I’m Sion, and this is a research I carried out about how Coronary Heart Disease (CHD) affects Health Related Quality of Life (HRQoL) of older adults in Korea using the HINT-8 index.

NOTE: This post summarizes an independent project I conducted, The full paper is not yet published. It will be updated with a link attached to the full paper once it gets published. 

Reasoning:

Over the past summer I did two major things: I travelled to Korea, my home country, and I participated in a summer course at Stanford that introduced me to cardiothoracic surgery. During my visit to Korea, I noticed a significant growth in elderly population. This observation, combined with what I learned about coronary heart diseases during the program, sparked the interest I have in public health and led to a question: How does CHD affect the aging population of Korea? I figured conducting research would help me to explore the question and help me gain hands-on experience with statistical methods, using tools like the IBM SPSS, all important for health data analysis while familiarizing with topics in AP Statistics. Here is a brief summary of my research and my paper. I did not include details regarding statistical analysis for the sake of simplicity, but you can find them in the journal I will link to once it gets published. 

Background: 

In 2024, South Korea entered a super-aged society with more than 20% of the population aged 65 or older. The elderly population is growing quickly, as well as the prevalence of chronic diseases such as Coronary Heart Disease. Under current situations, governments are focusing on health-related quality of life, a concept aimed to capture the overall well-being of a person, not only one’s survival. HRQoL is now emerging as a key indicator for senior health management and shaping policies for Korea’s aging society.

Coronary heart disease, such as myocardial infarction and angina, is generally known to lower quality of life in older adults. Previous studies relied mainly on Western-style instruments to measure this, and these tools have been criticized for failing to reflect Korean cultural characteristics and health perceptions. Also, many of the studies were limited by small sample sizes.

The HINT-8 index was developed in Korea as a solution to this issue. It is a survey with eight items that has demonstrated strong reliability and cultural relevance for evaluating the quality of life of Korean older adults. There hasn’t been a lot of empirical research that examined how coronary heart disease specifically affects health-related quality of life among older Koreans using this instrument. Therefore, I designed this study to investigate the impact of coronary heart disease on the health-related quality of life of older Korean adults.

Research questions:

1. Does coronary heart disease influence overall HINT-8 scores?
2. Are there differences of CHD’s impact across the eight subscales of the HINT-8?
3. Is the association between coronary heart disease and health-related quality of life still significant after controlling for sociodemographic factors (age, gender, education, and income)?

Study Design & Population:

I used a retrospective cross sectional design, analyzing data from the 2019 Korean National Health and Nutrition Examination Survey. It is the only year that variables for CHD diagnosis and the HINT-8 quality of life index were both included. The final population was 1279 adults 65 years or older, with 109 people in the CHD group and 1170 in the non CHD group. I used regression analysis, T-test, and chi-squared test for statistical analysis.

Results:

Through simple regression analysis, I found that CHD did not significantly predict HRQoL. However, when sociodemographic controls were added, the effect of CHD became significant which shows that controlling for these factors is essential to understand its independent impact. With the HINT-8 subscales, CHD had effects on stair climbing, daily work, and memory. These results are consistent with earlier studies that found CHD limiting mobility and daily functioning in older adults. Sociodemographic factors also showed association with HRQoL. Women reported lower quality of life compared to men, while higher education and higher income were both linked to better QoL suggesting that policy support and tailored intervention programs that consider such factors should be implemented to have positive influence on overall HRQoL of the population.

To conclude, CHD was a significant factor after controlling for sociodemographic variables. Interventions must target not only disease but also age, gender, education, and income disparities. Because men had higher prevalence of CHD and women diagnosed with CHD had lower HRQoL, strengthening early screening and prevention for men and post treatment and QoL support for women is a potentially effective policy. 

Reflection: 

The research process was not simple. Extracting necessary information from vast amounts of raw data and dealing with problems such as finding no significant association through simple regression were just some of many challenges I faced. However, it was a valuable experience as I came to realize that my personal experiences can inspire meaningful scientific questions. My visit to Korea and knowledge I gained from the program helped me identify a socially relevant topic where I could apply what I learned. It also taught me that public health research must consider the cultural context of the population, as it is important to be aware how people perceive health and well-being.

I also found some areas for improvement while participating in a youth research conference hosted by HOBY, where I decided to have my paper evaluated. The judges there provided great suggestions, such as considering alternative explanations for the observed correlation. There may have been things like selection bias that could affect the findings. Most importantly, I learned a classic lesson of research: correlation does not necessarily imply causation. 

Overall, it was a rewarding experience that helped me deepen my interest in public health research and showed me how people’s lives can be improved through my findings, a good foundation for my journey in research. I received the 2nd Professor’s Award among the Conference with 100 participants.