bpac - best tests

Best Tests DIABETES

Identifying the barriers to detecting people with diabetes

There has been a marked improvement in diabetes detection in New Zealand over the last few years, but there remains a small section of people who prove difficult to reach. While many of the barriers faced by GPs are common to most practices, there will be other barriers unique to each practice. Methods for identifying and overcoming barriers can not be prescriptive, ideas and solutions need to be as individual as the issues each practice faces.

The recent bpac resource “Detecting Diabetes: Tools for better care” provided a range of tools for identifying and overcoming barriers that will be applicable to many practices. The key questions asked were:

Is diabetes testing available: Does the practice have the knowledge and tools to provide testing?
Is diabetes testing appropriate: Are the right people getting the right tests at the right time?
Is diabetes testing accessible: Are the people that need testing able to access the service?
Is diabetes testing acceptable: Is testing culturally acceptable to your practice population?

A number of tools are available below to help address each of these questions:

Tool A: Practice Action plan

Plan for targeted testing:

Goal: To create an environment in the practice in which all staff acknowledge and recognise the importance of identifying people with risk factors for diabetes.

Are all team members familiar with the risk factors for diabetes and the best way to test people? If the answer is no, suggest ways of overcoming this.
Do all members of the team have adequate knowledge of diabetes testing, and are they aware of the importance of diabetes detection? If the answer is no, suggest ways of overcoming this.
For your practice patients, are there access issues/barriers that may be delaying their diabetes diagnosis? What might be some of the barriers that affect the practice patients?
Does the practice provide a service which is acceptable to all cultural groups within the practice? Are there ways in which the practice could be more culturally acceptable?
For each suggestion make someone responsible for implementing the change, and set a date for when this should be done by. The whole practice should agree on a date (maybe 4-6 weeks time) to reassess the process.

Download Tool A in rich text format (.rtf) here
Download Tool A in PDF format here

Detecting people with diabetes…

Who to test...

There is currently no recommendation for population wide screening in New Zealand. This is consistent with international recommendations.

People with symptoms of diabetes
People at high risk of diabetes*
People having CVD risk assessment

What test to use...

Fasting plasma glucose is recommended as the best initial test for the diagnosis of diabetes.

Note: non-fasting glucose has a role in opportunistic testing. A non-fasting glucose of <5.5 doesn’t require further testing while a result of ≥11.1 in symptomatic people is diagnostic of diabetes.

<5.5
No further testing

5.5 – 6.0
GTT for those with
risk factors

6.1 – 6.9
GTT for all

≥ 7.0
Asymptomatic: repeat fasting glucose
Symptomatic: diagnostic of diabetes

Interpreting results

Glucose tolerance test
Fasting		2 hour
6.1-6.9	and	<7.0	Impaired fasting glycaemia
<7.0	and	7.8-11	Impaired glucose tolerance
≥7.0	and/or	≥11.1	Diabetes mellitus

Diagnosing diabetes...

The following are diagnostic of diabetes

In people with symptoms typical of diabetes, a single fasting plasma glucose level of ≥7.0 mmol/L or a random glucose ≥11.1 mmol/L.
In people without symptoms of diabetes, a fasting plasma glucose result ≥7 mmol/L on two different days or a random result of ≥11.1 mmol/L on two different days.
Following a glucose tolerance test a fasting glucose ≥7 mmol/L and/or a 2 hour glucose of ≥11.1 mmol/L .

Role of other tests for diagnosis...

Non fasting blood glucose: limited role in opportunistic testing.
Urine glucose: non-sensitive and non-specific, not recommended.
HbA_1C: best test for monitoring, currently not recommended for diagnosis.

Laboratory monitoring of people with diabetes...

What to test...

HbA_1C

HbA_1c is the best test of glycaemic control in diabetes. Test six monthly in stable diabetics, and three monthly following changes in treatment. The goal is to achieve an HbA_1c as low as possible, preferably less than 7.0%, without causing unacceptable hypoglycaemia.

Self monitoring blood glucose
For further information see BPJ issue 14
(SMBG)

For people with non-insulin treated type 2 diabetes, self-monitoring of blood glucose (SMBG) appears to have little or no effect on glycaemic control.
SMBG is associated with higher costs and lower quality of life.
HbA_1c remains the most useful tool for assessing glycaemic control in people with non-insulin treated type 2 diabetes.

Lipids

Fasting lipid levels are measured three monthly until stable and then 6 – 12 monthly thereafter.

Diabetic renal disease

Urinary albumin:creatinine ratio (ACR) and serum creatinine with estimated glomerular filtration rate (eGFR) should be performed on everyone with diabetes at diagnosis and repeated at least annually – more frequently if there is proteinuria, microalbuminuria or reduced eGFR.

Self Monitoring of Blood Glucose – not for everyone

This report looks at your prescribing of glucose testing strips for patients with diabetes.

Historically, self monitoring of blood glucose (SMBG) has been considered an important component for the management of most people with diabetes. New evidence suggests SMBG is not of benefit for patients with diabetes not using insulin.

People on insulin and performing SMBG

For people on insulin, SMBG remains an essential component of maintaining glycaemic control. It is interesting to note that nationally, approximately 10% of all people receiving insulin are not receiving test strips. Data shows there is considerable variation between PHOs with the percentage of people receiving both insulin and SMBG ranging from 71% to 95%.

People with diabetes not using insulin and performing SMBG

Up until recently, the diagnosis of diabetes was accompanied by education of SMBG. This graph* demonstrates that nationally approximately 60% of all people receiving oral hypoglycaemics are performing SMBG. This varies between PHOs, with between 42% and 83% of people on oral hypoglycaemics (but not on insulin), performing SMBG.

For type 2 diabetes patients not using insulin, evidence shows SMBG does not lead to lower HbA_1c levels. SMBG is associated with increased cost and lower quality of life, therefore SMBG for this group is not recommended.

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