The frequency of testing for glycated haemoglobin, HbA1c, is linked to the probability of achieving target levels in patients with suboptimally controlled diabetes mellitus.

Duff, Christopher J.; Solis-Trapala, Ivonne; Driskell, Owen J.; Holland, David; Wright, Helen; Waldron, Jenna L.; Ford, Clare; Scargill, Jonathan J.; Tran, Martin; Hanna, Fahmy W.F.; Pemberton, R. John; Heald, Adrian; Fryer, Anthony A.

Abstract

Introduction:
We previously showed, in patients with diabetes, that >50% of monitoring tests for glycated hemoglobin (HbA1c) are outside recommended intervals and that this is linked to diabetes control. Here, we examined the impact of tests/year on achievement of commonly-utilised HbA1c targets and on HbA1c changes over time.

Subjects & Methods:
Data on 20,690 adults with diabetes with a baseline HbA1c of >53 mmol/mol (7%) were extracted from Clinical Biochemistry Laboratory records at three UK hospitals. We examined the impact of HbA1c tests/year on: (i) probability of achieving targets of =53mmol/mol (7%) and =48mmol/mol (6.5%) in a year using multi-state modelling and (ii) changes in mean HbA1c using a linear mixed-effects model.

Results:
The probabilities of achieving =53mmol/mol (7%) and =48mmol/mol (6.5%) targets within 1 year were 0.20 (95% confidence interval:0.19-0.21) and 0.10 (0.09-0.10), respectively. Compared with 4 tests/year, having 1 test or >4 tests/year were associated with lower likelihoods of achieving either target; 2-3 tests/year gave similar likelihoods to 4 tests/year. Mean HbA1c levels were higher in patients who had 1 test/year compared to those with 4 tests/year (mean difference: 2.64mmol/mol [0.24%], p<0.001).

Conclusions:
We showed that =80% of patients with sub-optimal control are not achieving commonly recommended HbA1c targets within 1 year, highlighting the major challenge facing healthcare services. We also demonstrated that, while appropriate monitoring frequency is important, 6-monthly testing is as effective as quarterly testing, supporting international recommendations. We suggest that the importance HbA1c monitoring frequency is being insufficiently recognised in diabetes management.

Citation

Duff, C. J., Solis-Trapala, I., Driskell, O. J., Holland, D., Wright, H., Waldron, J. L., …Fryer, A. A. (2018). The frequency of testing for glycated haemoglobin, HbA1c, is linked to the probability of achieving target levels in patients with suboptimally controlled diabetes mellitus. Clinical Chemistry and Laboratory Medicine, https://doi.org/10.1515/cclm-2018-0503

• Journal Article Type: Article
• Acceptance Date: Sep 4, 2018
• Online Publication Date: Oct 2, 2018
• Publication Date: Oct 2, 2018
• Publicly Available Date: May 26, 2023
• Journal: Clinical Chemistry and Laboratory Medicine
• Print ISSN: 1434-6621
• Publisher: De Gruyter
• DOI: https://doi.org/10.1515/cclm-2018-0503
• Keywords: glycated hemoglobin, diabetes mellitus, test utilization, monitoring, glycaemic 3 target
• Publisher URL: https://doi.org/10.1515/cclm-2018-0503
• PMID: 30281512