Relationship Between Functional Capacity and Health Related Quality of Life Among Cardiac Patients

Relationship


INTRODUCTION
Coronary artery disease (CAD) is causing disability and premature deaths around the world. 1 It has increased 9 times in India in the past twenty years.According to WHO, the highest estimated heart patients in the year 2025 will be Indians. 2According to a report on Medical Certification of Cause of Death, out of the total medically certified deaths i.e. 39,621, diseases of the circulatory system accounted for 36.2% in Punjab State. 3 Currently, Punjab has the highest prevalence rate of cardiac diseases (17.08%) against the nation's average of 8.66%. 4Previous researches had highlighted the negative impact of cardiac diseases on patients' lives, It has emphasized the necessity for further exploration into patient outcomes keeping in mind both subjective and objective evaluation.This includes an in-depth assessment of an individual's functional capacity and the health-related quality of life. 5So far, few studies have been conducted to assess the subjective aspects of cardiac diseases.Moreover, the studies conducted with such aim included a very small sample or done on a specific population, thus cannot be generalized. 5There are very few existing studies that formally evaluated the relationship between functional capacity and healthrelated quality of life.Though, functional capacity and health-related quality of life are frequently mentioned and sometimes used as equivalent terms but it is important to distinguish them.Functional capacity has been described as "the ability to perform activities of daily living that require sustained, submaximal aerobic metabolism" and health-related quality of life can be characterized as a self-reported evaluations of one's health status that cannot be interpreted by anyone else. 6 ameliorate quality of life, there is a need to understand the connection between both the aspects of health i.e., the function capacity and the healthrelated quality of life.

METHODOLOGY
The present study used a quantitative research approach with a correlational research design.The sample comprised of 196 cardiac patients receiving treatment at selected hospitals of district Jalandhar, Punjab.The present study used a quantitative research approach with a descriptive research design.The study's sample size was determined using the formula  8 This test was conducted in a 20m corridor of the selected hospitals by the researcher following the guidelines of the American Thoracic Society. 9Oxygen Saturation (SPO2) was recorded using finger-tip pulse oximeter before and after doing 6MWT.A 6MWT was performed and recorded on all the patients and the patient's perceived exertion was assessed with the BORG scale (where <6=No exertion at all and 20=Maximal exertion). 10If required, patients were given rest (whenever needed) during the walk.The distance covered over a time of 6 minutes was recorded using a stopwatch and was used as an outcome to compare changes in functional capacity.The reference values used in 6MWT were proposed by the American Thoracic Society guidelines. 9e Health-Related Quality of Life was evaluated using the Quality-of-Life SF-36 questionnaire including 36 questions related to limitations during any physical and social activity, bodily symptoms, psychological problems, and overall perception of health. 11The reliability of the tool was calculated using Cronbach's alpha and was found to be highly reliable (α=0.82).Patients were given the questionnaire and were helped in understanding the tool and instructions.Thus, they filled the questionnaire by themselves and later was scored by the researcher.Each domain consists of a 0-100 scale on the assumption that each question carries equal weightage.The lower the score the poor is the quality of life.A higher score indicates good quality of life. 12 Statistics: IBM SPSS (version 21) was utilized for data analysis.Demographic data (such as age, gender, marital status, etc.) as well as functional capacity and health-related quality of life (HRQOL) were presented as frequency and percentages.Pearson's correlation coefficient was used to determine the relationship between the Functional Capacity and HRQOL scores.Independent 't' test and One-way ANOVA were utilized to assess associations.Post-hoc tests were utilized to determine pairwise comparisons of means contributing to the overall significant difference observed while computing 'F' statistics.The level of significance for all tests was set at p<0.05.

RESULTS
All patients completed 6MWT and Quality of life SF-36.No clinical complications were recorded during and after the test.
In this study, 196 cardiac patients were studied and the results revealed that majority of the cardiac patients i.e., 157 (80.1%) covered <250m distance during 6MWT and 19.9 percent of patients covered 250m-400m distance, while there were no patients who were able to cover >400m distance during 6MWT (Table 1).The mean functional capacity or the average 6-minute walk distance of 196 patients was 25.71), ranging from 210m-320m which depicted a low functional capacity among cardiac patients.3).The null hypothesis was rejected as a statistically significant mild positive relationship between Functional capacity and HRQOL was observed.(Figure 1).  4.
The association of functional capacity and HRQOL with the selected demographic variables was calculated using One-way ANOVA and Student's 't' test (Table 4) which reveals a statistically significant association of all the selected demographic variables with the functional capacity of cardiac patients except with the age and co-morbidities.Whereas, all the selected demographic variables had a significant association with HRQOL except for gender, alcohol consumption, and therapeutic intervention done.

DISCUSSION
In the present study, the majority of the patients 78 (39.8%) were in the age group of 51-60 years of age with a male preponderance of 56.1% (110 out of 196) and the majority [137 (69.9%)] of the cardiac patients were married.These results were supported by the study conducted by Wu JR et al, 13 Forman DE et al, 14 Wang G et al, 15 Suman-Horduna I 16 and Firouzabadi MG et al, 17 that majority of subjects were in age group 50 years and above and were males.
In the present study, the 6MWT was used to assess the functional ability of cardiac patients and the results showed that 157 (80.1%) of the cardiac patients covered <250 m of walking distance during 6MWT which was lower than that of a previous correlational study where a majority of respondents covered the distance of 300m during 6MWT.One possible explanation for this finding could be the difference in patients' Body Mass Index, gender, diet, comorbidities, etc. 18 Whereas, research conducted by Straiton N et al 19 revealed similar results to that of the present study that patients had significantly reduced functional capacity after cardiac events.
In this study, all the cardiac patients i.e., 196 (100%) had poor quality of life and these results are similar to the results of a prospective study conducted by Wu JR et al 13 and Straiton N et al. 19 Despite cardiac disorders significantly impacting QOL, other factors play an important role as well, including age, marital status, education, job, diet, cause of heart disease, treatment done, comorbidities, depression, anxiety, social withdrawal, NYHA classification etc.Moreover, a prospective and an observational study revealed the strong impact of age, gender, residence, marital status, monthly income and clinical factors like comorbidities and number of hospitalizations on HRQOL and functional status of the patient. 15,20 observational study conducted by Wu JR 13 and a cross-sectional study conducted by Jellestad L et al. 21nd Wang G 15 concluded that the functional capacity is associated with the quality of life of patients who had undergone cardiac interventions.This is same as the results of present study.The present study elucidates a statistically significant mild positive correlation (.223) between functional capacity and HRQOL which is consistent with the results of the previous studies showing a mild to moderate positive correlation between functional capacity and QOL and also revealed that there are several key elements corresponding to a reduced health-related quality of life among older cardiac patients.The most common is functional capacity (as per New York Heart Association functional class) is highly associated with QOL. 6,14e results of a study conducted by Rahmani S 18 are contrary to the results of the present study which reveals a significant negative correlation between functional capacity and the QOL among heart failure patients.These results may be due to the choice of tool, as they used MLHFQ which mainly measures the physical ability of heart failure patients with questions like limitation in walking or climbing staircase.
Whereas, in the present study the Quality-of-Life SF-36 questionnaire was used which covers all the main domains of health including limitations in physical activities, social activities because of physical or emotional problems, psychological distress, and well-being and general health perceptions.

LIMITATIONS
Although a correlational design was appropriate for this research study, but it has its own inherent limitations as cause-and-effect relationship between functional capacity and health-related quality of life cannot be inferred.Furthermore, in addition to the assessment of the relationship between functional capacity and health-related quality of life among cardiac patients, future studies could investigate relationship of other mediating and moderating variables which were not included in the present study but can impact the main variables of these patients studied under present research.Additionally, the study subjects were enrolled from the selected hospitals of one district only, which might affect the generalizability of findings of the study.

CONCLUSION
Quality of life and functional capacity of cardiac patients are substantially reduced.Timely enrolment in cardiac rehabilitation programs can improve the functional capacity and can help in gain in healthrelated quality of life of these patients.

RECOMMENDATIONS
Though, there are many factors influencing the quality of life and functional capacity of cardiac patients, it is also suggested to identify the different factors affecting both functional capacity and quality of life.A qualitative enquiry can provide in-depth information on the impact of cardiac disease on different aspects of lives of patients including the functional limitations.Furthermore, impact of enrolment and completion of cardiac rehabilitation program on functional capacity and quality of life can be assessed.

Figure 1 :
Figure 1: Relationship between Functional Capacity and Health Related Quality of Life

Table 1 :
Distribution of Functional capacity among cardiac patients (N=196)

Table 3 :
Relationship between Functional capacity and Health Related Quality of Life among cardiac patients 'r' value 0.223; p value 0.002

Table 4 :
Association of selected demographic variables with compliance and selected health outcomes among cardiac patients (N=196)The results show that most (39.8%) of the patients were in the age group of 51-60 years with a male preponderance of 56.1% (110 out of 196), majority [137 (69.9%)] of the cardiac patients were married.Other patients' characteristics are shown in Table *t test applied; #ANOVA test applied