HbA1c levels and all-cause mortality in type 2 diabetic patients: epidemiological evidence of the need for personalised therapeutic targets.
OBJECTIVE
The aim of the present case-control study is to explore the effect of case mix on the relationship between glycated haemoglobin (HbA1c) and mortality in type 2 diabetic patients.


RESULTS
A nested case-control study data set was generated from the cohort-study data set (n = 4140 type 2 diabetic outpatients) by sampling controls from the risk sets. Cases (n = 427) were compared with an equal number of controls chosen from those members of the cohort who were at risk for the same follow-up time of the case, matched for age (±3 years), sex, body mass index (BMI) (±2 kg m(-2)), duration of diabetes (±5 years), and Charlson's Comorbidity Score (CCS) (±1). The main predefined analysis was the comparison of cases and controls for proportion of patients with each HbA1c class (<6.5%, 6.5-7.4%, 7.5-8.4% and ≥8.5%). During a mean follow-up of 5.7 ± 3.5 years, 427 deaths were recorded. The lowest risk of death was observed in the HbA1c 6.5-7.4% category; a lower HbA1c was associated with a non-significant trend towards a higher risk. The risk associated with a low (<6.5%) HbA1c was significantly greater in patients who were insulin-treated than in the rest of the sample.


CONCLUSIONS
The present study suggests that glycaemic targets should be individualised on the basis of the characteristics of each patient, considering age, co-morbidity and duration of diabetes. Caution should be used in prescribing insulin to reach near-normoglycaemia, particularly in older, frail patients.
Section of Geriatric Cardiology and Medicine, Department of Cardiovascular Medicine, University of Florence, Careggi Teaching Hospital, Florence, Italy.
M
M
Monami
V
V
Vitale
C
C
Lamanna
N
N
Bartoli
D
D
Martelli
S
S
Zannoni
A
A
Antenore
G
G
Toffanello
N
N
Marchionni
E
E
Mannucci
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D015897:Comorbidity; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000188:drug therapy / Q000401:mortality*; D005260:Female; D016330:Frail Elderly; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D007004:Hypoglycemic Agents / Q000009:adverse effects; D007328:Insulin / Q000009:adverse effects; D007558:Italy / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D057285:Precision Medicine; D011379:Prognosis; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors
D015415:Biomarkers; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D007328:Insulin; C517652:hemoglobin A1c protein, human