Factors Associated with Chronic Disease and Health Care Utilization Among Young Adults in South Korea

Abstract

Hypertension, diabetes, and hyperlipidemia have become prevalent in young adults. Health care utilization is a key factor in managing early onset chronic diseases. This study aimed to examine the factors affecting health care utilization among young South Korean adults with a single chronic disease. From the Korea Health Panel Survey data collected between 2014 and 2017, young adults who were 30–49 years old and diagnosed with a single chronic condition (hypertension, diabetes, or hyperlipidemia) were included in this study (n = 993). The factors affecting health care utilization were analyzed through multiple logistic regression. The health care utilization rate of the 40–49 and 30–39-year age groups was 84.2% and 71.1%, respectively, and it was significantly higher in the healthy behavior group, who had no smoking and drinking habits and joined in physical activities. Among the chronic diseases, hyperlipidemia obtained the lowest health care utilization rate (62.8%). From the multiple logistic regression analysis, medication intake was likely to increase in the older, unemployed, and healthy behavior groups. Patients with hypertension and diabetes were more likely to use health care services than those with hyperlipidemia. Given the rising prevalence of chronic diseases among young adults, these findings may be helpful in implementing new public health approaches for this type of population by encouraging proper health care utilization.

Introduction

Hypertension, diabetes, and hyperlipidemia are cardiometabolic risk factors that occur with age; unfortunately, even young adults are becoming vulnerable to these conditions. The age of chronic disease onset and diagnosis has gradually lowered,¹ and the global prevalence of early onset chronic disease has been increasing.² In a German study, hypertension, hypercholesterolemia, and diabetes were found in >30% of men and roughly a quarter of women, both aged 30–49 years.³ In South Korea, ∼30% of young adults aged 30–49 years were diagnosed with hypertension, 3.5% with diabetes, and >34.4% with dyslipidemia in 2018.⁴ The rapid increase in the number of patients having either of these chronic diseases largely influences medical expenses because of their prolonged nature, complications, and comorbidities.

Adults diagnosed with a chronic disease at 30–49 years old are more disadvantaged in many ways than those without chronic diseases until >65 years old. Compared with those with late-onset chronic diseases, individuals with early onset chronic diseases are more likely to have the same conditions considerably longer that might result in severe complications or multimorbidity. For example, the risks of cardiovascular disease and all-cause mortality are higher in those with hypertension onset <45 years old than in those at an older age of onset.⁵

Compared with late onset, early onset hypertension is associated with greater odds of exhibiting cardiovascular diseases, particularly coronary disease, and even death.⁶ Individuals with early onset type 2 diabetes are also at a higher risk of developing vascular complications than those with late-onset diabetes, and they will most likely die resulting from cardiovascular events.^2,7 In addition, hyperlipidemia in young adulthood (generally defined as early 20s to 30s) increases the subsequent risk for coronary heart disease.⁸

Unfortunately, individuals with early onset chronic disease are less likely to achieve treatment goals. Two-thirds of adults are seldom or never sick, and chronic disease can often occur without symptoms; thus, young adults do not practice routine care.⁹ Consequently, health care utilization is lower in younger age groups, resulting in poor disease control and delayed detection of disease-related complications.¹⁰ Cardiovascular risk in young patients with hypertension is negligible, and they hesitate to start active treatment.¹¹ Individuals with diabetes onset before 40 years of age have worse metabolic control, and few received organ-protective drugs than those with later onset diabetes.¹² In a previous study, only 10.6% of adults aged 20–39 years and 47.7% of adults aged 40–64 years with hyperlipidemia were receiving treatment.¹³

Many possible interventions are considered for early onset chronic disease. Clearly, primary prevention, such as tobacco control, physical activity, and salt reduction, can reduce the risk of developing chronic diseases.¹³ However, once the chronic disease occurs, early interventions are required for effective treatment outcomes, which can be achieved by appropriate health care utilization. The detection of abnormal findings (eg, elevated blood pressure, glucose level, and blood lipid level) is a fundamental step of any chronic disease management strategy. The prompt initiation of medication enables one to achieve therapeutic outcomes. Clinical treatment for chronic diseases has outstanding health benefits that might help reduce the risk of developing complications as they age and the risk for premature death from these diseases.¹⁴

Many studies have explored the characteristics of health care utilization among older adults with chronic disease or later life, or often discussed health care utilization in terms of health care expenditures.¹⁵ Although appropriate health care utilization should also be emphasized for young adults with early onset chronic disease, their health care utilization remains insufficiently known. Understanding the health care utilization among young adults with chronic disease is important because it could potentially help identify individuals who need appropriate health care utilization to prevent chronic disease progression and its complication. Therefore, this study aimed to investigate health care utilization and the factors affecting it in young adults (30–49 years old) with a single chronic disease in South Korea.

Methods

Study design and setting

This retrospective study examined the health care utilization of Koreans aged 30–49 years who were diagnosed with either hypertension, diabetes, or hyperlipidemia. These diseases were chosen because of their high prevalence, the economic burden on the Korean health care system, and potential for adverse health events if not controlled.

The appropriate institutional review board approved this study (No. CUPIRB-2021-01-004).

Sources of data

Data were acquired from the Korean Health Panel Survey (KHPS), which is organized by the Korea Institute for Health and Social Affair and National Health Insurance Service. The KHPS is a nationally representative statistical survey approved by the Korean government. Individual characteristics include gender, age, marital status, educational level, medical coverage, employment status, residential area, household income, and health behavior. The KHPS database also contains information on the morbidity of chronic disease and its associated health care utilization. For this study, the 2014–2017 (4 years) KHPS pooled data (beta version 1.6) (n = 581,967) were used. Of the 5538 participants with either hypertension, diabetes, or hyperlipidemia, 993 were young adults aged 30–49 years.

Definition of major variables

Patient-level sociodemographic measures included gender, age, marital status, educational level, medical coverage, employment status, residential area, and household income. The authors evaluated patients' health behaviors in terms of smoking, drinking, physical activity, and subjective health status. The 3 chronic diseases were defined using the International Classification of Disease 10 codes (ICD-10 codes): hypertension (I10–I15), diabetes (E10–E14), and hyperlipidemia (E78). The dependent variable was health care utilization, which was measured by binary variables. In this study, health care utilization was defined as whether a patient visited the outpatient care during the past year, and outpatient care was classified solely for chronic disease care, not for other conditions.

Data analysis

The baseline differences in the health care utilization were examined by descriptive analysis, and the differences in the distribution of sociodemographic variables and chronic disease types were determined by chi-square test. The factors affecting health care utilization among the participants were analyzed using multivariable logistic regression models. The odds ratios (ORs) and 95% confidence intervals (CIs) for logistic regression models were also calculated. All statistical data were analyzed using SAS 9.4 (SAS Institute, Inc., Cary, NC, USA). A 2-tailed P ≤ 0.05 was considered statistically significant.

Results

General characteristics and health care utilization

Table 1 describes the general characteristics and health care utilization of patients. Among the 993 participants diagnosed with either hypertension, diabetes, or hyperlipidemia, the 40–49-year age group used health care more frequently than the 30–39-year age group (84.2% vs. 71.1%). The health care utilization rate was highest among those who were unemployed. Socioeconomic variables such as marital status, educational level, medical coverage, residential area, and household income showed no statistically significant differences.

Table 1.

General Characteristics and Health Care Utilization

Variable	Total		Health care utilization				P
	Total		Yes		No
	N	%	N	%	N	%
Gender
Male	663	100.0	536	80.8	127	19.2	0.094
Female	330	100.0	281	85.2	49	14.8	0.094
Age(years)
30–39	149	100.0	106	71.1	43	28.9	0.000
40–49	844	100.0	711	84.2	133	15.8	0.000
Marital status
Married	853	100.0	700	82.1	153	17.9	0.665
Unmarried/divorced/widowed	140	100.0	117	83.6	23	16.4	0.665
Educational level
High school or below	467	100.0	388	83.1	79	16.9	0.530
College or above	526	100.0	429	81.6	97	18.4	0.530
Medical coverage
National Health Insurance	964	100.0	790	82.0	174	18.0	0.121
Medical aid	29	100.0	27	93.1	2	6.9	0.121
Employment status
Employed	852	100.0	690	81.0	162	19.0	0.009
Unemployed	141	100.0	127	90.1	14	9.9	0.009
Residential area
Metropolitan	392	100.0	323	82.4	69	17.6	0.935
Rural	601	100.0	494	82.2	107	17.8	0.935
Household income
Q1 (Low)	39	100.0	36	92.3	3	7.7	0.298
Q2	158	100.0	129	81.6	29	18.4
Q3	251	100.0	211	84.1	40	15.9
Q4	271	100.0	215	79.3	56	20.7
Q5 (High)	274	100.0	226	82.5	48	17.5

Health behavior, chronic disease, and health care utilization

Health care utilization demonstrated statistically significant differences between the health behavior groups (P < 0.01) (Table 2). The health care utilization rate was higher in the healthy behavior groups: nonsmoking group (85.2% vs. 77.0%), nondrinking (86.0% vs. 81.1%), and joining in physical activities (84.6% vs. 80.9%). Such rate was also higher in the poor subjective health status group than in the opposite group (83.4% vs. 80.1%). With regard to chronic disease type, hyperlipidemia showed the lowest health care utilization rate (62.8%).

Table 2.

Comparison in Health Care Utilization by Health Behavior and the Type of Chronic Disease

Variable	Total		Health care utilization				P
	Total		Yes		No
	N	%	N	%	N	%
Smoking
No	654	100.0	557	85.2	97	14.8	0.002
Yes	326	100.0	251	77.0	75	23.0	0.002
Drinking
No	264	100.0	227	86.0	37	14.0	0.007
Yes	716	100.0	581	81.1	135	18.9	0.007
Physical activity
No	572	100.0	463	80.9	109	19.1	0.014
Yes	408	100.0	345	84.6	63	15.4	0.014
Subjective health status
Good	342	100.0	274	80.1	68	19.9	0.042
Poor	601	100.0	501	83.4	100	16.6	0.042
Chronic disease
Hypertension	608	100.0	529	87.0	79	13.0	0.000
Diabetes	189	100.0	165	87.3	24	12.7
Hyperlipidemia	196	100.0	123	62.8	73	37.2

Factors associated with health care utilization

Table 3 presents the factors affecting health care utilization among the patients. The older age group (40–49 years) was more likely to receive health care (OR = 2.574; 95% CI, 1.624–4.079) than the younger age group (30–39 years). Those who were unemployed also had a higher probability of health care utilization (OR = 1.485; 95% CI, 0.760–2.905). Moreover, the odds of health care utilization were significantly higher in those having healthy behaviors, that is, nonsmoking (OR = 0.661; 95% CI, 1.089–2.534), nondrinking (OR = 1.199; 95% CI, 0.746–1.926), and joining in physical activities (OR = 1.199; 95% CI, 0.746–1.926). Patients with hypertension (OR = 5.187; 95% CI, 3.433–7.839) or diabetes (OR = 4.434; 95% CI, 2.539–7.741) were also more likely to avail health care than those with hyperlipidemia.

Table 3.

Adjusted Odds Ratio and Their 95% Confidence Intervals of Factors Affecting Health Care Utilization from Multiple Logistic Regression

Variable	OR	95% CI		P
Variable	OR	Low	High	P
Gender
Male	1
Female	1.286	0.785	2.109	0.318
Age (years)
30–39	1
40–49	2.574	1.624	4.079	0.000
Marital status
Unmarried/divorced/widowed	1
Married	1.170	0.669	2.049	0.581
Educational level
High school or below	1
College or above	1.284	0.860	1.918	0.221
Medical coverage
National Health Insurance	1
Medical aid	1.744	0.303	10.030	0.533
Employment status
Employed	1
Unemployed	1.485	0.760	2.905	0.024
Residential area
Metropolitan	1
Rural	1.005	0.692	1.460	0.978
Household income
Q1 (Low)	1
Q2	0.645	0.144	2.880	0.565
Q3	0.750	0.169	3.330	0.705
Q4	0.578	0.130	2.565	0.470
Q5 (High)	0.639	0.141	2.895	0.562
Smoking
Yes	1
No	1.661	1.089	2.534	0.018
Drinking
Yes	1
No	1.199	0.746	1.926	0.045
Physical activity
No	1
Yes	1.188	0.751	1.880	0.046
Subjective health status
Good	1
Poor	1.251	0.862	1.814	0.238
Chronic disease
Hyperlipidemia	1
Hypertension	5.187	3.433	7.839	0.000
Diabetes	4.434	2.539	7.741	0.000

Hosmer Lemeshow: 6.824, Hosmer Lemeshow P-value = 0.556.

CI, confidence intervals; OR, odds ratios.

Discussion

This study investigated the factors affecting the health care utilization of young adults with a chronic disease to understand the health care challenges associated with early onset chronic disease. The authors found several factors associated with health care utilization. The older and unemployed participants were more likely to use health care services. Furthermore, health care utilization was associated with health behaviors and chronic disease type. The participants having healthy behaviors were more possible to avail health care. Regarding the type of chronic disease, people with hypertension and diabetes were more likely to use health care services than those with hyperlipidemia.

The age factor among young adults with a chronic disease was also identified in this study. The health care utilization rate was higher in the older group (aged 40–49 years) than in the younger group (aged 30–39 years). This finding is consistent with prior reports in which the younger group (<40 years) had a lower treatment rate than the older group (>40 years).^10,16,17 Of note, factors such as marital status, educational level, and household income were not associated with health care utilization in this study. This finding is contrary to previous findings in which such factors contributed to health care utilization in the older population, especially marital status, which is a predictor of health care utilization.^18,19

Moreover, this study revealed a significant difference between unemployment and increased health care utilization. This result is supported by the results of previous studies of people with chronic conditions.^20,21 Employed people find health care services difficult to access.²² Therefore, new approaches of chronic disease intervention for working young adults should be considered.

In addition, young adults with healthy behaviors experienced higher health care services than those with unhealthy behaviors. Hence, young adults with unhealthy behaviors such as smoking, drinking, or physical inactivity have an increased risk for an uncontrolled chronic disease, eventually leading to complications and multimorbidity. Multimorbidity is associated with higher levels of health care utilization, including outpatient encounters and medication prescription, compared not only with people without a chronic disease but also those with a single chronic disease.^23,24 The increase in multimorbidity will result in an increase in disease-related and socioeconomic burdens, further leading to premature mortality.

Young adults with hypertension or diabetes were also more likely to use health care services than those with hyperlipidemia. Hypertension and diabetes are the most common chronic conditions in all ages in South Korea; thus, these conditions have been controlled by various public health programs that improve the awareness of the disease and its risk factors.^25,26 Meanwhile, people are generally less aware of hyperlipidemia, leading to lower health priority despite its increasing prevalence and incidence. Thus, current public health programs should expand the chronic disease scope and management targets.

With the increasing prevalence of chronic disease among young adults, the characteristics of young adults with chronic disease should be understood. Younger age being associated with the lack of a routine place of care hinders chronic disease awareness and management.⁹ Younger adults with multiple chronic diseases were less likely to report a recent routine checkup and be treated than adults aged 65 years or older.¹⁴ More than half of the young patients (30–49 years) with hypertension were not aware of their health status exactly, and younger age groups showed lower management levels of hypertension than other age groups.²⁶

The low demand for health care resulting from insensitivity to chronic disease leads to low health care utilization and eventually, poor chronic disease management.²⁷ Many public health campaigns have focused on older people and have been implemented based on the community; thus, their effectiveness and access are limited to a specific age group only. Therefore, the emphasis for chronic disease management should be diversified, with consideration on the changes in the prevalence and onset of chronic disease in younger populations.

One of the strengths of this study is that data from a Korean national representative survey were used. The variables used in KHPS had been validated for several years by specialists. Although the results may not be applicable to all settings, the current study results have important implications for the management of chronic diseases in young adults. To the authors' knowledge, this study is the first to analyze the association between young adults with a chronic disease and their health care utilization. Conversely, one of this study's limitations is that this study is retrospective and cross-sectional in design. Given the nature of administrative health data, the limitations of using data, such as lack of details regarding circumstances around health visits, also apply to this study.

Conclusion

Given the rising prevalence of chronic diseases among young adults, this study suggests that these young adults must have better understanding on proper health care utilization to manage their existing chronic diseases and prevent further complications. An integrated intervention must be tailored to the characteristics of young adults to promote health care utilization, avoid disease progression, and improve their quality of life. In addition to health behavior modification, new public health approaches to increase clinical interventions for young adults with chronic disease are required. Implementing chronic disease management program at the workplace is also recommended to ensure the access of health care service.

Footnotes

Authors' Contributions

Profs. Kim and Park both contributed to writing, reviewing, and revising the article for intellectual and technical content. Prof. Kim contributed to study design, and Prof. Park performed all data analyses.

Author Disclosure Statement

The authors declare that there are no conflicts of interest.

Funding Information

This study was conducted by research funds from Gwangju University in 2021.

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