Variability in hemoglobin A1c predicts all-cause mortality in patients with type 2 diabetes
ABSTRACT To evaluate the relationship between hemoglobin A1c variability and all-cause mortality in type 2 diabetic patients.
This was a retrospective cohort study in type 2 diabetic patients followed for at least 2 years between 2003 and 2009. A1C variability was determined from the standard deviation or coefficient of variation of serial A1C values (A1C(SD) or A1C(CV)). Subjects were categorized into either the high or low A1C variability group according to their A1C(CV) median. Hazard ratios (HRs) of various factors for all-cause mortality were determined from Cox's proportional hazard models.
A total of 881 subjects (422 men, 459 women) were included and 73 (8.3%) died during follow-up. The follow-up period was 4.7 ± 2.3 years. All-cause mortality was higher in subjects with high A1C(CV) (11.0% vs. 5.4%, p=0.002). In the Kaplan-Meier failure curve, subjects with higher A1C(CV) demonstrated a trend of higher mortality (p=0.1). In multivariate Cox's proportional hazards models, A1C(SD) and A1C(CV) significantly predicted all-cause mortality with an HR of 1.987 (p=0.02) and 1.062 (p=0.013), respectively, after adjusting for age, gender, body mass index, duration of diabetes, mean systolic blood pressure, use of antihypertensives and statins, mean LDL-cholesterol, smoking status, chronic kidney disease, and mean A1C values (A1C(MEAN)). The ability of A1C(SD) and A1C(CV) to predict all-cause mortality was more evident in subjects with relatively low A1C(MEAN.)
A1C variability is an important risk factor for all-cause mortality in type 2 diabetic patients.
Full-textDOI: · Available from: Kuo-Cheng Lu, May 14, 2015
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ABSTRACT: The effects of glucose on cardiovascular events or mortality in nondiabetic patients has been recently reported. However, since atherosclerosis can be formed over a long period of time, it is necessary to devote several years to unveil the relationship between the two factors. Here, we attempted to find out the relationship between the mean hemoglobin A1c (HbA1c) level and HbA1c variability for 5 years and coronary artery disease (CAD) by using coronary angiography (CAG) to assess nondiabetic patients. We reviewed patients who performed CAG who were followed up for at least 5 years after the initial diagnosis. The fasting blood test was performed annually for glucose and HbA1c level. CAD was defined as more than 50% of luminal narrowing. The severity of CAD was divided into two groups depending on whether no vessels were involved or one more vessel were involved (CAD(-) or CAD(+), respectively). The patients in CAD(+) group had higher mean HbA1c level for 5 years than CAD(-) group (5.71±0.40 vs. 5.86±0.68; P=0.04). Mean HbA1c was a significant predictor for CAD in multiple regression (odds ratio, 2.224; P=0.028). The percentage of patients with CAD was significantly higher in patients with >6.2% of mean HbA1c levels compared to patients with <6.2% of mean HbA1c levels (P<0.019). When the mean HbA1c levels were above 6.2%, the risk of CAD was higher. Also this study shows that HbA1c level can be one of the predictors for CAD even if the patients do not have diabetes.Diabetes & metabolism journal 02/2014; 38(1):58-63. DOI:10.4093/dmj.2014.38.1.58
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ABSTRACT: We assessed the relationship of mortality with glycated hemoglobin (HbA1c) variability and with absolute change in HbA1c. A population-based prospective observational study with a median follow-up time of 6 years. Based on a validated algorithm, 11 205 Danish individuals with type 2 diabetes during 2001-2006 were identified from public data files, with at least three HbA1c measurements: one index measure, one closing measure 22-26 months later, and one measurement in-between. Medium index HbA1c was 7.3%, median age was 63.9 years, and 48% were women. HbA1c variability was defined as the mean absolute residual around the line connecting index value with closing value. Cox proportional hazard models with restricted cubic splines were used, with all-cause mortality as the outcome. Variability between 0 and 0.5 HbA1c percentage point was not associated with mortality, but for index HbA1c ≤8% (64 mmol/mol), a variability above 0.5 was associated with increased mortality (HR of 1 HbA1c percentage point variability was 1.3 (95% CI 1.1 to 1.5) for index HbA1c 6.6-7.4%). For index HbA1c≤8%, mortality increased when HbA1c declined, but was stable when HbA1c rose. For index HbA1c>8%, change in HbA1c was associated with mortality, with the lowest mortality for greatest decline (HR=0.9 (95% CI 0.80 to 0.98) for a 2-percentage point decrease). For individuals with an index HbA1c below 8%, both high HbA1c variability and a decline in HbA1c were associated with increased mortality. For individuals with index HbA1c above 8%, change in HbA1c was associated with mortality, whereas variability was not.
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ABSTRACT: 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 2 years, 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.Journal of diabetes and its complications 07/2014; 28(4). DOI:10.1016/j.jdiacomp.2014.02.006 · 1.93 Impact Factor