Admission to an intensive care unit (ICU) was associated with a higher rate of suicide and self-harm after discharge compared with hospitalizations without an ICU stay in a large Canadian cohort study.

“When patients leave the ICU, we used to think that was the end of the battle—they had survived, and we had done our job,” Dr. Shannon Fernando of the The Ottawa Hospital told Reuters Health by email.

However, research began to show that ICU survivors had substantial morbidity, including functional impairment, reduced quality of life and financial difficulties for years after they left the hospital. “This has been collectively referred to as ‘post-intensive care syndrome,'” Dr. Fernando said.

Recent research demonstrated a higher incidence of depression, anxiety and post-traumatic stress disorder after an ICU discharge, he noted. “We then asked the natural question—If ICU survivors have a higher incidence of mental health diagnoses, does this mean they have higher risk of suicide?”

To investigate, Dr. Fernando and colleagues analyzed administrative databases in Ontario from 2009 through 2017 to compare ICU hospital survivors with hospital survivors who did not require ICU admission (non-ICU hospital survivors).

The primary outcome was the composite of death by suicide and deliberate self-harm events after discharge.

As reported in The BMJ, among 423,060 ICU survivors (mean age 61.7; 39 percent women), the crude incidence of suicide, self-harm, and the composite of suicide or self-harm per 100,000 person years was 41.4, 327.9, and 361.0 respectively; the corresponding incidence among non-ICU hospital survivors was 16.8, 177.3, and 191.6.

Weighted analyses showed that ICU survivors had a higher risk of suicide (adjusted hazard ratio, 1.22) and self-harm (aHR, 1.15). Several factors were associated with these outcomes: previous depression or anxiety (aHR, 5.69); previous post-traumatic stress disorder (1.87); invasive mechanical ventilation (1.45); and renal replacement therapy (1.35).

“I have to admit that, as a critical care physician, I often glossed over a patient’s pre-existing psychiatric history,” Dr. Fernando said. “When a patient is on life support, we focus on their pre-existing heart function, lung function, kidney function. I think screening these high-risk patients is something we can easily do once their condition has improved, and at least ensure that we are considering their mental health.”

“I would continue to reassure patients that the overall risk of death by suicide, while higher than the general public, is still relatively low,” he added. “But also it is worth acknowledging to patients that mental suffering after ICU admission is common, and by being aware of it, as clinicians we can potentially intervene.”