Patient using a diabetes testing machine

Diabetes

A review of medication prescribed to renal transplantation patients with diabetes

The work described here was presented at the Pharmacy Together 2019 conference.

Renal transplantation patients are at an increased cardiovascular risk compared to the general population. Hopefully their renal function is improved post-transplantation and therefore medicines contraindicated prior to transplant may be appropriate to use.

This observational study aimed to determine the prescribing practice for type 2 diabetes and new onset diabetes after transplant (NODAT) following renal transplantation, specifically focusing on the appropriate prescribing of metformin.

Local NHS Trust prescribing data was used to look at patients who had undergone a renal transplant and had been diagnosed with a form of diabetes pre- or post-transplant. The patients’ treatment for their diabetes, estimated glomerular filtration (eGFR), type and year of transplantation were recorded. Patients with type 2 diabetes or NODAT were assessed for the appropriateness of metformin being used in their therapy.

One hundred and eleven patients were identified via the local NHS Trust prescribing systems as a renal transplant patient with diabetes. Fifty-five were type 1, 40 were type 2, seven had NODAT and the remaining nine patients had incomplete data to determine the type of diabetes or had not received their transplant at this point. 

There is a cohort of individuals who may not be receiving the most appropriate medication for their diabetes in terms of preventing long-term vascular complications and mortality

Of the 40 patients with type 2 diabetes, five patients’ eGFR was not sufficient to be prescribed metformin (<30ml/min/1.73m2), six patients were already on metformin appropriately, nine were managed with diet alone, and four patients’ eGFR was between 30-45 ml/min/1.73m2 and therefore in theory metformin could be considered with caution. 

The remaining 16 patients with type 2 diabetes could have been on metformin based upon their eGFR (>45ml/min/1.73m2). A further analysis of these eligible patients showed that three were receiving other oral antidiabetic agents and thirteen were on insulin alone (eight on biphasic insulins, four single intermediate or long acting insulin, one unknown insulin regime). 

Of the seven patients with NODAT, two were on metformin, one had a contraindication to metformin, one was diet controlled and three had an eGFR >45ml/min/1.73m2 and could be considered for metformin (all three were being treated with insulin as a monotherapy). 

There is a cohort of individuals who may not be receiving the most appropriate medication for their diabetes in terms of preventing long-term vascular complications and mortality. Evidence shows that metformin has an additional cardiovascular benefit with guidance also supporting its use in type 2 diabetes. When it is determined that insulin is required for treating a patient’s type 2 diabetes it would still be recommended to continue metformin (if tolerated and no contraindications). 

Limitations of the study are the small sample size, the lack of HbA1c readings to assess the patients’ diabetes control, allergy status was not reviewed, and the medicines list was based upon the clinic letter information as a single source.

This work was presented as a poster at the Pharmacy Together 2019 conference, organised by UKCPA and Pharmacy Management.

Additional authors:

Alan Green, University of Sunderland

The opinions expressed in this article are those of the author. They do not purport to reflect the opinions or views of the UKCPA or its members. We encourage readers to follow links and references to primary research papers and guidance.

Competing interest statement: 

The author declares: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

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