Development and validation of the Korea Dementia Comorbidity Index (KDCI): A nationwide population-based cohort study from 2002 to 2013

Changes in the Place of Death of Patients With Cancer After the Introduction of Insurance-Covered, Home-Based Hospice Care in Korea

Importance

Although hospice care has been covered by health insurance for the purpose of improving the quality of life of patients with terminal cancer as well as their caregivers, few studies have evaluated the outcomes of the policy to cover home-based hospice care services.

Objective

To investigate the changes in the place of death of patients with cancer after the introduction of insurance-covered, home-based hospice care services in Korea.

Design, Setting, and Participants

This cohort study used data from February 1, 2018, to December 31, 2021, from the Causes of Death Statistics database, released annually by Statistics Korea, which contains information on all deaths in the country. Individuals who died of cancer, a representative hospice-eligible disease, were assigned to the case group, and those who died of dementia, a non-hospice-eligible disease, were assigned to the control group. A total of 218 522 individuals constituted the study population.

Exposure

Because the Korean Health Insurance Service had begun covering home-based hospice care services on September 1, 2020, and the last follow-up date was December 31, 2021, the follow-up periods for before and after intervention were 31 months and 16 months, respectively (preintervention period: February 1, 2018, to August 31, 2020; postintervention period: September 1, 2020 to December 31, 2021).

Main Outcomes and Measures

The place of death was categorized as a binary variable according to whether it was the person's own home or not. Comparative interrupted time-series models with segmented regression were applied to analyze the time trend and its change in outcomes.

Results

Of the 218 522 deaths eligible for the analysis (mean [SD] age at death, 78.6 [8.8] years; 130 435 men [59.7%]), 207 459 were due to cancer, and 11 063 were due to dementia. Immediately after the introduction of home-based hospice care, the rate of home deaths was 24.5% higher for patients with cancer than for those with dementia (estimate, 1.245 [95% CI, 1.030-1.504]; P = .02). The difference in the level change between cancer deaths and dementia deaths, on intervention, was more pronounced for those living in rural areas (estimate, 1.320 [95% CI, 1.118-1.558]; P = .001). In addition, a higher educational level was associated with a larger difference in the immediate effect size due to home-based hospice care (low educational level: estimate, 1.205 [95% CI, 1.025-1.416]; P = .02; middle educational level: estimate, 1.307 [95% CI, 0.987-1.730], P = .06; high educational level: estimate, 1.716 [95% CI, 0.932-3.159]; P = .08).

Conclusions and Relevance

In this cohort study exploring the changes in the place of death for patients with cancer after the insurance mandates for home-based hospice care in Korea, the probability of patients with cancer dying in their own homes increased after the intervention. This finding suggests the need to broaden the extent of home-based hospice care to honor the autonomy of individuals with terminal illness and improve their quality of death.

Conceptualising comorbidity and multimorbidity in dementia: A scoping review and syndemic framework

Background

Older people and people with dementia experience a high prevalence of multiple health conditions. The terms ‘comorbidity’ and ‘multimorbidity’ are often used interchangeably to describe this, however there are key conceptual differences between these terms and their definitions. This has led to issues in the validity and comparability of research findings, potentially inappropriate intervention development and differences in quality of health care.

Objective

To review how the terms ‘comorbidity’ and ‘multimorbidity’ are defined within peer-reviewed dementia research and propose an operational framework.

Design

A scoping review of definitions within dementia research was carried out. Searches took place across five databases: Academic Search Premier, CINAHL Complete, MEDLINE, PsycARTICLES and PsycINFO. PRISMA-ScR guidelines were followed.

Results

Content analysis revealed five key themes, showing significant overlap and inconsistencies from both within, and between, the comorbidity and multimorbidity definitions; 1. Number of conditions; 2. Type of health conditions; 3. The co-occurrence of conditions; 4. The inclusion of an index disease (or not); 5. Use of medical language. The analysis also revealed gaps in how the underlying concepts of the definitions relate to people with dementia living with multiple health conditions.

Conclusion

This scoping review found that current definitions of comorbidity and multimorbidity are heterogeneous, reductionist and disease-focussed. Recommendations are made on the design of research studies including transparency and consistency of any terms and definitions used. A syndemic framework could be a useful tool for researchers, clinicians and policy makers to consider a more holistic picture of a person with dementia’s health and wellbeing.

Additive interaction of mid- to late-life depression and cerebrovascular disease on the risk of dementia: a nationwide population-based cohort study

Background

Dementia is a progressive neurocognitive disease with a substantial social burden. No apparent breakthroughs in treatment options have emerged so far; thus, disease prevention is essential for at-risk populations. Depression and cerebrovascular disease (CVD) are independent risk factors for dementia, but no studies have examined their interaction effect on dementia risk. This study aimed to identify the association of depression and CVD with the risk of dementia and evaluate whether dementia risk among patients with comorbid depression and CVD is higher than the sum of the individual risk due to each condition.

Methods

A population-based cohort study was conducted to analyze the Korean National Health Insurance Service-National Sample Cohort data of all individuals over 50 years of age. Individuals who had not been diagnosed with dementia at baseline were included and followed up from January 1, 2005, to December 31, 2013. A time-varying Cox proportional hazard regression model adjusted for potential confounding factors was used for the analysis. The interaction between depression and CVD was estimated based on the attributable proportion (AP), relative excess risk due to interaction (RERI), synergy index (SI), and multiplicative-scale interaction.

Results

A total of 242,237 participants were included in the analytical sample, of which 12,735 (5.3%) developed dementia. Compared to that for participants without depression or CVD, the adjusted hazard ratio for the incidence of dementia for those with depression alone was 2.35 (95% confidence interval [CI] 2.21–2.49), CVD alone was 3.25 (95% CI 3.11–3.39), and comorbid depression and CVD was 5.02 (95% CI 4.66–5.42). The additive interaction between depression and CVD was statistically significant (AP—0.08, 95% CI 0.01–0.16; RERI—0.42, 95% CI 0.03–0.82; SI—1.12, 95% CI 1.01–1.24). The multiplicative interaction was significant too, but the effect was negative (0.66, 95% CI 0.60–0.73).

Conclusions

In this population-based nationwide cohort with long-term follow-up, depression and CVD were associated with an increased risk of dementia, and their coexistence additively increased dementia risk more than the sum of the individual risks.

Association between neurodegenerative dementia and chronic rhinosinusitis: A nested case-control study using a national health screening cohort

The aim of this case-control study was to evaluate the association between chronic rhinosinusitis (CRS) and neurodegenerative dementia in a large representative Korean population. The ≥ 50-year-old population was selected from the Korean Health Insurance Review and Assessment Service - National Sample Cohort from 2002 to 2015. A total of 17,634 neurodegenerative dementia patients were matched in a 1:4 ratio with 70,536 control participants for age, sex, income, and region of residence. Neurodegenerative dementia was defined using the ICD-10 codes G30 and F00. CRS was identified based on the ICD-10 code J32. Among the cohort, we selected participants who were treated ≥ 2 times and those who underwent head and neck computed tomography. The odds ratio (OR) for CRS in patients with dementia was analyzed using a conditional logistic regression model. Subgroup analyses were conducted according to age and sex. There was no difference in the prevalence of CRS with/without nasal polyps between the dementia (1.1%) and control (1.2%) groups (P = .825). CRS with/without nasal polyps was not significantly associated with dementia (adjusted OR = 0.96, 95% CI = 0.82-1.13, P = .653). In the subgroup analyses according to age and sex, the adjusted ORs for CRS with/without nasal polyps were not higher in the dementia group than in the control group. Previous CRS was not associated with neurodegenerative dementia in the Korean population.

Predicting Old-age Mortality Using Principal Component Analysis: Results from a National Panel Survey in Korea

Background and Objectives: This study aimed to group diseases classified by the International Classification of Diseases using principal component analysis, and discuss a systematic approach to reducing the preventable death rate from a perspective of public health. Materials and Methods: Using a 10-year follow-up analysis of the Korean Longitudinal Study of Aging (KLoSA) data, this study obtained de-identified data including participants’ data of community-dwelling individuals aged ≥45 years from 2006 to 2016. Participants were randomly selected using a multistage, stratified probability sampling based on geographical area and housing type. We excluded 37 participants with missing information at baseline and included 10,217 study participants. This study used the principal component analysis to extract comorbidity patterns, and chi-square test and Cox proportional hazards models for analyzing the association between the factors of interest. Results: Principal component 1 (diabetes, heart disease, and hypertension) was associated with an increased hazard ratio (HR) of 1.079 (95% confidence interval (CI) 1.031–1.129, p = 0.001). Principal component 3 (psychiatric and cerebrovascular diseases) was related to an increased HR of 1.134 (95% CI 1.094–1.175, p < 0.0001). Moreover, principal component 4 was associated with a high HR of 1.172 (95% CI 1.130–1.215, p < 0.0001). However, among participants aged between 45 and 64 years, principal component 4 showed a meaningfully increased HR of 1.262 (95% CI 1.184–1.346, p < 0.001). In this study, among the four principal components, three were statistically associated with increased mortality. Conclusions: The principal component analysis for predicting mortality may become a useful tool, and artificial intelligence (AI) will improve a value-based healthcare strategy, along with developing a clinical decision support model.

Hearing impairment and the risk of neurodegenerative dementia: A longitudinal follow-up study using a national sample cohort

This study aimed to explore the risk of dementia in a middle- and older-aged population with severe or profound hearing impairments. Data were collected for the Korean National Health Insurance Service-National Sample Cohort from 2002 to 2013. Participants aged 40 or older were selected. The 4,432 severely hearing-impaired participants were matched 1:4 with 17,728 controls, and the 958 profoundly hearing-impaired participants were matched 1:4 with 3,832 controls who had not reported any hearing impairment. Age, sex, income, region of residence, hypertension, diabetes mellitus, and dyslipidemia histories were matched between hearing-impaired and control groups. The crude (simple) and adjusted (age, sex, income, region of residence, dementia, hypertension, diabetes mellitus, dyslipidemia, ischemic heart disease, cerebrovascular disease, and depression) hazard ratios (HRs) of hearing impairment on dementia were analyzed using Cox-proportional hazard models. The severe hearing impairment group showed an increased risk of dementia (adjusted HR = 1.17, 95% confidence interval [CI] = 1.04–1.31, P = 0.010). The profound hearing impairment group also showed an increased risk of dementia (adjusted HR = 1.51, 95% CI = 1.14–2.00, P = 0.004). Both severe and profound hearing impairments were associated with elevated the risk of dementia in middle- and older-aged individuals.