigue, mental distress, and suicidal ideation. Further studies exploring the effects of Type D personality characteristics on patient-centered outcomes are needed.

Acknowledgments

This research was funded by a grant (LIG-03/2011) from the Research Council of Lithuania.

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© International Society of Behavioral Medicine 2013