BACKGROUND: Recent technological advances have made HBA1c a more standardized and user-friendly test with wide availability. This study evaluated HBA1c as a screening test for gestational diabetes mellitus (GDM) in a high-risk population. METHODS: A total of 442 pregnant women were assessed by HBA1c. Two thresholds were used to "rule in or rule out" GDM, which was confirmed by the "gold-standard" 75-g OGTT (World Health Organization criteria). RESULTS: Eighty-four (19%) women had GDM while 358 (81%) women were normal; there was a complete overlap of the HBA1c histograms of the two populations. The area under receiver operating characteristic curve of HBA1c to detect GDM was 0.54 (95% CI 0.48-0.61). Using a value of <5.5% to rule out GDM; a sensitivity of 82.1% was achieved, with 15 (16.7%) of 90 women below the threshold being false-negatives (NPV = 83.3%). Using a threshold of HBA1c > or = 7.5% to rule-in GDM; the specificity was 95.8% with 15 (71.4%) of 21 patients over the threshold being false-positives (PPV = 28.6%). HBA1c would eliminate the need for an OGTT in 25.1% (111/442) of whom 27% (30/111) women would be misclassified. At any HBA1c threshold with an acceptable sensitivity, the false-positive rate remained high making it necessary for too many healthy women to undergo the confirmatory OGTT. CONCLUSION: Despite all the progress in methodology, HBA1c remains a poor test to screen for GDM.
BACKGROUND: Recent technological advances have made HBA1c a more standardized and user-friendly test with wide availability. This study evaluated HBA1c as a screening test for gestational diabetes mellitus (GDM) in a high-risk population. METHODS: A total of 442 pregnant women were assessed by HBA1c. Two thresholds were used to "rule in or rule out" GDM, which was confirmed by the "gold-standard" 75-g OGTT (World Health Organization criteria). RESULTS: Eighty-four (19%) women had GDM while 358 (81%) women were normal; there was a complete overlap of the HBA1c histograms of the two populations. The area under receiver operating characteristic curve of HBA1c to detect GDM was 0.54 (95% CI 0.48-0.61). Using a value of <5.5% to rule out GDM; a sensitivity of 82.1% was achieved, with 15 (16.7%) of 90 women below the threshold being false-negatives (NPV = 83.3%). Using a threshold of HBA1c > or = 7.5% to rule-in GDM; the specificity was 95.8% with 15 (71.4%) of 21 patients over the threshold being false-positives (PPV = 28.6%). HBA1c would eliminate the need for an OGTT in 25.1% (111/442) of whom 27% (30/111) women would be misclassified. At any HBA1c threshold with an acceptable sensitivity, the false-positive rate remained high making it necessary for too many healthy women to undergo the confirmatory OGTT. CONCLUSION: Despite all the progress in methodology, HBA1c remains a poor test to screen for GDM.
Authors: Saleh A Aldasouqi; David J Solomon; Samia A Bokhari; Patan M Khan; Shareef Muneera; Ved V Gossain Journal: Int J Diabetes Dev Ctries Date: 2008-10
Authors: Alhossain Khalafallah; Eileen Phuah; Abdul Majeed Al-Barazan; Irena Nikakis; Andrea Radford; Wade Clarkson; Clinton Trevett; Terry Brain; Val Gebski; Anne Corbould Journal: BMJ Open Date: 2016-04-04 Impact factor: 2.692