A convergent parallel mixed-methods design was conducted in Public Health Region 4 from August to December 2018. Public Health Region 4 is one of the Public Health Regions in Thailand, where 9,146 persons were living with COPD in 2018. A multi-stage sampling procedure was used to determine a representative sample of the research participants in order to obtain a total of eight hospitals as follows: Pathum Thani Hospital; Thammasat University Hospital; Bang Yai Hospital; Bang Bua Thong Hospital; Sing Buri Hospital; Phrom Buri Hospital; Pra Na Khon Sri Ayutthaya Hospital; and Sena Hospital. Cross-sectional study design was used in the quantitative phase to examine the predictors among personal factors (age, gender, and nutritional status), social support, pulmonary function, and functional performance regarding HRQOL. The simple random sampling consisted of 240 persons with COPD that had come for follow-up at the chest clinics in the hospitals and whose characteristics met the following inclusion criteria: diagnosis with COPD and at least 40 years of age or over; no symptoms potentially affecting the ability to respond to the questions, and good command of spoken Thai language and willingness to participate in this study. Additionally, descriptive qualitative design was used in the qualitative phase in order to explore a comprehensive in-depth understanding of the factors associated with HRQOL. The purposive sampling for this phase consisted of 30 participants, including 15 participants with high SGRQ-C scores and 15 participants with low SGRQ-C scores with consideration given to those that had completed the data collection during the quantitative phase.

Data collection was conducted following the approval of the institutional review board (IRB)of Thammasat University(project no 086/2561) regarding the research settings, procedures, and anonymity of the participants, as well as the consent forms for the participants. Participants in the quantitative phase spent approximately 30 minutes responding to the six study questionnaires. Firstly, demographic data focused on age, gender, religion, marital status, and education level. Secondly, the St. George’s Respiratory Questionnaire for COPD patients (SGRQ-C) was used to measure HRQOL, in which higher scores meant higher levels of perceived effects of COPD leading to lower levels of HRQOL [10]. Thirdly, the value of the Fat-Free Mass Index (FFMI) was used to measure nutritional status, in which lower values indicated lower levels of nutritional status. Fourthly, the Multidimensional Scale of Perceived Social Support (MSPSS) was used to measure self-perceived social support, where the lower scores indicated lower levels of social support. Fifthly, the value of Peak Expiratory Flow Rate (PEFR) was used to measure pulmonary function where higher values indicated lower levels of airflow limitation leading to higher levels of pulmonary function. Finally, the Functional Performance Inventory Short Form (FPI-SF) was used to measure functional performance, where lower scores indicated lower levels of functional performance [11]. The Cronbach alpha coefficient of the SGRQ-C, MSPSS, and FPI-SF questionnaires was 0.914, 0.870, and 0.928, respectively.

Data collection during the qualitative phase was conducted in a private room at the chest clinics. Participants that were willing to participate in this phase spent approximately 30 minutes responding to the nine interview questions. The semi-structured interview guide was composed of the individual perceptions of the six predictor variables associated with HRQOL. The researcher created trustworthiness in order to ensure the rigor of the study. Firstly, the researcher created credibility by spending adequate time with the participants and accomplished member checking of all of the interview questions, audio records, and hand notes to make certain that the data were complete and accurate. The researcher created dependability by evaluating the research process and data analysis process with three qualitative research experts and a dissertation committee audit. The confirmability of the study was created through the confirmation of the data derived from the participants’ perceptions without researcher bias. Lastly, the researcher provided a detailed description of the findings that could be applicable for healthcare teams and other researchers.

The quantitative data were analyzed using SPSS version 22.0 software, and descriptive statistics were used to test the demographic data, six predictor variables, and HRQOL. Four steps of hierarchical stepwise multiple regression analysis were used to examine the predictability of HRQOL by using six predictor variables. During the first step, personal factors included age, gender, and nutritional status, all of which were entered into the first model. The second step involved adding social support to the regression model, and the third step involved adding pulmonary function to the regression model. During the fourth step, the researcher added functional performance to the regression model. The qualitative data were analyzed using ATLAS.ti version 8.0 software and content analysis was used to provide a conceptualized comprehensive in-depth understanding of the factors associated with HRQOL. The content analysis consisted of the following three main steps [12]. Firstly, the data obtained from the interviews were transcribed verbatim in the original Thai version and then translated into an English version by a bilingual expert. Secondly, the findings were submitted according to the following three steps: open coding, creating categories, and abstraction. The researcher listened to the audio recordings of the interview data, repeatedly read the transcripts, and wrote memos and generated initial codes. Next, the researcher grouped all of the relevant coded statements into broader categories and reviewed and refined the categories and sub-categories to make certain that the coded statements were relevant to each category [12]. The last process involved producing the report, where the researcher wrote up the findings. A side-by-side display table was used to merge the data from the analysis, first presenting the quantitative results, and then providing the qualitative findings involving either confirmation or disconfirmation of the statistical results.

Two hundred and forty persons with COPD participated in the quantitative phase. The age ranged from 44 to 92 years, with a mean age of 68.80 years (SD = 9.49). Most of the participants were males(85.00%), unemployed (68.30%), and lived with their extended families (78.30%), while approximately 7.10 percent lived alone. Similarly, 30 persons with COPD participated in the qualitative phase. Their ages ranged from 44 to 83 years, with a mean age of 70.07 years (SD = 9.05). Most of the participants were males(83.33%), unemployed (86.70%), and lived with their extended families (86.60%), while approximately 6.70 percent lived alone.

Two hundred and forty persons with COPD participated in completing the six research instruments examining the factors predicting HRQOL. Among the four steps of the regression model, social support (β = -0.412) was found to be the strongest predictor of HRQOL, followed by nutritional status (β = -0.320), pulmonary function (β = -0.210), and functional performance (β = -0.125), which were interpreted at a high level (R² = 0.801, p = 0.00) as shown in Tables 1 and 2. These results indicated that higher levels of social support, nutritional status, pulmonary function, and functional performance were correlated with lower SGR-C scores and lower levels of perceived effects of COPD. Consequently, higher levels of four of the above factors were correlated with better HRQOL in persons with COPD. However, neither age(β = -0.008, p = 0.80) nor gender (β = -0.037, p = 0.21) was a significant predictor of HRQOL.

Thirty persons with COPD responded to the nine interview questions, which explored a comprehensive in-depth understanding of the factors associated with HRQOL. The findings revealed that all of the predictor variables could ultimately be grouped into six categories that emerged during the data analysis: social support, nutritional status, pulmonary function, functional performance, age, and gender. A side-by-side joint display table was used to merge the data of the quantitative and qualitative results. These integrated findings were discussed and organized into six predictor variables as shown in Table 3. The findings of this study revealed that social support, nutritional status, pulmonary function, and functional performance were significant predictors of HRQOL. The above findings were consistent with the qualitative findings, which can explain a comprehensive in-depth understanding of the factors related to HRQOL. Each factor is fully described below.

Most of the participants had high levels of social support; persons with moderate levels of social support had high levels of the perceived effects of COPD that likely led to poor HRQOL compared with persons with COPD that had high levels of social support. With the same results, most persons with moderate to very severe COPD needed the help of a caregiver to accomplish daily tasks. They needed social support, including practical support with their finances and recreational life, in addition to maintaining independence with the help of their families and close relationships [8, 13]. Therefore, that social support was a significant predictor of HRQOL, and that the participants perceived that social support created encouragement and convenience, and they received good recommendations. The participants reported receiving the most support from family members, followed by support from healthcare providers and friends (their close friends and neighbors). They reported strong agreement that their family members were willing to offer emotional support (37.90%) and tried to help with daily activities (32.90%), and the healthcare providers cared for their feelings (35.40%) and were real sources of comfort to the participants (28.70%) while reporting with neutrality that they could trust their friends when things went wrong (35.00%) in addition to sharing their joys and sorrows (33.80%). This caused the participants to breathe better and to have no need to go to the hospital before their appointment dates. This is supported by the findings, where social support was seen to be positively correlated with fewer acute exacerbations (AEs), reduced hospitalizations, and increased HRQOL among persons with COPD [3, 14]. Similarly, living with others and having social support were positively correlated with physical activity and improved dyspnea management. The participants recommended that healthcare providers apply social support to the interventions, which can facilitate appropriate care for persons with COPD [13-15]. Interestingly, persons with COPD living alone tended to develop the disease and to rely on healthcare providers for support. This also agreed with the study of Raksayot and Sitthiban, who found that the intervention program that consisted of social networks, social support, and the patient’s self-care over 12 weeks was able to effectively reduce the readmission rate [16]. Nurses and healthcare teams should assess social support for persons with COPD, after that plan participatory intervention programs in caring for them.

Most of the participants had normal levels of nutritional status, and persons with a cachexia level of nutritional status had high perceived effects of COPD and poor HRQOL, while normal nutritional status indicated good HRQOL. Nutritional status was a significant predictor of HRQOL, where the participants perceived that the effects of COPD caused them to receive insufficient nutrients and self-care concerning food consumption. This was supported by the results. In other words, persons with severe to very severe COPD had malnutrition, and a significant decrease in their mean FFMI values was observed with increasing severity of COPD [7, 17]. Lack of social support and inadequate dietary intake were the commonly-cited reasons for malnutrition and have been identified as major risk factors for the decline of functional performance and poor HRQOL among persons with COPD [2, 18]. Consequently, the patients in this group require more self-care concerning food consumption by eating small amounts of healthy foods frequently, including high-fat and low-carbohydrate diets, and fruits and vegetables, to improve pulmonary function, prevent acute exacerbations, muscle strength, and exercise tolerance, leading to the enhancement of their functional performance and HRQOL [1, 19]. However, some of the participants reported that nutritional care was often overlooked both by themselves and their families. In this regard, it is challenging for the nurse and the healthcare team, especially nutritionists, to increase nutritional care, which should involve both the assessment of nutritional status and the encouragement of nutrition education programs in persons with COPD.

Most of the participants were classified with moderate stages of COPD, and persons with very severe COPD had high perceived effects of COPD and poor HRQOL compared with other stages of COPD. This was supported by the results in that airflow limitations in persons with COPD are progressive, involving the value of forced vital capacity (FVC) and forced expiratory volume in one second, while (FEV₁) and PEFR show a significant decrease [2, 8, 20]. Pulmonary function, therefore, can be considered a significant predictor of HRQOL, as the participants perceived that their lung function worsened as they coped with their degenerative lung function. Similarly, the pathophysiology of COPD involving both airflow obstruction and parenchymal destruction can lead to obstructed airflow that decreases lung compliance and hyperinflation [1, 2] and thereby increases the work of breathing and results in respiration difficulty with long-term effects on fatigue, sleep alterations, emotional reactions, memory function decline, and respiratory muscle weakness [7, 21]. Interestingly, the self-care experience involving both the exacerbation and remission period was as follows: first, the most useful methods during the exacerbation period were making minimum body movements, managing dyspnea, reducing the airway obstruction, and receiving assistance and advice from family members and others. Second, the most useful methods during the remission period were preventing the aggravation of dyspnea by using prescribed drugs and inhalers, avoiding exposure to allergy triggers, and performing daily activities as usual [22]. It can be concluded, therefore, that pulmonary function is correlated with functional performance and HRQOL among persons with COPD [20, 23]. However, most of the participants reported that self-care using pharmacological strategies was used more frequently than self-care using non-pharmacological strategies. Pulmonary rehabilitation is one of the non-pharmacological strategies and the main method used by persons with COPD, including energy conservation techniques, breathing techniques, exercise training, and secretion clearance strategies [1, 2, 24]. Nurses and healthcare teams, especially physical therapists, should employ pulmonary rehabilitation programs involving both physical and psychological training to improve pulmonary function.

The majority of the participants had high levels of functional performance, and persons with low levels of functional performance had high perceived effects of COPD and a likelihood to have poor HRQOL compared with those that had high levels of functional performance. The multiple factors contributing to functional performance included the following: physiological factors, including the severity of the disease, body composition, and pulmonary function; physical symptom clusters, including dyspnea, fatigue, and insomnia; psychological symptom clusters involving both anxiety and depression; and psychological factors involving both self-efficacy and health perception [25-27]. Functional performance, therefore, was found to be a significant predictor of HRQOL, where the participants perceived becoming weary as a result of the degenerative disease and dealing with the degeneration of functional performance. Some of them reported performing a light exercise with some difficulty and being unable to walk fast for more than 20 minutes due to shortness of breath (44.60%), and going to religious ceremonies with some difficulty (49.60%). This was supported by the results, thereby indicating that a reduction in physical activity can lead to a loss of previous role identification, and an inability to earn a living and social isolation [7, 23]. Interestingly, the difficulties in performing activities restrict interactions with the environment, thereby leading to a tendency for decreased spiritual activities and poor HRQOL among persons with COPD [8, 11]. With the same results, the study discussed how to lower the performance of physical activities during the exhalation phase of respiration, which is believed to reduce the respiratory rate and prolong the duration of exhalation, thereby leading to a decrease in dyspnea [18, 27]. Moreover, the exercise program with palunglompranover eight weeks was able to effectively reduce dyspnea and increase daily performance [28]. Nurses and healthcare teams can be used as evidence to develop home-based exercise programs to promote increased exercise capacity and perform activities and functional performance in persons with COPD.

Both age and gender are personal factors in persons with COPD. Most of the participants were elderly persons with COPD, and they had higher levels of perceived effects of COPD and were likely to have poorer HRQOL compared to other adults with COPD. However, age was not a significant predictor of HRQOL. This agreed with the study of Ekici et al., who found that age was not correlated with HRQOL in persons with COPD [8]. The participants perceived that a difference in age was not a predictor of the prognosis of the disease. Persons with COPD in adulthood reported that they have responsibilities as family leaders that care for family expenses and COPD makes it difficult for them to be able to work in the same way. The effects of COPD cause deteriorating physical impacts and psychosocial impacts, in line with the older age among persons with COPD. Similarly, the impact of increasing age involves trouble with sleeping, dyspnea, and loss of muscle mass, resulting in a decline in functional performance and HRQOL [1, 20, 23]. However, this was different from the study of Corlateanu et al., who found that both the elderly age group with COPD and the adult age group with COPD had a significantly positive correlation with HRQOL [29].

Most of the participants were males; however, women with COPD had higher levels of perceived effects of COPD and were likely to have poorer HRQOL than men. The results showed that gender was not seen to be a significant predictor of HRQOL either; the participants perceived that differences in gender did not predict the prognosis of the disease. The participants perceived that women with COPD had a greater response to multiple concurrent symptoms of the disease and this led to anxiety. Most of the men, on the other hand, exhibited smoking behaviors and duties and responsibilities toward their families, causing their symptoms of COPD to be more severe. This is supported by the results of De Torres et al., who found that men and women with COPD have different coping mechanisms; women with COPD expressed more dyspnea than men, despite having the same degree of airway obstructions [30]. This also agreed with the study of Raherison et al., who found that HRQOL was different in women compared with men, where chronic sputum was associated with HRQOL in women but not men, thereby resulting in the HRQOL of women being poorer than that of men with COPD [31]. Hence, nurses and healthcare teams should become more aware of the significance of age and gender, which need to be considered when planning appropriate care to increase HRQOL in persons with COPD.