Featured Articles from January 2015

Association of Adenotonsillectomy With Asthma Outcomes in Children: A Longitudinal Database Analysis

Bhattacharjee and Mokhlesi examined the 2003–2010 MarketScan database. MarketScan database provides access to a large database of over 25 million children capturing reimbursements from the health private insurance plans and payments accrued by patients including inpatient and outpatient settings as well as pharmacy expenses. Children were identified for a study period between January 1, 2003, and December 31, 2010. A total of 13,506 children with asthma in the United States who underwent adenotonsillectomy (AT). Asthma outcomes during 1 y preceding AT were compared to those during 1 y following AT. In addition, 27,012 age-, sex-, and geographically matched children with asthma without AT were included to examine asthma outcomes among children without known adenotonsillar tissue morbidity. AT was associated with significant improvements in several asthma outcomes such as asthma exacerbation, ER visits, hospitalizations, reduction in prescription refills for bronchodilators, inhaled corticosteroids and systemic corticosteroids. In contrast, there were no significant reductions in these outcomes in children with asthma who did not undergo AT over an overlapping follow-up period.


Obstructive Sleep Apnea During REM Sleep and Hypertension. Results of the Wisconsin Sleep Cohort

In another study, Mokhlesi and colleagues examined the Wisconsin Sleep Cohort to quantify the independent association between prevalent hypertension (cross-sectional analysis) and incident hypertension (longitudinal analysis). The analysis included 4,385 sleep studies on 1,451 individuals as well as a subset with ambulatory blood pressure data (n = 1,085 sleep studies on 742 individuals). Given the large sample size, they were also able to perform the analyses in a subset of subjects who had no disease in non-REM sleep (i.e. non-REM AHI < 5 events per hour). In individuals with non-REM AHI less than or equal to 5, a twofold increase in REM AHI was associated with 24% higher odds of hypertension (odds ratio, 1.24; 95% confidence interval, 1.08–1.41). Longitudinal analysis revealed a significant association between REM AHI categories and the development of hypertension (P trend = 0.017). Non-REM AHI was not a significant predictor of hypertension in any of the models. The authors concluded that REM OSA is cross-sectionally and longitudinally associated with hypertension. This is clinically relevant because treatment of OSA is often limited to the first half of the sleep period leaving most of REM sleep untreated.


Association of Obstructive Sleep Apnea in Rapid Eye Movement Sleep With Reduced Glycemic Control in Type 2 Diabetes: Therapeutic Implications

Obstructive sleep apnea has been associated with hypertension and type 2 diabetes (T2DM) in community-based and clinical cohorts. REM sleep usually accounts for 20–25% of total sleep time. To date, however, it remains unclear whether obstructive respiratory events during REM sleep have a different impact on cardiometabolic health compared with events during non-REM sleep. Because REM sleep predominates in the early morning hours before typical awakening, the cardiovascular and metabolic benefits of CPAP therapy may not be achieved with the typical CPAP use of 3–4 hours at the beginning of the night. In a cross-sectional analysis of 115 subjects with T2DM, Grimaldi and Mokhlesi demonstrated that only obstructive respiratory events and intermittent hypoxemia in REM sleep were associated with long-term glycemic control as assessed by HbA1c. Events in non-REM sleep were not associated with HbA1c. Their model predicted that 4 h of CPAP use would leave 60% of REM sleep untreated and would be associated with a decrease in HbA1c by approximately 0.25%. In contrast, 7 h of CPAP use would cover more than 85% of REM sleep and would be associated with a decrease in HbA1c by as much as 1%.