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Validation of an algorithm combining haemoglobin A 1c and fasting plasma glucose for diagnosis of diabetes mellitus in UK and Australian populations
Author(s) -
Manley S. E.,
Sikaris K. A.,
Lu Z. X.,
Nightingale P. G.,
Stratton I. M.,
Round R. A.,
Baskar V.,
Gough S. C. L.,
Smith J. M.
Publication year - 2009
Publication title -
diabetic medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.474
H-Index - 145
eISSN - 1464-5491
pISSN - 0742-3071
DOI - 10.1111/j.1464-5491.2008.02652.x
Subject(s) - medicine , diabetes mellitus , glycated haemoglobin , cohort , plasma glucose , confidence interval , impaired fasting glucose , gastroenterology , algorithm , endocrinology , type 2 diabetes , impaired glucose tolerance , computer science
Aim To determine whether glycated haemoglobin (HbA 1c ) can be used in combination with fasting plasma glucose (FPG) for the diagnosis of diabetes in patients with impaired fasting glucose (IFG) and in a broader spectrum of patients. Methods An algorithm was derived from oral glucose tolerance test (OGTT) capillary samples in 500 consecutive UK patients with IFG by World Health Organization criteria. It was validated in a further 500 UK patients and, with venous specimens, in 1175 unselected Australian patients. Results The derivation cohort was aged 61 years (50–69 years) (median IQ range) with 52% male and 12% South Asian. Diabetes Control and Complications Trial‐aligned HbA 1c was 6.2% (5.8–6.6%) (reference interval < 6.0%) and FPG 6.7 mmol/l (6.3–7.2 mmol/l). FPG was in the diabetes range in 36% of patients, with an OGTT identifying a further 12% with diabetes. The derived algorithm, (HbA 1c ≥ 6.0% with FPG < 7.0 mmol/l) identified those patients requiring an OGTT to diagnose diabetes. When applied to the UK validation cohort, sensitivity was 97% and specificity 100%. The algorithm was equally effective in the unselected group, aged 59 years (49–68 years) and 54% male, with sensitivity 93% and specificity 100%. HbA 1c was 6.0% (5.6–6.6%) and FPG 6.0 mmol/l (5.3–6.8 mmol/l), with 26% having IFG. Use of the algorithm would reduce the number of OGTTs performed in the UK validation cohort by 33% and by 66% in the Australian patients studied. Conclusions Use of this algorithm would simplify procedures for diagnosis of diabetes and could also be used for monitoring pre‐diabetes. Validation is now required in other populations and patient groups.