Dementia incidence and population-attributable fraction for dementia risk factors in Republic of Korea: a 12-year longitudinal follow-up study of a national cohort

Risk of long-term post-stroke dementia using a linked dataset of patients with ischemic stroke without a history of dementia

BACKGROUND

Post-stroke dementia (PSD) is a common and disabling sequela of stroke. However, the long-term incidence of PSD after an ischemic stroke and factors which predict its occurrence are incompletely understood. Linkage of large health datasets is being increasing used to study long-term outcomes after disease. We used large-scale linked data from Korea to determine the long-term incidence of PSD after ischemic stroke, and identify which factors predicted its occurrence.

METHODS

From January 2008 to December 2014, patients with ischemic stroke (n = 37,553) without a history of dementia were included in a linked dataset comprising the claims database of the Health Insurance Review and Assessment Service and the Clinical Research Center for Stroke registry data. The outcome measure was PSD after ischemic stroke. Clinical factors evaluated included vascular risk factors, acute stroke management including reperfusion therapy, antithrombotics, and statins, stroke severity, and educational levels, were evaluated.

RESULTS

Among 37,553 patients with ischemic stroke without a history of dementia (mean age: 64.9 years; 61.9% males), 6052 (16.1%) experienced PSD during a median follow-up period of 5 (interquartile range, 3.4-7.0) years. The 10-year estimated cumulative incidence of dementia was 23.5%. Age (hazard ratio (HR) 1.82 per 10 years, 95% confidence interval (CI) 1.75-1.88) and a lower educational level (illiteracy or no education HR 1.65 (CI = 1.44-1.88), 0-3 years 1.53 (CI = 1.31-1.79), 4-6 years 1.60 (CI = 1.43-1.80), 7-9 years 1.32 (CI = 1.16-1.49), 10-12 years 1.17 (CI = 1.04-1.32)) were independently associated with an elevated risk of PSD. Male sex was associated with a significantly lower risk of PSD (HR 0.86, CI = 0.79-0.92). Diabetes mellitus (HR 1.21, CI = 1.14-1.29), a history of stroke before index stroke (HR 1.31, CI = 1.21-1.41), and initial National Institutes of Health Stroke Scale (HR 1.03, CI = 1.03-1.04) were independent risk factors for PSD. Regarding medications, the use of anticoagulation and antipsychotic medications after stroke appeared to be associated with increased PSD risk, whereas statin therapy was associated with a reduced risk.

CONCLUSIONS

PSD is common with a 5- and 10-year incidence in patients with ischemic stroke without a history of dementia of 16.1% and 23.5%, respectively. Factors associated with PSD include age, female sex, lower educational level, diabetes mellitus, initial stroke severity, antipsychotics, and anticoagulants. Further studies are required to determine whether reducing those risk factors which are treatable reduces the incidence of PSD.

Modifiable risk factors for early- and late-onset dementia using the Korean national health insurance service database

BACKGROUND

Early-onset dementia (EOD) and late-onset dementia (LOD) may have distinct modifiable risk-factor profiles.

OBJECTIVE

To identify and compare factors associated with EOD and LOD using a nationwide cohort database.

DESIGN

Nationwide two nested case-control studies.

SETTING

We used the National Health Insurance Service-National Sample Cohort database (2004-2019).

PARTICIPANTS

The initial sample size was 514,866; 5157 EOD and 39,326 LOD cases were matched 1:1 with controls based on age, sex, and the Charlson Comorbidity Index.

MEASUREMENTS

Socioeconomic status, residential area, body mass index, alcohol consumption, smoking status, physical activity, blood pressure, and laboratory findings were analyzed. Multivariable logistic regression models were used to identify the risk factors.

RESULTS

Higher socioeconomic status and increased frequency of physical activity were associated with a lower risk of both EOD and LOD. Rural residence, heavy alcohol consumption, and higher fasting blood sugar levels were associated with an increased risk of LOD, although there was no significant association with EOD. Overall, these factors impacted LOD more strongly than EOD. Demographic and lifestyle factors had a greater effect on LOD than blood pressure and relevant laboratory findings.

CONCLUSION

Modifiable risk factors were associated with LOD and EOD. The influence of some modifiable risk factors was more pronounced in the LOD group than in the EOD group. Identifying modifiable risk factors associated with dementia can aid in the development of preventive strategies, underscoring the clinical importance of our findings.

Long-Term Impact of Delirium on the Risk of Dementia in Hospitalized Older Patients: A Real-World Multicenter Study

BACKGROUND

The association between delirium and dementia has been suggested, but mostly in the postoperative setting. This study aims to explore this relationship in a broader inpatient population, leveraging extensive real-world data to provide a more generalized understanding.

METHODS

In this retrospective cohort study, electronic health records of 11,970,475 hospitalized patients aged over 60 from nine institutions in South Korea were analyzed. Patients with and without delirium were identified, and propensity score matching (PSM) was used to create comparable groups. A 10-year longitudinal analysis was conducted using the Cox proportional hazards model, which calculated the hazard ratio (HR) and 95% confidence interval (CI). Additionally, a meta-analysis was performed, aggregating results from all nine medical institutions. Lastly, we conducted various subgroup and sensitivity analyses to demonstrate the consistency of our study results across diverse conditions.

RESULTS

After 1:1 PSM, a total of 47,306 patients were matched in both the delirium and nondelirium groups. Both groups had a median age group of 75-79 years, with 43.1% being female. The delirium group showed a significantly higher risk of all dementia compared with the nondelirium group (HR: 2.70 [95% CI: 2.27-3.20]). The incidence risk for different types of dementia was also notably higher in the delirium group (all dementia or mild cognitive impairment, HR: 2.46 [95% CI: 2.10-2.88]; Alzheimer's disease, HR: 2.74 [95% CI: 2.40-3.13]; vascular dementia, HR: 2.55 [95% CI: 2.07-3.13]). This pattern was consistent across all subgroup and sensitivity analyses.

CONCLUSIONS

Delirium significantly increases the risk of onset for all types of dementia. These findings highlight the importance of early detection of delirium and prompt intervention. Further research studies are warranted to investigate the mechanisms linking delirium and dementia.

Risk of dementia in patients with age-related medical conditions: a retrospective cohort study

OBJECTIVE

This retrospective cohort study aimed to investigate the impact of age-related medical conditions on the incidence of dementia, considering factors such as hypertension, diabetes mellitus, cerebrovascular disease, cardiovascular disease, chronic kidney disease, osteoarthritis, osteoporosis, chronic obstructive pulmonary disease, and hearing difficulties.

METHODS

Data from 513 640 patients at Keimyung University Dongsan Hospital were analyzed using the Observational Medical Outcomes Partnership Common Data Model. Patients with and without age-related medical conditions were assigned to experimental and control groups, respectively, with propensity score matching. Cox proportional hazards models assessed the association between each condition and dementia incidence.

RESULTS

Hypertension, diabetes mellitus, cerebrovascular disease, cardiovascular disease, chronic kidney disease, osteoarthritis, osteoporosis, and hearing difficulties were associated with increased dementia risk. Chronic obstructive pulmonary disease showed no significant association with increased risk of dementia. Incidence rates ranged from 4.52 to 8.05 per 1000 person-years in the control group and 7.46 to 14.99 per 1000 person-years in the experimental group. Hazard ratios ranged from 1.38 to 2.36.

CONCLUSIONS

The study highlights the importance of managing age-related medical conditions to mitigate dementia risk. Understanding these risk factors can inform preventive strategies and improve cognitive health outcomes. Problems with deidentification data analysis and the need for further multicentred studies are among the limitations of this study.

Effects of risk factors on the development and mortality of early- and late-onset dementia: an 11-year longitudinal nationwide population-based cohort study in South Korea

BACKGROUND

Early-onset dementia (EOD, onset age < 65) and late-onset dementia (LOD, onset age ≥ 65) exhibit distinct features. Understanding the risk factors for dementia development and mortality in EOD and LOD respectively is crucial for personalized care. While risk factors are known for LOD development and mortality, their impact on EOD remains unclear. We aimed to investigate how hypertension, diabetes mellitus, hyperlipidemia, atrial fibrillation, and osteoporosis influence the development and mortality of EOD and LOD, respectively.

METHODS

Using the Korean National Health Insurance Service (NHIS) database, we collected 546,709 dementia-free individuals and followed up for 11 years. In the two study groups, the Younger group (< 65 years old) and the Older group (≥ 65 years old), we applied Cox proportional hazard models to assess risk factors for development of EOD and LOD, respectively. Then, we assessed risk factors for mortality among EOD and LOD.

RESULTS

Diabetes mellitus and osteoporosis increased the risk of EOD and LOD development. Hypertension increased the risk of EOD, while atrial fibrillation increased the risk of LOD. Conversely, hyperlipidemia exhibited a protective effect against LOD development. Additionally, diabetes mellitus increased mortality in EOD and LOD. Hypertension and atrial fibrillation increased mortality in LOD, while hyperlipidemia decreased mortality in EOD and LOD.

CONCLUSIONS

Risk factors influencing dementia development and mortality differed in EOD and LOD. Targeted public health interventions addressing age-related risk factors may reduce dementia incidence and mortality.

Impact of the COVID-19 pandemic on mortality and loss to follow-up among patients with dementia receiving anti-dementia medications

The coronavirus disease 2019 (COVID-19) pandemic has profoundly impacted vulnerable groups, such as patients with dementia. We examined changes in mortality and loss to follow-up in patients with dementia using data from the Korean National Health Insurance Service research database. Patients with dementia who visited a medical institution with a recorded dementia-related diagnostic code, including Alzheimer's disease, and who received anti-dementia medication between February 2018 and January 2020 were included in this study. We divided patients with dementia receiving anti-dementia medications into two cohorts: those newly diagnosed with dementia between February 2018 and January 2019 (n = 62,631) and those diagnosed between February 2019 and January 2020 (n = 54,494). Then, we conducted a one-year follow-up of their records, tracking the cohort diagnosed between February 2018 and January 2019 from February 2019 to January 2020, as well as the cohort diagnosed between February 2019 and January 2020 from February 2020 to January 2021. There was a significant increase in follow-up loss among patients newly diagnosed with dementia during the COVID-19 outbreak, from 42.04% in 2019 to 45.89% in 2020. Female sex, younger age, fewer comorbidities, diagnosis of dementia at the Department of Neurology or Psychiatry, and higher income were associated with decreased follow-up loss and mortality. This study highlights the importance of paying extra attention to patients with dementia receiving anti-dementia medications, particularly during pandemics, given their increased risk of loss to follow-up.