Prognostic Factors Related to Sleep Quality in Patients With Obstructive Sleep Apnea After Positive Airway Pressure Therapy

Background and Objectives@#This study aimed to evaluate the factors that influence deep sleep restoration in patients with obstructive sleep apnea (OSA) following positive airway pressure (PAP) therapy. @*Methods@#In total, 363 patients diagnosed with OSA who received PAP therapy over at least 3 months were enrolled in the study. Polysomnographic parameters, anatomical characteristics, and subjective sleep-related parameters were evaluated according to the presence of daytime sleepiness and morning headache before and after 3 months of PAP treatment. @*Results@#Age was significantly different according to whether excessive daytime sleepiness (EDS) was alleviated (average: 49.35 years) or persisted (average: 52.82 years) (p=0.001). Age was also significantly associated with morning headache (p=0.037). Body mass index (BMI) was higher in the alleviated EDS group (28.70 kg/m2) than in the persistent EDS group (27.13 kg/m2; p=0.002). The apnea-hypopnea index (AHI) was correlated with the EDS outcome (p=0.011). The group with alleviated EDS had a longer mandibular plane to hyoid distance (MPH) than the group with persistent EDS (17.95 mm vs. 15.38 mm; p<0.001). However, BMI, AHI, and MPH showed no significant associations with morning headache. Epworth Sleepiness Scale scores were higher in the alleviated EDS and alleviated morning headache groups (EDS: p<0.001, morning headache: p=0.001). Self-Efficacy Measure for Sleep Apnea (SEMSA) values differed significantly between the EDS groups (p<0.001), but not between the morning headache groups (p=0.122). After 3 months of PAP therapy, the MPH was negatively correlated with EDS in univariate (odds ratio [OR]=0.921, p<0.001) and multivariate analyses (OR=0.937, p=0.028). The SEMSA score was also negatively correlated with EDS in univariate (OR=0.961, p<0.001) and multivariate (OR=0.973, p=0.019) analyses. @*Conclusion@#Age, polysomnographic metrics, and anatomical considerations were important for sleep quality-associated daytime symptoms. In addition, anatomical characteristics and the patient’s self-efficacy were significantly associated with the effect of PAP treatment on sleep quality.

Effect of Dipeptidyl Peptidase-4 Inhibitors on the Risk of Bone Fractures in a Korean Population

BACKGROUND: There have been equivocal results in studies of the effects of dipeptidyl peptidase-4 inhibitors (DPP-4i) on fractures. In this study, we analyzed the effect of DPP-4i on bone fracture risk in a Korean population. METHODS: We extracted subjects (n = 11,164) aged 50 years or older from the National Health Insurance Service–National Sample Cohort 2.0 from 2009 to 2014. Our control group included subjects without diabetes (n = 5,582), and our treatment groups with diabetes included DPP-4i users (n = 1,410) and DPP-4i non-users (n = 4,172). The primary endpoint was the incidence of a composite outcome consisting of osteoporosis diagnosis, osteoporotic fractures, vertebral fractures, non-vertebral fractures, and femoral fractures. The secondary endpoint was the incidence of each individual component of the composite outcome. Survival analysis was performed with adjustment for age, gender, diabetes complications severity index, Charlson comorbidity index, hypertension medication, and dyslipidemia treatment. RESULTS: The incidence of the composite outcome per 1,000 person-years was 0.089 in DPP-4i users, 0.099 in DPP-4i non-users, and 0.095 in controls. There was no significant difference in fracture risk between DPP-4i users and DPP-4i non-users or controls after the adjustments (P > 0.05). The incidences of osteoporosis diagnosis, osteoporotic fractures, vertebral fractures, non-vertebral fractures, and femoral fractures were not significantly different between DPP-4i users and non-users. The results of subgroup analyses by gender and age were consistent. CONCLUSION: DPP-4i had no significant effect on the risk of fractures in a Korean population.

Combined Genome-Wide Linkage and Association Analyses of Fasting Glucose Level in Healthy Twins and Families of Korea

This study was undertaken to identify genetic polymorphisms that are associated with the risk of an elevated fasting glucose (FG) level using genome-wide analyses. We explored a quantitative trait locus (QTL) for FG level in a genome-wide study from a Korean twin-family cohort (the Healthy Twin Study) using a combined linkage and family-based association analysis approach. We investigated 1,754 individuals, which included 432 families and 219 pairs of monozygotic twins. Regions of chromosomes 2q23.3-2q31.1, 15q26.1-15q26.3, 16p12.1, and 20p13-20p12.2, were found to show evidence of linkage with FG level, and several markers in these regions were found to be significantly associated with FG level using family-based or general association tests. In particular, a single-nucleotide polymorphism (rs6138953) on the PTPRA gene in the 20p13 region (combined P = 1.8 x 10(-6)) was found to be associated with FG level, and the PRKCB1 gene (in 16p12.1) to be possibly associated with FG level. In conclusion, multiple regions of chromosomes 2q23.3-2q31.1, 15q26.1-15q26.3, 16p12.1, and 20p13-20p12.2 are associated with FG level in our Korean twin-family cohort. The combined approach of genome-wide linkage and family-based association analysis is useful to identify novel or known genetic regions concerning FG level in a family cohort study.