After adjusting for physical and psychiatric illness, patients in Taiwan with an acute coronary syndrome had increased odds of suicide, according to a case-referent study.

The odds of suicide were highest during the six months following an acute coronary syndrome and remained high for at least four years.

Lead researcher Chao-Han Liu, MD, of the Graduate Institute of Applied Science and Technology in Taipei, Taiwan, and colleagues published their results online in the Journal of the American Heart Association on Dec. 7.

“We recommend that healthcare providers take the increased odds of suicide into their evaluation of patients newly diagnosed with [acute coronary syndrome],” Jung-Chen Chang, PhD, a co-senior author, said in a news release. “In addition to the existing efforts for managing depressive symptoms and reducing suicide, all cardiologists should be aware of the potential associations between [acute coronary syndrome] and suicide and make necessary referrals to specialists for suicide prevention.”

The researchers defined acute coronary syndrome as a range of clinical presentations ranging from ST-segment elevation MI (STEMI) to non-STEMI or unstable angina. Previous studies found that approximately 20 percent of patients with acute coronary syndrome have depressive disorders.

In this analysis, the researchers obtained data from the Health and Welfare Data Center of the Department of Health, which manages data for Taiwan’s health insurance program that covers approximately 99 percent of the country’s population.

The case group included adults who died from suicide between 2000 and 2012, while the referent group was randomly matched in a 1:4 ratio to the study group by age, sex and area of residence. Patients younger than 35 years old were excluded.

The researchers identified the following major physical diseases as potential confounders: hypertension, diabetes, dyslipidemia, cerebrovascular disease, congestive heart failure, chronic kidney disease, chronic obstructive pulmonary disease and cancer. They also adjusted for the following psychiatric comorbidities: depressive disorders, substance use disorders, anxiety disorders, mood disorders and psychotic-related disorders. In addition, they adjusted for the number of outpatient visits, emergency room visits and the number of hospitalizations in the year before the index date.

The study included 41,050 people who died from suicide and 164,200 matched referents. In each group, 68.5 percent of patients were men. The researchers found that married people had a lower risk of suicide compared with single, separated and divorced adults.

In addition, 1,027 patients in the case group and 2,412 patients in the referent group had acute coronary syndrome, while 315 and 788 patients, respectively, underwent coronary revascularization.

After adjusting for the potential confounders, patients with acute coronary syndrome had a 15 percent increased odds of suicide.

The researchers acknowledged a few limitations of the study, including that they relied on administrative claims data to determine the diagnosis of acute coronary syndrome, suicide and other physical comorbidities. They also might not have adjusted for all potential confounders, and they did not measure event-free survival. In addition, all of the adults were from Taiwan, so the results may not be generalizable to other countries. Further, they noted that the effect size was small and the data were retrospective and observational, so they could not prove a causal relation.

“Our results support the recommendation that screening for depression and suicidal ideation should be conducted for all patients with [acute coronary syndrome], particularly in the early stage of new diagnosis,” the researchers wrote. “Although integrating management of depression with cardiac rehabilitation makes good clinical sense, there is still enough evidence lacking on the effective identification and treatment of depression following MI. Future studies should recruit large samples of participants, such as over 15,000, to make evident the effectiveness of managing mental illness in general and depression in particular to improve various outcomes of [acute coronary syndrome], including suicide mortality.”