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Comparative evaluation of quality of diabetes care within a population using discrete HbA1c thresholds versus longitudinal trends within a defined time period
  1. Rohan Sadera1,
  2. Sethsiri Wijeratne2,
  3. Varadarajan Baskar1,2
  1. 1 Medicine, University of Buckingham, Buckingham, UK
  2. 2 Endocrinology, South Warwickshire NHS Foundation Trust, Warwick, Warwickshire, UK
  1. Correspondence to Mr Rohan Sadera, Medicine, University of Buckingham, Buckingham MK18 1EG, UK; 1606859{at}


Background HbA1c is a quality measurement for a population’s diabetes care. Currently, discrete values are used to judge the care quality. However, an improved trend may have been achieved without reaching a discrete threshold. We aimed to compare the quality of glycaemic care using discrete thresholds versus longitudinal trends of a patient’s HbA1c.

Methods We derived a study population of 4062 with two consecutive HbA1c’s within 1–6 months. We used current discrete thresholds and then used these to define the longitudinal thresholds (the change in HbA1c between the first and second measurement).

Results We found that even with discrete thresholds, overall care was improving with 61% (Excellent care), 13% (Good care), 13% (Average care) and 13% (Poor care) turning into 68%, 12%, 11% and 9%, respectively (χ² 3335, p<0.0001). Using longitudinal trends shows a greater improvement of care with the original values achieving 74%, 7%, 9%, 7% and 4%, respectively (χ² 4111.3, p<0.0001). There was an additional 28% (Good care), 15% (Average care) and 12% (Poor and Very poor care) who with longitudinal trends improved to an excellent category without being identified as such.

Conclusion Our study highlights the need to consider longitudinal trends when measuring quality of diabetes care.

  • diabetes & endocrinology
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  • Contributors VB conceived the original idea for the report. RS and VB analysed and interpreted results. RS and VB drafted the manuscript and figures. SW contributed to data retrieval and manuscript edit.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval Ethical approval was not considered necessary as the dataset was anonymous and no patient identifiable information was accessible.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement Data are available on request.

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