Quality of relationship, depression, and sleep quality in patients with chronic heart failure and their spouse: an Actor-Partner Interdependence Model

Abstract

Background

Sleep disturbances are highly prevalent in patients with chronic heart failure and may increase mortality risk. As primary caregivers, spouses often experience long-term care-giving responsibilities, leading to caregiver burden and reduced sleep quality. The sleep quality of spousal caregivers requires equal attention. There is an interdependence between the sleep health of patients and their spousal caregivers. Depression and the quality of the relationship may play an important role in this, but the mechanisms of the interaction are not yet clear. Therefore, we aimed to explore the correlation between sleep quality in patients with chronic heart failure and their spousal caregivers and the mechanisms by which depression plays a role in the quality of relationship and sleep quality.

Methods

A cross-sectional design was conducted from April to November 2023, involving 223 patients with chronic heart failure and spousal caregivers recruited from hospital outpatient clinics or home settings. Data were collected via on-site questionnaires or telephone follow-ups using validated instruments: Demographic questionnaire, Quality of Relationship Index, Hospital Anxiety and Depression Scale, and Pittsburgh Sleep Quality Index. SPSS 26.0 and AMOS 22.0 were employed for data analysis, including common method bias testing, paired samples t-tests, pearson correlations, and actor-partner interdependence mediation modeling.

Results

Strong correlation between sleep quality in patients with chronic heart failure and spousal caregivers (r = 0.361, P < 0.001). Quality of relationship in both patients and spousal caregivers significantly influenced each other’s sleep quality (β = -0.267, P < 0.001 for patients; β = -0.122, P < 0.001 for caregivers). Bootstrap analyses revealed that depression in both patients and caregivers partially mediated the relationship between caregivers’ quality of relationship and patients’ sleep quality (β = -0.091, 95% CI [-0.151, -0.041] for patients; β = -0.052, 95% CI [-0.099, -0.021] for caregivers), confirming partner-mediated effects.

Conclusion

Depression in both patients with chronic heart failure and caregivers are critical factors influencing sleep quality, underscoring the need to prioritize mental health support for chronic heart failure couples. Additionally, the positive impact of quality of relationship on sleep quality highlights the vital role of healthy spousal relationships in home-based healthy management.

Background

Chronic heart failure is characterized by high prevalence, mortality, and readmission rates, imposing a heavy burden on healthcare systems worldwide. According to the 2024 European Society of Cardiology report [1], the global prevalence of heart failure is 1–2%, affecting approximately 260 million people. It is estimated that heart failure prevalence in low- and middle-income countries will surge by 50% by 2030 [2]. Hospitalization costs with cardiovascular disease as the primary diagnosis was RMB 283.43 billion, of which heart failure consumed RMB 22.98 billion in China [3]. Given the heavy health burden faced by patients with chronic heart failure, sleep, as a key changeable factor, plays a vital role in maintaining health and homeostasis [4]. The American Heart Association has integrated sleep health into Life’s Essential 8 for cardiovascular disease prevention [5], emphasizing its importance in disease management. Poor sleep quality remains a major complaint among patients with chronic heart failure [6, 7], and sleep disturbances can increase [8] mortality. Therefore it is important to address sleep disturbances in patients with chronic heart failure.

Impaired sleep quality is prevalent in patients with heart failure and is associated with poor cardiac event-free survival [9]compared to healthy people. One study demonstrated longer sleep duration decreased the risk of heart failure [10], and poor sleep quality further diminished patients’ quality of life and self-care ability [11, 12]. Spousal caregivers as primary caregivers play a critical role in disease management with 42.8% reported sleep disturbances [13]. Long-term care-giving contributes to loneliness, anxiety, depression, which can reduce quality of life [14], further impair sleep health. In the short term, sleep disturbances can manifest as psychological distress and physical strain [15] while over the long term, chronic sleep deprivation impairs cognitive function [16], ultimately undermining the quality of care they provide. What these findings suggest is that an interaction exists between the sleep health of patients and their spousal caregivers. Thus, we proposed the first hypothesis (H1): patients with chronic heart failure and their spousal caregivers have poorer sleep quality and interact with each other.

Notably, while there may be an interdependent relationship in sleep quality between patients and their spousal caregivers, the underlying mechanisms driving this mutual influence remain to be explored. Among potential factors, negative emotions, such as depression, have emerged as important candidates. Existing research indicates that negative emotion has a significant negative correlation with sleep quality [17]. Notably, depression of patients with chronic heart failure face higher sleep disturbances compared to healthy people [6, 18]. As disease progresses, patients increasingly rely on caregivers for daily and disease-related support. However, caregivers often experience depression because of inadequate preparation, which further impairs their sleep quality [19]. Caregivers with severe depression report more sleep problems, compared to non-depressed caregivers [20]. Thus, depression in both patients with chronic heart failure and their spousal caregivers may directly impair their own sleep quality. However, the mutual influence between depression and sleep quality remains unclear. Among patients with cancer, depression demonstrated both actor effects and partner effects on sleep quality [21]. Similarly, studies in cardiovascular disease revealed that patients’ severe depressive symptoms correlate with poorer physical and mental health in caregivers [22]. These findings suggest that depression in patients with chronic heart failure and caregivers may affect both their own and each other’s sleep quality. In conclusion, we proposed hypothesis 2 (H2) that depression in patients with chronic heart failure and spousal caregivers affects their own and each other’s sleep quality.

Beyond the depression, another key factor is the quality of the relationship between patients and their spousal caregivers. Quality of relationship refers to the emotional closeness couples experience while confronting with illness [23]. Couples with high quality of relationship may have common sleep habits, which can minimize sleep-related conflicts and promote harmonious sleep experiences [24]. Furthermore, one study [25]demonstrated that depression of caregivers worsens sleep quality for both caregivers and patients, while strong quality of relationship mitigates the negative impact of caregiving burden on sleep. Therefore, depression would be considered as a mediator in the relationship between quality of relationship and sleep quality for patients with chronic heart failure and spousal caregivers. In the dyadic relationships of patients with chronic heart failure and their spousal caregivers, individual data exhibit non-independence. It shows that analyzing sleep quality determinants solely at the individual level (patient or caregiver) introduces bias. The Actor-Partner Interdependence Model (APIM) addresses this limitation by quantifying interdependent effects within paired data, offering a robust analytical framework for dyadic health research [26]. Thus, we proposed hypothesis 3 (H3), based on the Actor-Partner Interdependence Model, that quality of relationship may mutually affect sleep quality among patients and spousal caregivers, and their depression may mediate this pathway (Fig. 1).

Fig. 1.

Hypothetical Model. Note: Solid line = Actor effect, Dotted line = Partner effect

In conclusion, few studies have simultaneously examined the mutual effects of depression and quality of relationship on sleep quality in chronic heart failure dyads, highlighting a critical gap that this study aims to address. Hence, this study aims to investigate the sleep quality of both patients with chronic heart failure and their spousal caregivers within dyadic relationships. By employing the Actor-Partner Interdependence Model, we seek to establish a mediation framework that examines how quality of relationship influences sleep quality through the mediating role of depression. The findings are expected to provide novel insights into the mutual influence within chronic heart failure dyads and inform targeted interventions for improving sleep health in both of them.

Methods

Design

The study was cross-sectional design.

Sample

Patients with chronic heart failure and their spousal caregivers were recruited from hospital between April and November 2023 by convenience sampling. Inclusion Criteria: for patients with chronic heart failure: ① aged ≥ 18 years, ② meeting the diagnostic criteria for CHF in the Chinese Heart Failure Diagnosis and Treatment Guidelines 2018 ③able to complete questionnaires independently or with researcher assistance,④provided informed consent. For Spousal Caregivers: ①aged ≥ 18 years, ②living with patients with chronic heart failure and serving as their primary caregiver,③able to complete questionnaires independently or with researcher assistance, ④provided informed consent. Exclusion Criteria: for patients with chronic heart failure: ①with sleep disorders, ②with mental disorders such as cognitive dysfunction, depression, bipolar disorder, etc., ③with acute myocardial infarction, acute pulmonary embolism, acute infection and other acute diseases in the past month, ④accompanied by other serious diseases, such as malignant tumor, renal failure, respiratory failure,⑤drug dependence, alcohol dependence, or active suicidal orientation within the last year, ⑥abnormal sleep patterns or shift work with no overlap with the spouse’s sleep schedule. For Spousal Caregivers: ①mental disorders such as cognitive dysfunction, sleep disorders, etc. ②drug dependence, alcohol dependence, or active suicidal orientation within the last year, ③abnormal sleep patterns or shift work with no overlap with the spouse’s sleep schedule.

Sample size

The sample size was computed by G*Power, with a minimum of 187 dyads required assuming actor and partner effect sizes of 0.20 for both patients and caregivers (α = 0.05, power [1-β] = 0.80). But structural equation modeling guidelines recommend at least 200 participants (100 dyads). Thus, a 10% buffer for invalid or incomplete responses, the final sample size was determined to be 223 dyads.

Instruments

(1) Demographic and Clinical Characteristics Questionnaire

Collected data included:①Demographics Variables: Age, gender, employment status, education level, economic status, residence.②Clinical Variables: Body mass index (BMI), left ventricular ejection fraction (LVEF), NYHA functionalclass, disease duration, number of comorbidities.

(2) Pittsburgh Sleep Quality Index [27]

The scale comprises 18 items assessing seven dimensions. Each item is scored 0–3, total score range of 0–21, with higher scores indicating poorer sleep quality. Total score > 7 is defined as sleep disturbances. In our study, internal consistency was Cronbach’s α = 0.798 (patients with chronic heart failure) and 0.792 (spousal caregivers).

(3) Quality of Relationship Index [28]

The scale with 6 items assesses perceived satisfaction with intimate relationships rated on a 7-point Likert scale (1 = “strongly disagree” to 7 = “strongly agree”). Total scores range from 6 to 42, with higher scores indicating greater relationship satisfaction. In this study, internal consistency was Cronbach’s α = 0.952 (patients) and α = 0.956 (spousal caregivers).

(4) Hospital anxiety and depression scale [29]

The scale measures negative emotional (depression, psychic anxiety, psychomotor agitation) over the past month by 14 items scored on a 4-point Likert scale (0–3). Higher total scores reflect greater emotional distress. Internal consistency was α = 0.886 (patients) and α = 0.824 (spousal caregivers).

Data collection

The sample recruitment process was as follows:①Participants from the outpatient clinic were initially screened by a physician, and the researchers explained the purpose of the study and invited them. Discharged patients who met the inclusion criteria within the past 3 months were extracted from the hospital’s electronic medical record system and followed up by telephone in the order of the patients’ dates of discharge. ②When patients agreed to participate, researchers contacted with their spousal caregivers within 24 h to explain the purpose of the study and key points of cooperation. Informed consent was signed and coded by both parties before enrollment as a dyad. To prevent bias caused by intensive recruitment during a specific period, we set daily recruitment limits (≤ 2 dyads/day for outpatients and ≤ 2 dyads/day for discharged patients). Patients with chronic heart failure and their spousal caregivers completed questionnaires independently in separate settings to prevent answer sharing. Plain language was used for instructions, with investigators available to clarify ambiguities without leading responses. Questionnaires were immediately reviewed upon completion for missing/ambiguous responses. For assisted completions such as low-literacy participants, results were verbally reconfirmed with the participants. This process ensured data accuracy while respecting participant autonomy and reducing measurement bias.

Ethical considerations

The Ethics Committee of Zhengzhou University approved this study (approval number ZZUIRB2023-064). This study strictly adhered to the ethical principles set forth in the Declaration of Helsinki. Prior to the commencement of the study, participants were comprehensively informed about the research objectives, significance, and anticipated outcomes. Informed consent was obtained from all participants, who also provided their permission for participation.

Statistical analysis

Data from validated questionnaires were double-entered using EpiData 3.1 and analyzed with SPSS 26.0 and AMOS 22.0. Statistical significance was set at P < 0.05. Common method variance (CMV) refers to the common variation between traits that can be falsely generated by using the same instrument and is commonly found in the data collected by self-report scales. Bias induced by CMV is called common method bias, which is a trait-independent systematic error that affects the validity of the measure [30]. This study utilized Harman’s single-factor test to evaluate it. Paired samples t-tests compared total sleep quality scores and dimension differences between patients with chronic heart failure and their spousal caregivers. Actor-Partner Interdependence Mediation Modeling (APIMeM) [31]: Constrained actor/partner effects to equivalence across groups. Models were retained if constrained model fit comparisons yielded P > 0.20, indicating no significant goodness-of-fit differences. Mediation analysis: Tested indirect effects via 5,000 bias-corrected bootstrap resamples [32]. When both actor/partner effects and direct/indirect effects reached significance (P < 0.05), effect sizes were comparatively analyzed to determine magnitude differences.

Results

Common method bias test

• Common method bias was assessed using Harman’s single-factor test. Among patients with chronic heart failure, 8 factors with eigenvalues > 1 were identified, with the largest factor explaining 15.23% of the variance. For spousal caregivers, 7 factors had eigenvalues > 1, with the largest explaining 18.30% of the variance. As all values fell below the 40% threshold, no significant common method bias was detected.

Demographic and clinical characteristics

A total of 252 patients were recruited for this study, of which 223 dyads (88.49%) completed the survey. The main reasons for non-participation were: lost to visit (n = 7, 2.77%), without spousal caregiver (n = 1, 0.4%), patient refused (n = 11, 4.37%), spousal caregiver refused (n = 7, 2.78%), and questionnaire was invalid (n = 3, 1.19%). The study included 446 participants (223 patients with chronic heart failure-caregiver dyads). Patients with chronic heart failure:52.5% aged < 60 years; 61.4% male.59.2% had disease duration ≥ 6 months; 54.3% classified as NYHA class II. spousal caregivers: 53.4% aged < 60 years; 61.4% female.65.5% had ≤ 9 years of education; 59.2% resided in urban areas. 54.7% had chronic comorbidities; 50% self-rated health as “good.“See Table 1 for full details.

Table 1.

Characteristics of patients with chronic heart failure and their spousal caregivers

Variable		CHF patients (n = 223) (%)	Spousal caregivers (n = 223) (%)
Age	<60	117(52.5)	119(53.4)
	≥ 60	106(47.5)	104(46.6)
Gender	Male	137(61.4)	86(38.6)
	Female	86(38.6)	137(61.4)
Education level	Primary school and below	62(27.8)	77(34.5)
	Middle school	62(27.8)	70(31.4)
	High school	42(18.8)	29(13.0)
	Bachelor’s degree and above	57(25.6)	47(21.1)
Employment	Farmer	86(38.6)	93(41.7)
	Worker	66(29.6)	73(32.7)
	Retiree	58(26.0)	54(24.2)
	No working	13(5.8)	3(1.3)
Location	Urban	130(58.3)	132(59.2)
	Rural	93(41.7)	91(40.8)
religious belief	No	214(96.0)	217(97.3)
	Yes	9(4.0)	6(2.7)
Disease diagnosis time	< 6 months	91(40.8)
	≥ 6months	132(59.2)
New York Heart Association	II	121(54.3)
	III	75(33.6)
	IV	27(12.1)
Duration of care	< 6months		97(43.5)
	≥ 6months		126(56.5)
Chronic disease	No		101(45.3)
	Yes		122(54.7)

Note: CHF: chronic heart failure

Sleep quality of patients with chronic heart failure and spousal caregivers

Patients with chronic heart failure reported a total score of PSQI of 8.314 ± 3.472, with 58.7% exhibiting sleep disturbances. Spousal caregivers reported a total score of PSQI of 5.991 ± 2.636, with 22.9% exhibiting sleep disturbances. Paired samples t-tests revealed statistically significant differences (P < 0.01) in total sleep quality scores and all PSQI dimensions between patients with chronic heart failure and caregivers. Pearson correlation analyses further demonstrated significant positive correlations (P < 0.05) between them, except sleep efficiency (see Table 2).

Table 2.

Paired t-tests and correlation analyses of sleep quality between patients and spousal caregivers

	Patients with chronic heart failure	Spousal caregivers	t	r
Total Score	8.314 ± 3.472	5.991 ± 2.636	9.854**	0.361**
Subjective sleep quality	1.327 ± 0.582	1.031 ± 0.603	6.265**	0.292**
Sleep latency	2.009 ± 0.844	1.520 ± 0.656	8.348**	0.341**
Sleep duration	0.776 ± 0.819	0.390 ± 0.541	6.346**	0.158*
Sleep efficiency	0.740 ± 0.841	0.417 ± 0.554	5.096**	0.127
Sleep disturbances	1.550 ± 0.498	1.367 ± 0.519	4.478**	0.275**
Sleep medication use	0.350 ± 0.756	1.368 ± 0.519	4.740**	0.415**
Daytime dysfunction	1.561 ± 0.750	1.139 ± 0.580	7.916**	0.307**

Note: *P<0.05, **P<0.01.PSQI: higher scores indicate poorer sleep quality

Correlations between quality of relationship, depression, and sleep quality

Pearson correlation analyses revealed significant positive correlations between, sleep quality (r = 0.361, P < 0.001), depressive symptoms (r = 0.627, P < 0.001), quality of relationship (r = 0.811, P < 0.001), see Table 3.

Table 3.

Correlations among study variables

Variables	1	2	3	4	5	6
1. Patient Depression	1
2. Patient Quality of Relationship	-0.234**	1
3. Spousal caregivers Depression	0.627**	-0.209**	1
4. Spousal caregivers Quality of Relationship	-0.132*	0.811**	-0.166*	1
5. Patient Sleep Quality	0.602**	-0.174**	0.563**	-0.231**	1
6. Spousal caregivers Sleep Quality	0.403**	-0.228**	0.430**	-0.192**	0.361**	1

Note: * p < 0.05, ** p < 0.001

Actor–partner interdependence mediation model analysis

An Actor-Partner Interdependence Mediation Model was constructed to examine how depression mediates the effects of quality of relationship on sleep quality in chronic heart failure patient-caregiver dyads. Model distinguishable: the chi-square test for distinguishable yielded χ²=34.51 (P < 0.001), meeting the threshold of P < 0.20 [33] was concluded that the actor and partner effects could be significantly differentiated. Patients’ quality of relationship significantly worsened their own sleep quality (β = 0.174, P < 0.001), confirming actor effects, but it did not significantly predict depression in either partner (non-significant partner effects). Conversely, higher quality of relationship in both patients and spousal caregiver directly influenced each other’s sleep quality (β = -0.267, P < 0.001; β = -0.122, P < 0.001), validating partner effects. Bootstrap analyses further showed that depression partially mediated the relationship between caregivers’ quality of relationship and patients’ sleep quality (β = -0.091, 95% CI [-0.151, -0.041]; β = -0.052, 95% CI [-0.099, -0.021]), indicating significant partner-mediated pathways, see Table 4; Fig. 2.

Table 4.

APIMeM results of quality of relationship, depression on sleep quality

Effect		Beta*	P	95%CI
Actor effect (individual’s quality of relationship -individual’s sleep quality)				lower bound	upper bound
Patient	Total effect	0.194	0.001	0.090	0.286
	Total indirect effect	0.020	0.668	-0.059	0.099
	Actor-actor simple indirect effect	-0.007	0.695	-0.045	0.032
	Partner-partner simple indirect effect	0.027	0.264	-0.017	0.083
	Direct effect	0.174	<0.001	-0.237	-0.074
Caregivers	Total effect	-0.048	0.277	-0.125	0.041
	Total indirect effect	-0.144	<0.001	-0.237	-0.074
	Actor-actor simple indirect effect	-0.007	0.695	-0.045	0.032
	Partner-partner simple indirect effect	0.027	0.264	-0.017	0.083
	Direct effect	0.050	0.270	-0.039	0.150
Partner effect (individual’s quality of relationship-partner’s sleep quality)
Patient	Total effect	-0.410	0.001	-0.490	-0.321
	Total indirect effect	-0.143	0.001	-0.214	-0.076
	Actor-partner simple indirect effect	-0.091	0.001	-0.151	-0.041
	Partner-actor simple indirect effect	-0.052	<0.001	-0.099	-0.021
	Direct effect	-0.267	<0.001	-0.353	-0.183
Caregivers	Total effect	-0.246	<0.001	-0.357	0.137
	Total indirect effect	0.021	0.405	-0.028	0.076
	Actor-partner simple indirect effect	-0.002	0.506	-0.030	0.009
	Partner-actor simple indirect effect	0.023	0.219	-0.014	0.070
	Direct effect	-0.122	0.005	-0.204	-0.038

Note: APIMeM: Actor-partner interdependence mediation model; β: standardized coefficients

Fig. 2.

APIMeM results of quality of relationship, depression on sleep quality. Note: The standardized coefficients are reported in Fig. 2. All results were from modeling with the MLR estimator. Complete arrows represent significant direct effects, and dotted arrows represent nonsignificant effects. *p < 0.05, **p < 0.01, ***p < 0.001 (two-tailed)

Discussion

This study addresses an important and unexplored area by examining sleep quality among patients with chronic heart failure and their spousal caregivers using the Actor–Partner Interdependence Mediation Model. The research revealed a mutual influence of sleep quality between patients and their spousal caregivers. Further, it also identified depression as a common factor mediating between quality of relationship of spousal caregivers and sleep quality of patients with chronic heart failure.

Mutual influence of sleep quality

The sleep quality of both patients with chronic heart failure and their spousal caregivers was poor and interacting with each other (r = 0.361, P < 0.001). Also we found that the patients’ sleep quality was significantly worse than the spousal caregivers’ (P < 0.01). This is consistent with previous studies [11, 34] Hypothesis1 was confirmed, suggesting that sleep is a health behavior shared by both patients and spousal caregivers. Poor sleep quality in patients with chronic heart failure may be due to awakening from frequent symptom attacks during the night, which directly interrupts the sleep continuity. Patients’ symptom onset is unpredictable, and their spouses may need to maintain light sleep for a long time in order to cope with unexpected situations. In addition, the spouses may voluntarily sacrifice their own sleep requirements to ensure the patient’s sleep quality, such as giving up a comfortable bed and keeping the environment absolutely quiet at night, but such compensatory care may trigger the patient’s emotional burden and lead to sleep disturbance [35]. In summary, couples’ mutual accommodation may break the sleep pattern. And the main reason for patients’ poorer sleep quality compared with their spouses is the double pressure of symptoms and psychological burden overlapping.

Interrelationships between depression of patient and caregiver and sleep quality

While depression of patients with chronic heart failure impaired only their own sleep quality, spousal caregiver depression impaired both their own and the patient’s sleep quality. Hypothesis 2 was partially confirmed. This difference is a manifestation of unequal power in the care relationship. The spouse’s depression, as the active initiator of care behaviors, can directly lead to decreased responsiveness to night care. This can lead to frequent awakenings of patients due to lack of security [36]. Spouse’s depression often transmits stress through outward behavior, which then activates the patient’s emotional mirror neurons [37], triggering anxiety or guilt in the patient, leading to deterioration of both partners’ pre-sleep mood. In contrast, the patient’s depression is mostly unexpressed. Although the spouse can perceive the low mood, this non-feedback distress does not directly trigger emotional distress in the patient. The spouse’s depression is often accompanied by catastrophic perceptions of the progression of disease [38], and this mood can be passed on to the patient through daily conversations or nonverbal behaviors, such as over-monitoring the patient’s symptoms. The patient already has a fear of death due to heart failure, and the spouse’s negative belief can overlap their survival anxiety, leading to an increased frequency of nighttime symptom attacks. Spousal anxiety stems more from the stress of care than from the patient’s expression of depression. The spousal caregiver is the patient’s important source of emotional support. In depression, the spouse loses the ability to provide enough support and may even turn to the patient for help. This, role reversal, may cause the patient to fall into deeper loneliness and despair due to the loss of emotional buffer, further worsening sleep [39].

Patient and caregiver depression as vital mediators

Quality of relationship, defined as a relationship of mutual emotional reliance between patients and caregivers, directly impacts both partners’ physical and mental health [40]. The daily interactions of patients with chronic heart failure and caregivers foster this interdependent intimacy, which in turn influences their sleep quality. However, the model revealed patient with chronic heart failure and spousal caregivers depression mediating the associations between caregivers’ quality of relationship and sleep quality of patients. This implies that depression acts as critical mediators, serving as a bridge that impacts the spousal caregivers’ quality of relationship on patients’ sleep quality. Our explanation is that the quality of relationship of caregivers can influence their own depression through a actor effect, and poor relationship quality can directly increase their risk of depression [41]. Secondly, the quality of spousal relationship directly impairs patients’ sleep quality of patients’ depression. When patients perceived negative emotions or low levels of support from their spouses, they strengthened feelings of low self-worth, which increased depression levels [42]. In turn, patients’ depression directly disrupts sleep regulation through neurocircuit mechanisms such as enhanced functional connectivity between the lateral orbitofrontal cortex and the cuneate lobe [43]. In addition, spousal relationship problems can act as a common stressor, simultaneously raising depression levels in both spouses and patients, creating a bidirectional mediating effect. According to the emotional contagion theory [44], emotions can be transmitted unconsciously through imitation or consciously through comparison. Therefore, in couples with strong intimacy, the caregiver’s depressive mood may resonate with the patient, which may aggravate the mental burden of both partners and affect sleep. The depressive mood of both couples is amplified during the interaction, further deteriorating the shared sleep environment and affecting the patient’s sleep quality. Finally, from a dyadic coping perspective, the poor quality of the relationship of a spouse can lead to their own depression in advance, and a depressed spouse often has difficulty providing effective emotional support. In addition, our results did not demonstrate a predictive effect of patients’ quality of relationship on their own or caregivers’ depression. This may be a result of heart failure symptoms dominating patients’ sleep quality [45]. These findings emphasize the need to treat the patients and spousal caregivers as a unit. It is critical to actively assess and manage depression in both couples to improve mental health, sleep quality, and overall well-being. In addition, some indirect effects in the constructed model may not be significant. There is no direct relationship between the variables, or there may be a problem with low test efficiency, which may lead to the indirect effects being statistically insignificant.

Implementation for practice

Sleep disturbances are a core health problem for patients with chronic heart failure and their spousal caregivers. Improving sleep quality in both of them is critical for enhancing disease recovery, reducing adverse outcomes, and boosting their quality of life. Therefore, the following recommendations are made for future sleep quality interventions for patients with chronic heart failure and spousal caregivers. (1) The model suggested that depression is a common factor affecting both patients with chronic heart failure and spousal caregivers. Thus, dyadic sleep interventions should prioritize psychological strategies targeting emotional factors. Studies have demonstrated that motivational interviewing reduces the incidence of depression as well as sleep disturbances in patients and caregivers which can be safely applied in clinical practice [46]. Binary disease management, a phenomenon centered on patients with chronic illnesses and the family members who provide care for them [47], is more cost-effective than targeting patients only [48]. Therefore, from the perspective of binary disease management, we may consider combining motivational interviewing techniques to guide couples to identify depression caused by role stress in care, to transform intimate support into a buffer against depression, in order to reduce sleep disruptions. In addition, because of the complexity of symptom management in patients with heart failure, caregivers often have more severe care burdens, leading to the development of severe depression. It is also extremely important to improve the symptom identification and management skills of both patients and caregivers. An approach can be explored to build an intervention pathway that combines a visual symptom monitoring tool with collaborative management. A traffic light diary designed through a color coding system can improve symptom management skills [49]. Therefore, online binary diary can be designed to strengthen the disease management ability of patients and caregivers, reduce the care burden and negative emotions triggered by information imbalance, and minimize the sleep disruption caused by sudden onset of symptoms. (2) The model suggests that higher quality of relationship improves sleep quality for both partners. Research has shown that social zeitgeber can regulate the individual sleep-wake cycle through regular social activities, such as family shared activities [50]. Therefore, based on the social zeitgeber theory, the couple’s sleep intervention can improve sleep quality by building common social zeitgebers, such as fixed bedtime/wake-up time and pre-bedtime couple communication rituals, to synchronize the pattern of both partners’ biorhythms and emotional interactions.

Limitations of the study

To our knowledge, this study is the first to explore sleep quality in patients with chronic heart failure and their caregivers from a dyadic perspective. Using the Actor-Partner Interdependence Mediation Model, we identified interdependent mediation pathways, providing evidence for dyadic sleep interventions. However, challenges in recruiting matched patient-caregiver pairs limited data collection to a single hospital, though the study site was a national regional medical center, ensuring sample diversity. Additionally, shared bed status was not analyzed as a potential confounder and the cross-sectional design and reliance on self-reported data preclude causal inferences between sleep quality and influencing factors in chronic heart failure dyads sleep quality model.

Conclusions

The results of this study suggest a significant interaction between sleep quality of patients with chronic heart failure and spousal caregivers. The depression of spousal caregiver and patient played a key mediating role between the quality of the relationship of the spouse and the patient’s sleep quality. Future dyadic interventions should integrate relationship strengthening and mental health strategies to promote holistic chronic heart failure management at home. In addition, data sources should be expanded to further validate model results, and qualitative studies could be used to explore additional factors influencing couples’ sleep quality.

Abbreviations

CHF

Chronic heart failure

APIMeM

Actor-partner interdependence mediation model

Author contributions

Yu Wang: Preparation, creation and/or presentation of the published work, specifically writing the initial draft (including substantive translation). Development or design of methodology. Xinxin Guo: Application of statistical, mathematical, computational, or other formal techniques to analyze or synthesize study data. Authored or reviewed drafts of the paper. Yibo Wang and Nan Guo: Collected the data, and Provision of study materials, materials, patients, instrumentation, computing resources, and other analysis tools. Qiaofang Yang: Conceived the study, Audited the initial analyses and in terpretation, Authored or reviewed drafts of the paper, and Approved the fifinal draft.

Funding

This work was supported by the Henan Provincial Medical Science and Technology Tackling Project [grant numbers LHGJ20230153].

Data availability

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

This study has been approved by the ethics review committee of Zhengzhou university (Approval no. ZZUIRB2023-064). Informed consent was obtained from all participants, who also provided their permission for participation.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.