Leukotriene receptor antagonists and suicide: a self-controlled case series study

Abstract

Aim/Objective: In March 2008 the suicide of a 15 year old boy captured media attention. The suicide was attributed to the exposure of montelukast, a leukotriene receptor antagonist (LTRA) used to treat asthma and allergies. The presence of, unknown and unmeasured confounders are limitations in observational studies, particularly in the study of suicide which has several risk factors. The self-controlled case series (SCCS) method automatically controls for fi xed confounders. Objectives: To investigate the association of suicide and LTRAs using the SCCS method in the UK. Method: Electronic healthcare records of patients with a record of suicide attempt (including suicide and self -harm, poisoning-selfinfl icted, injury–self infl icted, cause of overdose-deliberate) and exposure to LTRAs during the period of 1st January 1998 to 1st January 2011 were extracted from the Health Improvement Network (THIN) database of anonymised records from contributing UK general practices. A risk period of thirty days before and after exposure to LTRA and control periods within the observation time of each patient were identifi ed. A Poisson analysis conditioned on the event was used to calculate the Incidence Rate Ratio (IRR). Results: A total of 236 cases of fi rst attempts of suicide were identifi ed. The IRR for a risk period of 30 days after the start of treatment with LTRA was 0.32 (95% CI 0.04-2.42; P=0.268). Conclusion: Our study does not support the association between the use of LTRA and suicide attempts within the fi rst thirty days of exposure to LTRA. Further studies with larger number of cases are needed.