Introduction
Chronic obstructive pulmonary disease (COPD) is one of the crucial causes of disability and death worldwide. The disease manifests with symptoms such as shortness of breath, cough, and sputum [1]. The prevalence of COPD in Iran is 9%-10% on average [2].
Due to the progressive nature of COPD, the impact of the disease on patients’ functional level varies, ranging from mild shortness of breath (without affecting the activity level) to the complete elimination of activity following the shortness of breath [3]. The patients spend most of their lives at home due to increasing disability and dependence. With increased functional limitations and patients’ dependence on the family, the role of family caregivers in providing care to patients becomes more visible than before [4, 5]. Family caregivers usually undertake tasks such as monitoring the disease, treatment, and coordination of doctor’s visits [6]. Following the changes in the caregivers’ life and accepting new responsibilities, they are exposed to psychological distress [7]. Psychological distress is an emotional response to a stressful factor leading to psychological damage in people [8]. Depression and the rejection feelings of caregivers from society due to psychological distress leads to decreased quality of life (QoL), so 37%-41% of caregivers experience depression with decreased QoL [9, 10].
Pulmonary rehabilitation is one of the main components of managing COPD, leading to maintaining patients’ independence, reducing complications, gaining self-confidence, and returning patients to society [1]. The results of various studies show the effect of pulmonary rehabilitation in reducing the severity of disease symptoms and improving the QoL of patients with COPD [11, 12]. In addition to the positive effects of pulmonary rehabilitation in patients with COPD, pulmonary rehabilitation training for caregivers is also an effective way to solve their problems [13], which is implemented in various ways. Among these methods, face-to-face, web-based and application-based training can be mentioned [14]. Despite the standardization of face-to-face education, some problems, such as geographical restrictions, prevent people from benefiting from this educational method [14].
With the emergence of the digital era, the use of mobile-based applications has increased as one of the new methods of training pulmonary rehabilitation and empowering caregivers [15, 16]. Also, problems like limited access to education do not exist in this method, unlike face-to-face education [17]. Based on Jael Lorca-Cabrera’s study, mobile-based educational interventions can reduce anxiety in caregivers of chronic patients [18]. According to previous studies, little attention has been paid to caregivers of COPD [19, 20] and mobile-based applications [21, 22]. On the other hand, due to the unknown aspects of COPD and its impact on the family caregivers of these patients, it is essential to have sufficient knowledge about pulmonary rehabilitation care [23, 24]. Therefore, this study was conducted to determine the effect of pulmonary rehabilitation training applications based on mobile on the psychological distress of caregivers of patients with COPD.

Materials and Methods 
This research was conducted on 70 family caregivers of patients with COPD referred to the comprehensive respiratory clinic of Khorshid in Isfahan Province, Iran. Family caregivers were selected according to the inclusion criteria using convenience sampling and then randomized using minimization software. The inclusion criteria comprised the age range of 18 to 65 years, having minimum literacy, access to the Internet, having a smartphone and the ability to use it, lacking hearing, vision, and mental impairment, agreeing to participate in the study, and having a history of caring for your patient for at least 6 years. The exclusion criteria included reluctance to participate in the study, absence of more than 2 sessions in pulmonary rehabilitation training programs, interruption of access to the application by the caregiver, and death of the patient or caregiver. The sample size was determined at least 32 people in each group by considering the first type error of 5%, the test power of 80%, and the results of a similar study [25]. Considering the 20% chance of dropping the sample, 38 caregivers were selected for each group. Data collection tools included Kessler’s demographic information and psychological distress questionnaire. This questionnaire contains 10 questions about people’s emotional states; the validity and reliability of this tool have been proven in the study conducted by Atai et al. [26].
The intervention was a mobile app-based pulmonary rehabilitation training designed by experts after examining the information needs of caregivers in the field of patient care using library studies and multi-stage content evaluations [3, 27]. The main structure of the application consists of two main panels of management and training; each has different sections. Some features of the user panel include educational content on pulmonary rehabilitation, exercises improving pulmonary function, relaxation, the possibility of asking questions and sending daily reminders. After explaining the method and obtaining informed consent to participate in the study, this application was provided to the intervention group for 6 weeks. Also, the caregivers were followed up twice a week on specific days via phone calls to monitor and ensure the study of the training. For the caregivers of the control group, the routine training in pulmonary rehabilitation care was provided in person by the nurse of the comprehensive respiratory clinic. Twelve face-to-face training sessions were held over 6 weeks. The educational content was similar in both intervention and control groups. The researcher called the control group twice a week to monitor and follow up on the attendance at the clinic rehabilitation sessions on the day before the training classes. After 6 weeks (the last training session), the caregivers of both groups were asked to re-complete Kessler’s distress questionnaire. Although 6 subjects left the study, statistical analysis was performed on 70 caregivers (35 in the intervention group and 35 in the control group) using the t test, the Fisher exact test, and the Chi-square test in SPSS software, version 24.

Results
In the intervention group, the average age of caregivers was 44.1±14.8 years; in the control group, the average age of caregivers was 47.7±13.8 years. In the intervention group, 71.4% and in the control group, 82.9% of the caregivers were women. No statistically significant difference was observed between the two groups regarding demographic variables (P>0.05). Table 1 presents the demographic characteristics of the samples in the intervention and the control groups.


According to the P value obtained by the independent t test, before the intervention, the average psychological distress score of the control group and the intervention group did not have a statistically significant difference (P=0.684). Still, after the intervention, a statistically significant difference was observed between the average psychological distress scores in the control and intervention groups (P=0.001). So that the average score of psychological distress in the intervention group decreased significantly after the implementation of the intervention (P≤ 0.000); however, in the control group, the average score of psychological distress did not change significantly (P=0.101) (Table 2).


Discussion
The results of the demographic data analysis indicate that most caregivers are women because it is customary for women to be more active in household affairs and be accountable for the family and the customs of society [28]. Similar to Dharana et al.’s study results, the highest ratio of caregivers to patients belonged to spouses who undertook the main task of caring for the patient. According to previous studies, couples in which one of them is sick are affected by each other, and their spouses are more vulnerable to problems [29].
Caregivers of the control group were at a moderate level of distress (15.68) before the intervention. After the intervention, their distress score was mild (14.6), but the changes were small and insignificant. However, the caregivers of the intervention group were on the borderline between mild and moderate (14.97) distress. After the intervention, they were placed in the mild category (25.10) and had a significant decrease compared to the control group (P<0.001). Laura Núñez-Naveira showed that using a web-based training program for caregivers of patients with dementia can reduce depression and improve the feeling of competence and satisfaction from the caregiving experience as a training and support method for caregivers [19].
One of the reasons to reduce psychological distress is that supporting caregivers via mobile base applications can increase the skills and knowledge of caregivers. This way, they are more ready to provide care and have less stress [17].
According to the mobile base application’s monitoring function, the caregiver’s time to take care of the patient is reduced. On the other hand, the patient’s visit to the doctor is reduced, and cost and time are saved [28]. Therefore, educational interventions improve the caregivers’ emotional state and stress by providing the required skills to caregivers. In this regard, mobile base applications, as an efficient educational method with caregivers’ support, lead to a pleasant experience in caring, positive behavioral changes, and reduced mental health disorders [29]. In various studies conducted by John D. Piette and Marco M. Blom on web-based educational intervention in caregivers of patients with heart failure and dementia, the results showed that caregivers’ depression and anxiety improved after the intervention [30, 31]. Also, Douglas’s study showed that a combination of videoconference-based training and an educational website effectively reduced the caregivers’ stress of patients with cancer [32]. Hence, mobile base applications lead to positive behavioral changes and reduced mental disorders like depression [33].
On the contrary, Kajiyama, in a study, examined the effectiveness of a web-based educational program for stress management of caregivers of patients with dementia, and no significant change was observed in depression after the implementation of the intervention [34]. Also, Gudarzian investigated the effectiveness of mobile-based nursing care training on depression and anxiety of caregivers of patients with stroke, and no significant change was observed in the depression score of caregivers after the intervention was implemented [35].
The inconsistent results with the present study can be due to the difference in the type of disease and educational intervention because caregivers of patients with dementia and COPD face different challenges in caring for patients [36]. COPD is a type of debilitating physical disease with respiratory symptoms gradually leaving adverse physical and psychological effects on patients during the disease. On the other hand, dementia is associated with impaired cognitive function. According to the results of studies, caring for patients with COPD and dementia is stressful, but caregivers of patients with dementia have more stress [36, 37]. Also, since the patients’ lifestyle suddenly changes following the loss of functional abilities of people during the stroke, it puts more pressure on the family [38].
On the other hand, the type of educational intervention in previous studies is a web-based educational program. It is different from a mobile-based application regarding access and understanding of education. The possibility of disruption in sites in web-based methods leads to difficult access to the resources, but this obstacle does not exist in education via mobile-based applications [39].
The results in the control group showed no significant difference in the mean psychological distress score of family caregivers of patients with COPD before and after the intervention (P>0.05), indicating no effect of face-to-face routine training on the caregivers. Consistent with the results of the current research, Shush et al. examined the impact of family-centered care training on caregivers’ depression, anxiety, and stress of patients with cardiac surgery and concluded that the average scores of these three variables did not change in the control group caregivers who only received routine training (P>0.05) [40]. The lack of attention to grouping caregivers in terms of age, literacy, and educational needs, the limited access of caregivers to training at a specific time and place, and the possibility of forgetting the material can be considered the reason for the lack of effect of routine face-to-face training on the psychological distress of caregivers in the control group. 
This study has some limitations, including lengthening the sampling process and reducing patients’ visits to the rehabilitation center due to the simultaneous study during COVID-19. Also, the number of days the pulmonary rehabilitation center was allocated to provide services to patients with other chronic respiratory diseases than COVID-19 was reduced so that patients with COVID-19 can also access pulmonary rehabilitation services.

Conclusion
Mobile app-based pulmonary rehabilitation training can effectively reduce the caregivers’ psychological distress of patients with COPD. The advantages of this mobile base application are ease of access and installation, practical content, a user environment suitable for any level of education, the possibility of following up with users by the therapist, motivating users by sending reminder messages, and talking to health professionals. All of these factors lead to ease of use by the caregivers. Therefore, considering the huge financial costs of the treatment system in the long term, the limited number of pulmonary rehabilitation centers and professional personnel in the field of rehabilitation training leading to the neglect of the educational needs of patients and caregivers, it is suggested to use the mobile app-based pulmonary rehabilitation by the caregivers of patients with COPD.

Ethical Considerations
Compliance with ethical guidelines
This research received the ethical (Code: IRCT20161203031200N3) from the Isfahan University of Medical Sciences Ethics Committee. To comply with ethical considerations, the research objectives were explained to the officials of the comprehensive respiratory clinic of Khorshid, caregivers, and patients. Also, while obtaining a written consent form, they were assured that the received information from the questionnaires would remain confidential and participation in the research implies no loss or damage. People who did not want to cooperate could refuse to continue the investigation.

Funding
This article was extracted from the Master’s thesis of Mobina Bahadori from the Adult Health Department of Isfahan University of Medical Sciences.

Authors' contributions
CConceptualization: Vajiheh Atashi, Mobina Bahadori, and Shahla Abolhasani; Methodology and validation: Vajihe Atashi, Mobina Bahadori, and Ramin Sami; Analysis, editing, and finalization: Vajihe Atashi and Mobina Bahadori; Research and review, writing the draft: Mobina Bahadori; Sources: All Authors; Supervision: Vajihe Atashi, Shahla Abolhasani, and Ramin Sami.

Conflict of interest
The authors declared no conflict of interest.

Acknowledgments
We are thankful to the Research and Technology Administration of this university, the authorities and staff of Khorshid comprehensive respiratory clinic in Isfahan, Iran, and all patients and their family caregivers who participated in this study.


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