Insomnia is a sleep disorder, in which there is an inability to fall asleep or to stay asleep as long as desired. According to the Centers for Disease Control and Prevention, an estimated 50-70 million United States adults have some type of sleep or wakefulness disorder. In order to fall asleep, nine million Americans use prescription sleeping pills.
Now, a new study, led by Dr. Masahiko Setoguchi of the Social Insurance Central General Hospital in Tokyo, Japan, suggests that sleeping problems are a common side effect of heart failure.
Approximately 5.1 million people in the United States have heart failure - a condition where the heart is unable to pump enough blood and oxygen around the body to support other organs. The more hospitalizations a heart failure patient has, the worse their cardiac function seems to be, according to the researchers.
Many patients are prescribed sleeping pills when they are discharged from the hospital, as well as diuretics, antihypertensives, anticoagulants, antiarrhythmics and antiplatelets. Therefore, the researchers were interested whether the drugs that patients are prescribed at discharge are associated with hospital readmission and cardiac events.
The researchers reviewed 111 medical records of heart failure patients who were admitted to the Tokyo Yamate Medical Center in Japan between 2011 and 2013.
The patients were divided into two groups: those with diastolic heart failure, or preserved ejection fraction (HFpEF), and those with systolic heart failure, or reduced ejection fraction (HFrEF). The ejection fraction is a measurement of the volume of blood pumped out of the left and right ventricle with each heartbeat.
They gathered the patients' cardiovascular conditions, coexisting medical conditions, medication administered during hospitalization and prescribed at discharge, vital signs at hospital admission and discharge, laboratory test results and information from electrocardiograms (ECGs), echocardiograms and chest radiographs.
For 180 days, the researchers followed the patients after they were discharged from the hospital or until patients reached the "study endpoint" through hospital readmission for heart failure or passing away from cardiovascular causes.
During the follow-up period, the researchers found that 15 of 47 diastolic heart failure patients reached study endpoint. When comparing patients who reached study endpoint with those who did not, they found differences in prescription of sleeping pills (benzodiazepine hypnotics), blood sodium levels at hospital admission and blood hemoglobin levels at discharge.
Diastolic heart failure patients who were prescribed sleeping pills were eight times more likely to experience hospital readmission for heart failure or suffer cardiovascular-related death, compared with diastolic heart failure patients who were not prescribed sleeping medication.
Dr. Masahiko Setoguchi of the Social Insurance Central General Hospital in Tokyo, Japan says, “The main finding of our study is that HFpEF patients prescribed sleeping pills have an increased risk of cardiovascular events. The number of HFpEF patients is increasing and becoming a larger proportion of heart failure patients overall. Our results therefore are of growing relevance to heart failure patients and the professionals who treat them.”
“Benzodiazepine hypnotics may have cardiodepressant actions,” he continues. “They may also exert respiratory depressant actions which could exacerbate sleep disordered breathing and lead to a worse prognosis.”
Dr. Setoguchi adds that larger studies among diastolic heart failure are needed to confirm the findings. Heart failure patients should not be advised to stop using sleeping medication until more data is gathered.