Lower distress tolerance is associated with greater anxiety and depression symptoms among patients after acute coronary syndrome

Following acute coronary syndrome (ACS; e.g., a heart attack), 40–50% of patients experience elevated anxiety or depression symptoms, and many have distressing physical symptoms and difficulty with positive health behaviors [1]. Elevated depressive and anxiety symptoms increase the risk for recurrent cardiac events and mortality after ACS [2].

Distress tolerance, defined as the ability to withstand aversive emotions, plays a significant role in depression and anxiety [3]. Distress tolerance is an individual-level characteristic that impacts the way people experience and respond to negative emotions [4]. Individuals with low distress tolerance are unable to endure negative emotions, experience negative emotions as unacceptable, and use unhealthy emotional coping strategies, which in turn create further exacerbations in symptoms [4]. Distress tolerance can be improved with behavioral interventions [5], but no research has explored whether distress tolerance is related to emotional outcomes in patients after ACS.

The purpose of this study was to explore the relationship between distress tolerance and anxiety symptoms, depression symptoms, distress about physical symptoms, and distress about engaging in cardiac health behaviors in patients after ACS. The hypothesis was that irrespective of gender, age, time since ACS, and medical and psychiatric comorbidities, low distress tolerance would be associated with greater levels of each outcome.

From July 2018–January 2019, N = 92 patients with a lifetime history of ACS were recruited for a cross-sectional survey study at a U.S. academic medical center. The participant pool was hospital patients with a medical record diagnosis of acute coronary syndrome as identified in a hospital research database. Identified patients were mailed an opt-out letter and then contacted by phone to assess interest. Eligibility criteria were: (1) ≥18 years of age; (2) treated for a myocardial infarction or unstable angina; (3) English-speaking; and (4) able to provide informed consent. Of 297 patients contacted by phone, 92 agreed to participate and provided verbal consent by phone. Surveys were completed by phone, mailed paper forms, or a secure online data collection system (REDCap). 11 patients did not return their survey, for an analytic sample of N = 81 (81/297 = 27% enrollment rate). All procedures were IRB approved.

Survey measures included the 15-item Distress Tolerance Scale (e.g., “I’ll do anything to avoid feeling distressed or upset” and “I can’t handle feeling distressed or upset”, rated from 1 = strongly agree to 5 = strongly disagree) [4]; PROMIS- anxiety and depression [6]; and a researcher-developed checklist of distress due to physical symptoms (tired, weak, low energy, shortness of breath, sleep problems, pain) and cardiac health behaviors (taking medications, attending doctor visits, making dietary changes, exercising), for which “yes” responses were summed to create total scores (Table S1). ACS history and comorbidities (medical: heart failure, type 2 diabetes, COPD, obesity, cancer, neurological disorder; psychiatric: depression, anxiety) were extracted from the electronic medical record. Participants received $10 remuneration. All research procedures were IRB-approved.

Four multivariable linear regression models were used to explore the contribution of distress tolerance (independent variable) to anxiety symptoms, depression symptoms, distress about physical symptoms, and distress about cardiac health behaviors (separate dependent variables), above and beyond age, gender, time since ACS, and total number of medical and psychiatric comorbidities (covariates). Alpha levels were set at p < .05. Analyses were conducted using SPSS v25.

Participants were, on average, 66.43 years (SD=12.07), 65% male, 94% white, and 7.64 (9.28) years since ACS (Table S2). Multivariable regression results are shown in Table 1. Lower distress tolerance was significantly associated with greater anxiety symptoms (b = −.60, p<.001), depression symptoms (b = −.50, p<.001), and distress about physical symptoms (b = −.34, p< .05). There was a non-significant trend for lower distress tolerance associated with greater distress about health behaviors (b = −.24, p=.08). Bivariate correlation results are presented in Table S3.

Table 1.

Multivariable regression models of distress tolerance and emotional outcomes.

	R2	t	β	p	95% CI
Anxiety Symptoms	0.42			<0.001**
Age		−0.53	−0.06	0.61	−0.07–0.04
Gender		−0.49	−0.05	0.63	−1.53 - 0.93
Time Since ACS		−1.17	−0.12	0.25	−0.12–0.03
Medical Comorbidities		0.03	0.00	0.98	−0.53–0.55
Psychiatric Comorbidities		1.45	0.16	0.15	−0.26–1.61
Distress Tolerance		−5.61	−0.60	<0.001**	−0.22 - −0.11
Depression Symptoms	0.29			<0.001**
Age		−0.32	−0.04	0.75	−0.06–0.04
Gender		−0.13	−0.02	0.90	−1.22–1.07
Time Since ACS		−0.80	−0.09	0.43	−0.10–0.04
Medical Comorbidities		−0.10	−0.01	0.92	−0.53–0.48
Psychiatric Comorbidities		1.17	0.15	0.25	−0.36–0.138
Distress Tolerance		−4.22	−0.50	< 0.001**	−0.17 - −0.60
Distress about Physical Symptoms	0.20			0.04*
Age		−0.01	−0.00	0.99	−0.04–0.04
Gender		0.33	0.04	0.74	−0.77–1.08
Time Since ACS		0.86	0.11	0.40	−0.03–0.08
Medical Comorbidities		0.05	0.01	0.96	−0.45–0.47
Psychiatric Comorbidities		1.72	0.23	0.09	−0.10–1.31
Distress Tolerance		−2.70	−0.34	0.01*	−0.10 - −0.02
Distress about Health Behaviors	0.18			0.09
Age		−0.81	.−11	0.43	−0.04–0.02
Gender		0.93	0.12	0.36	−0.32–0.88
Time Since ACS		0.23	0.03	0.82	−0.03–0.04
Medical Comorbidities		0.93	0.12	0.36	−0.16–0.43
Psychiatric Comorbidities		1.25	0.17	0.22	−0.17–0.74
Distress Tolerance		−1.80	−0.24	0.08	−0.05–0.00

Note. Higher scores on each measure indicate greater levels of the variable (i.e., higher distress tolerance scores indicate better functioning). CI = confidence interval.

This is the first study to demonstrate that distress tolerance is associated with emotional outcomes among patients after ACS – regardless of age, gender, time since ACS, and comorbidities. It may be important for psychological treatments to intervene upon not only the emotional symptom itself, but also the ability to tolerate and cope with distress, which is indeed separate from the level of emotional symptoms [7]. Behavioral interventions increasingly focus on targeting underlying emotional processes such a distress tolerance, rather than disorder-specific protocols for one type of problem (e.g., Unified Protocol) [8]. Currently, cognitive-behavioral therapy is the recommended treatment for emotional problems after ACS, but it has limited effects [9] and does not necessarily aim to target distress tolerance. Mindfulness-based approaches target and improve distress tolerance and may be a useful addition to CBT for patients after ACS [10].

Limitations include limited demographic variability and generaliz-ability, relatively small sample size, researcher-developed measure of distress about physical symptoms and health behaviors, and cross-sectional design. We were unable to control for number of symptoms and could not differentiate those who had many symptoms but no distress from those who had no symptoms and therefore no distress. Future research should explore associations between distress tolerance and positive health behavior engagement, and associations between other vulnerability characteristics (e.g., anxiety sensitivity, intolerance of uncertainty) and emotional outcomes after ACS. Overall, the results suggest a role of distress tolerance in emotional outcomes after ACS and point toward future research with the potential to inform novel treatment targets.

Data availability

Data will be made available on request.