Factors Affecting Quality of Life in Patients with Chronic Respiratory Diseases

Research Article

Int J Nutr Sci. 2021; 6(3): 1059.

Factors Affecting Quality of Life in Patients with Chronic Respiratory Diseases

Fekete M1, Szarvas ZS1, Fazekas-Pongor V1, Szollosi G2, Tarantini S3,4 and Varga JT5*

1Department of Public Health, Semmelweis University, Faculty of Medicine, Budapest, Hungary

2Faculty of Public Health, University of Debrecen, Hungary

3Department of Biochemistry and Molecular Biology at University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA

4Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA

5Department of Pulmonology, Semmelweis University, Budapest, Hungary

*Corresponding author: Janos T Varga, Department of Pulmonology, Semmelweis University, Budapest, Tömo u. 25-29, H-1083, Hungary

Received: August 20, 2021; Accepted: September 14, 2021; Published: September 21, 2021


Introduction: Chronic Obstructive Pulmonary Disease (COPD) is a progressive disease associated with worsening lung function, exacerbations and myriad factors affecting quality of life.

Aim: Our cross-sectional study aims was to assess the quality of life of COPD patients and its determinants.

Methods: 200 COPD patients aged over 40 years completed our questionnaire in Budapest at the Department of Pulmonary Rehabilitation of the National Koranyi Institute of Pulmonology between September 1, 2019 and March 1, 2020. We used the disease-specific COPD Assessment Test (CAT) questionnaire to measure quality of life, furthermore the Morisky Medication Adherence Scale (MMAS) to measure patients’ medication adherence.

Results: The median age of patients was 67 years, with a sex ratio of 48.0% male and 52.0% female. Malnourished patients (n=44) had a significantly lower quality of life (CAT: 27 vs. 25; p=0.046) than normal or overweight patients. Vitamin D is taken regularly by 27.0% of patients (CAT: 25.0 vs. 26.5; p=0.049), while omega-3 fatty acid is taken by 5.0%, also with improved quality of life. There was a significant difference in quality of life indicators between patients who cooperated (69.0%) and those who did not (31.0%). Patients’ education level, smoking status, influenza-, pneumococcal vaccination and physical activity also played a role in patients’ quality of life.

Conclusion: Patients with COPD have low quality of life indicators due to their disease, which is influenced by a myriad of factors. Professionals, who treating patients, need to take these factors into account in order to improve the effectiveness of treatment.

Keywords: Chronic obstructive pulmonary disease; Quality of life; Nutritional status; Vitamin D; Omega-3; Adherence


6MWT: Six-Minute Walking Test; BMI: Body Mass Index; CAT: COPD Assessment Test; COPD: Chronic Obstructive Pulmonary Disease; CRP: C-Reactive Protein; DHA: Docosahexaenoic Acid; EPA: Eicosapentaenoic Acid; FEV1: Forced Expiratory Volume in One Second; FVC: Forced Vital Capacity; GOLD: Global Initiative for Chronic Obstructive Lung Disease; HDL: High-Density Lipoprotein; IL-6: Interleukin-6; IL-8: Interleukin-8; LDL: Low- Density Lipoprotein; mMRC: Modified Medical Research Council Dyspnea Scale; OR: Odds Ratio; PUFA: Polyunsaturated Fatty Acid; SD: Standard Deviation; TNF-a: Tumor Necrosis Factor Alpha; TUKEB: Regional Institutional Scientific Research Ethics Committee of Semmelweis University; WHO: World Health Organization


Chronic Obstructive Pulmonary Disease (COPD) is a preventable chronic respiratory disease characterized by persistent and usually progressive bronchial obstruction [1]. Airway resistance flow obstruction is the result of an abnormally increased inflammatory response to inhalation of tissue-damaging gases and particles (most commonly tobacco smoke) in the lungs [2]. It has increase morbidity and mortality worldwide. The World Health Organization (WHO) projecting that it will become the third leading cause of death by 2030 [3]. Changes in smoking habits, ageing population and certain respiratory infectious diseases also being identified as causes of the disease [4].

Different factors influence the quality of life and the life expectancy of the COPD patients, like early detection of the disease, early diagnosis, patients’ lifestyle, smoking, alcohol consumption, and physical activity [5]. It is essential that medication is optimally adjusted, that the patient is under long-term care, and that respiratory function is monitored regularly, at least annually, with possible medication modifications [6]. The cooperation, psychological support and motivation of the patient are essential factors. However, the quality of life is also influenced by a number of other co-morbidities such as vascular stenosis, heart disease, hypertension, other circulatory diseases (e.g. stroke), pneumonia, lung cancer, diabetes mellitus, osteoporosis, anxiety, depression, anaemia. The proper management or avoidance of that, which significantly increases the life expectancy of COPD patients and improves the outcome of the disease [7].

However, a less frequently mentioned factor affecting patients’ quality of life is nutritional status. Malnutrition is common (10-45%) among COPD patients and is often associated with poor prognosis, increasing the number of exacerbations, length of hospital stay and health care costs [8, 9]. Recent observations have highlighted that the opposite of the aforementioned malnutrition, overweight is also a risk factor in COPD patients, because it is associated with a higher likelihood of developing the “cardiometabolic syndrome”, which is associated with a worse disease course, more frequent exacerbations, poorer exercise tolerance, i.e. an increased co-morbidity index [10].

There is even less discussion of medical therapeutic cooperation (adherence) and its determinants, i.e. their awareness of their disease and their social support, which play a key role in the care of COPD patients. Patients’ awareness and uptake of the different vaccines recommended for them (e.g. influenza, pneumococcal vaccine) is closely related to quality of life and the frequency of exacerbations with life-threatening complications, because the most frequent causes of exacerbations are tracheobronchial infections (70%) and air pollution [11].

Their quality of life is also positively affected by vitamin D supplementation, because vitamin D deficiency increases chronic airway and systemic inflammation, which is particularly dangerous in severe COPD patients with low FEV1 (forced expiratory volume in one second) [12]. It should be noted that low serum 25-hydroxyvitamin D (25 (OH) D) levels, which reproduce vitamin D status, occur in 60-75% of patients with severe COPD [13]. An even less frequently mentioned important nutritional supplement is omega-3 polyunsaturated fatty acids, which have been shown to reduce blood inflammatory parameters (C-Reactive Protein (CRP); Interleukin-6 (IL-6); Interleukin-8 (IL-8); Tumour Necrosis Factor-alpha (TNF-a) and to reduce pulmonary vasoconstriction and hypertension caused by hypoxia by altering cell membrane composition [14].

The aim of the present study is to explore the quality of life of COPD patients and its determinants. We will analyses the impact of age, sex, education and medication adherence on quality of life, and identify and associate quality of life with patients who are taking vitamin D and omega-3 essential fatty acid supplementation. It may help professionals in patient care to improve the effectiveness of treatment, so that patients may live better quality of life.


Data collection was performed with volunteer participants, anonymously, using self-completed paper-based questionnaires between September 1, 2019 and March 1, 2020 among patients in the Department of Pulmonary Rehabilitation of the National Korányi Institute for Pulmonology, Budapest, Hungary. Two hundred patients over the age of 40 with COPD participated. Prior to completing the questionnaire, patients received detailed information about the purpose and time of the survey, anonymous and aggregated data processing, and the essence of the research. The study was approved by TUKEB (Scientific and Research Ethics Committee) (license number: TUKEB 44402-2/2018/EKU) and complies with the Declaration of Helsinki. Participants in the research did not receive any financial, any remuneration or any other allowances. Postbronchodilator FEV1 was measured in each patient and expressed as a percentage of the estimated values. Patients were graded into GOLD A-D (Global Initiative for Obstructive Lung Disease (international recommendation for COPD) stages based on current and future risk parameters according to spirometry values, symptoms and exacerbation rate [15]. Exclusion criteria included acute exacerbation, chronic oxygen therapy (resting oxygen saturation less than 89%), history of asthma, lung surgery or severe comorbidities such as severe heart failure or severe liver or kidney failure; acute coronary syndrome or acute cerebrovascular event.

We used the Hungarian validated version of the disease-specific COPD Assessment Test (CAT) [16] to measure quality of life, which provides a comprehensive assessment of the impact of COPD on health. The COPD Assessment Test asks the patient to rate their current symptoms of their disease. The CAT consists of 8 items, each scored between 0 and 5, giving a total score between 0 and 40, with 40 being the worst. A CAT score of ≥10 indicates a significant symptomatic level (GOLD, 2014) [16]. The questionnaire was completed by the patient in stable condition at the institution under the supervision of a coordinator. During the 6-Minute Walking Distance (6MWD) test, patients were asked to walk with the maximal speed in the corridor for 6 minutes and the maximum walking distance was detected [17].

The nutritional status of the patients was assessed by taking their body weight and height with an instrument, and further data were collected with a self-designed questionnaire. The questionnaire asked patients about their gender, age, education, smoking history and disease status, and they completed the Morisky Medication Adherence Scale (MMAS), which measures patients’ adherence to therapy [18]. The MMAS is a 4-question, self-report questionnaire that can be used to reliably measure medication adherence in COPD patients. The questionnaire examines the disease-specific aspect of cooperation in terms of forgetfulness, inattention, worsening of the condition and improvement of the condition. The total score ranges from 0 to 4 points, with higher scores indicating better adherence, and the result is used to divide patients into cooperative and noncooperative groups. Patients were considered to be cooperative with drug therapy if they scored 3-4, and non-cooperative if they scored 0-2 [18].

Statistical analysis

Descriptive analyses were performed using the STATA SE-10.0 (StataCorp, College Station, TX) software package. The distribution of the sample was checked using the Shapiro-Wilk test, continuous variables were not normally distributed, so median and interquartile range data were reported in the tables. A non-parametric test (Kruskal-Wallis test) was used to compare the different groups. Statistical tests were performed at 95% confidence intervals, with significance at p <0.05.


The median age of patients (n=200) was 67 (61-72) years, with a sex ratio of 48.0% male and 52.0% female. Median BMI was 25 (21- 31) kg/m² and median FEV1 (ref%) was 45 (33-58). Patients who had ever (95%) and currently smoked (43.5%); smoked an average of 20 cigarettes/day for 40 years. In terms of highest educational attainment, 37.5% of patients had primary school, 46.5% had secondary school/ vocational secondary school/high school and 16.0% had college/ university. Lung function and various anthropometric parameters are presented in Table 1.