May 23, 2012

Antidepressant and Mortality among Critically Ill Patients

(Ivanhoe Newswire) — A new study shows that critically ill patients were more likely to die if they were taking commonly prescribed antidepressants before being admitted to the intensive care unit (ICU).

The study was conducted by researchers at Beth Israel Deaconess Medical Center in Boston and the Massachusetts Institute of Technology in Cambridge. Using a retrospective study, they analyzed the electronic medical records of 10,568 patients to look at in-hospital mortality and mortality a year after being admitted into the ICU. Out of the 10,568 records analyzed, 1,876 patients were taking either a selective serotonin reuptake inhibitor (SSRI) or a serotonin and norepinephrine reuptake inhibitor (SNRI) before their admission to the ICU. This group of patients was compared to patients not taking any of those medications that were admitted to the ICU. After adjusting for the variables of age, gender, ICD-9 diagnosis, disease severity and co-morbidities, the researchers found that patients on SSRI/SNRI´s prior to being admitted to the ICU were 73% more likely to die in the hospital, and that risk increase continued after one year.

"We also found that certain subgroups of patients, particularly patients admitted for cardiac problems, appeared to be at even greater risk," Katherine M. Berg, M.D., one of the study´s physicians, was quoted as saying.

Among the patient groups, the risk of mortality was higher for those who had acute coronary syndrome and those who had undergone cardiac surgery. For both of those patient groups, the risk of dying in the hospital was more than double if they were on one of the two types of antidepressants before ICU admission.

Despite this risk, not all patient groups that were taking antidepressants demonstrated increased mortality; those who had sepsis, for example, showed no increased risk.

Both SSRI´s and SNRI´s are thought to have fewer side effects than previous generations of antidepressants, but recent studies show that SSRI´s may increase the risk of bleeding, dizziness, falls, and stroke. SSRI´s are the most commonly prescribed medication class for depression, and though the benefits are well-documented, the long term risks remain unknown.

The study´s researchers acknowledge the fact that this study only shows an association, not a definite cause. The patients´ antidepressant use before admittance may not have been the cause of increased mortality; attempts to control other important variables like smoking and depression proved to be futile. These results also require validation through other similar studies that use ICU databases, but it spotlights the need for alternative ways to monitor potentially adverse effects of medications in patients and the positive role that large clinical databases can have in the area of investigation.

Source: ATS 2012 International Conference in San Francisco, May 2012