Variability in Test Interval Is Linked to Glycated Haemoglobin (HbA1c) Trajectory over Time

Aims. We previously showed that the glycated haemoglobin (HbA1c) testing frequency links to diabetes control. Here, we examine the effect of variability in test interval, adjusted for the frequency, on change in HbA1c (ΔHbA1c). Materials & Methods. HbA1c results were collected on 83,872 people w...

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Main Authors: Anthony A. Fryer, David Holland, Michael Stedman, Christopher J. Duff, Lewis Green, Jonathan Scargill, Fahmy W. F. Hanna, Pensée Wu, R. John Pemberton, Christine Bloor, Adrian H. Heald
Format: Article
Language:English
Published: Wiley 2022-01-01
Series:Journal of Diabetes Research
Online Access:http://dx.doi.org/10.1155/2022/7093707
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author Anthony A. Fryer
David Holland
Michael Stedman
Christopher J. Duff
Lewis Green
Jonathan Scargill
Fahmy W. F. Hanna
Pensée Wu
R. John Pemberton
Christine Bloor
Adrian H. Heald
author_facet Anthony A. Fryer
David Holland
Michael Stedman
Christopher J. Duff
Lewis Green
Jonathan Scargill
Fahmy W. F. Hanna
Pensée Wu
R. John Pemberton
Christine Bloor
Adrian H. Heald
author_sort Anthony A. Fryer
collection DOAJ
description Aims. We previously showed that the glycated haemoglobin (HbA1c) testing frequency links to diabetes control. Here, we examine the effect of variability in test interval, adjusted for the frequency, on change in HbA1c (ΔHbA1c). Materials & Methods. HbA1c results were collected on 83,872 people with HbA1c results at baseline and 5 years (±3 months) later and ≥6 tests during this period. We calculated the standard deviation (SD) of test interval for each individual and examined the link between deciles of SD of the test interval and ΔHbA1c level, stratified by baseline HbA1c. Results. In general, less variability in testing frequency (more consistent monitoring) was associated with better diabetes control. This was most evident with moderately raised baseline HbA1c levels (7.0–9.0% (54–75 mmol/mol)). For example, in those with a starting HbA1c of 7.0–7.5% (54–58 mmol/mol), the lowest SD decile was associated with little change in HbA1c over 5 years, while for those with the highest decile, HbA1c rose by 0.4–0.6% (4–6 mmol/mol; p<0.0001). Multivariate analysis showed that the association was independent of the age/sex/hospital site. Subanalysis suggested that the effect was most pronounced in those aged <65 years with baseline HbA1c of 7.0–7.5% (54–58 mmol/mol). We observed a 6.7-fold variation in the proportion of people in the top-three SD deciles across general practices. Conclusions. These findings indicate that the consistency of testing interval, not the just number of tests/year, is important in maintaining diabetes control, especially in those with moderately raised HbA1c levels. Systems to improve regularity of HbA1c testing are therefore needed, especially given the impact of COVID-19 on diabetes monitoring.
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spelling doaj-art-a0a3840898014d9cb88cf90fd9c667ed2025-02-03T06:05:24ZengWileyJournal of Diabetes Research2314-67532022-01-01202210.1155/2022/7093707Variability in Test Interval Is Linked to Glycated Haemoglobin (HbA1c) Trajectory over TimeAnthony A. Fryer0David Holland1Michael Stedman2Christopher J. Duff3Lewis Green4Jonathan Scargill5Fahmy W. F. Hanna6Pensée Wu7R. John Pemberton8Christine Bloor9Adrian H. Heald10School of MedicineThe Benchmarking PartnershipRes ConsortiumSchool of MedicineDepartment of Clinical BiochemistryDepartment of Clinical BiochemistryDepartment of Diabetes and EndocrinologySchool of MedicineDiabetes UK (North Staffordshire Branch)Diabetes UK (North Staffordshire Branch)Department of Diabetes and EndocrinologyAims. We previously showed that the glycated haemoglobin (HbA1c) testing frequency links to diabetes control. Here, we examine the effect of variability in test interval, adjusted for the frequency, on change in HbA1c (ΔHbA1c). Materials & Methods. HbA1c results were collected on 83,872 people with HbA1c results at baseline and 5 years (±3 months) later and ≥6 tests during this period. We calculated the standard deviation (SD) of test interval for each individual and examined the link between deciles of SD of the test interval and ΔHbA1c level, stratified by baseline HbA1c. Results. In general, less variability in testing frequency (more consistent monitoring) was associated with better diabetes control. This was most evident with moderately raised baseline HbA1c levels (7.0–9.0% (54–75 mmol/mol)). For example, in those with a starting HbA1c of 7.0–7.5% (54–58 mmol/mol), the lowest SD decile was associated with little change in HbA1c over 5 years, while for those with the highest decile, HbA1c rose by 0.4–0.6% (4–6 mmol/mol; p<0.0001). Multivariate analysis showed that the association was independent of the age/sex/hospital site. Subanalysis suggested that the effect was most pronounced in those aged <65 years with baseline HbA1c of 7.0–7.5% (54–58 mmol/mol). We observed a 6.7-fold variation in the proportion of people in the top-three SD deciles across general practices. Conclusions. These findings indicate that the consistency of testing interval, not the just number of tests/year, is important in maintaining diabetes control, especially in those with moderately raised HbA1c levels. Systems to improve regularity of HbA1c testing are therefore needed, especially given the impact of COVID-19 on diabetes monitoring.http://dx.doi.org/10.1155/2022/7093707
spellingShingle Anthony A. Fryer
David Holland
Michael Stedman
Christopher J. Duff
Lewis Green
Jonathan Scargill
Fahmy W. F. Hanna
Pensée Wu
R. John Pemberton
Christine Bloor
Adrian H. Heald
Variability in Test Interval Is Linked to Glycated Haemoglobin (HbA1c) Trajectory over Time
Journal of Diabetes Research
title Variability in Test Interval Is Linked to Glycated Haemoglobin (HbA1c) Trajectory over Time
title_full Variability in Test Interval Is Linked to Glycated Haemoglobin (HbA1c) Trajectory over Time
title_fullStr Variability in Test Interval Is Linked to Glycated Haemoglobin (HbA1c) Trajectory over Time
title_full_unstemmed Variability in Test Interval Is Linked to Glycated Haemoglobin (HbA1c) Trajectory over Time
title_short Variability in Test Interval Is Linked to Glycated Haemoglobin (HbA1c) Trajectory over Time
title_sort variability in test interval is linked to glycated haemoglobin hba1c trajectory over time
url http://dx.doi.org/10.1155/2022/7093707
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