Trends and Clinical Characteristics of Next-Generation Sequencing–Based Genetic Panel Tests: An Analysis of Korean Nationwide Claims Data / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#In the modern era of precision medicine, next-generation sequencing (NGS) is employed for a variety of clinical purposes. The aim of this study was to investigate the trends and clinical characteristics of NGS testing in South Korea. @*Materials and Methods@#This nationwide, population-based, retrospective cohort study examined National Health Insurance Service claims data from 2017 to 2021 for NGS and from 2008 to 2021 for gene-targeted anticancer drugs. @*Results@#Among the total 98,748 claims, there were 51,407 (52.1%) solid cancer panels, 30,173 (30.5%) hereditary disease panels, and 17,168 (17.4%) hematolymphoid cancer panels. The number of annual claims showed a persistent upward trend, exhibiting a 5.4-fold increase, from 5,436 in 2017 to 29,557 in 2021. In the solid cancer panel, colorectal cancer was the most common (19.2%), followed by lung cancer (18.8%). The annual claims for targeted cancer drugs have increased 25.7-fold, from 3,932 in 2008 to 101,211 in 2020. Drugs for the treatment of lung cancer accounted for 488,819 (71.9%) claims. The number of patients who received non-hereditary NGS testing has substantially increased, and among them, the count of patients prescribed targeted anticancer drugs consistently rose from 508 (13.9%) in 2017 to 2,245 (12.3%) in 2020. @*Conclusion@#This study highlights the rising nationwide demand for comprehensive genetic testing for disease diagnosis and treatment following NGS reimbursement by the National Health Insurance in South Korea, in addition to the need for greater utilization of targeted anticancer drugs.

Prevalence and Characteristics by Age and Sex in Pediatric Trigger Digits: Nationwide Analysis Using Korea Health Insurance Dataset

Background@#Pediatric trigger digit (TD) does not appear at birth but is diagnosed after birth by finding a flexion contracture of the thumb or other fingers. The reported incidence of pediatric TDs varies from 0.5 to 5 cases per 1,000 live births without sex-specific predominance. We performed a nationwide large-scale study to determine the prevalence and incidence of pediatric TDs and analyzed operative treatment for pediatric TDs using the National Health Insurance data of South Korea. @*Methods@#Patients with pediatric TDs, aged 0–10 years between 2011 and 2020, were included in this study. Children born between 2011 and 2015 were set as the reference population and followed up until 2020. We calculated the prevalence and incidence rates of pediatric TDs according to age and sex and analyzed the operation rate, age at surgery, time interval from initial diagnosis to surgery, and follow-up period. Patient selection and treatment were based on International Classification of Diseases, 10th Revision (ICD-10). @*Results@#The prevalence rates of pediatric TDs ranged from 0.063% to 0.084%. Girls had a higher prevalence rate (0.066%–0.094%) than boys (0.060%–0.075%). The total incidence rate was 77.6/100,000 person-years, and the incidence rate was higher in girls (84.8) than in boys (70.7). Among 2,181,814 children born between 2011 and 2015, 12,729 were diagnosed with pediatric TDs, of which 1,128 (8.9%) underwent operative management. The means of age at initial diagnosis, age at surgery, and the time interval between diagnosis and operation were 2.76 ± 1.91 years, 3.79 ± 2.19 years, and 1.15 ± 1.71 years, respectively. @*Conclusions@#High prevalence and incidence rates of pediatric TDs were found in 2- to 3-year-old patients. Among pediatric patients, 8.9% underwent operative management that was most frequently conducted between 2 and 3 years of age (within 1 year of initial diagnosis).

Uric Acid and Risk of Cardiovascular Disease and Mortality: A Longitudinal Cohort Study

Background@#This study aimed to examine the association of serum uric acid levels with incident cardiovascular disease and mortality in Korean adults without gout. @*Methods@#This large longitudinal cohort study included adults aged > 19 years who had serum uric acid levels measured at least once at the National Health Insurance Service Ilsan Hospital from January 1, 2006 to December 31, 2015. Longitudinal data on person-level cardiovascular disease and cardiovascular mortality were linked to the National Health Insurance Service claims database and National Death Index. @*Results@#Among a total of 92,454 study participants with a median follow-up of 4.7 years, 7,670 (8.3%) composite events of cardiovascular disease or cardiovascular mortality were observed. Multivariable Cox proportional-hazards models revealed that each 1 mg/dL increment in uric acid level was associated with a 6% higher risk of composite outcomes.Compared with that for the uric acid level category of 4.0 to < 5.0 mg/dL, adjusted hazard ratios (95% confidence interval) for uric acid level categories of 5.0 to < 6.0, 6.0 to < 7.0, and ≥ 7.0 mg/dL were 1.10 (1.04–1.18), 1.20 (1.11–1.30), and 1.36 (1.25–1.47), respectively. In the secondary analyses for cardiovascular disease or cardiovascular mortality examined separately, a higher uric acid level was similarly associated with a higher risk of each adverse outcome. These associations were generally consistent across clinically relevant subgroups. @*Conclusion@#A graded association was noted between serum uric acid levels and cardiovascular risk, suggesting that higher uric acid levels may adversely affect cardiovascular health and survival in individuals without gout.

Risk of Pregnancy Complications and Low Birth Weight Offsprings in Korean Women With Rheumatic Diseases: A Nationwide Population-Based Study

Background@#To determine the risk of pregnancy complications and adverse offspring outcomes in Korean women with rheumatic diseases (RDs). @*Methods@#Women aged 20–44 years with pregnancies ending in delivery were identified from the National Health Insurance Service-National Health Information Database (2009–2016).Women with RD including systemic lupus erythematosus (SLE), seropositive rheumatoid arthritis (SPRA), and ankylosing spondylitis (AS) (n = 4,284) were age-matched with controls (n = 26,023). Outcome variables included threatened abortion (TA), preterm birth (PB), preeclampsia/eclampsia (PE/E), intrauterine growth retardation (IGR), urinary tract infection, low birth weight (LBW) offsprings, and offspring death within 1 year of birth. @*Results@#Women with RDs had increased risks for cesarean section delivery (odds ratio [OR], 1.5; 95% confidence interval [CI], 1.4–1.6), TA (OR, 1.4; 95% CI, 1.2–1.5), PB (OR, 2.4; 95% CI, 1.9–3.2), PE/E (OR, 4.4; 95% CI, 3.3–5.9), and IGR (OR, 2.4; 95% CI, 2.0–3.1) than the controls. The risk of pregnancy complications was increased in SLE and SPRA pregnancies but not in AS pregnancies. Offsprings of women with RDs had an increased risk of LBW (OR, 4.0; 95% CI, 3.2–4.9). The offspring mortality rate within 1 year of birth was higher in women with RDs (6.2/10,000 persons) than in the controls (4.9/10,000 persons). @*Conclusion@#Women with RDs are at a risk of developing pregnancy complications, and the risk of LBW offsprings and offspring death within 1 year of birth is increased in these women.Therefore, this population requires special attention during their childbearing years.

The Effect of Chronic Disease Management Program on the Risk of Complications in Patients With Hypertension in Korea

Background@#A chronic disease management program was implemented in April 2012 to lower out-of-pocket costs for repeat visits to the same clinic. The aim of this study was to investigate the association between participating in this program and the onset of complications among patients with hypertension using whole-nation claims data. @*Methods@#We used National Health Insurance Service data (2011–2018) and patients with newly detected hypertension from 2012 to 2014 were selected. Chronic disease management program reduces the out-of-pocket expenses of consultation fee from 30% to 20% when patients enroll in this program by agreeing to visit the same clinic for the treatment of hypertension or diabetes. As the dependent variable, acute myocardial infarction (MI), stroke, chronic kidney disease (CKD), and heart failure (HF) were selected. For analysis, cox proportional hazards model was used. @*Results@#Total participants were 827,577, among which 102,831(12.6%) subjects participated in the chronic disease management. Participants of the chronic disease management program were more likely to show lower hazard ratios (HRs) than those of non-participants in terms of all complications (MI: HR, 0.75; 95% confidence interval [CI], 0.68–0.82; stroke: HR, 0.75; 95% CI, 0.72–0.78; CKD: HR, 0.90; 95% CI, 0.85–0.96; HF: HR, 0.56; 95% CI, 0.52–0.61). @*Conclusion@#The results showed that participants of the chronic disease management program were less likely to have hypertension complications compared to non-participants. Enhancing the participation rate may be related to better outcomes and reducing medical expenses among patients with chronic diseases.

Distribution of Medical Service Use for Facial Palsy Between Medicine and Traditional Korean Medicine Based on Population-Based Data of Korea

We investigated the distribution of medical service uses for Bell’s palsy and Ramsay Hunt syndrome between medicine and traditional Korean medicine using the National Health Insurance Service National Sample Cohort data of Korea from 2006 to 2015. Patients were identified with diagnostic codes and medication or treatment claim codes. For Bell’s palsy, there were 5,970 (68.8%) patients who used traditional Korean medical service only, whereas for Ramsay Hunt syndrome, there were 749 (93.6%) patients who used medical service only.The proportion of traditional Korean medical service use was higher than that of medical service use in patients with Bell’s palsy, while the opposite was found in patients with Ramsay Hunt syndrome.

Analysis of the incidence of dementia in complete edentulous patients using the National Health Insurance Service-Elderly Cohort Database (NHIS-ECD) / 대한치과보철학회지

Purpose@#To investigate the relationship between dementia and complete tooth loss on both sides or one side using large demographic data. @*Materials and methods@#A retrospective cohort study was designed using the National Health Insurance Service-Elderly Cohort Database (NHIS-ECD) which was established for people over the age of 60. The experimental group was the complete edentulous cohort, which had a history of treatment for national health insurance covered complete denture on both sides or one side from July 1, 2012 to December 31, 2013. And the control group was the dentulous cohort, which had a history of conservative dental treatment for the same period. All subjects had no history of diagnosis or treatment of dementia during this time. These cohorts were matched 1:1 by age, gender, and place of residence according to the propensity score matching method. Then the incidence of dementia was compared between these cohorts. @*Results@#Compared with those groups, the incidence of dementia was significantly higher in the experimental group (12.13%) than in the control group (9.74%) (P<.05). No clear association between other factors has been identified. @*Conclusion@#The analysis of large-scale demographic data shows that the incidence of dementia is high in complete edentulous patients on both sides or one side.

The socioeconomic impact of Korean dental health insurance policy on the elderly: a nationwide cohort study in South Korea

PURPOSE: The purpose of this retrospective study was to investigate the relationships of types of dental insurance coverage in Korea with sociodemographic characteristics and the prevalence of systemic and oral diseases, as well as to evaluate the socioeconomic impact of Korean dental insurance policies. METHODS: Sample cohort data from 2006 to 2015 were obtained from the National Health Insurance Service. Patients were divided into 2 groups. The exposed group comprised patients who received insurance benefits for complete dentures, removable partial dentures, and implant care, while the control group comprised patients who did not receive these benefits. The type of insurance coverage and the prevalence of systemic and oral diseases were compared between the 2 groups. RESULTS: Patients who received benefits in the form of complete dentures, removable partial dentures, and implants had similar sociodemographic characteristics in terms of sex, age, income quintile, and type of insurance coverage to the control group. The prevalence of hypertension, anemia, renal disease, rheumatoid arthritis, osteoporosis, asthma, and cerebral infarction was higher in the exposed group than in the control group (P<0.05). The prevalence of periodontal diseases and dental caries was also higher in the exposed group. CONCLUSIONS: Korean dental health insurance policy has been beneficial for the medical expenses of low-income and elderly people suffering from a cost burden due to systemic diseases. However, since there is a tendency to avoid invasive interventions in older patients due to the high risk of systemic diseases, insurance coverage of dentures may be more helpful from a socioeconomic perspective than coverage of dental implant treatments.

Prognosis of proximal upper-third gastric cancer excluding tumors originating in the esophagogastric junction

PURPOSE: The objective of the current study was to compare surgical outcomes and prognosis based on the longitudinal location of stomach tumors in patients undergoing curative treatment. The specific focus was on the prognosis for adenocarcinomas in the proximal upper-third of the stomach, excluding tumors in the esophagogastric junction (EGJ).METHODS: Data from patients who underwent curative treatment for gastric adenocarcinoma between 2000 and 2010 at a single institution were analyzed retrospectively. Excluding tumors of EGJ origin, data from 797 patients were reviewed—686 with distal gastric cancer and 111 with proximal gastric cancer. Clinicopathology features, tumor stage, surgical outcomes, recurrence, and survival were compared between the groups.RESULTS: Gastric cancer recurred in 136 of the patients (17.1%). Although differences were detected between proximal and distal cancer patients in the prevalence in males versus females (74.8% vs. 63.4%, P=0.020) and in undifferentiated histology (60.4% vs. 47.7%, P=0.013), the prognosis for proximal gastric cancer did not differ from distal gastric cancer. The overall 5-year disease-free survival rate was 84.9% and 81.4% in proximal and distal cancer patients, respectively (P=0.389).CONCLUSION: The prognosis of proximal cancer, excluding tumors of EGJ origin, did not differ from the prognosis of more distal gastric cancer. Clarifying the prognosis of proximal gastric cancer will require the large-scale comparison of an organized, multi-institution database.

Cerebrospinal Biomarker Cut-off Methods Defined Only by Alzheimer's Disease Predict More Precisely Conversions of Mild Cognitive Impairment

BACKGROUND AND PURPOSE: The cerebrospinal fluid (CSF) biomarkers play an important supportive role as diagnostic and predictive indicators of Alzheimer's disease (AD). About 30% of controls in old age show abnormal values of CSF biomarkers and display a higher risk for AD compared with those showing normal values. The cut-off values are determined by their diagnostic accuracy. However, the current cut-off values may be less accurate, because controls include high-risk groups of AD. We sought to develop models of patients with AD, who are homogenous for CSF biomarkers. METHODS: We included participants who had CSF biomarker data in the Alzheimer's Disease Neuroimaging Initiative database. We investigated the factors related to CSF biomarkers in patients with AD using linear mixed models. Using the factors, we developed models corresponding to CSF biomarkers to classify patients with mild cognitive impairment (MCI) into high risk and low risk and analyzed the conversion from MCI to AD using the Cox proportional hazards model. RESULTS: APOE ε4 status and age were significantly related to CSF Aβ1-42. CSF t-tau, APOE ε2 status and sex were significant factors. The CSF p-tau181 was associated with age and frequency of diagnosis. Accordingly, we modeled the three CSF biomarkers of AD. In MCI without APOE ε4, our models were better predictors of conversion. CONCLUSIONS: We can interpret CSF biomarkers based on the models derived from the data obtained from patients with AD.

Analysis of New Patient's Willingness to Pay Additional Costs for Securing Satisfactory Consultation Time / 보건행정학회지

BACKGROUND: We evaluated new patient's satisfactory consultation time (SCT) and their willingness to pay additional costs (WPAC) for their SCT. METHODS: We surveyed medical service satisfaction, SCT, WPAC for their SCT, and payable amount to 612 new patients of single general hospital and measured their real consultation time (RCT). To compare WPAC and payable amount, we divided RCT into 4 groups (≤3 minutes, 3–5 minutes, 5–10 minutes, and >10 minutes), and SCT into 3 groups (≤5 minutes, 5–10 minutes, and >10 minutes). On the basis of WPAC, we estimated new patient's SCT. RESULTS: RCT was 6.2 minutes, SCT was 8.9 minutes, and medical service satisfaction score was 4.3 (out of 5). The number of patients having WPAC (payable group) was 381 (62.3%) and the amount was 5,853 Korean won. Their RCT and SCT were longer than non-payable group (6.4 minutes vs. 5.7 minutes, 9.3 minutes vs. 8.2 minutes). From multiple logistic regression analysis, WPAC of RCT 5–10 minutes was higher than that RCT ≤3 minutes (odds ratio=1.78). Payable amount was highest in RCT >10 minutes (6,950 Korea won) and SCT >10 minutes (7,458 Korean won). Intuitively we suggest 10 minutes as SCT, based on payable group's SCT (9.3 minutes) and cut-off time differentiating payable group with non-payable group (10 minutes). CONCLUSION: We found that new patient had WPAC for their SCT and the longer the SCT, the greater the amount. From this, we hope that current simplified new patient consultation fee calculating system should be modified combining the consultation time factor.

Fatty liver associated with metabolic derangement in patients with chronic kidney disease: A controlled attenuation parameter study

BACKGROUND: Hepatic steatosis measured with controlled attenuation parameter (CAP) using transient elastography predicts metabolic syndrome in the general population. We investigated whether CAP predicted metabolic syndrome in chronic kidney disease patients. METHODS: CAP was measured with transient elastography in 465 predialysis chronic kidney disease patients (mean age, 57.5 years). RESULTS: The median CAP value was 239 (202–274) dB/m. In 195 (41.9%) patients with metabolic syndrome, diabetes mellitus was more prevalent (105 [53.8%] vs. 71 [26.3%], P < 0.001), with significantly increased urine albumin-to-creatinine ratio (184 [38–706] vs. 56 [16–408] mg/g Cr, P = 0.003), high sensitivity C-reactive protein levels (5.4 [1.4–28.2] vs. 1.7 [0.6–9.9] mg/L, P < 0.001), and CAP (248 [210–302] vs. 226 [196–259] dB/m, P < 0.001). In multiple linear regression analysis, CAP was independently related to body mass index (β = 0.742, P < 0.001), triglyceride levels (β = 2.034, P < 0.001), estimated glomerular filtration rate (β = 0.316, P = 0.001), serum albumin (β = 1.386, P < 0.001), alanine aminotransferase (β = 0.064, P = 0.029), and total bilirubin (β = −0.881, P = 0.009). In multiple logistic regression analysis, increased CAP was independently associated with increased metabolic syndrome risk (per 10 dB/m increase; odds ratio, 1.093; 95% confidence interval, 1.009–1.183; P = 0.029) even after adjusting for multiple confounding factors. CONCLUSION: Increased CAP measured with transient elastography significantly correlated with and could predict increased metabolic syndrome risk in chronic kidney disease patients.

A Descriptive Study on Meningitis and Meningoencephalitis Caused by Varicella Zoster Virus / 대한피부과학회지

BACKGROUND: Herpes zoster meningitis and meningoencephalitis, rare complications of herpes zoster, may follow the onset of rash, precede it, or even occur without rash. There have been few studies describing the order of occurrence of neurological symptoms and zoster. OBJECTIVE: We compared the clinical and laboratory features, treatments, and progress of the conditions among patients with herpes zoster meningitis and meningoencephalitis according to the timing of zoster onset in relation to neurological symptoms and also according to the immune status. METHODS: We performed a retrospective review of 21 patients with meningitis and 3 patients with meningoencephalitis who showed the characteristic rash of herpes zoster at National Health Insurance Service Ilsan Hospital between March 2000 and June 2015. RESULTS: The 11 patients in whom zoster preceded neurological symptoms had a shorter duration of neurological symptoms (median 3 days; range 1~10) than did the 13 patients who experienced neurological symptoms first (median 10 days; range 4~27) (p<0.05). The intervals between the onset of neurological symptoms and a) presentation to the hospital, b) cerebrospinal fluid tests, and c) intravenous acyclovir treatment were all shorter in the patients with zoster preceding neurological symptoms (p<0.05). No significant differences in age or immune status were observed between the two groups. In the 9 immunocompromised patients, higher incidence of meningoencephalitis and neurologic complications was noted in comparison to the 15 immunocompetent patients (p<0.05). CONCLUSION: Antecedent zoster rash in varicella zoster virus-induced meningitis and meningoencephalitis appears to lead to more rapid initiation of diagnostic tests and antiviral treatment. The possibility of central nervous system complications should not be overlooked even in patients with herpes zoster.

Difference in Bone Mineral Density Change at the Lateral Femoral Cortices according to Administration of Different Bisphosphonate Agents

BACKGROUND: To retrospectively assess whether the response of subtrochanteric lateral cortex (STLC) is different according to the bisphosphonate agents in terms of bone mineral density (BMD) change. METHODS: A total of 149 subjects, who had 2- to 4-year interval follow-up of BMD using dual energy X-ray absorptiometry (DXA), were included in this retrospective study divided into following 3 groups: control group (no consumption of any anti-osteoporotic drugs, n=38), alendronate group (naïve alendronate users, n=48), risedronate group (naïve risedronate users, n=63). BMD was measured at the STLC and subtrochanteric medial cortex (STMC) in each patient by drawing rectangular ROIs at the bone cortices. The percent change of BMD at the STLC were compared between the aforementioned 3 groups by using analysis of covariance model to control five independent variables of age, body mass index, percent change of STMC, hip axis length, time interval between DXA examinations. RESULTS: The least square mean values±standard deviation of the percent change of BMD in the control, alendronate, and risedronate groups were 1.46±1.50, 2.23±1.26, and 6.96±1.11, respectively. The risedronate group showed significantly higher change of BMD percentage compared with the control (adjusted P=0.012) or alendronate (adjusted P=0.016) groups. CONCLUSIONS: The percent change of BMD at the STLC in the risedronate user group was greater than the alendronate and control groups. The implication of these changes needs to be further verified.

Papillary Thyroid Microcarcinomas Are Different from Latent Papillary Thyroid Carcinomas at Autopsy

The aim of this study was to review the literature of latent papillary thyroid carcinomas (PTCs) discovered at autopsy and describe the available pathologic and demographic differences from a group of papillary thyroid microcarcinomas (PTMCs) the reported in a previous publication. We searched the PubMed for published articles describing latent thyroid carcinomas detected at autopsy. Meta-analysis was performed to identify differences between the clinicopathologic features of PTMCs analyzed previously in our institution (Group I) and those of latent PTCs described in autopsy studies (Group II). We identified 1,355 patients with PTMC (Group I) and 989 with latent PTCs (Group II). Mean patient age was 47.3 yr in Group I and 64.5 yr in Group II. The male:female ratio was 1:10.9 in Group I and 1:1 in Group II. Most PTMCs (67.6%) were larger than 0.5 cm in size, whereas most latent PTCs were <1-3 mm in diameter. The rates of multifocality were 24.7% in Group I and 30.5% in Group II, and the rates of cervical lymph node metastasis were 33.4% in Group I and 10.0% in Group II. Currently available data indicated that clinically evident PTMCs differ from latent PTCs detected at autopsy. Therefore, these two entities should be regarded as different.

Effects of APACHE II Score and Initial Nutritional Status on Prognosis of the Critically Ill Patients / 대한구급학회지

BACKGROUND: Malnutrition is common in hospitalized patients, especially in critically ill patients and affects their mortality and morbidity. However, the correlation between malnutrition and poor outcome is not fully understood. Our hypothesis is that the nutritional effect on the patient's prognosis would differ depending on the severity of the disease. METHODS: 3,758 patients admitted to the intensive care unit (ICU) were observed retrospectively. Patients were divided into well, moderate and severe groups, according to their nutritional status as assessed by their serum albumin level and total lymphocyte count (TLC). The severity of the disease was assessed by the Acute Physiologic and Chronic Health Evaluation (APACHE II score). All patients were followed clinically until discharge or death and ICU days, hospital days, ventilator days, and mortality rates were recorded. RESULTS: Depending on the definition used, the prevalence of hospital malnutrition is reported to be 68.3%. Hospital days, ICU days, as well as ventilator days of moderate and severe groups were longer than the well group. In patients exhibiting mild severity of disease, moderate and severe malnutrition groups have 3-5 times the mortality rate than the well group. CONCLUSIONS: Malnutrition affects the prognosis of patients who have an APACHE II score ranging from 4-29 points. Active nutritional support may be more effective for patients with a disease of mild severity.

A Formula to Predict Spectral Domain Optical Coherence Tomography (OCT) Retinal Nerve Fiber Layer Measurements Based on Time Domain OCT Measurements

PURPOSE: To establish and validate a formula to predict spectral domain (SD)-optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) thickness from time domain (TD)-OCT RNFL measurements and other factors. METHODS: SD-OCT and TD-OCT scans were obtained on the same day from healthy participants and patients with glaucoma. Univariate and multivariate linear regression relationships were analyzed to convert average Stratus TD-OCT measurements to average Cirrus SD-OCT measurements. Additional baseline characteristics included age, sex, intraocular pressure, central corneal thickness, spherical equivalent, anterior chamber depth, optic disc area, visual field (VF) mean deviation, and pattern standard deviation. The formula was generated using a training set of 220 patients and then evaluated on a validation dataset of 105 patients. RESULTS: The training set included 71 healthy participants and 149 patients with glaucoma. The validation set included 27 healthy participants and 78 patients with glaucoma. Univariate analysis determined that TD-OCT RNFL thickness, age, optic disc area, VF mean deviation, and pattern standard deviation were significantly associated with SD-OCT RNFL thickness. Multivariate regression analysis using available variables yielded the following equation: SD-OCT RNFL = 0.746 x TD-OCT RNFL + 17.104 (determination coefficient [R2] = 0.879). In the validation sample, the multiple regression model explained 85.6% of the variance in the SD-OCT RNFL thickness. CONCLUSIONS: The proposed formula based on TD-OCT RNFL thickness may be useful in predicting SD-OCT RNFL thickness. Other factors associated with SD-OCT RNFL thickness, such as age, disc area, and mean deviation, did not contribute to the accuracy of the final equation.