Sleeping pills may significantly increase the risk of cardiovascular events in heart failure patients, according to a recent study.

Researchers found sleeping pills in this risk by 8-fold.

Sleeping problems are a frequent side effect of heart failure and it is common for patients to be prescribed sleeping pills when they are discharged from hospital, according to researchers.

"Cardiac function of heart failure patients worsens with repeated hospitalizations. We therefore decided it was important to investigate the relationships between drugs prescribed at discharge, rehospitalization and cardiovascular events in heart failure patients," researcher Dr. Masahiko Setoguchi said in a statement.

For the study, researchers examined the medical records of 111 heart failure patients admitted to Tokyo Yamate Medical Center from 2011 to 2013. Information was collected on the presence of coexisting cardiovascular and other medical conditions, medications administered during hospitalization and those prescribed at discharge, laboratory test results, electrocardiogram, echocardiogram and chest radiographic data and vital signs at admission and discharge.

Study participants were followed up for 180 days after they were discharged from hospital.

Based on their findings, sleeping pills dramatically increase the risk of cardiovascular events in patients with who had heart failure with preserved ejection fraction.

"The finding was consistent across univariate and multivariate analyses. Given that many heart failure patients have difficulty sleeping, this is an issue that needs further investigation in larger studies,"Setoguchi said.

"Our results need confirmation in larger, prospective studies before heart failure patients can be advised to stop taking sleeping pills. But patients [who have had heart failure with preserved ejection fraction and] use sleeping pills, particularly those who have sleep disordered breathing, should be carefully monitored," he added.

However, researchers said their results are of growing relevance to heart failure patients and the professionals who treat them."

The findings were recently presented at the Heart Failure Congress 2014 in Athens, Greece.