Antipsychotic drug exposure and risk of pulmonary embolism: a population-based, nested case-control study.
BACKGROUND
Only three observational studies investigated whether exposure to antipsychotics is associated with an increased risk of pulmonary embolism, with conflicting results. This study was therefore carried out to establish the risk of pulmonary embolism associated with antipsychotic drugs, and to ascertain the risk associated with first- and second-generation antipsychotic drugs, and with exposure to individual drugs.


METHODS
We identified 84,253 adult individuals who began antipsychotic treatment in a large Italian health care system. Cases were all cohort members who were hospitalized for non-fatal or fatal pulmonary embolism during follow-up. Up to 20 controls for each case were extracted from the study cohort using incidence density sampling and matched by age at cohort entry and gender. Each individual was classified as current, recent or past antipsychotic user. The occurrence non-fatal or fatal pulmonary embolism was the outcome of interest.


RESULTS
Compared to past use, current antipsychotic use more than double the risk of pulmonary embolism (odds ratio 2.31, 95% confidence interval 1.16 to 4.59), while recent use did not increase the risk. Both conventional and atypical antipsychotic exposure was associated with an increase in risk, and the concomitant use of both classes increased the risk of four times (odds ratio 4.21, 95% confidence interval 1.53 to 11.59).


CONCLUSIONS
Adding the results of this case-control study to a recent meta-analysis of three observational studies substantially changed the overall estimate, which now indicates that antipsychotic exposure significantly increases the risk of pulmonary embolism.
Regional Centre for Pharmacovigilance, Lombardy Region, Milano, Italy. valentino.conti@gmail.com.
Valentino
V
Conti
Regional Centre for Pharmacovigilance, Lombardy Region, Milano, Italy. mauro_venegoni@regione.lombardia.it.
Mauro
M
Venegoni
Regional Centre for Pharmacovigilance, Lombardy Region, Milano, Italy. alfredo_cocci@regione.lombardia.it.
Alfredo
A
Cocci
Unit of Community Health Services, Regional Health Ministry, Lombardy Region, Milan, Italy. ida_fortino@regione.lombardia.it.
Ida
I
Fortino
Department of Mental Health, Lecco, Italy. a.lora@ospedale.lecco.it.
Antonio
A
Lora
WHO Collaborating Centre for Research and Training in Mental Health and Service Evaluation, Department of Public Health and Community Medicine, Section of Psychiatry, University of Verona, Verona, Italy. corrado.barbui@univr.it.
Corrado
C
Barbui
D000293:Adolescent; D000328:Adult; D000368:Aged; D014150:Antipsychotic Agents / Q000009:adverse effects*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000139:chemically induced* / Q000453:epidemiology*; D012307:Risk Factors; D055815:Young Adult
D014150:Antipsychotic Agents