Internet overuse and excessive daytime sleepiness in adolescents.

AIM: The purpose of this study was to examine the association of Internet overuse with excessive daytime sleepiness (EDS). METHODS: A total of 2336 high school students in South Korea (boys, 57.5%; girls, 42.5%) completed the structured questionnaire. The severity of Internet addiction was evaluated using Young's Internet addiction test. RESULTS: The proportions of boys who were classified as Internet addicts and possible Internet addicts were 2.5% and 53.7%, respectively. For girls, the corresponding proportions were 1.9% and 38.9%, respectively. The prevalence of EDS was 11.2% (boys, 11.2%; girls, 11.1%). When Internet addicts were compared with non-addicts, they consisted of more boys, drank alcohol more, and considered their own health condition as poor. But smoking was not related with Internet addiction. The prevalence rate of EDS for Internet addicts was 37.7%, whereas that for possible Internet addicts and non-addicts was 13.9% and 7.4%, respectively. The prevalence of insomnia, witnessed snoring, apnea, teeth grinding, and nightmares was highest in Internet addicts, middle in possible addicts, and lowest in non-addicts. With adjustment for duration of Internet use, duration of sleep time, age, gender, smoking, taking painkillers due to headache, insomnia symptoms, witnessed apnea, and nightmares, the odds of EDS were 5.2-fold greater (95% confidence interval [CI]: 2.7-10.2) in Internet addicts and 1.9-fold greater (95%CI: 1.4-2.6) in possible Internet addicts compared to non-addicts. CONCLUSION: Internet addiction is strongly associated with EDS in adolescents. Clinicians should consider examining Internet addiction in adolescent cases of EDS.

Factors affecting warfarin therapy following cardiac valve surgery.

OBJECTIVE: To determine the factors that affect the initial response to warfarin therapy in Korean patients after cardiac valve surgery. METHODS: A retrospective analysis of 127 patients who had undergone cardiac valve surgery at Seoul National University Hospital was performed. On the first day, most patients received warfarin 5 mg, while some received an individualized warfarin dose according to their physician's decision. Doses to be given on the following days were determined based on daily international normalized ratio (INR) and the previous doses. To measure warfarin sensitivity, the warfarin dose index (WDI), defined as the INR divided by the mean warfarin dose administered during the preceding 3 days, was introduced. The effects of age, gender, weight, serum albumin concentration, baseline INR, cardiopulmonary bypass time, and concurrent administration of amiodarone were evaluated. RESULTS: The patients' weight, initial serum albumin concentration, and baseline INR value influenced their initial response to warfarin. The initial WDI correlated negatively with the initial serum albumin concentration (p < 0.001) and body weight (p < 0.05) and positively with the baseline INR (p < 0.01). The initial WDI of the patients taking amiodarone was significantly higher (mean +/- SD 0.74 +/- 0.34) than that of patients without amiodarone (0.46 +/- 0.22) (p < 0.001). Maintenance doses correlated negatively with the initial warfarin response (p < 0.001) and positively with body weight (p = 0.053). CONCLUSIONS: The factors associated with an increased initial warfarin response in patients after cardiac valve surgery were high baseline INR, low postoperative serum albumin concentration, and concurrent administration of amiodarone. Thus, patients with any of these factors should receive a smaller initial warfarin dose. Also, to predict the warfarin maintenance dose from the initial response, the effect of transient changes in the sensitivity to warfarin during the initial period should be considered.