Long-Term Effect of Income Level on Mortality after Stroke: A Nationwide Cohort Study in South Korea

Socioeconomic Disparities in the Association Between All-Cause Mortality and Health Check-Up Participation Among Healthy Middle-Aged Workers: A Nationwide Study

BACKGROUND

This study assessed the relationship between non-participation in health check-ups and all-cause mortality and morbidity, considering socioeconomic status.

METHODS

Healthy, middle-aged (35-54 years) working individuals who maintained either self-employed or employee status from 2006-2010 were recruited in this retrospective cohort study from the National Health Insurance Service in Korea. Health check-up participation was calculated as the sum of the number of health check-ups in 2007-2008 and 2009-2010. Adjusted hazard ratio (HR) and 95% confidence interval (CI) of all-cause mortality were estimated for each gender using multivariable Cox proportional hazard models, adjusting for age, income, residential area, and employment status. Interaction of non-participation in health check-ups and employment status on the risk of all-cause mortality was further analyzed.

RESULTS

Among 4,267,243 individuals with a median 12-year follow-up (median age, 44; men, 74.43%), 89,030 (2.09%) died. The proportion (number) of deaths of individuals with no, one-time, and two-time participation in health check-ups was 3.53% (n = 47,496), 1.66% (n = 13,835), and 1.33% (n = 27,699), respectively. The association between health check-up participation and all-cause mortality showed a reverse J-shaped curve with the highest adjusted HR (95% CI) of 1.575 (1.541-1.611) and 1.718 (1.628-1.813) for men and women who did not attend any health check-ups, respectively. According to the interaction analysis, both genders showed significant additive and multiplicative interaction, with more pronounced additive interaction among women who did not attend health check-ups (relative excess risk due to interaction, 1.014 [0.871-1.158]).

CONCLUSION

Our study highlights the significant reverse J-shaped association between health check-up participation and all-cause mortality. A pronounced association was found among self-employed individuals, regardless of gender.

Individual socioeconomic status and risk of out-of-hospital cardiac arrest: A nationwide case-control analysis

OBJECTIVES

Area-level socioeconomic status (SES) is associated with the incidence of out-of-hospital cardiac arrest (OHCA); however, the effects of individual-level SES on OHCA occurrence are unknown. This study investigated whether individual-level SES is associated with the occurrence of OHCA.

METHODS

This case-control study used data from the nationwide OHCA registry and the National Health Information Database (NHID) in Korea. All adult patients with OHCA of a medical etiology from 2013 to 2018 were included. Four controls were matched to each OHCA patient based on age and sex. The exposure was individual-level SES measured by insurance type and premium, which is based on income in Korea. National Health Insurance (NHI) beneficiaries were divided into four groups (Q1-Q4), and medical aid beneficiaries were separately classified as the lowest SES group. The adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for the outcomes were calculated. Stratified analyses were conducted according to age and sex.

RESULTS

A total of 105,443 cases were matched with 421,772 controls. OHCA occurred more frequently in the lower SES groups. Compared with the highest SES group (Q1), the aORs for OHCA occurrence increased as the SES decreased (aORs [95% CI] were 1.21 [1.19-1.24] for Q2, 1.33 [1.31-1.36] for Q3, 1.32 [1.30-1.35] for Q4, and 2.08 [2.02-2.13] for medical aid). Disparity by individual-level SES appeared to be greater in males than in females and greater in the young and middle-aged adults than in older adults.

CONCLUSIONS

Low individual-level SES was associated with a higher probability of OHCA occurrence. Efforts are needed to reduce SES disparities in the occurrence of OHCA.

Stroke mortality attributable to high red meat intake in China and South Korea: An age-period-cohort and joinpoint analysis

The high intake of red meat is well recognized as a major health concern worldwide. It has been recognized as a risk factor for several non-communicable chronic diseases, including stroke. However, previously published studies have not performed a comprehensive analysis of the long-time trend of stroke mortality attributable to high red meat intake in China and South Korea, two countries with similar dietary patterns and changing trends. Therefore, this study aimed to reveal the influence of age, time period, and birth cohort on long-term trends of stroke mortality attributable to high red meat intake and relative gender differences in China and South Korea. Data were obtained from the Global Burden of Disease 2019 database. The age–period–cohort model was used to estimate the effect of age, time period, and birth cohort. The average and annual percent changes were estimated using the joinpoint regression analysis. Results indicated that the overall attributable age-standardized mortality rates of stroke in China decreased by 1.0% (P < 0.05) for female and 0.1% (P > 0.05) for male individuals, compared with a decrease of 4.9% for female and 3.7% for male individuals in South Korea (both P < 0.05). Age–period–cohort analysis revealed that the attributable stroke mortality decreased along with the time period, and increased along with age. Significant gender differences were observed, male individuals in both countries were at higher risk than their female counterparts, especially in China. Joinpoint analysis suggested that the attributable stroke mortality for both genders in South Korea and female individuals in China showed a decreasing trend, while it is stable for male individuals in China. Although prominent reductions were observed during the past decades, the attributable stroke mortality risk in China and South Korea is still high. Our findings indicate that controlling the intake of red meat may be a cost-effective strategy to reduce stroke mortality risk and the corresponding disease burden, especially for Chinese male individuals.

Impact of intensive rehabilitation on long-term prognosis after stroke: A Korean nationwide retrospective cohort study

An increasing number of patients are receiving rehabilitation after stroke. But the impact of intensive rehabilitation on the long-term prognosis of patients with stroke remains to be elucidated. The purpose of this study was to identify the impact of intensive rehabilitation on the long-term prognosis of patients with stroke using data from the National Health Insurance Service database. This is a register-based, retrospective cohort study. Using data from the National Health Insurance Service database, we included the patients who received rehabilitation for stroke from 2006 to 2013. Of the 14,984 patients diagnosed with stroke, 2483 died within 1 year, and 2866 did not receive rehabilitation; hence, they were also excluded. The final sample included 9635 (49.2% men, 50.8% women) patients. After correcting for covariates, the Cox model was used to evaluate the effects of physical therapy (PT) and occupational therapy (OT) on survival. We estimated the independent contribution of each factor to the risk of death from the initiation of rehabilitation. Significant differences in mortality were observed according to age, Charlson comorbidity index (CCI), income level, and stroke type. Patients with stroke who received both PT and OT had a better long-term prognosis than those who received either treatment alone. Therapy performed by a physical therapist with more than 120 hours of training effectively improved the patients' long-term prognosis. Intensive PT and OT will help improve the long-term prognosis of patients with stroke. This study emphasizes the importance of intensive rehabilitation in these patients.

Sex and Economic Disparity Related to Reperfusion Therapies for Patients with Acute Ischemic Stroke in South Korea across a 10-Year Period: A Nationwide Population-Based Study Using the National Health Insurance Database

A complete enumeration study was conducted to evaluate trends related to reperfusion therapies (intravenous thrombolysis (IVT) and endovascular treatment (EVT)) in acute ischemic stroke (AIS) in South Korea, according to sex, economic status, and age, over a 10-year period retrospectively, using the National Health Information Database (NHIS-2020-1-481). This study included AIS patients aged ≥20 years who were hospitalized in a general hospital or tertiary hospital for ≥4 days and underwent brain imaging during the same period. Study participants were classified by sex, economic status (Medical Aid beneficiaries and National Health Insurance beneficiaries) and age (20-44, 45-64, 65-79, and ≥80 years). Women showed a significantly lower OR (Odds ratio) than men in IVT (OR: 0.75; 95% CI: 0.73-0.77), EVT (OR: 0.96; 95% CI: 0.93-0.99), and any therapy (OR: 0.82; 95% CI: 0.80-0.84). The Medical Aid beneficiaries showed significantly lower OR in IVT (OR 0.91, 95% CI 0.88-0.95), EVT (OR 0.93, 95% CI 0.89-0.98), and either therapy (OR 0.92, 95% CI 0.90-0.95) than the National Health Insurance beneficiaries. This study showed sex and economic disparity related to reperfusion therapies in patients with AIS in Korea.