Metformin and cancer occurrence in insulin-treated type 2 diabetic patients.
OBJECTIVE
Metformin is associated with reduced cancer-related morbidity and mortality. The aim of this study was to assess the effect of metformin on cancer incidence in a consecutive series of insulin-treated patients.


METHODS
A nested case-control study was performed in a cohort of 1,340 patients by sampling, for each case subject, age-, sex-, and BMI-matched control subjects from the same cohort.


RESULTS
During a median follow-up of 75.9 months, 112 case patients who developed incident cancer and were compared with 370 control subjects. A significantly lower proportion of case subjects were exposed to metformin and sulfonylureas. After adjustment for comorbidity, glargine, and total insulin doses, exposure to metformin, but not to sulfonylureas, was associated with reduced incidence of cancer (odds ratio 0.46 [95% CI 0.25-0.85], P = 0.014 and 0.75 [0.39-1.45], P = 0.40, respectively).


CONCLUSIONS
The reduction of cancer risk could be a further relevant reason for maintaining use of metformin in insulin-treated patients.
Monami
Matteo
M
Section of Geriatric Cardiology and Medicine, Department of Cardiovascular Medicine, University of Florence and Careggi Teaching Hospital, Florence, Italy.
Colombi
Claudia
C
Balzi
Daniela
D
Dicembrini
Ilaria
I
Giannini
Stefano
S
Melani
Cecilia
C
Vitale
Valentina
V
Romano
Desiderio
D
Barchielli
Alessandro
A
Marchionni
Niccolò
N
Rotella
Carlo Maria
CM
Mannucci
Edoardo
E
D000368:Aged; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007328:Insulin / Q000031:analogs & derivatives / Q000627:therapeutic use*; D000069036:Insulin Glargine; D049528:Insulin, Long-Acting; D008297:Male; D008687:Metformin / Q000627:therapeutic use*; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology / Q000517:prevention & control*; D013453:Sulfonylurea Compounds / Q000627:therapeutic use
D007004:Hypoglycemic Agents; D007328:Insulin; D049528:Insulin, Long-Acting; D013453:Sulfonylurea Compounds; D000069036:Insulin Glargine; D008687:Metformin