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Management of Suboptimally Controlled Type 2 Diabetes Mellitus in General Practice

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posted on 13.12.2021, 16:56 authored by Mark Murphy
DSuboptimal control of cardiovascular risk factors and significant hyperglycaemia is a major burden for persons with type 2 diabetes mellitus (T2DM) and for healthcare systems. Failure to intensify medications for patients with poor control of T2DM, when indicated, is called clinical inertia and is one contributory factor to suboptimal control of T2DM. The aim of this thesis was to explore and develop the understanding of suboptimally controlled T2DM. I did this through studying the impact of interventions which can best support the management of suboptimally controlled T2DM and the development and assessment of the feasibility of a theory and evidence-based complex intervention to support treatment intensification in Irish General Practice.
A systematic review of interventions for T2DM targeting patient with poor control of T2DM (HbA1c ≥ 59 mmol/mol), in community settings, including 42 randomised controlled trials, led to modest reductions in HbA1c compared to usual care (-3.7 mmol/mol). Few professionally targeted interventions to support the management of suboptimally controlled T2DM were present and interventions targeting patients with very poorly controlled T2DM were more effective.
Clinical guidelines for T2DM have become more complex with the introduction of new therapeutic agents. Substantial geographical variation in the prescribing of newer T2DM medications was shown in this thesis, with very high levels of geographical variation of GLP-1 agonists (systematic component of variation of 11.4 in 2013 and 10.3 in 2014) and moderate variation for DPP-4 inhibitors. This prescribing variation may represent differences in the application of clinical guidelines, but also variation in professional opinion or patient preferences.
The PhD thesis outlined the development of a complex intervention, using the Medical Research Council Framework, to support GP-led intensification of medications, where appropriate, for patients with poor control of T2DM. The intervention was found to be feasible and acceptable to patients and GPs, finding decision support helpful navigating increasingly complex medication algorithms. However, GPs thought that non-engagement by patients, with GP and hospital services, was a primary contributing factor determining suboptimal control of T2DM.
Some intervention GPs consciously chose not to intensify medications for some patients who often did not engage with traditional healthcare services. This PhD thesis develops the concept of clinical inertia, with poor control of T2DM risk factors representing an understandable phenomenon for a certain cohort of patients, given significant co-morbidities.


First Supervisor

Prof. Susan M Smith

Second Supervisor

Prof. Tom Fahey

Third Supervisor

Prof. Molly Byrne


Submitted for the Award of Doctor of Philosophy to the Royal College of Surgeons in Ireland, 2020

Published Citation

Murphy M,. Management of Suboptimally Controlled Type 2 Diabetes Mellitus in General Practice [PhD Thesis] Dublin: Royal College of Surgeons in Ireland; 2020

Degree Name

Doctor of Philosophy (PhD)

Date of award



  • Doctor of Philosophy (PhD)

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