Tuesday, April 26, 2011

Sleep Apnea, Sleepiness, and Mortality in Older Adults

In this months edition of the Sleep Journal there is an article about obstructive sleep apnea (OSA), excessive daytime sleepiness (EDS), and mortality risk in the elderly. Studies have not been able to conclusively show that OSA increases the risk of death in older adults. Studies have shown that EDS (from whatever cause) does increase mortality risk in older adults.

Researchers studied 289 patients greater than age 65 years old and followed them for an average of 13.8 years. EDS was assessed with subjective questionnaires and objective testing - MSLT. OSA was measured with an overnight sleep study.

The results showed that EDS by itself increased mortality risk and that EDS with OSA increased it even more. However, OSA without EDS did not increase mortality risk. The study authors concluded that OSA with EDS is significant, and that treatment should be discussed with the patient.

Bottom Line: The findings support my and the authors current practices for treating OSA in the elderly. Treatment is not necessarily warranted for mild OSA in the absence of EDS. In those with OSA and EDS, treatment should be offered. In those with moderate to severe OSA without EDS, decisions to treat should be made on an individual basis.

Saturday, April 23, 2011

Restless Legs Syndrome, Heat Damage and Heart Attack

Data was presented at a study at the American College of Cardiology about Restless Legs Syndrome (RLS) and cardiovascular health. RLS affects an estimated 12 million Americans. Researchers measured leg movements in patients with RLS during an overnight sleep study and then assessed their heart health. They divided the patients into two groups - those whose legs twitched more or less than 35 times per hour. Patients whose legs twitched more than 35 times per hour were more likely to have thickened heart muscle. In the three years of follow up, those with the most leg twitches and thickest heart walls were more than twice as likely to have suffered a heart attack or died. It's not clear if treating the RLS lowers cardiovascular risk. The study authors suggest that patients with restless legs symptoms consult with their doctor about monitoring their heart health.

Tuesday, April 19, 2011

Cysteine as a Biomarker for Obstructive Sleep Apnea


There is an article in the Chest Journal about cysteine and obstructive sleep apnea (OSA). Homocysteine and cysteine are reagarded as cardiovascular risk factors. The researchers performed an overnight sleep study, fasting blood draws, physical exam, ECG, and an echocardiogram patients. The researchers included non-overweight patients to account for the possible influence of obesity. A proportion of the patients were randomized to measure the effect of CPAP treatment on the obtained measurements.

The results showed that cysteine levels were highter in OSA patients than with control subjects, but homocysteine levels were not different. Cysteine levels were also higher in the non-overweight patients with OSA than in those non-overweight patients without OSA. There was a significant decrease in cysteine levels after 6 months of effective CPAP therapy.

The authors conclude that cysteine could be a potential biomarker for OSA, regardless of obesity. One thing not mentioned in the abstract is if the researchers analyzed the cysteine levels based on OSA severity.

Tuesday, April 12, 2011

Behavioral Therapy Improves Sleep and Psychosocial Quality of Life

At the annual meeting of the Pediatric Academic Societies, researchers presented data from a study of 108 families with children (mean age 5.6 years) that had moderate to severe sleep problems based on a survey of parents. Right off, this should raise a flag as to the conclusions, since these children were not officially diagnosed by a physician.

The intervention was an initial 45 minute private consultation with parents at the school, a 20-minute telephone call 10 days later, and a 30-minute private consulation at the school if needed (the study report does not state how many needed that extra 30-minute consultation). The report does not state specifically what the behavioral interventions were or who did them.

The results showed a 74% improvement in the intervention group vs a 53% improvement in the control group in the parents report of their childrens sleep at 6 months. Also, the children in the intervention group had less bedtime delay and resistance, and less daytime tiredness than the control group. The intervention group also had inmproved social and emotional functioning, but no effect on ADHD symptoms.

The authors conclude that a brief, behavioral intervention had significant benefits in the short to medium term, and that it is possible to deliver such an intervention in the school environment. Of note, over half of the patients in the control group got better on their own. But still, behavioral therapy for children can be beneficial, especially for those parents who find it difficult to set limits - one of the most common causes of insomnia in children.

Saturday, April 9, 2011

Sleep and Aging

Last week I gave an in-service at a rehab facility about sleep and aging. I thought I would put the highlights here.

There are several changes in sleep structure and quality that occur with aging. For many people, especially after age 65, they develop more problems starting and staying asleep. Their sleep is less deep, making it easier to wake up in the middle of the night. There is a shift in their sleep times, going to bed earlier and getting up earlier - the morning lark. Sleep amount does not go down, as is commonly thought. In fact, people over age 65 sleep a little more due to napping. Most of use will sleep the least from age 35-55, which is usually our most productive working years.

There are several sleep disorders that occur more frequently with age. The most common one is insomnia. Medical illness like chronic pain, diabetes, prostate disease, COPD, heart disease, reflux disease, dementia, and psychiatric disorders like depression can contribute to insomnia. Caffeine, alcohol, and nicotine intake close to bedtime can make it difficult to sleep.

Restless legs are more frequent as we age and can be made worse by certain medications, anemia, kidney disease, rheumatoid arthritis, or neuropathy.

Finally, snoring and obstructive sleep apnea (OSA) increase with age, regardless of weight. In those with underlying heart or neurological disease (like stroke), some patients develop central sleep apnea, which is different than the more common OSA.

My point to the residents and employees of the rehab hospital is that it can be difficult to tell if the sleep problem is from aging or an underlying sleep disorder. Hopefully, patients will seek appropriate medical care to figure that out.

Thursday, April 7, 2011

Nighttime Urination, Prostate Disease, and Sleep Apnea

Just read an article in the March-April 2011 edition of the JABFM. It's a study showing that nighttime urination (called nocturia) in patients with benign prostate enlargement (BPE) may suggest the presence of co-existing obstructive sleep apnea (OSA).

The reason the authors did this study is because nocturia can be a common reason for interrupted sleep in adults. My clinical experience and research data has shown that untreated OSA can cause nocturia. Studies have shown that the more severe the OSA, the more nocturia. Use of CPAP can drastically reduce the number of nocturia episodes caused by OSA. Nocturia is also common in men with BPE.

The study is cross-sectional and examined men between 55-75 years old who had BPE and nocturia based on chart review. There was a control sample of similar aged men without BPE. Symptoms of OSA were assessed using a validated questionnaire administered via telephone.

Based on the results of the OSA screening, participants were classified as either high or low risk of having OSA. The results showed that in those with BPE and nocturia had a high probability of falling into the high-risk group via OSA screening. The more nocturia episodes per night that the men reported, the higher the odds that those men would be high risk for OSA symptoms. What this means is that if a physician assumes that nocturia is from BPE, that doctor might not think of OSA. The study results suggest that in patients with nocturia, even with BPE, physicians should consider testing for OSA.

So if you suffer from nocturia, even with an enlarged prostate, consider talking to your doctor about getting tested for OSA.

Treatment of Cheyne-Stokes Respiration

There is an article in Therapeutic Advances in Respiratory Disease that reviews Cheyne-Stokes respiration and its treatment. Viewer warning, this is a technically complicated subject.

There are two main types of sleep apnea. The most common is obstructive (OSA) characterized by repetitive closure of the throat while asleep. The other is central sleep apnea CSA), where the upper airway is open, but the brain does not tell the lungs to breathe often or deep enough. One type of CSA is Cheyne-Stokes respiration (CSR) characterized by brief, repetitive periods of waxing and waning breath depths and brief, repetitive complete pauses in breathing. It is most common in neurological and heart disease.

The exact reasons of why or how patients develop CSR is unknown. Breathing during sleep is controlled by carbon dioxide levels (and oxygen to some degree). In CSR, it is theorized that the brain is over- and under-reacting to changes in CO2 in such a way that the patient breathes too deep sometimes and not at all at other times.

Treatment of CSR is more challenging than OSA. Maximizing medical treatment of the underlyinig heart or brain disease is the first step. Supplemental oxygen used during sleep can help some CSR patients. Certain medications can help because, in theory, they are respiratory stimulants, but objective data do not overwhelmingly support their use.

CPAP has been shown to be effective in some, but not all CSR patients. There was a large trial in Canada that showed that CPAP can improve cardiac function, respiratory disturbances, sympatheticoadrenal activity, and exercise performance, but NOT survival times. However, a re-analysis of the Canadian trial showed a survival benefit in those patients whose breathing disturbances were sufficiently reduced as compared to those without improvement in respiratory disturbances. Therefore, optimal suppression of respiratory disturbances is essential in CSR patients.

Bilevel positive airway pressure (BiPAP) is occasionally used in CSR patients, but there is very limited data on this mode of therapy. Adaptive servo-ventilation (ASV) is a new type of airway pressure that adapts to the patient's waxing and waning breathing patterns. It has been shown to be effective in CSR patients and studies have shown it superior to CPAP and BiPAP.

Monday, April 4, 2011

OSA and Perioperative Complications in Bariatric Patients

Article in the British Journal of Anaesthesia about OSA and complications around the time of surgery in obese patients. Obese patients, with and without OSA, are at higher surgical risk. It's assumed that OSA is an independent risk factor for perioperative complications, but the article says there is not much objective data to support that.

Currently, bariatric surgeons typically have their patients have a sleep study prior to weight loss surgery. If there is significant OSA, than the patient is treated for several weeks to months with CPAP prior and upto the weight loss surgery.

The authors of this study studied patients that had a pre-op sleep study. Ninety-three percent of the patients with OSA received perioperative positive airway pressure therapy. All patients were closely monitored after operation. The overall complication rate was increased with open procedures compared with laparoscopic. In addition, increased BMI and age were associated with increased likelihood of pulmonary and other complications. Complication rates were not associated with OSA severity.

The authors concluded that in obese patients evaluated by sleep study before bariatric surgery and managed accordingly, the severity of OSA (the AHI), was not associated with the rate of perioperative complications. Thus, either OSA is not an independent risk factor for complications or the recognition and management of OSA in the perioperative period mitigates this risk. These results cannot determine whether unrecognized and untreated OSA increases risk.