Venous thromboembolism among elderly patients treated with atypical and conventional antipsychotic agents.
BACKGROUND
Some antipsychotic agents have been indicated as a possible risk factor for venous thromboembolism (VTE) in adult patients with psychiatric disorders. The aim of this study was to estimate the effect of atypical and conventional antipsychotic agents on the risk of hospitalization for VTE among elderly patients.


METHODS
We conducted a retrospective cohort study on nursing home residents in 5 states. We used data from the Minimum Data Set to identify 19 940 new users of antipsychotic agents and 112 078 nonusers. Hospitalization with VTE as primary discharge diagnosis was determined during a 6-month follow-up period using Medicare inpatient claims. Cox proportional hazards models provided estimates of effect adjusted for confounders.


RESULTS
The rate of hospitalization for VTE was 0.91 per 100 person-years. Venous thrombosis accounted for 77.6% of events and 22.4% were pulmonary embolisms. Relative to nonusers, the rate of hospitalization for VTE was increased for users of atypical antipsychotic agents, including risperidone (adjusted hazard ratio [HR], 1.98; 95% confidence interval [CI], 1.40-2.78), olanzapine (adjusted HR, 1.87; 95% CI, 1.06-3.27), and clozapine and quetiapine fumarate (adjusted HR, 2.68; 95% CI, 1.15-6.28). No increased rate was associated with phenothiazines (adjusted HR, 1.03; 95% CI, 0.60-1.77) or other conventional agents (adjusted HR, 0.98; 95% CI, 0.52-1.87).


CONCLUSIONS
Atypical antipsychotic agents appear to increase the risk of VTE. However, these events are rare, and in clinical practice the absolute risk should be weighed against the effectiveness of these medications in the elderly population.
Liperoti
Rosa
R
Centro di Medicina dell'Invecchiamento, Dipartimento di Scienze Gerontologiche, Geriatriche e Fisiatriche, Università Cattolica del Sacro Cuore, Largo A. Gemelli, 80168 Rome, Italy. rossella_liperoti@rm.unicatt.it
Pedone
Claudio
C
Lapane
Kate L
KL
Mor
Vincent
V
Bernabei
Roberto
R
Gambassi
Giovanni
G
D000368:Aged; D000369:Aged, 80 and over; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D015331:Cohort Studies; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D009735:Nursing Homes; D016016:Proportional Hazards Models; D011655:Pulmonary Embolism / Q000453:epidemiology; D012189:Retrospective Studies; D013923:Thromboembolism / Q000453:epidemiology*; D014481:United States / Q000453:epidemiology; D020246:Venous Thrombosis / Q000453:epidemiology*
D014150:Antipsychotic Agents