Healthcare utilization and psychiatric and physical comorbidities before suicide mortality in patients with methamphetamine use disorder: A nationwide case–control study

Background: Since the late 1990s, methamphetamine use has become a considerable public health concern. Despite high suicide rates among methamphetamine users, studies exploring medical utilization and psychiatric and physical comorbidities before suicide are scant. We aim to examine the pattern of medical utilization and distribution of comorbidities shortly before suicide in methamphetamine users who died of suicide and compared these data with those of living methamphetamine users. Methods: From Taiwan's National Health Insurance Research Database, we identified the cohort with methamphetamine use disorder (n = 23,248) between January 1, 2001, and December 31, 2005. We identified 5972 deceased patients (of whom 745 died of suicide) by linking each patient with the national mortality database during the study period. By conducting a nested case–control study with risk-set sampling, from the methamphetamine cohort, we selected four age- and sex-matched controls for each patient who died of suicide (cases). We applied conditional logistic regression to investigate differences in medical utilization and physical and psychiatric comorbidities between cases and controls. Results: Cases had higher medical utilization within 3 months before suicide, particularly in the departments of psychiatry, internal medicine, emergency, and family practice. Cases had higher risks of physical comorbidities, including pneumonia and renal disease, and psychiatric comorbidities, including depressive disorder, sleep disorder, drug-induced mental disorder, schizophrenia, and bipolar disorder. Conclusions: The findings of increased medical utilization and the higher risks of physical and psychiatric comorbidities in cases are crucial for developing specific interventions to prevent suicide in this patient population.