Association between HbA1c variability and mortality in patients with type 2 diabetes.
AIMS
We aimed to evaluate the association between HbA1c variability and mortality due to all causes, cancer, and non-cancer in patients with type 2 diabetes independently of mean HbA1c levels.


METHODS
We enrolled 754 patients with type 2 diabetes who first visited our hospital between 1995 and 1996, had been followed for at least 2years, and had undergone four or more HbA1c determinations. Patients were followed through June 2012. The standard deviation (SD) or coefficient of variation (CV) was used as a measure of HbA1c variability. Risk of death was evaluated by multivariate Cox proportional hazard models.


RESULTS
Through June 2012, 63 patients died. Hazard ratios (HRs) for all-cause mortality and non-cancer mortality including cardiovascular diseases (CVD) increased across tertiles of both HbA1cSD and HbA1cCV. HRs for cancer mortality did not increase across tertiles of either HbA1cSD or HbA1cCV. Using a stepwise regression method, both HbA1cSD and HbA1cCV predicted all-cause mortality, especially non-cancer mortality. In contrast, mean HbA1c predicted cancer mortality.


CONCLUSIONS
HbA1c variability is a predictor of all-cause mortality, especially non-cancer mortality including CVD, in patients with type 2 diabetes, independent of mean HbA1c level. In contrast, mean HbA1c, but not HbA1c variability, might predict cancer mortality.
['Takao|Toshiko|T|', 'Matsuyama|Yutaka|Y|', 'Yanagisawa|Hiroyuki|H|', 'Kikuchi|Masatoshi|M|', 'Kawazu|Shoji|S|']
D000328:Adult D000368:Aged D002318:Cardiovascular Diseases D015331:Cohort Studies D003924:Diabetes Mellitus, Type 2 D003925:Diabetic Angiopathies D058065:Diabetic Cardiomyopathies D005260:Female D005500:Follow-Up Studies D006442:Glycated Hemoglobin A D006801:Humans D007564:Japan D008297:Male D008875:Middle Aged D009026:Mortality D009369:Neoplasms D010044:Outpatient Clinics, Hospital D016016:Proportional Hazards Models D015203:Reproducibility of Results D012189:Retrospective Studies
HbA1c variability Type 2 diabetes All-cause mortality Non-cancer mortality Cancer mortality