Retinal Vein Occlusion and the Risk of Stroke Development

Risk of stroke development following retinal vein occlusion: A systematic review and meta-analysis

Retinal vein occlusion (RVO) and cerebrovascular disease share common risk factors and may be independently associated; however, the strength and nature of this association remain unclear. We conducted a systematic review and meta-analysis, informed by studies from PubMed, Scopus, EMBASE, Web of Science, and Google Scholar until January 6, 2024, aimed to clarify this relationship. Eligible studies included cohorts observing stroke incidence in RVO patients for over a year. Pooled effect estimates were calculated using random-effects models, with subgroup analyses evaluating associations between RVO types (central and branch) and stroke subtypes (ischemic and hemorrhagic). Ten cohort studies with a total of 428,650 participants (86,299 RVO patients) were included. Compared to controls, RVO patients exhibited a significantly increased risk of stroke (pooled risk ratio [RR]=1.38, 95 % confidence interval (95 %CI)=1.34-1.41). Subgroup analyses indicated elevated risk for both ischemic (RR=1.37, 95 %CI=1.32-1.42) and hemorrhagic (RR=1.55, 95 %CI=1.08-2.22) strokes in RVO patients. Additionally, both central (RR=1.50, 95 %CI=1.27-1.78) and branch (RR=1.41, 95 %CI=1.32-1.50) RVO were associated with stroke risk. Sensitivity analyses confirmed consistent results across various criteria, and funnel plots indicated no publication bias. RVO significantly increases the risk of both ischemic and hemorrhagic stroke, regardless of RVO type, suggesting a strong independent association between these conditions.

[Retinal venous occlusion and its association with atherosclerotic vascular disease]

Retinal venous occlusion (RVO) is the second most frequent cause of decreased visual acuity due to retinal vascular, after diabetic retinopathy. Its etiology is not completely clear. Current scientific evidence suggests that it is related to the atherosclerotic process given the high number of cardiovascular risk factors and the higher incidence of cardiovascular events in these patients. In fact, RVO implies a 45% higher risk of stroke, 26% of acute myocardial infarction and peripheral vascular disease, 53% of heart failure and 36% of overall mortality, compared to the general population adjusted for age, sex and the different cardiovascular risk factors. However, no increase in cardiovascular mortality has been detected. Therefore, a multidisciplinary clinical approach to this pathology is essential.

Genetically predicted retinal vascular occlusion in relation to cardiovascular diseases: A bidirectional two-sample Mendelian randomization analysis

INTRODUCTION

Increasing evidence implicates retinal vascular occlusions as a susceptibility factor for cardiovascular diseases (CVDs), whereas inconsistent results on the relationship were reported in previous observational studies. This research using a bidirectional two-sample Mendelian randomization (MR) analysis aimed to investigate the potential association between genetically determined central/branch retinal artery and retinal vein occlusions (CRAO/BRAO/RVO) and the risk of CVD.

METHODS

Summary statistics of retinal vascular occlusions from the largest available genome-wide association study of European descent were used to investigate their relationship with CVDs, and vice versa. Primary analyses were conducted using the common inverse-variance weighted approach. Several complementary sensitivity analyses were performed to verify the reliability of our results.

RESULTS

Inverse variance weighted method showed suggestive effects of genetically determined RVO on ischemic stroke (IS) (odds ratio [OR] = 1.021, 95% confidence [CI] = 1.004-1.037, p = 0.012), a genetic liability to CRAO increased the risk of myocardial infarction (MI) (OR = 1.014, 95% CI = 1.006-1.023, p = 7.0 × 10-4). In addition, genetic predisposition to BRAO had a positive effect on stroke (OR = 1.008, 95% CI = 1.002-1.013, p = 0.011), IS (OR = 1.007, 95% CI = 1.001-1.014, p = 0.022), and cardioembolic stroke (CES) (OR = 1.018, 95% CI = 1.006-1.031, p = 0.004). The point estimates from sensitivity analyses were in the same direction. Reverse MR analyses found no significant evidence for the effect of CVDs on retinal vascular occlusions.

CONCLUSION

Our MR study provides potential evidence that retinal vascular occlusions are causally linked to increased risk of CVDs including IS, MI, stroke, and CES. This supports the need for clinical CVD screening in individuals with retinal vascular occlusions. Further investigations are warranted to clarify the effects of CVDs on ocular comorbidities.

Distinctive Imaging Characteristics of Retinal and Cerebral Vessels between Central and Branch Retinal Vein Occlusion by MRI and AI-Based Image Analyzer

Retinal vessels have been good predictive and prognostic imaging biomarkers for systemic or eye diseases. Numerous studies have shown that the two retinal vein occlusion entities may correlate with cardiovascular and cerebrovascular events or primary open-angle glaucoma. This study aims to investigate if there is a disparity in the correlations between branch RVO (BRVO) and central RVO (CRVO) with systemic disorders or POAG, thus explaining the pathogenic difference between BRVO and CRVO. This retrospective case-control study enrolled 59 RVO subjects (118 eyes), including 25 CRVO and 34 BRVO subjects, who received routine eye and brain MRI examinations. The geometric characteristics of the caliber of the retinal and cerebral blood vessels and the optic nerve subarachnoid space width (ONSASW) were measured. Multivariable logistic regression analysis showed that ONSASW at 3 mm behind the globe (p = 0.044) and the relative retinal venular calibers (p = 0.031) were independent risk factors for the CRVO-affected eyes group in comparison with the BRVO-affected eyes group after adjusting for age, duration of hypertension, BMI, and IOP. In the CRVO-affected eyes, narrower relative retinal arteriolar calibers (p = 0.041) and wider relative venular calibers (p = 0.011) were independent risk factors compared with the CRVO-contralateral normal eyes when adjusting for IOP. We concluded that BRVO may be more associated with cerebrovascular diseases, and CRVO may be correlated with primary angle glaucoma. The geometric characteristics difference between the retinal and cerebrovascular may explain the pathological difference between CRVO and BRVO.

The characteristic large-scale annual analysis by gender and age in heart failure patients: cohort for 10 years in Korea

AIMS

The prevalence and incidence rate of heart failure (HF) continues to increase along with the aging of the population and the increase of ischaemic heart disease. The morbidity and mortality of HF are also on the rise in the industrialized countries; it can be a great public health problem. A detailed and accurate analysis of the demographical incidence and prevalence of HF is an important first step in predicting the occurrence of the disease in the future and proper preparing for prevention. Here, we aimed to analyse the annual prevalence and incidence of HF by gender and age using long-term national health insurance service data in the Republic of Korea.

METHODS AND RESULTS

A total of 47 243 patients newly diagnosed with HF between 2006 and 2015 among nationally representative random subjects of 1 000 000 were included. The data of age and gender were analysed by year, and the total population information of the Ministry of Land, Infrastructure, and Transport of Korea was referred to compare the data of HF patients with the total population (2008-15). Over the decade from 2006 to 2015, the prevalence of HF patients showed tendency of increase (P < 0.001). The overall incidence rate was also gradually increasing (P < 0.001), but in women, it tended to decrease gradually. Women significantly accounted higher than the male group in incidence of HF over the period (54.6% vs. 45.4%, P < 0.001). The mean age at the time of diagnosis gradually increased (P = 0.002 for total, P = 0.001 for each gender). Total incidence was highest in 70s (27.22%), but males were the most in their 60s and females were in their 70s. Analysis of annual trend by age and gender distribution of HF incidence in men presented highest in the 50s-70s with a similar pattern annually, and the incidence is increasing more recently. Different from that of men, in the case of women, the incidence gradually increased with age in a similar annual pattern, peaking in their 70s and gradually decreasing in recent years.

CONCLUSIONS

The prevalence and incidence of HF are gradually increasing. It increased rapidly in their 50s and older. It showed an increased incidence of HF especially in men between their 50s and 70s, and more observation and caution for the management of the risk factors may be needed to prevent HF in the male group.

Cardiovascular morbidity and all-cause mortality in patients with retinal vein occlusion: a Danish nationwide cohort study

BACKGROUND/AIMS

Associations between retinal vein occlusion (RVO) and subsequent cardiovascular disease (CVD) or mortality have not been evaluated in a recent cohort, after novel therapeutic options have increased referrals for treatment of the condition. We aimed to evaluate overall and subtype-stratified risk of CVD and all-cause mortality following RVO and assess any alterations after the introduction of angiostatic therapy in Denmark in 2011.

METHODS

This nationwide, registry-based cohort study from 1998 to 2018 evaluated 4 194 781 individuals. Hazard ratios (HRs) were reported for RVO as an overall measure and subclassified as branch and central RVO.

RESULTS

Patients with RVO (n=15 665) were median 71.8 years old at the time of exposure and 50.7% were women. RVO associated with incident CVD (adjusted HR 1.13, 95% CI 1.09 to 1.17) but not mortality (adjusted HR 1.00, 95% CI 0.97 to 1.03). Almost similar risks of CVD were found for patients with branch and central RVO (adjusted HRs 1.14, 95% CI 1.03 to 1.25, and 1.12, 95% CI 1.00 to 1.25, respectively), but only patients with central RVO exhibited increased mortality (adjusted HR 1.12, 95% CI 1.04 to 1.21). Risk of CVD, especially non-ischaemic, was higher for patients diagnosed after 2011 (adjusted HRs 1.24, 95% CI 1.15 to 1.33 vs 1.06, 95% CI 1.01 to 1.12).

CONCLUSION

In a cohort of the Danish population aged 40 years or more, patients with RVO had a 13% increased risk of incident CVD compared with unexposed individuals. Risk of CVD was increased after 2011, when intravitreal angiostatic treatment was introduced and referral practices altered.

Retinal vein occlusion is associated with stroke independent of underlying cardiovascular disease

BACKGROUND

Stroke is a leading cause of mortality and morbidity. Thus, identifying associated risk factors may lead to earlier interventions aimed at reducing the risk of stroke development. Since cardiovascular disease simultaneously increases the risk of stroke and retinal vein occlusion (RVO), we sought to determine whether RVO is associated with the risk of stroke independent of underlying cardiovascular co-morbidities.

METHODS

In this cross-sectional study, we reviewed the records of 80,754 individuals who were evaluated by an ophthalmologist over a 6-year period. We identified individuals with RVO, stroke and cardiovascular diseases including hypertension, diabetes mellitus, carotid disease, coronary artery disease and atrial fibrillation. Multivariable logistic regression models were used to analyze odds ratios for RVO and stroke.

RESULTS

After adjusting for age, sex, cardiovascular disease and other risk factors, we found that the presence of RVO was associated with an odds ratio for stroke of 1.73 (CI, 1.40-2.12, p < 0.001). The association between RVO and stroke, after adjusting for sex and cardiovascular co-morbidities, was significantly stronger in individuals younger than 50 years of age, with an odds ratio of having a stroke of 3.06 (1.34-6.25, p < 0.001), while the presence of RVO in individuals older than 85 years was not significantly associated with stroke 1.19 (0.77-1.79, p = 0.41).

CONCLUSIONS

Our findings demonstrate that RVO is significantly associated with stroke, even after adjusting for underlying cardiovascular co-morbidities. This association was highly significant in younger subjects, while not significant in older individuals.

Retinal age gap as a predictive biomarker of stroke risk

BACKGROUND

The aim of this study is to investigate the association of retinal age gap with the risk of incident stroke and its predictive value for incident stroke.

METHODS

A total of 80,169 fundus images from 46,969 participants in the UK Biobank cohort met the image quality standard. A deep learning model was constructed based on 19,200 fundus images of 11,052 disease-free participants at baseline for age prediction. Retinal age gap (retinal age predicted based on the fundus image minus chronological age) was generated for the remaining 35,917 participants. Stroke events were determined by data linkage to hospital records on admissions and diagnoses, and national death registers, whichever occurred earliest. Cox proportional hazards regression models were used to estimate the effect of retinal age gap on risk of stroke. Logistic regression models were used to estimate the predictive value of retinal age and well-established risk factors in 10-year stroke risk.

RESULTS

A total of 35,304 participants without history of stroke at baseline were included. During a median follow-up of 5.83 years, 282 (0.80%) participants had stroke events. In the fully adjusted model, each one-year increase in the retinal age gap was associated with a 4% increase in the risk of stroke (hazard ratio [HR] = 1.04, 95% confidence interval [CI]: 1.00-1.08, P = 0.029). Compared to participants with retinal age gap in the first quintile, participants with retinal age gap in the fifth quintile had significantly higher risks of stroke events (HR = 2.37, 95% CI: 1.37-4.10, P = 0.002). The predictive capability of retinal age alone was comparable to the well-established risk factor-based model (AUC=0.676 vs AUC=0.661, p=0.511).

CONCLUSIONS

We found that retinal age gap was significantly associated with incident stroke, implying the potential of retinal age gap as a predictive biomarker of stroke risk.

Glaucoma Is Associated with the Risk of Obstructive Sleep Apnea: A Population-Based Nationwide Cohort Study

The association between glaucoma and the risk of obstructive sleep apnea (OSA) has not been fully evaluated. Therefore, this study aimed to investigate the prospective association between glaucoma and OSA. In total, 1437 patients with glaucoma and 5748 patients without glaucoma were enrolled after 1:4 propensity score matching using a nationwide cohort sample. We investigated OSA events during a 10-year follow-up period. Survival analysis, the log-rank test, and Cox proportional hazards regression models were used to calculate the incidence, disease-free survival rate, and hazard ratio (HR). The incidence of OSA was 12,509.0 person-years among those with glaucoma. The adjusted HR for patients with glaucoma developing OSA events during the follow-up period was 1.52 (95% confidence interval [CI]: 0.64-3.621) after other covariates. In a subgroup analysis, primary angle-closure glaucoma (PACG) showed a significantly increased adjusted HR for OSA events (5.65, 95% CI: 1.65-19.41), whereas we could not find any significant association between primary open-angle glaucoma (POAG) and OSA. The adjusted HR of OSA events in POAG was considerably increased 4 years after POAG diagnosis. PACG may be associated with an increased incidence of OSA. Clinicians should pay attention to early detection of OSA in patients with PACG.

Altered synchronous neural activities in retinal vein occlusion patients: A resting-state fMRI study

Objective

Retinal vein occlusion (RVO) is the second most common retinal vascular disorder after diabetic retinopathy, which is the main cause of vision loss. Retinal vein occlusion might lead to macular edema, causing severe vision loss. Previous neuroimaging studies of patients with RVO demonstrated that RVO was accompanied by cerebral changes, and was related to stroke. The purpose of the study is to investigate synchronous neural activity changes in patients with RVO.

Methods

A total of 50 patients with RVO and 48 healthy subjects with matched sex, age, and education were enrolled in the study. The ReHo method was applied to investigate synchronous neural activity changes in patients with RVO.

Results

Compared with HC, patients with RVO showed increased ReHo values in the bilateral cerebellum_4_5. On the contrary, patients with RVO had decreased ReHo values in the bilateral middle occipital gyrus, right cerebelum_crus1, and right inferior temporal gyrus.

Conclusion

Our study demonstrated that patients with RVO were associated with abnormal synchronous neural activities in the cerebellum, middle occipital gyrus, and inferior temporal gyrus. These findings shed new insight into neural mechanisms of vision loss in patients with RVO.

Review: The Development of Risk Factors and Cytokines in Retinal Vein Occlusion

Retinal vein occlusion (RVO) is the second most prevalent retinal disease. Despite this, the pathogenic mechanisms and risk factors are not entirely clear. In this article, we review recent publications on the classification, pathogenesis, risk factors, ischemic changes, cytokines, and vital complications of RVO. Risk factors and cytokines are important for exploring the mechanisms and new treatment targets. Furthermore, risk factors are interrelated, making RVO mechanisms more complex. Cytokines act as powerful mediators of pathological conditions, such as inflammation, neovascularization, and macular edema. This review aims to summarize the updated knowledge on risk factors, cytokines of RVO and signaling in order to provide valuable insight on managing the disease.

Association between proteinuria and retinal vein occlusion in individuals with preserved renal function: a retrospective cohort study

PURPOSE

To investigate the association between proteinuria and the incidence of retinal vein occlusion (RVO) in individuals with preserved renal function.

METHODS

We conducted a retrospective cohort study from 2005 to 2020 using the JMDC Claims Database, a large database of health check-ups and administrative claims in Japan. Individuals who underwent annual health check-ups were included. Participants were classified into three groups based on the protein concentration in their urine: negative (≤10 mg/dl), trace (10-30 mg/dl) and positive (≥30 mg/dl). We estimated hazard ratios (HRs) for the development of RVO using Cox regression analyses with adjustment for baseline characteristics by the matching weights calculated from the multiple propensity scores. The cumulative incidence of RVO between the weighted groups was calculated using the Kaplan-Meier estimator.

RESULTS

There were 1 635 212 eligible participants, among whom 2360 developed RVO. The mean follow-up period was 1036 ± 951 days. The adjusted HRs for RVO were 1.10 (95% confidence interval 0.92-1.33) and 1.46 (1.19-1.78) in the groups with trace and positive proteinuria compared with negative proteinuria respectively. The cumulative incidence rates of RVO at 7 years were 0.40%, 0.43% and 0.55% in the groups with negative, trace and positive proteinuria, respectively.

CONCLUSION

Positive proteinuria was independently associated with an increased incidence of RVO in individuals with preserved renal function. Proteinuria may be a novel risk factor for RVO development.

Sudden Sensorineural Hearing Loss May Increase the Risk of Retinal Vein Occlusion: A Nationwide Cohort Study

Sudden sensorineural hearing loss (SSNHL) is thought to be a vascular disease. Retinal vein occlusion (RVO) is an also common ophthalmic vascular disease. Thus, we investigated the potential relationship between these using a retrospective nationwide cohort dataset. We compared 49,584 subjects in the SSNHL and the comparison (non-SSNHL) groups using patients randomly selected via propensity-score matching. We calculated the incidence, survival rate, and hazards ratio (HR) using log-rank test, and Cox proportional hazards regression models. This study examined a total of 375,490.4 person-years in the SSNHL group and 373,698.2 person-years in the comparison group. We found that 673 patients in the SSNHL group (1.8 cases per 1000 person-years) and 592 in the comparison group (1.6 cases per 1000 person-years) developed RVO during the 8-year follow-up period. The adjusted HR of RVO was 1.13 (95% confidence interval [CI] 1.01–1.26). The adjusted HR of developing RVO in SSNHL was the greatest in elderly patients (adjusted HR, 1.21; 95% CI, 1.01–1.46) and male patients (adjusted HR, 1.18; 95% CI, 1.03–1.34). Our findings suggest that clinicians should remain vigilant of the possibility of RVO development in SSNHL patients, specifically elderly male patients.

Association between Late-Onset Ménière's Disease and the Risk of Incident All-Cause Dementia

Studies reported an association between impaired hearing and vestibular function with the risk of dementia. This study investigated the association between Ménière’s disease (MD) and the risk of dementia using a nationwide cohort sample of data obtained from the South Korea National Health Insurance Service. The MD group (n = 496) included patients aged over 55 years and diagnosed between 2003 and 2006. The comparison group was selected using propensity score matching (n = 1984). Cox proportional hazards regression models were used to calculate incidence and hazard ratios for dementia events. The incidence of dementia was 14.3 per 1000 person–years in the MD group. After adjustment for certain variables, the incidence of dementia was higher in the MD group than in the comparison group (adjusted hazard ratio (HR) = 1.57, 95% confidence interval = 1.17–2.12). Subgroup analysis showed a significantly increased adjusted HR for developing Alzheimer’s disease (1.69, 95% confidence interval = 1.20–2.37) and vascular dementia (1.99, 95% confidence interval = 1.10–3.57) in the MD group. Patients with dementia experienced a higher frequency of MD episodes than those without dementia. Our findings suggest that late-onset MD is associated with an increased incidence of all-cause dementia, and it might be used as a basis for an earlier diagnosis of dementia.

Impact of retinal vein occlusion on cardiovascular events in elderly Japanese patients

To assess the relationship between retinal vein occlusion (RVO) and the incidence of cardiovascular (CV) events.This was a single-institution, retrospective cohort study. We enrolled 57 patients diagnosed with RVO between January 2012 and December 2019, and 125 non-RVO patients who had undergone cataract surgery by a single surgeon between January and April 2012. We compared the relative risk and incidence rate ratio of CV events between the 2 groups. In addition, survival analysis was performed to calculate the hazard ratio (HR) using the Cox proportional hazards model. RVO, age, sex, blood pressure, body mass index, presence of diabetes, blood sample data, and smoking were considered confounders.The mean observation period (± standard deviation) for the RVO and non-RVO groups was 2.68 ± 2.04 and 2.81 ± 2.70 years, respectively. Seven CV events were observed in the RVO group and 2 in the non-RVO group. Relative risk and incidence rate ratio were 7.68 (95% confidence interval [CI]: 1.65-35.8) and 8.07 (95% CI: 1.54-79.6), respectively. Multivariate analysis revealed that the RVO group had a high HR for CV events (HR: 16.13 [95% CI: 2.29-113.74]) and older age (HR: 1.26 [95% CI: 1.06-1.49]).RVO can predict future CV events, especially in the elderly population. Fundus observations should be shared between ophthalmologists and internists to prevent future CV events.

Clinical significance of subclinical atherosclerosis in retinal vein occlusion

Retinal vein occlusion (RVO) is associated with atherosclerotic cardiovascular risk factors; however, its association with the specific markers of subclinical atherosclerosis has not yet been established. To investigate this association, we compared 70 patients with RVO to 70 age- and sex-matched patients without RVO. Low-density lipoprotein cholesterol (LDL-C) levels and brachial-ankle pulse wave velocity (baPWV) were significantly higher in the RVO group than in the control group. Carotid plaques (54.3% vs. 28.6%, p = 0.004) were more frequent in the RVO group. Multivariate logistic regression analysis showed that the presence of carotid plaques (odds ratio [OR]: 3.15, 95% confidence interval [CI] 1.38–7.16, p = 0.006), as well as smoking, LDL-C level, and baPWV were associated with RVO. Additionally, a multinomial logistic regression model showed that the presence of carotid plaques (OR: 3.94, 95% CI 1.65–9.41, p = 0.002) and LDL-C level were associated with branch RVO, whereas smoking and baPWV were associated with central RVO. In conclusion, RVO was associated with subclinical atherosclerosis markers, including carotid plaques and baPWV. These results support the hypothesis that atherosclerosis contributes to the etiology of RVO and suggest the evaluation of subclinical atherosclerosis in patients with RVO.

Retinal Vascular Signs and Cerebrovascular Diseases

BACKGROUND

Cerebrovascular disease (CeVD), including stroke, is a leading cause of death globally. The retina is an extension of the cerebrum, sharing embryological and vascular pathways. The association between different retinal signs and CeVD has been extensively evaluated. In this review, we summarize recent studies which have examined this association.

EVIDENCE ACQUISITION

We searched 6 databases through July 2019 for studies evaluating the link between retinal vascular signs and diseases with CeVD. CeVD was classified into 2 groups: clinical CeVD (including clinical stroke, silent cerebral infarction, cerebral hemorrhage, and stroke mortality), and sub-clinical CeVD (including MRI-defined lacunar infarct and white matter lesions [WMLs]). Retinal vascular signs were classified into 3 groups: classic hypertensive retinopathy (including retinal microaneurysms, retinal microhemorrhage, focal/generalized arteriolar narrowing, cotton-wool spots, and arteriovenous nicking), clinical retinal diseases (including diabetic retinopathy [DR], age-related macular degeneration [AMD], retinal vein occlusion, retinal artery occlusion [RAO], and retinal emboli), and retinal vascular imaging measures (including retinal vessel diameter and geometry). We also examined emerging retinal vascular imaging measures and the use of artificial intelligence (AI) deep learning (DL) techniques.

RESULTS

Hypertensive retinopathy signs were consistently associated with clinical CeVD and subclinical CeVD subtypes including subclinical cerebral large artery infarction, lacunar infarction, and WMLs. Some clinical retinal diseases such as DR, retinal arterial and venous occlusion, and transient monocular vision loss are consistently associated with clinical CeVD. There is an increased risk of recurrent stroke immediately after RAO. Less consistent associations are seen with AMD. Retinal vascular imaging using computer assisted, semi-automated software to measure retinal vascular caliber and other parameters (tortuosity, fractal dimension, and branching angle) has shown strong associations to clinical and subclinical CeVD. Other new retinal vascular imaging techniques (dynamic retinal vessel analysis, adaptive optics, and optical coherence tomography angiography) are emerging technologies in this field. Application of AI-DL is expected to detect subclinical retinal changes and discrete retinal features in predicting systemic conditions including CeVD.

CONCLUSIONS

There is extensive and increasing evidence that a range of retinal vascular signs and disease are closely linked to CeVD, including subclinical and clinical CeVD. New technology including AI-DL will allow further translation to clinical utilization.

Non-dipping pattern of nocturnal blood pressure as a risk factor for macular ischemia in branch retinal vein occlusion

Branch retinal vein occlusion (BRVO) is ocular vascular disease affecting approximately 14 million people worldwide, and is closely associated with high blood pressure (BP). Although macular ischemia is a critical factor in the visual prognosis of BRVO, the relationship between macular ischemia and different patterns of nocturnal BP is unknown. Here, we investigated whether a dipping pattern of nocturnal BP is associated with the development of macular ischemia in patients with BRVO. A total of 273 patients were reviewed; of these, 86 (86 eyes) patients were included. All recruited patients had a macular thickness map by optical coherence tomography and underwent 24-h ambulatory BP monitoring. According to their dipping patterns, the participants were divided into dipper and non-dipper groups. The non-dipper group had worse visual outcomes at the initial and 6-month visits (P = 0.014 and P = 0.003, respectively). Five of 32 eyes (15.6%) in the dipper group and 32 of 54 (59.3%) in the non-dipper group had macular ischemia. In a multivariate analysis, the night-to-day systolic BP ratio was associated with the degree of macular ischemia (β = − 0.313, P = 0.004). Thus, a non-dipping pattern may be a risk factor for macular ischemia in patients with BRVO.

Prevalence of subclinical retinal ischemia in patients with cardiovascular disease - a hypothesis driven study

BACKGROUND

Cardiovascular disease is the leading cause of mortality and disability worldwide. A noninvasive test that can detect underlying cardiovascular disease has the potential to identify patients at risk prior to the occurrence of adverse cardiovascular events. We sought to determine whether an easily observed imaging finding indicative of retinal ischemia, which we term 'retinal ischemic perivascular lesions' (RIPLs), could serve as a biomarker for cardiovascular disease.

METHODS

We reviewed optical coherence tomography (OCT) scans of individuals, with no underlying retinal pathology, obtained at UC San Diego Health from July 2014 to July 2019. We identified 84 patients with documented cardiovascular disease and 76 healthy controls. OCT scans were assessed for evidence of RIPLs. In addition, the 10-year atherosclerotic cardiovascular disease (ASCVD) risk calculator was used to risk-stratify the subjects into four different categories.

FINDINGS

Patients with documented cardiovascular disease had higher number of RIPLs compared to healthy controls (2.8 vs 0.8, p < 0.001). After adjusting for age, sex, smoking history, systolic blood pressure and triglycerides, cholesterol and hemoglobin A1C levels, each RIPL was associated with an odds ratio of having cardiovascular disease of 1·60 (1.09-2>37). The number of RIPLs in individuals with intermediate and high 10-year ASCVD risk scores was higher than in those with low ASCVD risk scores (1.7 vs 0.64, p = 0.02 and 2.9 vs 0.64, p 0.002, respectively).

INTERPRETATION

The presence of RIPLs, which are anatomical markers of prior retinal ischemic infarcts, is suggestive of coexisting cardiovascular disease. RIPLs detection, obtained from routine retinal scans, may thus provide an additional biomarker to identify patients at risk of developing adverse cardiovascular events.

FUNDING

None.

Association Between Burning Mouth Syndrome and the Development of Depression, Anxiety, Dementia, and Parkinson Disease

Importance

Burning mouth syndrome is a chronic oral pain disorder that is characterized by a generalized or localized burning sensation without the presence of any specific mucosal lesions. It remains unclear, however, whether burning mouth syndrome is associated with the development of psychoneurological conditions among patients with the syndrome.

Objective

To evaluate the risk of developing psychoneurological conditions, including depression, anxiety, dementia, and Parkinson disease, in patients with burning mouth syndrome.

Design, Setting, and Participants

This retrospective population-based cohort study was conducted using a nationwide representative cohort sample from the Korean National Health Insurance Service-National Sample Cohort, which consists of data from approximately 1 million patients in South Korea. The study included 586 patients with burning mouth syndrome (patient group) and 1172 individuals without burning mouth syndrome (comparison group). The patient group included all patients who received inpatient and outpatient care for an initial diagnosis of burning mouth syndrome between January 1, 2002, and December 31, 2012. The comparison group was selected (2 individuals without burning mouth syndrome for each patient with burning mouth syndrome) using propensity score matching for sex, age, location of residence, household income level, and comorbidities. Data were collected and analyzed from January 1, 2002, to December 31, 2013.

Main Outcomes and Measures

Death and the incidence of psychopathological diseases. Affective disorder events that occurred among participants during the follow-up period were investigated using survival analysis, a log-rank test, and Cox proportional hazards regression models to estimate the incidence rates, survival rates, and hazard ratios, respectively, of participants who developed psychoneurological conditions.

Results

Of 1758 total participants, 1086 (61.8%) were female; 701 participants (39.9%) were younger than 45 years, 667 (37.9%) were aged 45 to 64 years, and 390 (22.2%) were older than 64 years. The overall incidence of depression and anxiety was higher in patients with burning mouth syndrome (n = 586; 30.8 incidents and 44.2 incidents per 1000 person-years, respectively) than in individuals without burning mouth syndrome (n = 1172; 11.7 incidents and 19.0 incidents per 1000 person-years, respectively). The results also indicated a similar incidence of dementia and Parkinson disease between the patient group (6.5 incidents and 2.5 incidents per 1000 person-years, respectively) and the comparison group (4.9 incidents and 1.7 incidents per 1000 person-years, respectively). After adjusting for sociodemographic factors (age, location of residence, household income level, and comorbidities), the adjusted hazard ratios for the development of depression and anxiety among patients with burning mouth syndrome were 2.77 (95% CI, 2.22-3.45) and 2.42 (95% CI, 2.02-2.90), respectively. However, no association was found between burning mouth syndrome and the risk of developing dementia and Parkinson disease.

Conclusions and Relevance

Results of this observational study suggest that burning mouth syndrome is associated with increases in the incidence of depression and anxiety but not in the incidence of dementia and Parkinson disease among patients with the syndrome. Clinicians should be aware of this association and be prepared to make referrals to appropriate mental health care professionals.

Reporting of Safety Events during Anti-VEGF Treatment: Pharmacovigilance in a Noninterventional Trial

Aim

The prospective, noninterventional OCEAN study assessed the safety of intravitreal ranibizumab injections for treatment of neovascular age-related macular degeneration, diabetic macular edema, and retinal vein occlusion under real-world conditions in Germany.

Methods

Adults receiving ≥1 ranibizumab (0.5 mg) injections were recruited by 369 ophthalmologists and followed for 24 months. Information on adverse events (AEs) was reported by the treating physician or detected by the data management team. Collected information included observed AE, AE start and end date, intensity, causal relationship, outcome, severity, suspected drug, and actions taken.

Results

2,687 AEs were reported for 1,176 of the 5,781 patients who had received a total of 32,621 injections: 27.4% nonserious AEs, 30.3% serious AEs, 27.3% nonserious adverse drug reactions (ADRs), and 15.0% serious ADRs. Most patients reported no AEs (79.7%) or only 1 AE (10.3%). AEs were most commonly reported in the Medical Dictionary for Regulatory Activities (MedDRA) System Organ Class (SOC) Eye disorders (9.4% of patients) and General disorders and administration site conditions (5.8%). The most frequent AEs by MedDRA preferred term (PT) were visual acuity reduced (3.5% of patients), intraocular pressure increased (2.5%), and drug ineffective (2.1%). AEs occurred most frequently after 3 or 4 injections (1,129 of 2,687 AEs). The proportion of AEs in the SOC Eye disorders decreased slightly with increasing number of injections, from 39.8% of events after 1 or 2 injections to 29.1% after 5 or more injections. Rates of the most frequently reported PTs did not show any consistent increase with increasing number of injections. A decrease in overall AE rates was observed over the study course.

Conclusions

The results did not raise any new safety concerns for ranibizumab. The findings allow conclusions to be drawn on how pharmacovigilance data can be collected even more effectively in real-world studies to facilitate discussion on benefit-risk ratio.

Increased risk of cancer in patients with retinal vein occlusion: a 12-year nationwide cohort study

Aims

To investigate the association between incident retinal vein occlusion (RVO) and the subsequent development of cancer.

Methods

In this nationwide population-based retrospective study using 2002–2013 National Health Insurance Service database which covers the entire South Korean population, 186 701 incident RVO patients and their 1:1 propensity-score matched controls were included. We defined the fixed cohort from January 1st, 2004 to December 31st, 2013; the cohort included patients who suffered incident RVO after entering the cohort and their matched controls, and excluded patients having any cancer history before entering the cohort. The association of RVO and cancer was assessed by time-varying covariate Cox regression models; Model 1 included RVO as a time-varying covariate, Model 2 included Model 1 plus demographic information and Model 3 included Model 2 and comorbidities.

Results

RVO was associated with an increased risk of subsequent cancer (HR=1.29; 95% CI, 1.26–1.31 in Model 1), which was consistent in Models 2 and 3. The incidence rate of overall cancer during the study period was 25.55 (95% CI, 25.19–25.91) per 1000 person-years in the RVO group and 18.62 (95% CI, 18.46–18.79) per 1000 person-years in the control group. In the subgroup analysis, haematological malignancies showed the highest association with RVO (HR=1.65; 95% CI, 1.49–1.83).

Conclusion

Patients with RVO have an increased risk of subsequent cancer development even after adjusting for demographic factors and comorbidities. Further study is warranted to elucidate these associations to provide proper recommendations for RVO patients regarding the cancer screening.

ASSOCIATION OF RETINAL VEIN OCCLUSION WITH CARDIOVASCULAR EVENTS AND MORTALITY: A Systematic Review and Meta-analysis

PURPOSE

Previous studies examining the association of retinal vein occlusion (RVO) and cardiovascular events have been inconsistent and have mostly focused on stroke and myocardial infarction. The goal of this study is to use meta-analysis to examine the available evidence examining the association of RVO with incident cardiovascular events and mortality.

METHODS

Systematic review and meta-analysis of all longitudinal cohort studies published in PubMed, Embase, and the Cochrane Library from inception to April 7, 2018, that evaluated the association of baseline RVO and incident cardiovascular events and/or mortality, that provided multivariate-adjusted risk estimates with 95% confidence intervals (95% CIs), and that had average follow-up ≥1 year. The Newcastle-Ottawa scale was used to assess study quality. Multivariate-adjusted risk estimates with 95% CI along with study characteristics were extracted from each study, and pooled risk ratios (RRs) with 95% CI were generated using a random-effects model with inverse-variance weighting to account for heterogeneity. Main outcomes were incident stroke (fatal or nonfatal), myocardial infarction, heart failure, peripheral arterial disease, all-cause mortality, and cardiovascular mortality.

RESULTS

Fifteen cohort studies with a total of 474,466 patients (60,069 with RVO and 414,397 without RVO) were included. Each study had Newcastle-Ottawa scale score ≥6, indicating moderate-to-high quality. Retinal vein occlusion was associated with increased risk of stroke (RR = 1.45; 95% CI, 1.31-1.60), myocardial infarction (RR = 1.26; 95% CI, 1.17-1.37), heart failure (RR = 1.53; 95% CI, 1.22-1.92), peripheral arterial disease (RR = 1.26; 95% CI, 1.09-1.46), and all-cause mortality (RR = 1.36; 95% CI, 1.02-1.81), but was not associated with increased risk of cardiovascular mortality (RR = 1.78; 95% CI, 0.70-4.48).

CONCLUSION

This review suggests patients with RVO have an increased risk of cardiovascular events and all-cause mortality. More studies are needed to determine the highest risk periods for cardiovascular events and mortality after RVO and whether immediate cardiovascular evaluation and intervention will improve outcomes.

Hypertension and multiple cardiovascular risk factors increase the risk for retinal vein occlusions: results from the Gutenberg Retinal Vein Occlusion Study

OBJECTIVE

Although several risk factors for retinal vein occlusion (RVO) are known, what triggers RVO is unclear in many cases. We aimed to evaluate the relevance of multiple risk factors in patients with RVO.

METHODS

The Gutenberg RVO Study is an observational case-control study that assessed thrombophilic, cardiovascular, ophthalmic, and drug-related risk factors in participants with RVO and the same number of matched controls. Conditional logistic regression analysis was chosen to estimate the risk of RVO due to several risk factors.

RESULTS

Of 92 patients with RVO, 46 (50%) had central RVO, 31 (33.7%) had branch RVO, and 15 (16.3) had hemi-RVO. Systemic hypertension was associated with RVO [any RVO: odds ratio (OR): 1.81; 95% confidence interval (CI): 1.14-2.88; branch RVO: OR: 2.56; 95% CI: 1.08-6.10]. The most frequent combinations of risk factors were hypertension with dyslipidemia (33 of 92, 35.9%) and hyperhomocysteinemia and high levels of factor VIII (10 of 92, 10.9%). An increase in the risk sum score by one additional risk factor corresponded to ORs of 1.74 (95% CI: 1.31-2.32) for cardiovascular risk factors, 1.38 (95% CI: 1.04-1.82) for thrombophilic risk factors, and 1.43 (95% CI: 1.20-1.70) for the total number of risk factors for RVO.

CONCLUSION

Cardiovascular risk factors are more important than other risk factors for the presence of RVO. The risk of RVO increased by approximately 40% with any additional risk factor and by 70% with any additional cardiovascular risk factor.

Assessment of cerebral low-frequency oscillations in patients with retinal vein occlusion: a preliminary functional MRI study

BACKGROUND

There is increasing evidence that patients with retinal vein occlusion exhibit cerebral vascular changes and are at an increased risk of stroke. However, it remains unknown whether patients with retinal vein occlusion exhibit changes in intrinsic brain activity.

PURPOSE

This study investigated intrinsic brain activity changes in patients with retinal vein occlusion by assessing the amplitude of low-frequency fluctuations.

MATERIAL AND METHODS

Forty-five patients with retinal vein occlusion (22 men, 23 women, mean age 56.55 ± 6.97 years) and 43 healthy controls (13 men, 30 women; mean age 53.53 ± 8.19 years) closely matched in age, sex, and education level underwent resting-state MRI scans. The amplitude of low-frequency fluctuation method was used to compare intrinsic brain activity between the two groups.

RESULTS

Compared with healthy controls, patients with retinal vein occlusion exhibited significantly lower amplitude of low-frequency fluctuation values in the left middle occipital gyrus, right middle occipital gyrus, and right calcarine. However, patients with retinal vein occlusion showed significantly higher amplitude of low-frequency fluctuations in the bilateral cerebellum 6, right hippocampus, left insula, and left fusiform (voxel-level P < 0.01, Gaussian random field correction, cluster-level P < 0.05).

CONCLUSION

Our results demonstrated that patients with retinal vein occlusion showed abnormal spontaneous neural activities in the visual cortices, cerebellum, and Papez circuit, which might indicate impaired vision, cognition, and emotional function in patients with retinal vein occlusion. These findings offer important insights into the neural mechanism of retinal vein occlusion.

Risk Factors for Intraocular Lens Dislocation After Phacoemulsification: A Nationwide Population-Based Cohort Study

PURPOSE

Few studies have measured the incidence and risk factors of intraocular lens (IOL) dislocation in the total population. We investigate the risk factors for IOL dislocation in a nationwide Korean cohort.

DESIGN

Retrospective cohort study.

METHODS

National data on 2,162,191 subjects who underwent cataract surgery were collected from the Health Insurance Review and Assessment service database of health claims from 2009 to 2016. The Health Insurance Review and Assessment database was used to identify potential risk factors for IOL dislocation, including age, sex, and various pre- and postoperative ophthalmic conditions. The hazard ratios (HRs) and confidence intervals (CIs) of these risk factors were assessed with a multivariable-adjusted Cox regression model.

RESULTS

IOL dislocation occurred in 15,170 patients (0.7%) in the cataract surgery cohort (2,162,191 patients). The incidence rate of IOL dislocation peaked at 40-50 years of age, although the mean age of IOL dislocation was 65.25 ± 10.81 years. The average male:female ratio was 1.8. The adjusted HR for IOL dislocation in patients with partial vitrectomy was 11.93 (95% CI 10.95-12.99; P < .0001). Posterior capsulotomy performed within 1 year after the cataract surgery significantly decreased IOL dislocation, with an adjusted HR of 0.48 (95% CI 0.44-0.51; P < .0001).

CONCLUSIONS

IOL dislocation tended to occur in young males. Anterior vitrectomy was a significant risk factor for IOL dislocation, while posterior capsulotomy after surgery was associated with a decreased risk of IOL dislocation.

Screening for obstructive sleep apnea amongst patients with retinal vein occlusion

OBJECTIVE

To evaluate the prevalence and varying severity of obstructive sleep apnea (OSA) amongst those newly diagnosed with retinal vein occlusion (RVO), and screen patients with the use of 2 in-office-administered questionnaires validated against polysomnography.

DESIGN

Prospective cross-sectional study.

PARTICIPANTS

Consecutive adult patients (≥18 years of age) with a new diagnosis of RVO confirmed with intravenous fluorescein angiography were enrolled.

METHODS

The study was conducted at a tertiary academic centre between March 22, 2017, and April 7, 2018. Patients completed the Berlin and STOP-BANG questionnaires screening for OSA at presentation. Diagnostic test properties of the 2 questionnaires compared with polysomnography at a certified sleep laboratory centre as the gold standard for detection of OSA were calculated.

RESULTS

A total of 27 patients (37% females) with a mean (standard deviation) age of 69.6 (11.5) years completed the study. The diagnosis of OSA based on polysomnography was made in 96% (41% severe OSA) of patients with RVO. The Berlin questionnaire had a sensitivity of 43% (confidence interval [CI]: 22%-66%) and specificity of 67% (CI: 22%-96%). The STOP-BANG questionnaire had a sensitivity of 86% (CI: 64%-97%) and specificity of 50% (CI: 12%-88%).

CONCLUSIONS

Given the high prevalence of severe OSA amongst those with a new diagnosis of RVO, all patients should be strongly considered for polysomnography. The use of in-office questionnaires may aid in triaging urgency of referrals.

Temporal trajectories of accompanying comorbidities in patients with type 2 diabetes: a Korean nationwide observational study

Type 2 diabetes mellitus is a major concern globally and well known for increasing risk of complications. However, diabetes complications often remain undiagnosed and untreated in a large number of high-risk patients. In this study based on claims data collected in South Korea, we aimed to explore the diagnostic progression and sex- and age-related differences among patients with type 2 diabetes using time-considered patterns of the incidence of comorbidities that evolved after a diagnosis of type 2 diabetes. This study compared 164,593 patients who met the full criteria for type 2 diabetes with age group-, sex-, encounter type-, and diagnosis date-matched controls who had not been diagnosed with type 2 diabetes. We identified 76,423 significant trajectories of four diagnoses from the dataset. The top 30 trajectories with the highest average relative risks comprised microvascular, macrovascular, and miscellaneous complications. Compared with the trajectories of male groups, those of female groups included relatively fewer second-order nodes and contained hubs. Moreover, the trajectories of male groups contained diagnoses belonging to various categories. Our trajectories provide additional information about sex- and age-related differences in the risks of complications and identifying sequential relationships between type 2 diabetes and potentially complications.

Association of Obstructive Sleep Apnea With the Risk of Affective Disorders

Importance

Obstructive sleep apnea (OSA) is a common subtype of sleep breathing disorder; however, the association between OSA and the psychological health of affected individuals has not been fully evaluated.

Objective

To investigate the association between OSA and development of affective disorders.

Design, Setting, and Participants

This study used a nationwide representative cohort sample from the Korea National Health Insurance Service-National Sample Cohort database comprising data from 1 025 340 patients. The study included 197 patients with OSA diagnosed between January 2004 and December 2006 and 780 individuals without OSA who were matched using propensity score matching. Data were analyzed from September 28, 2018, to March 30, 2019.

Main Outcomes and Measures

Affective disorder events over a 9-year follow-up period. Kaplan-Meier survival curves with log-rank tests and Cox proportional hazards regression models were used to calculate cumulative incidence and hazard ratios (HRs) of affective disorders for each group.

Results

Of the total population of 985 (860 male [87.3%], 540 [54.8%] were aged <45 years), the incidences per 1000 person-years of affective disorders were 49.57 and 27.18 in the OSA and comparison groups, respectively. A total of 1371.7 person-years in the OSA group and 6328.6 person-years in the comparison group were evaluated for affective disorder events. After adjustment for sociodemographic factors (age, residential area, and household income), disability, and comorbidities, the adjusted HRs for patients with OSA developing affective disorders in patients with OSA during the 9-year follow-up period was 2.04 (95% CI, 1.53-2.70). In a subgroup analysis, the adjusted HRs for patients with OSA who developed depressive and anxiety disorders were 2.90 (95% CI, 1.98-4.24) and 1.75 (95% CI, 1.26-2.44), respectively. Moreover, female patients with OSA had a significant likelihood of prospective development of depression and anxiety (adjusted HR for depression, 3.97 [95% CI, 1.54-10.19]; adjusted HR for anxiety, 2.42 [95% CI, 1.17-5.02]) compared with male patients with OSA (adjusted HR for depression, 2.74 [95% CI, 1.80-4.17]; adjusted HR for anxiety, 1.64 [95% CI, 1.13-2.39]).

Conclusions and Relevance

This observational study using nationwide data suggests that OSA is associated with an increased incidence of affective disorder, such as depression and anxiety. Further studies appear to be needed to confirm our findings and, if validated, then studies are needed to explore the nature of the observed association, including potential causality, between OSA and affective symptoms.

Association of Corticosteroid Use With Incidence of Central Serous Chorioretinopathy in South Korea

Importance

Information on the incidence of central serous chorioretinopathy (CSC) in individuals who receive corticosteroids is scarce but clinically important because these agents are useful and widely used.

Objective

To estimate the annual and 5-year incidence of CSC in South Korea in the overall population and in those who have used corticosteroid medications.

Design, Setting, and Participants

A cohort study of a population-based random sample included East Asian adults for whom records are held in the Korean National Health Insurance Service database for calendar years 2011 through 2015. The data analysis was performed from July 1, 2017 to January 5, 2018.

Exposures

Any type of corticosteroid use from 2002 through 2015.

Main Outcomes and Measures

Incidence of CSC.

Results

The data set contained data from 868 939 adults (4 117 768 person-years). From 2011 through 2015, 1423 individuals (among whom the mean [SD] age was 46.8 [16.4] years and 1091 [76.7%] were male) with newly diagnosed CSC were identified. From 2002 to 2015, 783 099 individuals in the data set (90.1%) had ever used corticosteroids. The incidence of CSC per 10 000 person-years was 3.5 (5.4 in men; 1.6 in women) among the total population, 2.5 (3.0 in men; 1.2 in women) in those who had never used corticosteroids, and 3.6 (5.7 in men; 1.6 in women) among those who had ever used corticosteroids. The risk of CSCR with individuals who had ever used corticosteroids was estimated as an adjusted hazard ratio of 1.81 (95% CI, 1.47-2.23) compared with those who have never used these drugs. Current or recent corticosteroid use showed a positive association with the incidence of CSC (depending on duration of use, adjusted hazard ratio ranged from 1.54 to 2.15). Corticosteroid use in 2006 through 2009 was associated with an increased incidence of CSC after 2011 (adjusted hazard ratio 1.57 [95% CI, 1.13-2.18]).

Conclusions and Relevance

In 2002 through 2015, 90.1% of adults in Korea received corticosteroids at least once. Although there was a clear difference in relative risk, this data analysis could not replicate the more than 30-fold increase in the risk ratio of CSC that has been reported previously. The incidence of CSC in the most vulnerable group, middle-aged men, was estimated to be approximately 1 case per 1000 corticosteroid users in the year following medication use. The overall incidence among those who had ever used corticosteroids and those who had never used these drugs was 2.5 and 3.6 per 10 000 person-years, respectively. This study provides additional evidence to support the potential role of corticosteroids in CSC.

Association of Obstructive Sleep Apnea With the Risk of Ménière's Disease and Sudden Sensorineural Hearing Loss: A Study Using Data From the Korean National Health Insurance Service

STUDY OBJECTIVES

Several studies have reported an association between obstructive sleep apnea (OSA) and neuro-otologic diseases, such as Ménière's disease or sudden sensorineural hearing loss (SSNHL). However, the exact relationship between OSA and those diseases has not been fully evaluated. Therefore, the aim of this study was to investigate the prospective link between OSA and Ménière's disease or SSNHL.

METHODS

We used a nationwide cohort sample of data for 2002-2013 representing approximately 1 million patients. The OSA group (n = 942) included patients diagnosed between 2004 and 2006; the comparison group was selected using propensity score matching (n = 3,768). We investigated Ménière's disease and SSNHL events over a 9-year follow-up period. Survival analysis, log-rank test, and Cox proportional hazards regression models were used to calculate incidence, survival rate, and hazard ratios for each group.

RESULTS

In the OSA group, the incidences of Ménière's disease and SSNHL were 7,854.4 and 7,876.3 person-years, respectively. Cox proportional hazards analysis revealed no overall association between patients with OSA and the risk of subsequent Ménière's disease or SSNHL. In a subgroup analysis, female and middle-aged patients with OSA were independently associated with a two-fold higher incidence of subsequent Ménière's disease, compared to those without OSA. However, we could not find any significant association between patients with OSA and SSNHL even in the subgroup analysis.

CONCLUSIONS

Our findings suggest that female or middle-aged patients with OSA are associated with an increased incidence of Ménière's disease. However, there was no association between OSA and SSNHL.

CITATION

Kim J-Y, Ko I, Cho B-J, Kim D-K. Association of obstructive sleep apnea with the risk of Ménière's disease and sudden sensorineural hearing loss: a study using data from the Korean National Health Insurance Service. J Clin Sleep Med. 2019;15(9):1293-1301.

Association of Sudden Sensorineural Hearing Loss With Risk of Cardiocerebrovascular Disease: A Study Using Data From the Korea National Health Insurance Service

Importance

The interruption of vascular supply to the cochlea has been proposed as a major etiological factor for sudden sensorineural hearing loss (SSNHL), and several risk factors for cardiocerebrovascular disease (CCVD) are associated with SSNHL, including heavy smoking, alcohol consumption, and thromboembolic events. However, the link between SSNHL and CCVD has not been fully evaluated.

Objective

To investigate the association between SSNHL and CCVD.

Design, Setting, and Participants

A retrospective propensity score-matched cohort study was conducted using a nationwide representative sample from the National Sample Cohort 2002 through 2013 data from the Korea National Health Insurance Service. The SSNHL group (n = 154) included certain patients who were diagnosed with SSNHL between January 2003 and December 2005. The comparison group was selected (4 patients for every 1 patient with SSNHL; n = 616) using propensity score matching, according to sociodemographic factors and the year of enrollment. Each patient was monitored until 2013.

Main Outcomes and Measures

Survival analysis, the log-rank test, and Cox proportional hazards regression models were used to calculate the incidence, survival rate, and hazard ratio of CCVD for each group.

Results

Among the 770 patients, 385 (50.0%) were female and 370 (48.1%) were aged between 45 and 64 years. Of the total study population, 66 patients developed CCVD, such as stroke and acute myocardial infarction, during the 11-year follow-up period: 18 patients in the SSNHL group (incidence, 13.5 cases per 1000 person-years) and 48 from the comparison group (incidence, 7.5 cases per 1000 person-years). After adjustment for other factors, the hazard ratio of CCVD during the 11-year follow-up period was 2.18 times (95% CI, 1.20-3.96) greater for patients with SSNHL. An increased risk of stroke was associated with SSNHL (HR, 2.02; 95% CI, 1.16-3.51); however, there was no relation between SSNHL and risk of myocardial infarction (HR, 1.18; 95% CI, 0.25-5.50).

Conclusions and Relevance

This observational study using nationwide data suggests that SSNHL is associated with an increased incidence of CCVD, specifically stroke. Therefore, patient surveillance for signs of CCVD should be considered for patients who receive a diagnosis of SSNHL.

Comparison of systemic conditions at diagnosis between central retinal vein occlusion and branch retinal vein occlusion

Objective

To compare systemic conditions at the time of diagnosis between patients with central retinal vein occlusion (CRVO) and branch retinal vein occlusion (BRVO).

Design

This study included patients diagnosed with CRVO or BRVO between February 2009 and August 2017 at three branch hospitals of Hallym University Medical Center. Demographic and anthropometric variables, systemic comorbidity profiles, and laboratory findings at diagnosis were collected from a clinical data warehouse system, and were compared between the CRVO and BRVO groups.

Result

Four hundred and seventeen patients with CRVO and 1,511 patients with BRVO were included. The mean age was 61.8 ± 13.9 years, which was comparable between two groups (P = .332). Female proportion was higher in the BRVO group (55.0%) than in the CRVO group (48.0%; P = .013). Diabetes mellitus (P = .017) and chronic kidney disease (P = .004) were more prevalent in the CRVO group. Serum homocysteine level was abnormally high in 23.5% of CRVO patients and in 8.4% of BRVO patients (P < .001). Blood urea nitrogen and serum creatinine levels were abnormally elevated in more subjects with CRVO (P = .002).

Conclusion

CRVO is associated with higher prevalence of diabetes mellitus and chronic kidney disease, as well as with elevated serum homocysteine level. These results might suggest a difference between the pathophysiologies of CRVO and BRVO.

Dementia is Associated with an Increased Risk of Hip Fractures: A Nationwide Analysis in Korea

Background and Purpose

Dementia has been reported to be associated with an increased risk of hip fracture, but few case-control studies have been performed to actually confirm this. This study investigated the association between dementia and hip fracture by comparing the risk of hip fracture between subjects with and without dementia.

Methods

We examined a population-based matched cohort from the National Health Insurance Service-Senior Cohort data set that covers approximately half a million recipients of medical insurance in South Korea. Subjects with new clinically verified dementia during 2003–2007 were included, and five subjects without dementia were matched for age, sex, and index year to each subject with dementia as the controls. The risk of hip fracture for dementia was evaluated up to 2015 using Cox regression analysis.

Results

During the 12-year follow-up period, 284 subjects with dementia (10.66%) and 603 subjects without dementia (4.53%) experienced hip fractures. Dementia was independently associated with a higher risk of hip fracture [hazard ratio (HR)=2.840, 95% CI=2.449–3.293] and the adjusted HR for hip fracture in the subjects with dementia was highest within 2 years after the initial diagnosis (HR=2.862, 95% CI=2.053–3.990).

Conclusions

This study found that dementia could be an independent risk factor for hip fracture even at the early stage. This necessitates consideration of the future risk of falls and balance deficits in terms of physical activity after a diagnosis of dementia.

Incidence of exudative age-related macular degeneration and treatment load under the Korean national health insurance system in 2010-2015

BACKGROUND/AIM

The aim of this study was to estimate the nationwide incidence of clinically diagnosed exudative age-related macular degeneration (AMD) and associated use of ranibizumab and aflibercept in South Korea.

METHODS

In this retrospective, population-based cohort study, claims data for 2010-2015 were analysed in a randomly selected sample of 519 661 adults aged ≥40 years. The incidence per 10 000 person-years was estimated, along with the 95% CI. Incident exudative AMD was defined based on the registration code for rare intractable diseases. Use of ranibizumab and aflibercept and the incidence of exudative AMD were recorded.

RESULTS

Nine hundred and twelve patients were newly diagnosed with exudative AMD in 2010-2015. The 6-year incidence in the general population aged ≥40 years was 2.9 (95% CI 2.8 to 3.0) per 10 000 person-years. The incidence was highest in individuals aged 75-79 years (12.0, 95% CI 10.3 to 13.8). The incidence was higher in men than in women in all age groups. Six hundred and twenty-five (69%) of the 912 newly diagnosed patients started ranibizumab or aflibercept as a first-line treatment. The average number of injections administered was 6.1 (SD 3.9; minimum of 1 injection and maximum government-supported limit of 14) during 2010-2015; the number increased with increasing government funding support (from 5 to 10 and from 10 to 14 in 2013 and 2014, respectively).

CONCLUSIONS

This study describes the incidence of exudative AMD in South Korea and its treatment under the national health insurance system in this country. Its findings could be used for reference purposes and be useful when planning treatment for exudative AMD.

Long-Term Regular Use of Low-Dose Aspirin and Neovascular Age-Related Macular Degeneration: National Sample Cohort 2010-2015

PURPOSE

The association between long-term cardioprotective aspirin use and neovascular age-related macular degeneration (AMD) is controversial. This study was undertaken to estimate the risk of neovascular AMD with long-term regular use of low-dose aspirin.

DESIGN

Retrospective population-based study, using a nationwide cohort from a variety of clinics and hospitals in South Korea.

PARTICIPANTS

Nonregular aspirin users and regular aspirin users under national health insurance, aged ≥45 years, who were followed from 2010 to 2015, were identified.

METHODS

Incidence per 10 000 person-years for neovascular AMD was estimated. Long-term regular use of low-dose aspirin was defined as sustained intake of ≤100 mg aspirin with ≥1044 days prescription between 2005 and 2009. Nonregular aspirin users included occasional users or nonusers. The analyses included a propensity score-adjusted analysis in a large, randomly selected, unmatched whole cohort (n = 482 613); propensity score-matched analysis in a matched cohort (n = 74 196); and maximally adjusted analysis in the unmatched whole cohort (n = 482 613).

MAIN OUTCOME MEASURES

Incidence of newly developed neovascular AMD using the registration code for intractable disease under national health insurance.

RESULTS

Incidence of neovascular AMD was 3.5 among nonregular aspirin users and 7.2 among regular aspirin users per 10 000 person-years in the unmatched whole cohort. However, propensity score-adjusted analyses revealed no association between aspirin use and neovascular AMD (adjusted hazard ratio [HR], 0.98; 95% confidence interval [CI], 0.73-1.30). Likewise, propensity score-matched analyses showed no association; incidences of neovascular AMD were 7.5 and 7.1 among nonregular aspirin users and regular aspirin users (crude HR, 0.94; 95% CI, 0.70-1.28), respectively. A maximally adjusted model, including age, sex, income, residential area, and history of 100 randomly selected types of generic drugs, showed no association (adjusted HR, 0.95; 95% CI, 0.71-1.28).

CONCLUSIONS

We found no association between long-term regular use of low-dose aspirin for 5 years and future incidence of neovascular AMD. Thus, this large-scale study suggests that regular, long-term use of low-dose aspirin appears to be safe with respect to the new development of neovascular AMD.

Risk of Ischemic Stroke, Hemorrhagic Stroke, and All-Cause Mortality in Retinal Vein Occlusion: A Nationwide Population-Based Cohort Study

Purpose

To investigate whether the risk of subsequent stroke, ischemic stroke, hemorrhagic stroke, and all-cause mortality is increased among retinal vein occlusion (RVO) patients compared to non-RVO patients.

Methods

From the entire population of the Taiwan National Health Insurance Research Database (NHIRD) from 2001 to 2013, a total of 22919 subjects with RVO were enrolled in the RVO group, and 114595 propensity score (PS)-matched non-RVOs were enrolled in the comparison group. PS matching was based on age, gender, obesity, diabetes, hypertension, hyperlipidemia, coronary artery disease, atrial fibrillation, hyperviscosity syndrome, Charlson comorbidity index, glaucoma, and the use of antithrombotic drugs. A multivariate Cox regression analysis was used to estimate the adjusted hazard ratios (HRs) with a 95% confidence interval (CI) for each of the clinical outcomes, including stroke, ischemic stroke, hemorrhagic stroke, and all-cause mortality. Furthermore, we divided the RVO group into the branch retinal vein occlusion (BRVO) group and the central retinal vein occlusion (CRVO) group and separately compared their subsequent risks of the clinical outcomes with those of the comparison group.

Results

After adjusting for PS, the RVO group had a significantly higher risk of stroke (adjusted HR = 1.36; 95% CI: 1.32–1.40), ischemic stroke (adjusted HR = 1.36; 95% CI: 1.32–1.40), and hemorrhagic stroke (adjusted HR = 1.34; 95% CI: 1.24–1.44). However, the all-cause mortality did not exhibit significant differences. Furthermore, both the BRVOs and CRVOs had a significantly higher risk of subsequent stroke, ischemic stroke, and hemorrhagic stroke than did the comparisons, whereas all-cause mortality was similar among the groups.

Conclusions

People with RVO are at a significantly greater risk of developing stroke, ischemic stroke, and hemorrhagic stroke. However, RVO does not significantly increase the risk of all-cause mortality.

Air pollution influences the incidence of otitis media in children: A national population-based study

Background

Otitis media (OM) is a major reason for children’s visits to physicians and a major cause of their being treated with antibiotics. It not only causes economic burdens but also influences hearing, speech, and education. To our knowledge, no nationwide population-based study has assessed the association between air pollution and OM. Therefore, this study evaluated the association between air pollution levels and the incidence of OM.

Methods

We identified cases of OM that occurred in South Korea between January 2011 and December 2012 from the Korea National Health Insurance Service-National Sample Cohort database, and evaluated its relationship with five air pollutants: particulate matter (PM₁₀, particulates ≤10 μm in diameter), nitrogen dioxide (NO₂), ozone (O₃), sulfur dioxide, and carbon monoxide. Associations between the weekly incidence of OM and the five air pollutants were analyzed using generalized estimating equations. Conditional logistic regression analysis was used to obtain odds ratios (ORs) and their 99.9% Bonferroni-corrected confidence intervals after adjusting for gender, age, season, and region.

Results

We based our analysis on 160,875 hospital visits for OM by children aged <15 years. Correlations with higher concentrations of the five pollutants showed higher ORs than did the reference values at most time lags. PM₁₀ had the largest influence on the OM incidence at a time lag of 0 weeks, whereas NO₂ and O₃ had the largest impacts on OM incidence at time lags of 1 and 4 weeks, respectively.

Conclusion

These findings support the notion that the incidence of OM is associated with ambient air pollution.

Factors influencing the incidence and treatment of intracranial aneurysm and subarachnoid hemorrhage: time trends and socioeconomic disparities under an universal healthcare system

Background

Despite increasing usage of endovascular treatments for intracranial aneurysms, few research studies have been conducted on the incidence of unruptured aneurysm (UA) and subarachnoid hemorrhage (SAH), and could not show a decrease in the incidence of SAH. Moreover, research on socioeconomic disparities with respect to the diagnosis and treatment of UA and SAH is lacking.

Method

Trends in the incidences of newly detected UA and SAH and trends in the treatment modalities used were assessed from 2005 to 2015 using the nationwide database of the Korean National Health Insurance Service in South Korea. We also evaluated the influence of demographic characteristics including socioeconomic factors on the incidence and treatment of UA and SAH.

Result

The rates of newly detected UA and SAH were 28.3 and 13.7 per 100 000 of the general population, respectively, in 2015. The incidence of UA increased markedly over the 11-year study period, whereas that of SAH decreased slightly. UA patients were more likely to be female, older, employee-insured, and to have high incomes than SAH patients. In 2015, coiling was the most common treatment modality for both UA and SAH patients. Those who were female, employee-insured, or self-employed, with high income were likely to have a higher probability to be treated for UA and SAH.

Conclusion

The marked increase in the detection and treatment of UA might have contributed to the decreasing incidence of SAH, though levels of contribution depend on socioeconomic status despite universal medical insurance coverage.

Sex-specific age threshold for increased risk of retinal vein occlusion in Koreans

PURPOSE

Retinal vein occlusion (RVO) is one of most common retinal vascular disorders. It can lead to visual impairment and subsequent socioeconomic loss among the working population. RVO peak incidence is known to occur in the fifth and sixth decades of life, and is more predominant in males. To date, there has been no consensus regarding the optimal screening age for individuals at high risk for RVO, or whether sex-dependent cut-offs may be appropriate. Therefore, the purpose of this study was to predict the sex-specific age threshold for increased risk of RVO in Koreans.

METHODS

The analysis was based on data from the Korean National Health Insurance Database from 2013. Patients diagnosed with new cases of RVO from January 2013 to December 2013 were included. Individuals younger than 20 years of age and those with other retinal diseases were excluded. Multivariate logistic regression analysis and odds ratios with 95% confidence intervals were conducted to identify the age-related risk factors for RVO. A receiver operating characteristic (ROC) curve for RVO incidence was constructed.

RESULTS

Among the 754,749 individuals included in the study, 623 (0.08%) developed RVO. The optimal cut-off age for increased risk of RVO was 54 years overall, (sensitivity 0.78, specificity 0.70), 48 years in males (sensitivity 0.90, specificity 0.58), and 54 years in females (sensitivity 0.80, specificity 0.68). The incidence of RVO in females over 50 years of age was 3 times higher than that in females under the age of 50 after adjusting for confounding factors, and these differences tended to increase with age. The area under the ROC curve was 0.80 (95% CI; 0.79-0.82) overall, 0.81 (95% CI; 0.79-0.83) in males, and 0.79 (95% CI; 0.78-0.81) in females.

CONCLUSION

RVO incidence was higher in females, and increased more rapidly with age. The incidence of RVO more than doubled after 50 years of age for both sexes after adjusting for confounding factors. Females had an older age cut-off for RVO than males. However, the clinical impact of the use of sex-specific age cut-offs for RVO would benefit from additional validation from further studies.

Risk of incident atrial fibrillation in patients presenting with retinal artery or vein occlusion: a nationwide cohort study

BACKGROUND

The inter-relationships of atrial fibrillation (AF) to retinal vascular occlusions (whether retinal artery occlusion (RAO) or retinal venous occlusion (RVO)) remain unclear. It is unknown if a presentation of retinal artery or venous occlusions may indicate a new onset cardiac arrhythmia. To shed light on this association, we investigated the risk of new onset AF in patients with known RAO and RVO.

METHODS

Patients with retinal occlusions from 1997 to 2011 were identified through Danish nationwide registries and matched 1:5 according to sex and age. Cumulative incidence and unadjusted rates of AF according to retinal vascular occlusions (i.e. RAO or RVO) were determined. Hazard ratios (HR) of AF according to retinal vascular occlusion were adjusted for hypertension, diabetes, vascular disease and prior stroke/systemic thromboembolism/transient ischemic attack.

RESULTS

One thousand three hundred sixty-eight cases with retinal vascular occlusions were identified (median age 71.4 (inter quartile range (IQR); 61.2-79.8), 47.3% male). RAO constituted 706 cases (51.6%) and RVO 529 (38.7%). The rate of incident AF amongst all cases with retinal vascular occlusion was 1.74 per 100 person-years (95% confidence interval (CI), 1.47-2.06) compared to 1.22 (95% CI, 1.12-1.33) in the matched control group. The rate of AF in RAO was 2.01 (95% CI, 1.6-2.52) and 1.52 (1.15-2.01) in RVO. HRs of incident AF adjusted for cardiovascular comorbidities were 1.26 (95% CI; 1.04-1.53, p = 0.019) for any retinal vascular occlusion, 1.45 (95% CI; 1.10-1.89, p = 0.015) for RAO, and 1.02 (95% CI; 0.74-1.39, p = 0.920) for RVO.

CONCLUSIONS

A new diagnosis of retinal vascular occlusion in patients without prior AF was associated with increased risk of incident AF, particularly amongst patients with RAO. Awareness of AF in patients with retinal vascular occlusions is advised.

Ten-year prediction of suicide death using Cox regression and machine learning in a nationwide retrospective cohort study in South Korea

BACKGROUND

Death by suicide is a preventable public health concern worldwide. The aim of this study is to investigate the probability of suicide death using baseline characteristics and simple medical facility visit history data using Cox regression, support vector machines (SVMs), and deep neural networks (DNNs).

METHOD

This study included 819,951 subjects in the National Health Insurance Service (NHIS)-Cohort Sample Database from 2004 to 2013. The dataset was divided randomly into two independent training and validation groups. To improve the performance of predicting suicide death, we applied SVM and DNN to the same training set as the Cox regression model.

RESULTS

Among the study population, 2546 people died by intentional self-harm during the follow-up time. Sex, age, type of insurance, household income, disability, and medical records of eight ICD-10 codes (including mental and behavioural disorders) were selected by a Cox regression model with backward stepwise elimination. The area of under the curve (AUC) of Cox regression (0.688), SVM (0.687), and DNN (0.683) were approximately the same. The group with top .5% of predicted probability had hazard ratio of 26.21 compared to that with the lowest 10% of predicted probability.

LIMITATIONS

This study is limited by the lack of information on suicidal ideation and attempts, other potential covariates such as information of medication and subcategory ICD-10 codes. Moreover, predictors from the prior 12-24 months of the date of death could be expected to show better performances than predictors from up to 10 years ago.

CONCLUSIONS

We suggest a 10-year probability prediction model for suicide death using general characteristics and simple insurance data, which are annually conducted by the Korean government. Suicide death prevention might be enhanced by our prediction model.

Administration of oral fluoroquinolone and the risk of rhegmatogenous retinal detachment: A nationwide population-based study in Korea

PURPOSE

To investigate the association between oral fluoroquinolones (FQ) and the risk of rhegmatogenous retinal detachment (RRD) using a nationwide population-based study in Korea, designed to control for time-related bias.

METHODS

As a nested case-control study within a cohort, the KNHIS-NSC 2002-2013 (Korean National Health Insurance Service National Sample Cohort) data used for the investigation. The subjects who visited an ophthalmologist were included in a cohort. Subjects with infectious ocular diseases, severe ocular trauma, and congenital diseases were excluded. Within the cohort, subjects who underwent surgery for RRD were defined as cases, and controls were matched by age group, sex, and cohort entry date using an incidence density sampling method. After investigating the exposure to oral FQ, the odds ratio was calculated by the FQ exposure rate of both groups and adjusted by the confounding factors of demography, health service utilization, and comorbidities.

RESULTS

A total of 1,151 subjects in the case group and 11,470 subjects in the control group were included. There were intergroup differences in household income, numbers of ophthalmologic visits and drug prescriptions, events of intraocular surgeries, and prevalence of diabetes and degenerative myopia (all P's<0.05). The crude odds ratio of the total group was 1.06 (P = 0.53, 95% CI 0.88-1.28), and the odds ratio adjusted for all pre-defined confounders was 1.00 (P = 0.99, 95% CI 0.81-1.24). The crude and adjusted odds ratios were not showed statistical significance (all P's>0.05).

CONCLUSIONS

By the nested case-control design, this study showed that oral administration of FQ was not associated with the increased risk of development of RRD.

Cohort study of cervical ossification of posterior longitudinal ligament in a Korean populations: Demographics of prevalence, surgical treatment, and disability

OBJECTIVE

To investigate the demographic characteristics of cervical ossification of posterior longitudinal ligament (OPLL) including prevalence, surgical treatment, and disability in Korean population using Korean National Health Insurance Service National Sample Cohort (NHIS-NSC) data, and to analyze association between accessibility for surgical treatment and socioeconomic factors.

PATIENTS AND METHODS

A population-based cohort study was conducted using stratified representative sampling from NHIS-NSC data from the year 2002 to 2013. We analyzed prevalence and distribution of cervical OPLL according to age, sex, and socioeconomic factors. Multiple logistic regression analysis was conducted to investigate associations between independent variables and the rate of surgical treatment.

RESULTS

The overall prevalence of cervical OPLL was 190 per 100,000 people in Korea, and 11.4% of male patients and 4.0% of female patients received surgical treatment. Logistic regression analysis revealed that male patients received more surgical treatment than did female patients, also income level and residential area influence the rate of surgical treatment in females after adjustment of covariates (p< 0.05). Disability rate associated with cervical OPLL was 2.27% in male and 0.99% in female patients.

CONCLUSION

In this cohort study, the prevalence of cervical OPLL was 190 per 100,000 people. Male patients received more surgery, and disability rate of male was higher than female patients. Although surgical treatment is covered by medical insurance in Korea, socioeconomic factors such as income level and residential area influence the treatment plans in females. These findings can help in the understanding of disease progression and can inform surgical treatment plans to reduce disability.

Review of the association between retinal microvascular characteristics and eye disease

Computerized retinal imaging technologies enable the static and dynamic measurement of a range of retinal microvascular parameters. Large population-based studies have reported associations between these microvascular indices and various ophthalmic diseases including diabetes, age-related macular degeneration, retinal artery embolism, retinal vein occlusion, glaucoma and non-glaucomatous optic neuropathies. Increasingly, sophisticated imaging and analysis techniques have the potential to provide relevant clinical information regarding disease risk and progression; however, further studies are required to verify associations and strengthen the predictive power of these techniques. We summarize the current state of knowledge regarding retinal microvascular characteristics and eye disease.

Increased risk of hip fractures in Korean patients with type 2 diabetes: a 6-year nationwide population-based study

We compared the incidence and risk of hip fractures in Korean patients with type 2 diabetes and non-diabetic subjects in a nationwide population-based study. The study included 17,110 patients diagnosed with type 2 diabetes in 2004 and 34,220 randomly selected age- and sex-matched control subjects drawn from the Korean National Health Insurance Research database. Fracture events occurring between 2004 and 2010 were identified from medical claims data. The adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for fractures associated with diabetes were calculated. A total of 3855 fractures of any type (3029 in females and 826 in males) and 493 hip fractures (353 in females and 140 in males) were observed in 51,330 subjects over a 6-year follow-up period. The risk of hip fractures was significantly higher in female (HR 1.73; 95% CI 1.38-2.16) and male (HR 1.84; 95% CI 1.29-2.63) diabetics than in non-diabetic controls after adjusting for multiple confounders. Stratification by age revealed that the adjusted HR for hip fractures was highest in diabetic patients aged 50-64 years (HR 2.54 in females and 2.70 in males) and decreased with increasing age. The risk of other fractures did not differ between the groups. Korean males and females with type 2 diabetes are at an increased risk of hip fractures compared with non-diabetic individuals. Osteoporosis assessments and fracture prevention strategies are necessary for Koreans with type 2 diabetes.