SAN FRANCISCO – Patients on selective serotonin reuptake inhibitors or serotonin norepinephrine reuptake inhibitors when they were admitted to an intensive care unit were 73% more likely to die in the hospital, compared with ICU patients who were not on these antidepressants, a retrospective study found.
Dr. Katherine M. Berg and her associates analyzed electronic records from admissions to four ICUs in 2001-2008 to compare outcomes for 1,876 patients who were on a selective serotonin reuptake inhibitor (SSRI) or serotonin norepinephrine reuptake inhibitor (SNRI) and 8,692 control patients who were not taking an SSRI or SNRI before admission.
Sherry Boschert/IMNG Medical Media
Dr. Katherine M. Berg
The mortality risk remained elevated at 1,000 days after ICU admission, she reported in a late-breaking poster presentation and discussion session at an international conference of the American Thoracic Society.
Certain subgroups were at even greater risk of dying in the hospital if they were on an SSRI or SNRI when admitted to the ICU. Patients who had acute coronary syndrome or had undergone cardiac surgery were more than twice as likely to die if they were on an SSRI/SNRI when entering the ICU, compared with controls, said Dr. Berg, a pulmonary/critical care fellow at Massachusetts General Hospital and Harvard University, Boston.
The increased mortality risk appeared to be associated mainly with medications that have higher degrees of serotonin reuptake inhibition. "Citalopram, which is a lower-potency drug, by itself did not incur a higher mortality risk, but sertraline, which is one of the more potent drugs, did. Even comparing the two drugs to each other, if you were on sertraline, your mortality risk was higher" than if you were on citalopram, Dr. Berg said in an interview.
Fluoxetine, paroxetine, and sertraline were associated with significantly higher mortality, but no significant mortality differences were seen between patients on citalopram or escitalopram and control patients.
Of the 8,692 control patients, 7% died in the hospital, compared with in-hospital death rates of 10% in 286 patients on fluoxetine, 13% in 320 patients on paroxetine, and 15% in 426 patients on sertraline at the time of ICU admission. The remaining 844 patients were on other antidepressants.
The study adjusted for the effects of each patient’s age, Simplified Acute Physiology Score, and combined Elixhauser comorbidity score on in-hospital mortality risk.
Slight but statistically significant differences in the characteristics of the two groups included a greater proportion of women in the SSRI/SNRI group, compared with controls (57% vs. 40%), and a higher prevalence of diabetes (21% vs. 17%) or chronic obstructive pulmonary disease (11% vs. 7%) in patients on an SSRI/SNRI, compared with controls. Patients in the SSRI/SNRI group were more likely to have an infection than were controls (11% vs. 8%), but less likely to have acute coronary syndrome (8% vs. 10%) or cardiovascular disease (67% vs. 70%).
Further studies are needed to ascertain if this is a causal relationship or just an association between SSRI/SNRI use and mortality in ICU patients, she said. The findings are limited by the retrospective nature of the study, which also was unable to control for the effects of potentially important confounders such as smoking status or the presence of depression.
The data came from the Multiparameter Intelligent Monitoring in Intensive Care II database, a public collection of data with patient identifiers removed.
Antidepressants were the most commonly prescribed medication class in the United States in 2011, and SSRIs were the most common type of antidepressant, she said. SSRI use has been associated with increased risk of bleeding, falls, bradycardia, and stroke in previous studies, which also suggest a possible protective effect of SSRIs in patients with coronary artery disease.
Dr. Berg reported having no financial disclosures.