The use of pioglitazone and the risk of bladder cancer in people with type 2 diabetes: nested case-control study.
OBJECTIVE
To determine if the use of pioglitazone is associated with an increased risk of incident bladder cancer in people with type 2 diabetes.


METHODS
Retrospective cohort study using a nested case-control analysis.


METHODS
Over 600 general practices in the United Kingdom contributing to the general practice research database.


METHODS
The cohort consisted of people with type 2 diabetes who were newly treated with oral hypoglycaemic agents between 1 January 1988 and 31 December 2009. All incident cases of bladder cancer occurring during follow-up were identified and matched to up to 20 controls on year of birth, year of cohort entry, sex, and duration of follow-up. Exposure was defined as ever use of pioglitazone, along with measures of duration and cumulative dosage.


METHODS
Risk of incident bladder cancer associated with use of pioglitazone.


RESULTS
The cohort included 115,727 new users of oral hypoglycaemic agents, with 470 patients diagnosed as having bladder cancer during follow-up (rate 89.4 per 100,000 person years). The 376 cases of bladder cancer that were diagnosed beyond one year of follow-up were matched to 6699 controls. Overall, ever use of pioglitazone was associated with an increased rate of bladder cancer (rate ratio 1.83, 95% confidence interval 1.10 to 3.05). The rate increased as a function of duration of use, with the highest rate observed in patients exposed for more than 24 months (1.99, 1.14 to 3.45) and in those with a cumulative dosage greater than 28,000 mg (2.54, 1.05 to 6.14).


CONCLUSIONS
The use of pioglitazone is associated with an increased risk of incident bladder cancer among people with type 2 diabetes.
Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital, 3755 Côte Sainte-Catherine, H-425.1, Montreal, Quebec, Canada H3T 1E2. laurent.azoulay@mcgill.ca
Laurent
L
Azoulay
Hui
H
Yin
Kristian B
KB
Filion
Jonathan
J
Assayag
Agnieszka
A
Majdan
Michael N
MN
Pollak
Samy
S
Suissa
D000284:Administration, Oral; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D000077205:Pioglitazone; D012189:Retrospective Studies; D045162:Thiazolidinediones / Q000008:administration & dosage / Q000009:adverse effects*; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced*
D007004:Hypoglycemic Agents; D045162:Thiazolidinediones; D000077205:Pioglitazone