Wednesday, May 27, 2015

CPAP therapy and cognitive performance in elderly patients with severe obstructive sleep apnea

Obstructive sleep apnea (OSA) is more common with age, regardless of weight. OSA in elderly patients can contribute to daytime sleepiness and impair cognitive performance. OSA has even been associated with development of early dementia, called mild cognitive impairment. There is not a lot of data showing the effects of CPAP use on cognitive functioning in elderly patients. But that is just what this study sought to do.

The study population was a subset of a larger study, and participants were at least 65 years old. Participants received extensive neuropsychological testing at the start and end of the study period (6-10 years between the two time points). Participants had a sleep study at the beginning of the study and only those with severe OSA were included. The researchers then divided the participants into those that used CPAP therapy and those that did not. This was a smaller study, with only 126 subjects included, 33 of which used CPAP. Also, note that CPAP use was determined by the patient's self-report. In other words, CPAP use was not determined objectively by checking what the CPAP machine had recorded. So it's possible that CPAP use may have been over-estimated. The researchers also did not separate out CPAP use into the number of hours per night - participants either did or did not report CPAP use. Interestingly, all of the CPAP users reported using CPAP for the minimal 4 hours per night. Finally, participants who used CPAP tended to have more severe OSA, were more overweight, and had more daytime sleepiness. There was no difference in age, gender, or level of education in those that used CPAP versus those that did not.

The results showed that subjects with OSA had a more severe deterioration of cognitive function and memory over time. Also, CPAP therapy helped preserve some cognitive functions like memory, attention, and decision making ability. The authors concluded that long term CPAP use is associated with a protective effect on cognitive performance in elderly patients with severe OSA. They suggest that physicians who treat elderly patients consider screening for and treating OSA to help maintain cognitive performance.

Wednesday, May 20, 2015

CPAP and blood sugar levels in Prediabetes

Prediabetes is a condition in which blood sugar levels are elevated above normal, but not high enough to meet criteria for diabetes. Here is a study that measured blood sugar levels (and other parameters) during two weeks of CPAP use versus an oral placebo in patients diagnosed with obstructive sleep apnea. I only have access to the abstract and an article about the study. In this study, researchers ensured that those randomized to CPAP used it for 8 hours a night for two weeks straight. The results showed that the CPAP users had lower blood sugar levels as the main outcome. A secondary outcome measure showed lower blood pressure levels in the CPAP users when compared to the controls.

Wednesday, May 13, 2015

Bedtime routines and children's sleep

In my practice, I recommend that all parents follow a regular bedtime routine with their younger children. Research has shown that a consistent bedtime routine is linked to better sleep in kids. However, there are no studies that have looked at whether a bedtime routine works better if done every night or just once a week. This study did just that. It involved a questionnaire of over 10,000 moms who had children up to 5 years old. Results showed that less than half of all families had a consistent bedtime routine every night. In those families with a consistent bedtime routine, the children had earlier bedtimes, shorter time to fall asleep, fewer number and duration of awakenings, and more total sleep per 24 hours. Also, there was a linear relationship between number of nights per week of bedtime routine and sleep outcomes - meaning that the more times per week there was a bedtime routine, the better the sleep outcomes. Perceived sleep problems also went up as the number of bedtime routine nights per week went down. Finally, there was a relationship between daytime behaviors (including hyperactivity, attention deficit, and difficult behaviors) and consistent bedtime routine. Again, the relationship was such that a more frequent bedtime routine meant less problematic daytime behaviors.

The authors conclude that pediatricians could easily recommend a consistent bedtime routine to all of their patients. Pediatricians could explain that a bedtime routine is a set of the same activities done in the same order on a nightly basis prior to turning the lights out. For example, brushing teeth, putting on pajamas, and then reading a story before turning out the lights.

Wednesday, May 6, 2015

Pictures of infants' sleeping positions in media

Here is an interesting abstract presented at the Pediatric Academic Societies annual meeting in San Diego. I didn't attend this meeting, but saw a write-up about this abstract here. The abstract is about a study designed to evaluate images in popular stock photograph websites and pictures of infants in magazines published for women of childbearing age. The study authors were attempting to determine if the pictures were in compliance with the American Academy of Pediatrics guidelines for safe infant sleep practices - meaning having your infant sleep on its back to prevent Sudden Infant Death Syndrome (SIDS).

The results showed that just over half (50.3%) of the stock photos from websites showed the baby sleeping on its back. And only 15.7% of all infant sleep environments were compliant with American Academy of Pediatrics recommendations - meaning that the infant was not bed-sharing and the crib did not have soft objects like pillows, blankets, or bumper pads. With regard to the magazine pictures, there were 4 out of 12 pictures showing an infant sleeping on its stomach, which may raise the risk of SIDS. And only 7 of 24 magazine pictures properly demonstrated a safe infant sleep environment.

The study authors are concerned that stock photo websites and magazine pictures of infants sleeping in positions and environments not recommended by the American Academy of Pediatrics could confuse some women, causing them to think it's ok to let their infant sleep on its stomach, for example.

Wednesday, April 22, 2015

Obstructive sleep apnea and tooth wear

In my practice, I see lots of patients with excessive tooth wear, or irreversible loss of the tops of the teeth. It gets more common with age. It's not always due to teeth grinding - it can occur from eating certain foods, especially those high in acidity. This study looked at the association between tooth wear and obstructive sleep apnea (OSA). This was a study done in a private dental clinic in Spain, and patients diagnosed with tooth wear each had an overnight home sleep study to assess for OSA. The results showed that the prevalence of OSA was three times higher in patients with tooth wear. And there was a positive correlation between OSA severity and tooth wear, meaning the more severe the OSA, the more severe the tooth wear. The relationship was not diminished after controlling for body mass index, age, and gender.

The study authors speculated that there could be a common mechanism behind the OSA and tooth wear, such as arousal from sleep contributing to tooth clenching or grinding. The study authors also pointed out that the association between OSA and tooth wear could be coincidental, as both conditions become more prevalent with advancing age.

Finally, the study authors recommended that dentists consider referring patients with tooth wear to their primary care provider or sleep doctor for evaluation of possible OSA.

Wednesday, April 15, 2015

Sleep apnea and high blood pressure

Another post about obstructive sleep apnea (OSA) and high blood pressure (HTN). This study is a meta-analysis of observational studies and randomized controlled clinical trials. The study authors studied patients with resistant HTN, meaning blood pressure that was not responding to multiple medications. The study participants also had OSA.

I don't have access to full article, only the link above and the abstract. The results suggest that those patients with the highest blood pressures had the greatest reduction in blood pressure after using CPAP therapy. The study authors concluded that untreated OSA may be why some patients' blood pressure just won't come down with multiple medications.

The results from this study are not new, but do provide more evidence of the importance of screening patients with resistant HTN for underlying OSA. In my community, primary care doctors have been doing this for years already. However, this may not be the case in other medical communities around the country.

Wednesday, April 8, 2015

Blood pressure and sleep apnea

Several research studies have linked high blood pressure (HTN) to obstructive sleep apnea (OSA). The etiology is not clear, however. With OSA, there is sleep disturbance from brief awakenings, thought secondary to adrenaline release that is triggered when breathing resumes. Also, oxygen level reductions, called desaturations, could lead to elevated blood pressures. Respiratory events that are detected during a sleep study have specific scoring criteria - the event has to last at least 10 seconds and result in either a brief arousal from sleep and / or an oxygen desaturation.

This study sought to determine which types of respiratory events were most likely to result in HTN. The researchers followed 2040 participants and used sophisticated statistical models to study the sleep study results and blood pressure measurements. Results showed that those respiratory events with at least a 4% oxygen desaturation were most consistently associated with HTN. Interestingly, the other sleep study measurement that correlated with HTN was periodic limb movements that resulted in brief arousals from sleep.