Development of Various Diabetes Prediction Models Using Machine Learning Techniques

Background@#There are many models for predicting diabetes mellitus (DM), but their clinical implication remains vague. Therefore, we aimed to create various DM prediction models using easily accessible health screening test parameters. @*Methods@#Two sets of variables were used to develop eight DM prediction models. One set comprised 62 easily accessible examination results of commonly used variables from a tertiary university hospital. The second set comprised 27 of the 62 variables included in the national routine health checkups. Gradient boosting and random forest algorithms were used to develop the models. Internal validation was performed using the stratified 10-fold cross-validation method. @*Results@#The area under the receiver operating characteristic curve (ROC-AUC) for the 62-variable DM model making 12-month predictions for subjects without diabetes was the largest (0.928) among those of the eight DM prediction models. The ROC-AUC dropped by more than 0.04 when training with the simplified 27-variable set but still showed fairly good performance with ROC-AUCs between 0.842 and 0.880. The accuracy was up to 11.5% higher (from 0.807 to 0.714) when fasting glucose was included. @*Conclusion@#We created easily applicable diabetes prediction models that deliver good performance using parameters commonly assessed during tertiary university hospital and national routine health checkups. We plan to perform prospective external validation, hoping that the developed DM prediction models will be widely used in clinical practice.

Association between Lung Function and New-Onset Diabetes Mellitus in Healthy Individuals after a 6-Year Follow-up

Background@#We analyzed hemoglobin A1c (HbA1c) levels and various lung function test results in healthy individuals after a 6-year follow-up period to explore the influence of lung function changes on glycemic control. @*Methods@#Subjects whose HbA1c levels did not qualify as diabetes mellitus (DM) and who had at least two consecutive lung function tests were selected among the people who visited a health promotion center. Lung function parameters, including forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), FEV/FVC ratio, and forced expiratory flow 25% to 75% (FEF25%−75%), were divided into four groups based on their baseline quantiles. To evaluate future DM onset risk in relation to lung function changes, the correlation between baseline HbA1c levels and changes in lung function parameters after a 6-year follow-up period was analyzed. @*Results@#Overall, 17,568 individuals were included; 0.9% of the subjects were diagnosed with DM. The individuals included in the quartile with FEV1/FVC ratio values of 78% to 82% had lower risk of DM than those in the quartile with FEV1/FVC ratio values of ≥86% after adjusting for age, sex, and body mass index (P=0.04). Baseline percent predicted FEV1, FVC, FEV1/FVC ratio, and FEF25%−75%, and differences in the FEV1/FVC ratio or FEF25%−75%, showed negative linear correlations with baseline HbA1c levels. @*Conclusion@#Healthy subjects with FEV1/FVC ratio values between 78% and 82% had 40% lower risk for future DM. Smaller differences and lower baseline FEV1/FVC ratio or FEF25%−75% values were associated with higher baseline HbA1c levels. These findings suggest that airflow limitation affects systemic glucose control and that the FEV1/FVC ratio could be one of the factors predicting future DM risk in healthy individuals.

Increasing Individual Target Glucose Levels to Prevent Hypoglycemia in Patients with Diabetes / 가정의학회지

Hypoglycemia is one of the severe complications of diabetes. To prevent hypoglycemia, an emphasis is placed on maintaining an appropriate balance between nutrition, activity, and treatment, which can be achieved by the repetition of self-trials based on self-monitoring. Clinicians routinely focus on patients’ contribution, including timely intake of an adequate amount of carbohydrates, physical activity, antidiabetic medication, and abstinence from alcohol. Recently, many guidelines have highlighted the importance of clinicians’ factors and recommend individualized treatments according to lifestyle patterns and specific needs following the de-intensification of treatment. The optimal value of hemoglobin A1c (HbA1c) levels for blood glucose level regulation remains controversial among countries, but it generally does not exceed 8.0%. In populations that are at a risk of hypoglycemia, such as the older adults, it is advisable to adjust the target blood glucose level to less than 8.0%. Meanwhile, a blood glucose level of 7.0%–7.5% is generally recommended for healthy older adults. If the expected lifetime is shorter than 10 years or in patients with chronic kidney disease and severe cardiovascular disease, the HbA1c level target can be increased to 7.5%–8.0%. For even shorter lifetime expectancy, the target can be adjusted up to 8.0%–9.0%. To prevent hypoglycemia, the target blood glucose level needs to be adjusted, particularly in older adult patients. Ultimately, it is important to identify the maximum blood glucose levels that do not cause hypoglycemia and the minimum blood glucose levels that do not cause hyperglycemia-associated complications.

Increasing Individual Target Glucose Levels to Prevent Hypoglycemia in Patients with Diabetes / 가정의학회지

Hypoglycemia is one of the severe complications of diabetes. To prevent hypoglycemia, an emphasis is placed on maintaining an appropriate balance between nutrition, activity, and treatment, which can be achieved by the repetition of self-trials based on self-monitoring. Clinicians routinely focus on patients’ contribution, including timely intake of an adequate amount of carbohydrates, physical activity, antidiabetic medication, and abstinence from alcohol. Recently, many guidelines have highlighted the importance of clinicians’ factors and recommend individualized treatments according to lifestyle patterns and specific needs following the de-intensification of treatment. The optimal value of hemoglobin A1c (HbA1c) levels for blood glucose level regulation remains controversial among countries, but it generally does not exceed 8.0%. In populations that are at a risk of hypoglycemia, such as the older adults, it is advisable to adjust the target blood glucose level to less than 8.0%. Meanwhile, a blood glucose level of 7.0%–7.5% is generally recommended for healthy older adults. If the expected lifetime is shorter than 10 years or in patients with chronic kidney disease and severe cardiovascular disease, the HbA1c level target can be increased to 7.5%–8.0%. For even shorter lifetime expectancy, the target can be adjusted up to 8.0%–9.0%. To prevent hypoglycemia, the target blood glucose level needs to be adjusted, particularly in older adult patients. Ultimately, it is important to identify the maximum blood glucose levels that do not cause hypoglycemia and the minimum blood glucose levels that do not cause hyperglycemia-associated complications.

Acarbose Add-on Therapy in Patients with Type 2 Diabetes Mellitus with Metformin and Sitagliptin Failure: A Multicenter, Randomized, Double-Blind, Placebo-Controlled Study

BACKGROUND: We evaluated the efficacy and safety of acarbose add-on therapy in Korean patients with type 2 diabetes mellitus (T2DM) who are inadequately controlled with metformin and sitagliptin. METHODS: A total of 165 subjects were randomized to metformin and sitagliptin (Met+Sita, n=65), metformin, sitagliptin, and acarbose (Met+Sita+Acarb, n=66) and sitagliptin and acarbose (Sita+Acarb, exploratory assessment, n=34) therapy in five institutions in Korea. After 16 weeks of acarbose add-on or metformin-switch therapy, a triple combination therapy was maintained from week 16 to 24. RESULTS: The add-on of acarbose (Met+Sita+Acarb group) demonstrated a 0.44%±0.08% (P<0.001 vs. baseline) decrease in glycosylated hemoglobin (HbA1c) at week 16, while changes in HbA1c were insignificant in the Met+Sita group (−0.09%±0.10%, P=0.113). After 8 weeks of triple combination therapy, HbA1c levels were comparable between Met+Sita and Met+Sita+Acarb group (7.66%±0.13% vs. 7.47%±0.12%, P=0.321). Acarbose add-on therapy demonstrated suppressed glucagon secretion (area under the curve of glucagon, 4,726.17±415.80 ng·min/L vs. 3,314.38±191.63 ng·min/L, P=0.004) in the absence of excess insulin secretion during the meal tolerance tests at week 16 versus baseline. The incidence of adverse or serious adverse events was similar between two groups. CONCLUSION: In conclusion, a 16-week acarbose add-on therapy to metformin and sitagliptin, effectively lowered HbA1c without significant adverse events. Acarbose might be a good choice as a third-line therapy in addition to metformin and sitagliptin in Korean subjects with T2DM who have predominant postprandial hyperglycemia and a high carbohydrate intake.

Relationship between metabolic syndrome and thyroid nodules in healthy Koreans

BACKGROUND/AIMS: This study evaluated the relationship between thyroid nodules and metabolic syndrome (MS) and its components in apparently healthy Koreans. METHODS: We reviewed the records of 3,298 subjects with no noticeable symptoms who underwent thyroid ultrasound imaging as part of a routine check-up between July 2009 and June 2010; of these, 1,308 were excluded based upon predefined criteria. Among the remaining 1,990 patients, we examined the association between MS and its components and the incidence of thyroid nodules. RESULTS: Of the 1,990 subjects included in this study, 38.4% (n = 764) had thyroid nodules and 12.7% (n = 253) had MS. Female sex, older age, higher body mass index, larger waist circumference, higher glycated hemoglobin level, lower thyroid stimulating hormone level, and presence of MS were all closely related with the presence of thyroid nodules (all p < 0.05). Furthermore, the relevant number of MS components showed a positive linear correlation with the occurrence of thyroid nodules (p < 0.001). Evidence of MS alone was not independently associated with thyroid nodules after adjusting for sex and age in a multivariate binary logistic regression analysis; however, glycated hemoglobin for females and waist circumference for males, as well as both age and thyroid stimulating hormone for all patients, were identified as independent predictors for the existence of thyroid nodules (all p < 0.05). CONCLUSIONS: This study suggests a positive relationship between the components of MS and thyroid nodules in an ostensibly healthy Korean population. Our data support the idea that the recent increase in thyroid nodules is partly due to increases in both MS and obesity.

Predictive Clinical Parameters and Glycemic Efficacy of Vildagliptin Treatment in Korean Subjects with Type 2 Diabetes

BACKGROUND: The aims of this study are to investigate the glycemic efficacy and predictive parameters of vildagliptin therapy in Korean subjects with type 2 diabetes. METHODS: In this retrospective study, we retrieved data for subjects who were on twice-daily 50 mg vildagliptin for at least 6 months, and classified the subjects into five treatment groups. In three of the groups, we added vildagliptin to their existing medication regimen; in the other two groups, we replaced one of their existing medications with vildagliptin. We then analyzed the changes in glucose parameters and clinical characteristics. RESULTS: Ultimately, 327 subjects were analyzed in this study. Vildagliptin significantly improved hemoglobin A1c (HbA1c) levels over 6 months. The changes in HbA1c levels (DeltaHbA1c) at month 6 were -2.24% (P=0.000), -0.77% (P=0.000), -0.80% (P=0.001), -0.61% (P=0.000), and -0.34% (P=0.025) for groups 1, 2, 3, 4, and 5, respectively, with significance. We also found significant decrements in fasting plasma glucose levels in groups 1, 2, 3, and 4 (P<0.05). Of the variables, initial HbA1c levels (P=0.032) and history of sulfonylurea use (P=0.026) were independently associated with responsiveness to vildagliptin treatment. CONCLUSION: Vildagliptin was effective when it was used in subjects with poor glycemic control. It controlled fasting plasma glucose levels as well as sulfonylurea treatment in Korean type 2 diabetic subjects.

Effects of a 6-Month Exenatide Therapy on HbA1c and Weight in Korean Patients with Type 2 Diabetes: A Retrospective Cohort Study

BACKGROUND: While many studies have shown the good efficacy and safety of exenatide in patients with diabetes, limited information is available about exenatide in clinical practice in Korean populations. Therefore, this retrospective cohort study was designed to analyze the effects of exenatide on blood glucose level and body weight in Korean patients with type 2 diabetes mellitus. METHODS: We reviewed the records of the patients with diabetes who visited Seoul St. Mary's Hospital and for whom exenatide was prescribed from June 2009 to October 2011. After excluding subjects based on their race/ethnicity, medical history, whether or not they changed more than 2 kinds of oral hypoglycemic agents with exenatide treatment, loss to follow-up, or whether they stopped exenatide therapy within 6 months, a total of 52 subjects were included in the final analysis. RESULTS: The mean glycated hemoglobin (HbA1c) level and weight remarkably decreased from 8.5+/-1.7% to 6.7+/-1.0% (P<0.001) and from 82.3+/-15.8 kg to 78.6+/-16.3 kg (P<0.001), respectively. The multiple regression analysis indicated that the reduction in HbA1c level was significantly associated with a shorter duration of diabetes, a higher baseline HbA1c level, and greater weight reduction, whereas weight loss had no significant correlation with other factors. No severe adverse events were observed. CONCLUSION: These results suggest that a 6-month exenatide injection therapy significantly improved patients' HbA1c levels and body weights without causing serious adverse effects in Korean patients with type 2 diabetes.

A case of HELLP syndrome accompanied by retinal detachment / 대한내과학회지

Weinstein et al. first described the HELLP (hemolytic anemia, elevated liver enzymes, and low platelets) syndrome in 1982. The incidence of HELLP syndrome is 0.2~0.6% in normal pregnant women and 4~12% in women with preeclampsia. This syndrome is accompanied by serious medical complications, including hepatic and renal failure, coagulopathy, hypertension, and pulmonary edema. Retinal detachment is an unusual, but well documented, complication of hypertensive disorder in pregnancy affecting 0.2~2% of patients with severe preeclampsia and 0.9% of patients with HELLP syndrome. This paper reports on a patient with HELLP syndrome accompanied by retinal detachment who recovered after controlling the blood pressure and receiving systemic steroids.

A Case of Retrograde Jejunogastric Intussusception Diagnosed by Gastroscopy / 대한소화기내시경학회지

Retrograde intussusception of the jejunum into the stomach through the stroma of a gastroenterostomy is a very rare, but potentially fatal complication after gastrectomy. Once symptoms develop, the mortality rate is high if this is not treated within 48 hours, so making an early diagnosis with a high index of suspicion and administering prompt treatment are mandatory. Gastroscopy could be a useful diagnostic tool for patients with a history of gastrectomy and who present with abdominal pain and hematemesis, and with considering the possibility of intussusception. A 65-year-old man with a history of Billroth II gastrectomy that was done 35 years ago due to gastric ulcer perforation was admitted with abdominal pain and hematemesis. A necrotic mucosa that was suspicious of an intussuscepted small bowel tissue was detected on gastroscopy. Subsequent open reduction and small bowel resection was performed with successful results. We report here on a case of postoperative retrograde jejunogastric intussusception that occurred 35 years after Billroth II gastrectomy, and it was first diagnosed by performing gastroscopy.