Korean National Health Insurance System Research Articles

Smoking Cessation Reduces the Risk of Heart Failure: A Nationwide Cohort Study

BackgroundThere is a lack of data for the incidence of heart failure (HF) according to changes in smoking behaviors. ObjectivesThe authors aimed to investigate the effects of smoking behavior change on development of HF. MethodsIn this population-based, retrospective cohort study using the Korean National Health Insurance System database, the authors identified 778,608 current smokers who participated in a health screening program in 2009 and in a follow-up screening in 2011. Participants were categorized into quitters, reducers I (≥50% reduction) and II (<50% reduction), sustainers, and increasers. ResultsDuring a median follow-up of 6.3 years, there were 23,329 HF events (4.8 per 1,000 person-years). Compared with sustainers, the risk of HF was increased among increasers (adjusted hazard ratio [aHR]: 1.06 [95% CI: 1.02-1.10]). By contrast, quitters had a reduced risk for HF (aHR: 0.86 [95% CI: 0.83-0.90]). Even heavy smokers who quit smoking had a lower risk for HF than those who sustained heavy smoking (aHR: 0.90 [95% CI: 0.85-0.95]). In reducers, the risk of HF was not reduced but rather increased slightly (≥50% reduction, aHR: 1.06 [95% CI: 1.01-1.11]; <50% reduction, aHR: 1.04 [95% CI: 1.00-1.08]). ConclusionsCurrent smokers who increased their smoking amount were associated with a higher risk for HF development compared to sustainers, whereas self-reported smoking cessation was associated with a lower risk of HF. There was no benefit from reduction in smoking amount. Self-reported smoking cessation should be reinforced whenever possible to prevent HF.

Neurodevelopment at 6 years of age in children with atopic dermatitis

BackgroundFew studies have reported an association between atopic dermatitis and cognitive impairment in children. Therefore, we evaluated the association between atopic dermatitis (AD) and neurodevelopmental dysfunction in children. MethodsWe analyzed 2,395,966 children born between 2008 and 2012 in Korea. All data were acquired from the databases of the Korean National Health Insurance System. AD was defined as five or more diagnoses before age 24 months. The outcome was suspected neurodevelopmental dysfunction in the gross motor skill, fine motor skill, cognition, language, sociality, and self-care domains of the Korean Developmental Screening Test for Infants and Children at age 6 years. The positive control outcome was defined as attention deficit hyperactive disorder (ADHD). The associations were assessed using ordinal logistic regression, adjusting for asthma and allergic rhinitis. ResultsAmong the eligible children, 89,452 and 30,557 were allocated to the control and AD groups, respectively. In the weighted data, the AD group showed a higher risk of suspected neurodevelopmental dysfunction in the total score (weighted adjusted odds ratio [95% CI] 1.10 [1.05–1.16]), gross motor skills (1.14 [1.04–1.25]), and fine motor skills (1.15 [1.06–1.25]) than the control group. The AD with steroids or hospitalization groups showed an increased risk of suspected neurodevelopmental dysfunction. In addition, the AD group showed a significant association with mental retardation, psychological development disorder, and behavioral and emotional disorders as well as ADHD. ConclusionsAD before age 2 years may be associated with an increased risk of neurodevelopmental dysfunction including gross and fine motor skills in the young childhood period.

The Demands and Awareness of Pediatric Dentists on the Korean National Health Insurance System

The aim of this study is to investigate the awareness and perception of pediatric dentists regarding dental health insurance (DHI) system in Korea. Online surveys were sent to the members of the Korean Academy of Pediatric Dentistry (KAPD), and the responses were collected. The survey, consisting of 41 questions, was subdivided into ‘general background of the respondents’, ‘the awareness on national health insurance (NHI) and DHI’, ‘the awareness on DHI pertaining to pediatric dentistry’, ‘issues that need improvement on DHI pertaining to pediatric dentistry’, ‘DHI claims’, and ‘the roles of KAPD in DHI’. In total, 302 responded, with a response rate of 28.9%. Excluding 2 questionnaires with insufficient answers, a total of 300 survey results were analyzed. According to the analysis, pediatric dentists thought that the coverage of DHI was not as sufficient compared to that of NHI, but were expecting its scope to broaden in the future. The satisfaction rate was higher in pit and fissure sealant and composite resin filling than in caries-detecting quantitative light-induced fluorescence. Pediatric dentists considered permanent tooth composite resin filling (65.7%) needed an increase in insurance copayment, while topical fluoride application (74.7%) to require insurance coverage. DHI claims were generally handled by dental hygienists and/or nursing assistants. Approximately half of the respondents answered that they have had experiences on appealing for insurance denials. Lastly, pediatric dentists generally had a positive attitude towards providing information for the DHI. This study is expected to be used as a sound dataset for the DHI policy development concerning pediatric dentistry.

The Cumulative Effect of Antipsychotic Usage on Mortality in Schizophrenia: A Nationwide Population-based Cohort Study in Korea.

ObjectiveTo investigate the cumulative effect of antipsychotics at different dosages on mortality in patients with schizo-phrenia.MethodsWe analyzed data from the Korean National Health Insurance System−National Sample Cohort covering the 2002−2013 period. We used Cox regression analysis to calculate hazard ratios for mortality risks according to cumulative antipsychotic exposure levels (low, moderate, and high).ResultsOur analyses revealed no significant association between antipsychotic exposure and mortality (either all-cause or cause-specific) in patients with schizophrenia.ConclusionOur results imply that the excess mortality of patients with schizophrenia is attributable to factors other than antipsychotic usage.

Risk for Behçet’s disease gauged via high-density lipoprotein cholesterol: a nationwide population-based study in Korea

Behçet’s disease (BD) is a chronic inflammatory disease. Low levels of plasma high-density lipoprotein cholesterol (HDL-C) are associated with Crohn’s disease, another chronic inflammatory disease. However, the effects of low HDL-C levels on BD are unclear. We investigated the effects of HDL-C levels, and variability therein, on the risk for BD. We used the Korean National Health Insurance System database to identify 5,587,754 adults without a history of BD who underwent ≥ 3 medical examinations between 2010 and 2013. Mean HDL-C levels at each visit were used to calculate variability independent of the mean (VIM) and the coefficient of variation (CV). There were 676 new cases of BD (0.012%). The risk for BD was increased in participants with highly variable and low mean HDL-C levels. In a multivariate-adjusted model, the hazard ratios (95% confidence intervals) for BD incidence were 1.335 (1.058–1.684) in a high mean/high VIM group, 1.527 (1.211–1.925) in a low mean/low VIM group, and 2.096 (1.67–2.63) in a low mean/high VIM group compared to a high mean/low VIM group. Low mean HDL-C levels, and high variability therein, are independent risk factors for BD.

Lipid cutoffs for increased cardiovascular disease risk in non-diabetic young people.

The relevance of blood lipid abnormalities to cardiovascular disease (CVD) risk in young populations is unclear. Here, we aimed to identify the cutoff levels of lipid parameters for increased risk of CVD among nondiabetic young adults aged 20-39 years. Using data from a nationally representative Korean National Health Insurance System database, we followed up 6 204 153 subjects who underwent health examinations between 2009 and 2012 until the end of 2018. The primary outcome was incident CVD, defined as a composite of myocardial infarction and stroke. We assessed the associations between pre-specified lipid levels and CVD risk. Subgroup analysis of the number of cardiovascular risk factors (obesity, hypertension, and current smoking) was also conducted. During a median follow-up of 7.7 years, there were 14 569 (0.23%) cases of myocardial infarction, 9,459 (0.15%) cases of stroke, and 23 680 (0.38%) cases of composite CVD. Using total cholesterol (TC) level of &lt;140 mg/dL, triglyceride (TG) level of &lt;60 mg/dL, LDL-cholesterol level of &lt;100 mg/dL, and non-HDL-cholesterol level of &lt;130 mg/dL as reference groups, a significantly higher risk of CVD was observed in subjects with a TC level of ≥200 mg/dL, TG level of ≥60 mg/dL, LDL-cholesterol level of ≥130 mg/dL, or non-HDL-cholesterol level of ≥140 mg/dL. The cutoff levels of TC that had statistical significance for increased risk of CVD were 240, 220, and 200 mg/dL in subjects with 0, 1, or 2-3 risk factors, respectively. Even modest increases in lipid levels were associated with increased risk of CVD in this nondiabetic young population. Our data provide potential criteria for stratifying CVD risk based on real-world evidence.

Cumulative Exposure to High γ-Glutamyl Transferase Level and Risk of Diabetes: A Nationwide Population-Based Study.

BackgroundElevated γ-glutamyl transferase (γ-GTP) level is associated with metabolic syndrome, impaired glucose tolerance, and insulin resistance, which are risk factors for type 2 diabetes. We aimed to investigate the association of cumulative exposure to high γ-GTP level with risk of diabetes.MethodsUsing nationally representative data from the Korean National Health Insurance system, 346,206 people who were free of diabetes and who underwent 5 consecutive health examinations from 2005 to 2009 were followed to the end of 2018. High γ-GTP level was defined as those in the highest quartile, and the number of exposures to high γ-GTP level ranged from 0 to 5. Hazard ratio (HR) and 95% confidence interval (CI) for diabetes were analyzed using the multivariable Cox proportional-hazards model.ResultsThe mean follow-up duration was 9.2±1.0 years, during which 15,183 (4.4%) patients developed diabetes. There was a linear increase in the incidence rate and the risk of diabetes with cumulative exposure to high γ-GTP level. After adjusting for possible confounders, the HR of diabetes in subjects with five consecutive high γ-GTP levels were 2.60 (95% CI, 2.47 to 2.73) in men and 3.05 (95% CI, 2.73 to 3.41) in women compared with those who never had a high γ-GTP level. Similar results were observed in various subgroup and sensitivity analyses.ConclusionThere was a linear relationship between cumulative exposure to high γ-GTP level and risk of diabetes. Monitoring and lowering γ-GTP level should be considered for prevention of diabetes in the general population.

Blood pressure and mortality after percutaneous coronary intervention: a population-based cohort study

Revascularization procedures, including percutaneous coronary intervention (PCI), for coronary artery disease (CAD) are increasingly performed in Korea. However, studies on blood pressure control targets in these patients remain insufficient. To assess the relationship between baseline blood pressure and all-cause mortality in CAD patients who underwent PCI. A population-based retrospective cohort study based on the national claims database of the Korean National Health Insurance System, which represents the entire Korean population. A total 38,330 patients with a history of PCI for CAD between 2005 and 2008 were recruited and followed up for all-cause mortality until December 31, 2017. Baseline systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured, and they were classified into eight SBP and DBP groups each. The hazard ratios (HRs) for all-cause mortality were measured for each group. The pattern of SBP and DBP in this population followed a J-curve relationship for all-cause mortality, with the nadir point at 119 and 74 mmHg, respectively. In subjects aged > 60 years, high SBP (≥ 160 mmHg) and high DBP (≥ 90 mmHg) were significantly related to death. Moreover, in subjects aged > 60 years, low DBP (< 70 mmHg) was significantly related to mortality. There is a J-curve relationship between baseline blood pressure and all-cause mortality in patients who underwent PCI, and intensive lowering of blood pressure may be beneficial for these patients. However, the elderly population needs more attention as excessive BP lowering, particularly DBP, could instead increase the risk of death.

Low waist circumference prior to percutaneous coronary intervention predict the risk for end-stage renal disease: a nationwide Korean population based-cohort study.

Background/AimsThe obesity paradox has been known in end-stage renal disease (ESRD). However, the effect of body mass index (BMI) or waist circumference (WC) prior to percutaneous coronary intervention (PCI) on the development of ESRD is not clear.MethodsUsing nationally representative data from the Korean National Health Insurance System, we enrolled 140,164 subjects without ESRD at enrolment who underwent PCI between 2010 and 2015, and were followed-up until 2017. Patients were stratified into five levels based on their baseline BMI and six levels based on their WC with 5-cm increments. BMI and WC were measured at least 2 years prior to PCI. The primary outcome was the development of ESRD.ResultsDuring a median follow-up of 5.4 years, 2,082 (1.49%) participants developed ESRD. The underweight group (hazard ratio [HR], 1.331; 95% confidence interval [CI], 0.955 to 1.856) and low WC (< 80/< 75) (HR, 1.589; 95% CI, 1.379 to 1.831) showed the highest ESRD risk and the BMI 25 to 30 group showed the lowest ESRD risk (HR, 0.604; 95% CI, 0542 to 0.673) in all participants after adjusting for all covariates. In the subgroup analysis for diabetes mellitus (DM) duration, WC < 85/80 cm (men/women) increased ESRD risk in only the DM group (DM < 5 years and DM ≥ 5 years) compared to the reference group (85–90/80–85 of WC), but not the normal or impaired fasting glucose group.ConclusionsLow WC prior to PCI showed an increased ESRD risk in patients with DM undergoing PCI as compared to those without DM.

Reproductive Life Span and Severe Hypoglycemia Risk in Postmenopausal Women with Type 2 Diabetes Mellitus.

BackgroundEstrogen promotes glucose homeostasis, enhances insulin sensitivity, and maintains counter regulatory responses in recurrent hypoglycemia in women of reproductive age. Postmenopausal women with type 2 diabetes mellitus (T2DM) might be more vulnerable to severe hypoglycemia (SH) events. However, the relationship between reproductive factors and SH occurrence in T2DM remains unelucidated.MethodsThis study included data on 181,263 women with postmenopausal T2DM who participated in a national health screening program from January 1 to December 31, 2009, obtained using the Korean National Health Insurance System database. Outcome data were obtained until December 31, 2018. Associations between reproductive factors and SH incidence were assessed using Cox proportional hazards models.ResultsDuring the mean follow-up of 7.9 years, 11,279 (6.22%) postmenopausal women with T2DM experienced SH episodes. A longer reproductive life span (RLS) (≥40 years) was associated with a lower SH risk compared to a shorter RLS (<30 years) (adjusted hazard ratio [HR], 0.74; 95% confidence interval [CI], 0.69 to 0.80; P for trend <0.001) after multivariable adjustment. SH risk decreased with every 5-year increment of RLS (with <30 years as a reference [adjusted HR, 0.91; 95% CI, 0.86 to 0.95; P=0.0001 for 30–34 years], [adjusted HR, 0.80; 95% CI, 0.76 to 0.84; P<0.001 for 35–39 years], [adjusted HR, 0.74; 95% CI, 0.68 to 0.81; P<0.001 for ≥40 years]). The use of hormone replacement therapy (HRT) was associated with a lower SH risk than HRT nonuse.ConclusionExtended exposure to endogenous ovarian hormone during lifetime may decrease the number of SH events in women with T2DM after menopause.

The risk of dementia in adults with abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) and dementia have similar epidemiological profiles and common pathogenic mechanisms. However, there have been few studies on the link between these two diseases. For this study, information from 2009 to 2015 was extracted from the Korean National Health Insurance system database. A total of 15,251 participants with a new diagnosis of AAA was included. Propensity score matching by age and sex with patients in whom AAA was not diagnosed was used to select the control group of 45,753 participants. The primary endpoint of this study was newly diagnosed dementia (Alzheimer’s disease (AD), vascular dementia (VD), or other type of dementia). The incidence of dementia was 23.084 per 1000 person years in the AAA group, which was higher than that of the control group (15.438 per 1000 person years). When divided into AD and VD groups, the incidence of AD was higher than that of VD, but the HR of AAA for occurrence of dementia was higher in VD (1.382 vs. 1.784). Among the various risk factors, there was an interaction of age, hypertension, and history of cardiovascular disease with incidence of dementia (p < 0.05). In the presence of hypertension, the HR for occurrence of dementia was high according to presence or absence of AAA (1.474 vs 1.165). In addition, this study showed higher HR in the younger age group (age < 65) and in the group with no history of cardiovascular disease [1.659 vs. 1.403 (age), 1.521 vs. 1.255 (history of cardiovascular disease)]. AAA was associated with increased risk of dementia regardless of AD or VD, even after adjusting for several comorbidities. These findings indicate that follow-up with AAA patients is necessary for early detection of signs and symptoms of dementia.

Low-Density Lipoprotein Cholesterol Level, Statin Use and Myocardial Infarction Risk in Young Adults.

ObjectiveThe consequences of blood lipid abnormalities for cardiovascular disease risk in young adults is unclear. Optimal lipid levels may also vary depending on whether a statin drug is taken. It aimed to determine whether the optimal lipid levels in young adults differ depending on statin use.MethodsUsing a nationally representative database from the Korean National Health Insurance System, 6,350,400 participants aged 20–39 years who underwent a health examination between 2009–2012 were followed through to 2018. The primary outcome was incident myocardial infarction (MI). We assessed the associations between prespecified lipid levels and MI risk according to statin use.ResultsAmong participants not taking statins, low-density lipoprotein cholesterol (LDL-C) levels ≥120 mg/dL were significantly associated with MI risk (hazard ratio [HR], 1.33; 95% confidence interval [CI], 1.27–1.40) compared with statin nonusers with LDL-C <80 mg/dL. Statin users with LDL-C categories <80, 80–100, 100–120, and ≥120 mg/dL all had significantly higher MI risk compared with statin nonusers with LDL-C <80 mg/dL; these HRs (95% CIs) were 1.66 (1.39–1.99), 1.68 (1.36–2.09), 1.63 (1.31–2.02), and 2.32 (2.07–2.60), respectively.ConclusionYoung adults taking statins have an increased MI risk compared with statin nonusers, even when they have similar LDL-C levels. Specific lipid targets may need to differ depending on statin use.

Chronic kidney disease as a risk factor for abdominal aortic aneurysm: a nationwide population-based study.

Chronic kidney disease (CKD) is a well-known risk factor for cardiovascular outcomes; however, its association with abdominal aortic aneurysm (AAA) remains unknown. To investigate this association, a national wide population study has been undertaken. This cohort study extracted data from the Korean National Health Insurance System database for individuals who had health checkups in 2009. The incidence of AAA was ascertained through the end of 2019. The study population was classified into 4 groups based on the CKD stage: stages 1, 2, 3, and ≥4. The primary endpoint was newly diagnosed AAA. During the mean follow-up of 9.3 years, a total of 20,760 patients (0.2%) were diagnosed with AAA. The incidence rates of AAA were 0.10, 0.23, 0.67, and 1.19 per 1,000 person-years in stages 1, 2, 3, and ≥4, respectively. In Cox proportional hazard model, advanced stage of CKD was associate with an increased risk of AAA development after adjusting full covariates (hazard ratio [95% confidence interval]: 1.12 [1.07-1.67], 1.16 [1.10-1.23], and 1.3 [1.15-1.46]; CKD stage 2 to ≥4, respectively; P < 0.001). There was a positive correlation between the degree of dipstick proteinuria and the risk of AAA, which was consistent regardless of age group, sex, smoking, dyslipidemia, diabetes mellitus, and hypertension. CKD demonstrated positively associated with the development of AAA, its association showed graded risk as stage of CKD advanced.

High Bodyweight Variability Increases Depression Risk in Patients With Type 2 Diabetes Mellitus: A Nationwide Cohort Study in Korea.

Objectives: Although obesity is associated with increased risk for depression in patients with type 2 diabetes mellitus (DM), the relationship between body weight variability (BWV) and depression remains poorly studied. This study was to investigate the incidence of depression in patients with type 2 DM according to their BWV.Methods: Intraindividual variation in body weight were measured in the nationwide, population-based retrospective cohort of 540,293 patients with type 2 DM from the Korean national health insurance system between 2009 and 2010. The diagnoses of new-onset depression occurring until the end of 2017 were ascertained. Risk of new-onset depression was examined using multivariate-adjusted Cox proportional hazards regression analysis by BWV quartile.Results: 93,149 (17.2%) patients developed new-onset depression for the follow up. BWV was significantly associated with an increased risk of depression after adjusting for confounding factors. The highest BWV quartile group had a hazard ratio (HR) of 1.17 (95% CI 1.15–1.19) compared to the lowest BWV quartile group as a reference. Obese patients in the highest BWV quartile group showed 12% increased risk of depression (HR 1.12, 95% CI 1.09–1.15) while non-obese patients in the highest BWV quartile group showed 20% increased risk of depression (HR: 1.20, 95% CI: 1.17–1.23) compared to their respective lowest BWV quartile groups.Conclusion: A higher BWV was significantly associated with an increased risk of depression in patients with type 2 DM. Thus, BWV may serve as an indicator for early detection of depression in type 2 DM patients.

Incidence and prevalence of pressure ulcers in hospitals: 10-year cohort study.

Pressure ulcers (PUs) are a serious problem in patients with multiple comorbidities and are associated with a longer duration of hospital stay and higher medical costs. The aetiology and rate of PU occurrence in South Korea remains unclear. Therefore, we aimed to determine the incidence, prevalence, mortality and common comorbidities of hospitalised patients with PUs in the South Korean healthcare system. A 10-year cohort study using the healthcare insurance reimbursement claims from the South Korean National Health Insurance System database. Patients diagnosed with a PU on admission to hospital [ICD-10: L89 + procedure code] between January 2002 and December 2016 were included and their comorbidities evaluated. Patients <20 years of age and recurrent PU cases were excluded. Incidence, prevalence, survival rate and risk factors related to survival rate of patients with PUs were determined. The study population in 2006 was 36,195,121 (all patients admitted to hospital that year), which changed yearly because of the inclusion of additional patients who met the study inclusion criteria, and removal of patients who had died during the year. Standardised PU incidence rate decreased from 17.1 in 2006 to 14.9 in 2015 per 10,000 people. Standardised PU prevalence also showed a slightly decreasing trend from 20.2 in 2006 to 18.9 in 2015 per 10,000 people. This findings of this 10-year study showed that incidence and prevalence of PUs markedly increased with age after the seventh decade. Incidence of PUs increased in patients with pneumonia, cerebral infarction, sepsis, femoral neck fracture and malignant neoplasm of the bronchus. Patients with femoral neck fracture and cerebral infarction showed a higher rate of survival than those with other high-risk comorbidities.

An increasing trend of posterior cruciate ligament reconstruction in South Korea: epidemiologic analysis using Korean National Health Insurance System Database

BackgroundThe posterior cruciate ligament is crucial for posterior stability of the knee joint, and, as well as anterior cruciate ligament reconstruction, posterior cruciate ligament reconstruction (PCLR) has attracted interest in orthopedic literature. A few studies have investigated epidemiologic data of PCLR in Western countries. However, there has been no report on the epidemiological pattern of PCLR in the Asian population, including South Korea. Therefore, this study investigated the incidence and trends of PCLR in South Korea using the Korean National Health Insurance (NHI) System Database.MethodsThe data was collected by the Korean Health Insurance Review and Assessment Service (HIRA) from 2008 to 2016 in South Korea. Patients with a record of cruciate ligament reconstruction and PCLR were allocated from the database. An analysis of the total number and incidence per 100,000 people/year of PCLR procedures and other epidemiologic parameters was conducted according to sex and age.ResultsThe incidence of PCLR procedures rose from 2.3 to 2.6 per 100,000 people (from 1101 to 1299 total cases; 13% increase) between 2008 and 2016: from 3.8 to 4.0 (from 901 to 1000) in males, and from 0.8 to 1.2 (from 200 to 299) in females. PCLR was performed more frequently in males than in females, however, the rate of increase was higher in females than males. The incidence of PCLR over 9 years was highest in patients in their 20s, followed by patients in their 40s and 30s.ConclusionThe incidence of PCLR procedures increased by 13% over 9 years in South Korea. PCLR was performed approximately three times more in men than in women. The incidence of PCLR was highest in patients in their 20s, followed by those in their 40s. The current study will enhance our understanding of the epidemiology of PCLR.Study designDescriptive Epidemiology Study.

Clinical Application of Automated Breast Ultrasound

Automatic breast ultrasound (ABUS) has been developed to compensate for the shortcomings of hand-held ultrasound (HHUS) and is mainly used for breast cancer screening purposes in women with dense breasts. Since 2021, ABUS has been covered by the Korean National Health Insurance System. It is important to scan the entire breast on ABUS and to identify the poor-quality images requiring re-scanning. In addition, a general understanding of the unique ABUS display mode, distinguishing benign from malignant lesions, the diagnostic performance of breast cancer screening, and the application of computer-aided detection/diagnosis systems is necessary to use ABUS efficiently. This review explores the acquisition method, image quality, and image characteristics of ABUS to improve general understanding of this procedure and its advantages over HHUS, so that ABUS can be applied efficiently in clinical practice.

Blood Pressure Variability and the Risk of Fracture: A Nationwide Cohort Study.

Although blood pressure variability (BPV) is associated with various health outcomes, only 1 study suggested that BPV is correlated with hip fractures. As cardiovascular disease and fractures share similar pathophysiology, there might be a link between BPV and fractures. To investigate the association between BPV and the incident fractures. Retrospective cohort study. Population-based, using the Korean National Health Insurance System database. A total of 3 256 070 participants aged ≥50 who participated in ≥3 health examinations within the previous 5 years, including the index year (2009-2010), were included. Outcome data were obtained through the end of 2016. BPV was calculated using variability independent of the mean. High variability was defined as the highest quartile of variability. Newly diagnosed fractures. During the median follow-up of 7.0 years, there were 337 045 cases of any fracture (10.4%). After adjusting for age, sex, income, lifestyle factors, and comorbidities, a higher risk of fracture was observed with higher quartiles of BPV than the lowest quartile group: the adjusted hazard ratios (95% CIs) for incident any fracture were 1.07 (1.06-1.08) in the higher quartile of systolic BPV, 1.06 (1.05-1.07) in that of diastolic BPV, and 1.07 (1.06-1.08) in that of both systolic and diastolic BPV. Consistent results were noted for vertebral fractures and hip fractures, as well as in various subgroup analyses. A positive association was noted between higher BPV and fracture incidence. BPV is an independent predictor for developing fracture.

Relationship between blood pressure levels and ischemic stroke, myocardial infarction, and mortality in very elderly patients taking antihypertensives: a nationwide population-based cohort study

BackgroundIn the very elderly, “the lower the better” hypothesis has constantly been contradicted by randomized control trials and various cohort studies, but inconsistency in results led to unclear blood pressure treatment targets. This study aimed to assess the relationship between baseline blood pressure (BP) and ischemic stroke, myocardial infarction, and all-cause mortality in very elderly people treated for hypertension.MethodsThis large population-based retrospective cohort study was based on the national claims database of the Korean National Health Insurance System, which covers the entire Korean population. 374,250 participants aged ≥ 75 years taking antihypertensive agents were recruited, excluding patients with a history of previous ischemic stroke or myocardial infarction.ResultsSystolic BP (SBP) followed a J curve for ischemic stroke and a U curve for all-cause mortality, with nadir ranges of 120 to 129 mmHg and 140 to 149 mmHg, respectively. While increasing diastolic BP (DBP) generally resulted in higher HRs for ischemic stroke, HRs for myocardial infarction and all-cause mortality significantly increased only when DBP was ≥ 80 mmHg and ≥ 90 mmHg, respectively. The SBP/DBP combination analysis showed that even with SBP < 130 mmHg, higher DBP ≥ 90 mmHg had higher HRs for all three outcomes compared to the reference group (130 to 149 / < 80 mmHg).ConclusionsThere were no further benefits or even harm below certain BP levels for ischemic stroke, myocardial infarction, and all-cause mortality in very elderly hypertensive patients.

Association of Physical Activity, Including Amount and Maintenance, With All-Cause Mortality in Parkinson Disease

The protective effects of physical activity (PA) against Parkinson disease (PD) development have been suggested; however, the association of PA with mortality in PD has rarely been investigated. To evaluate the association between PA and mortality in individuals with PD and determine how the amount and maintenance of PA are associated with mortality. This nationwide population-based cohort study used Korean National Health Insurance System data. Participants were included from January 1, 2010, and December 31, 2013, and were followed up until December 31, 2017. Data were analyzed from September 2020 to March 2021. Individuals who were newly diagnosed with PD were selected using the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision code G20 and registration code V124 in the program for rare intractable diseases in 2010 through 2013. Individuals who underwent health checkups within 2 years before and after the PD diagnosis were enrolled. Those aged younger than 40 years or with missing data were excluded. Physical activity levels were collected using self-reported questionnaires. All-cause mortality. A total of 45 923 individuals were identified; 10 987 were enrolled, and 34 individuals younger than 40 years and 254 with missing data were excluded. A total of 10 699 individuals with PD were included; 4925 (46%) were male and 5774 (54%) were female, and the mean (SD) age was 69.2 (8.8) years. During the 8-year follow-up period, there were 1823 deaths (17%). The mortality rate was lower among individuals who were physically active vs inactive at all PA intensities (vigorous: hazard ratio [HR], 0.80 [95% CI, 0.69-0.93]; moderate: HR, 0.66 [95% CI, 0.55-0.78]; light: HR, 0.81 [95% CI, 0.73-0.90]). There was a significant inverse dose-response association between the total amount of PA and mortality (HRs: vigorous, 0.80 [95% CI, 0.69-0.93]; moderate, 0.66 [95% CI, 0.55-0.78]; light, 0.81 [95% CI, 0.73-0.90]; P < .001). Moreover, maintenance of PA was associated with the mortality rate. Individuals with PD who were physically active both before and after the PD diagnosis had the greatest reduction in mortality rate across all PA intensities (HRs: vigorous, 0.66 [95% CI, 0.50-0.88]; moderate, 0.49 [95% CI, 0.32-0.75]; light, 0.76 [95% CI, 0.66-0.89]). Individuals who started PA after receiving the PD diagnosis had a lower mortality rate than those who remained physically inactive (HRs: vigorous, 0.82 [95% CI, 0.70-0.97]; moderate, 0.69 [95% CI, 0.57-0.83]; light, 0.86 [95% CI, 0.78-0.98]). This analysis found a dose-response association between PA and all-cause mortality in PD. Reverse causality may exist, and future prospective randomized clinical trials are warranted to determine the effect of PA on mortality in PD.