One thing I thought I knew was that overweight and obesity cause coronary artery disease and make it worse. People with CAD who are obese should lose weight … right? Recent research shows it’s not that simple (although the answer is still “yes, probably”). Did you know about the “obesity paradox?” Or the “lean paradox,” [... read more]
Mah et al followed 11 Stanford varsity basketball players for ~7-10 weeks. During the first ~3 weeks, players maintained their usual sleep schedules. For the next ~6 weeks, they were encouraged to sleep as long as possible each night, with a goal of 10 hours in bed. After the sleep extension period, their shooting accuracy [... read more]
Carter et al followed 244 children in New Zealand from birth to age 3-7. Between ages 3-5, each additional hour of sleep was associated with a 0.48 reduction in BMI, and a 61% reduction in the risk of being obese or overweight by age 7, after controlling for multiple covariates. BMJ 2011;342:d2712. FREE FULL TEXT
Wijesinghe et al randomized and crossed-over 24 people who were recently diagnosed with obesity hypoventilation syndrome to breathe either 100% oxygen or room air for 20 minutes on 2 separate days, while measuring their minute ventilation, expired tidal pCO2, and dead space-to-tidal volume ratio. In 44% of patients, pCO2 increased by at least 4 mm [... read more]
If you spend your nights lying awake worrying about having a heart attack, you’re entirely justified. But you’re probably just making it more likely. Lars Laugsand et al followed 52,610 Norwegian people for 11 years after the subjects completed an initial survey (investigators can do this in Norway, since they’ve got everyone’s health records in [... read more]
Obesity may impose extra burdens on critical care staff (think turning, transport, intubation and central line placement), but reviews suggest people with “ordinary” obesity (BMI 30-39) with have the same mortality from critical illness as overweight or healthy-weight people. In fact, obese people may have a survival advantage, despite possible longer durations of mechanical ventilation and ICU stays. But what about extreme obesity (BMI > [... read more]
Poor people have higher rates of obesity. There are those who believe that’s because the poor lack self-control and discipline, overeating when they should be pulling themselves up by their bootstraps. That hard-core personal responsibility ethic is hard to refute, maybe because it contains a grain of truth, maybe because it lets all us non-poor [... read more]
Non-invasive positive pressure ventilation (NIPPV or NPPV or NIV), overnight or during the day, has not been shown to help most people with stable COPD and daytime hypercarbia. Citing their own previous findings, Dreher, Windisch et al argue that’s because you can’t just use wimpy ordinary settings — you’ve got to crank that sucker to [... read more]
Obesity was named as a risk factor for severe H1N1 influenza during the pandemic. What about for influenza in general? Kwong et al analyzed community survey data in Ontario over 12 influenza seasons, 1996-2008. Severe obesity (BMI >= 35) carried an odds ratio of 2.1 for respiratory hospitalization during flu season. In those with no [... read more]
Drager LF et al. Obstructive Sleep Apnea: An Emerging Risk Factor for Atherosclerosis. CHEST 2011;140:534-542. OSA and CAD review.
Obstructive sleep apnea and other sleep disorders have long been associated with cognitive dysfunction, but so far not in a prospective study. So, Yaffe et al followed 298 older women (~82 years) who had already had polysomnography as part of an osteoporosis study. 105 had sleep disordered breathing (cases), defined as an apnea-hypopnea index >= [... read more]
A minority of people develop central sleep apneas during polysomnography with continuous positive airway pressure titration for obstructive sleep apnea. Others develop central apneas later, discovered on interrogation of their CPAP machine. The fact is, no one knows much about this so-called complex sleep apnea — its natural course, prognosis / risks, and whether or [... read more]
Kuniyoshi et al prospectively observed people admitted to Mayo for myocardial infarction, performing polysomnography and measuring flow-mediated dilation in their brachial arteries. A whopping 69% (45 of 64) were found to have obstructive sleep apnea. Those with moderate to severe OSA had poorer arterial responsiveness, a surrogate marker for subsequent cardiovascular risk, compared to people [... read more]
Teo et al randomized 24 people with newly diagnosed obstructive sleep apnea (AHI > 15) to crossover between nasal and oronasal (full-face) masks during 2 consecutive nights of CPAP titration. The nasal mask had more leaks and people wearing it had more arousals. However, they liked it better than the face mask, and there was [... read more]
Flexible pressure CPAP reduces pressure briefly during expiration, to try to make it more comfortable. Bakker & Marshall meta-analyzed 10 randomized trials in >500 patients testing flexible pressure vs standard CPAP in people with obstructive sleep apnea; there were no differences in compliance or any other outcome. CHEST 2011;139:1322-1330.
Lee et al report phase III trial results for this prodrug of gabapentin. It improved symptoms in people with moderate-to-severe RLS at the end of 12 weeks, compared to placebo. However, time (placebo) also worked well. The FDA approved the drug for moderate-to-severe RLS in April 2011. J Clin Sleep Med 2011;7:282-292.
In 63 Swedish men with obstructive sleep apnea, a one-year weight loss program initiated by a supervised 9-week crash diet resulted in a ~12 kg weight loss. At one year, patients’ apnea-hypopnea index improved by ~17 events / hour; 48% no longer needed CPAP, and 10% were cured. The more weight lost, the greater the [... read more]
Allen et al surveyed 266 people under treatment for RLS for symptoms of augmentation. Fully 20% treated for ~2.7 years had definite or very likely augmentation; only 25% were completely free of augmentation symptoms, as assessed using NIH guidelines. Sleep Med 2011;12:431-439.
Bitter et al performed CPAP titration on 192 patients with congestive heart failure and obstructive sleep apnea, unmasking residual central sleep apnea (so-called complex sleep apnea) in 34 (18%). Providing adaptive servoventilation (dynamic delivery of pressure support to achieve a target minute ventilation) improved AHI, NYHA class, BNP levels, ejection fraction, and other variables, at ~1 year [... read more]
Parra et al diagnosed OSA in 140 patients hospitalized for stroke in Spain and randomized them to nasal auto-titrating CPAP or no therapy. The CPAP-treated patients had better Rankin and Canadian stroke outcome scores at all follow-up visits. They had the same rate of subsequent cardiovascular events, but events occurred at a median 15 months [... read more]