The association between cataract surgery and atypical antipsychotic use: a nested case-control study.
OBJECTIVE
To investigate cataract risk associated with the use of atypical antipsychotics.


METHODS
Retrospective, nested case-control study.


METHODS
A large health claims database (The British Columbia Ministry of Health Databases) from British Columbia, Canada, was used from January 2000 through December 2007. Cases were defined as clinically significant cataracts requiring surgery and were identified using cataract surgery procedure codes. For each case, 4 to 10 controls were selected randomly using a density-based sampling approach and were matched to cases by age and calendar time. Rate ratios were calculated for users of atypical and typical antipsychotics adjusting for known cataractogenic factors.


RESULTS
One hundred sixty-two thousand five hundred one cases of cataract surgery and 650 004 controls were included. The adjusted rate ratio for current users of atypical antipsychotics was 0.84 (95% confidence interval, 0.80 to 0.89) compared with nonusers. A greater number of prescriptions filled in the year before cataract surgery compared with the median number of filled prescriptions was associated with a lower cataract surgery rate (adjusted rate ratio, 0.70; 95% confidence interval, 0.65 to 0.75) than those with fewer prescriptions filled (adjusted rate ratio, 0.85; 95% confidence interval, 0.79 to 0.91).


CONCLUSIONS
A protective association between the use of atypical antipsychotics and risk of clinically significant cataracts requiring surgery was established. Potential biochemical and neurochemical mechanisms for this protective effect are discussed.
Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, Canada. Electronic address: kaivon@interchange.ubc.ca.
Kaivon L
KL
Pakzad-Vaezi
Mahyar
M
Etminan
Frederick S
FS
Mikelberg
D000368:Aged; D014150:Antipsychotic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001955:British Columbia / Q000453:epidemiology; D016022:Case-Control Studies; D002386:Cataract / Q000139:chemically induced / Q000453:epidemiology* / Q000517:prevention & control; D002387:Cataract Extraction / Q000706:statistics & numerical data*; D016208:Databases, Factual; D011307:Drug Prescriptions / Q000706:statistics & numerical data; D004363:Drug Utilization; D005260:Female; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors
D014150:Antipsychotic Agents