The bidirectional relationship between myocardial infarction and depressive disorders: a follow-up study

Background: Data from multiple studies have shown the relationship between myocardial infarction (MI) and depressive disorders; however, most of these studies have focused only on one direction in evaluating the effect of depressive disorders on MI outcomes. This study analyzed data compiled from a large-scale dataset, the National Health Insurance Research Database, to determine whether a bidirectional relationship exists between MI and depressive disorders.

Methods: A total of 3482 patients diagnosed with MI between 2002 and 2004 were included in analyzing the effects of MI on depressive disorders. A total of 26,418 patients diagnosed with depressive disorders between 2002 and 2004 were included in studying the effect of depressive disorders on MI. The comparison groups of both analyses were 4-fold larger than the case group. The Cox proportional hazard regression model was used to analyze the results.

Results: The risk of MI patients developing depressive disorders was significantly higher (P<.001) than that of the comparison group, even after the data were adjusted for the variables of age, gender, income, region, and the Charlson Comorbidity Index. Conversely, the risk of patients with depressive disorders developing MI was not significantly higher than that of the comparison group after we controlled for covariates.

Conclusion: The patients with MI exhibited a significantly higher risk of developing depressive disorders compared with the patients without MI. The results suggest that health providers should carefully manage the treatment offered for mental conditions and sensitively detect the psychological reactions of patients with MI.