The minimum period of polysomnography required to confirm a diagnosis of severe obstructive sleep apnoea.

BACKGROUND AND OBJECTIVE: To combine the diagnosis of OSA with titration of positive airway pressure (PAP), current guidelines recommend that split-night polysomnography (PSG) be performed if an AHI of ≥40/h is recorded over 2h. However, the diagnostic validity of partial-night PSG is uncertain. This study aimed to test the validity of partial-night PSG and to determine the optimum AHI cut-off points. METHODS: Patients who visited the sleep centre at a tertiary medical centre between January and December 2008, for symptoms related to sleep disorders (sleepiness, snoring, sleep disturbance), and who completed full-night PSG, were evaluated for this study. Full-night PSG data were processed to obtain partial-night PSG data, from which AHI were computed as a reference for diagnosing severe OSA. Full-night and partial-night PSG data obtained over different recording times (expressed as x-h PSG, where xONL001831140 =1-6) were compared using receiver operating characteristic (ROC) curve analysis. The diagnostic validity of 2-h PSG with different AHI cut-off points (25/h to 45/h) was also calculated. RESULTS: Data from 198 PSG recordings was processed. For 2-h PSG, an AHI cut-off point of 30/h gave the highest accuracy of 90.9%. Comparing areas under the ROC curves (AUC), 2-h PSG (AUC=0.97) was as good as 2.5-h PSG (AUC=0.977, P=0.057) and 3-h PSG (AUC=0.978, P=0.125), but was better than 1.5-h PSG (AUC=0.955, P=0.016). CONCLUSIONS: Partial-night PSG is effective for diagnosing severe OSA. If there is an unabridged PSG recording indicating an AHI of ≥30/h for 2h, severe OSA can be diagnosed and PAP titration initiated.

Asthma and risk of erectile dysfunction--a nationwide population-based study.

INTRODUCTION: The increased prevalence of erectile dysfunction (ED) has been reported in patients with chronic obstructive pulmonary disease, and sustained systemic inflammation seems to play a central role in this linkage. Asthma is also a chronic inflammatory airway disorder, eliciting a low-grade systemic inflammation; however, the influence of asthma on ED has not been investigated. AIM: Our study strived to explore the relationship of asthma and the subsequent development of ED using a nationwide, population-based database. METHODS: From 2000 to 2007, we identified newly diagnosed asthma cases involving male patients 18-55 years old. A control cohort without asthma, which was matched for age and comorbidities, was selected for comparison. MAIN OUTCOME MEASURES: The two cohorts were followed up, and we observed the occurrence of ED by registry of ED diagnosis in the database. RESULTS: Of the 17,302 sampled patients (3,466 asthma patients vs. 13,836 control), 114 (0.66%) experienced ED during a mean follow-up period of 4.56 years, including 34 (0.98% of the asthma patients) from the asthma cohort and 80 (0.58%) from the control group. Subjects with asthma experienced a 1.909-fold (95% confidence interval [CI], 1.276-2.856; P=0.002) increase in incident ED, which was independent of age, the number of clinical visits for urologist, and other comorbidities. Kaplan-Meier analysis also revealed the tendency of asthma patients for ED development (log rank test, P=0.002). The risk of ED was higher in cases with more frequent clinical visits for asthma (asthma patients with clinical visits with >24 times/year vs. <12 times/year: hazard ratio [HR]: 4.154 [95% CI:1.392-12.396], P=0.011; clinical visits with 12-24 times/year vs. <12 times/year HR: 3.534 [95% CI:1.245-10.032], P=0.018). CONCLUSIONS: Asthma may be an independent risk factor for ED, and risk of ED probably increases in accordance with asthma severity.