Inappropriate Requesting of Glycated Hemoglobin (Hb A1c) Is Widespread: Assessment of Prevalence, Impact of National Guidance, and Practice-to-Practice Variability

O.J. Driskell, D. Holland, F.W. Hanna, P.W. Jones, R.J. Pemberton, M. Tran, and A.A. Fryer

May 2012

www.clinchem.org/cgi/content/article/58/5/906

© Copyright 2012 by the American Association for Clinical Chemistry

© Copyright 2009 by the American Association for Clinical Chemistry

IntroductionIntroductionPressures on clinical laboratories

>Reduce costs>Maintain quality>Manage increasing workload>Improve turnaround times

Increasing emphasis on managing appropriate test utilization

>Reduce unnecessary testing (over-testing)>What about missed tests (under-testing)?

© Copyright 2009 by the American Association for Clinical Chemistry

Introduction (contd.)Introduction (contd.)How common is inappropriate testing?

(This will depend on how an inappropriate test is defined)>Prevalence estimated at 25-40% in some studies>Under-testing more difficult to quantify & less researched>Huge variability in test requesting patterns between general practitioners suggests it is widespread

Urgent need to assess inappropriate test utilization, particularly impact on:

>Healthcare resource allocation>Clinical outcome>Patient experience

© Copyright 2009 by the American Association for Clinical Chemistry

Introduction (contd.): Study AimsIntroduction (contd.): Study Aims

Using the diabetes marker glycated hemoglobin (HbA1c) as a model to assess:

>Prevalence of over- and under-testing>Impact of national guidance>Variability between requestors

© Copyright 2009 by the American Association for Clinical Chemistry

Introduction - QuestionsIntroduction - Questions

What are the key drivers for reducing inappropriate test requesting?

How would you define an inappropriate request?

© Copyright 2009 by the American Association for Clinical Chemistry

Materials & Methods – PatientsMaterials & Methods – PatientsAll HbA1c requests between January 2001 and March 2011 (n=520,273) from the University Hospital of North Staffordshire (UK) Clinical Biochemistry Department

Data collected included patient demographics (unique identifier, age, gender), request date and source, test result

QC tests removed to leave dataset comprising 519,664 requests from 115,730 unique patients

© Copyright 2009 by the American Association for Clinical Chemistry© Copyright 2009 by the American Association for Clinical Chemistry

Materials & Methods (contd.) Materials & Methods (contd.)

Table 1. Definitions of over- and under-requesting(Based on UK and US guidance on recommended testing frequencies)

Interval between requestsToo soon (Over-requesting)

Appropriate request

Too late (Under-requesting)

Well controlled (HbA1c <53 mmol/mol) <6 months 6-12 months >12 months

Poorly controlled (HbA1c ≥53 mmol/mol) <2 months 2-6 months >6 months

© Copyright 2009 by the American Association for Clinical Chemistry

Materials & Methods - Data analysisMaterials & Methods - Data analysis

© Copyright 2009 by the American Association for Clinical Chemistry

Materials & Methods - QuestionsMaterials & Methods - Questions

How and why does length of run-in period affect the prevalence estimates (see Supplemental Figure 1)?

What other factors might cause an under- or over- estimate of prevalence using these data?

© Copyright 2009 by the American Association for Clinical Chemistry© Copyright 2009 by the American Association for Clinical Chemistry

ResultsResults

Table 2. Prevalence of inappropriate repeat requesting for HbA1c (2010 dataset).

© Copyright 2009 by the American Association for Clinical Chemistry© Copyright 2009 by the American Association for Clinical Chemistry

Figure 1. Relative frequency plots showing the distribution of repeat request intervals in well-controlled (initial HbA1c <7%) and poorly-controlled (initial HbA1c ≥7.0%) patients: A) primary care, B) secondary care.

Results (contd.)Results (contd.)

© Copyright 2009 by the American Association for Clinical Chemistry© Copyright 2009 by the American Association for Clinical Chemistry

Figure 2. The impact of national guidance from UK Diabetes National Service Frameworks (NSF), UK National Institute for Health and Clinical Excellence (NICE), the UK general practice Quality and Outcomes Frameworks (QOF), and the American Diabetic Association (ADA) on the proportion of HbA1c tests requested ‘too soon’ and ‘too late’ (according to guidance on testing frequency [minimum re-test interval]) between 2003 and 2011.

Results (contd.)Results (contd.)

© Copyright 2009 by the American Association for Clinical Chemistry© Copyright 2009 by the American Association for Clinical Chemistry

Figure 3. The variability in proportion of repeat tests requested A) ‘too soon’ and B) ‘too late’ between the 87 GP practices in North Staffordshire, using the 2010 data set. The illustrated practice (GP42) requested less than 40% of tests within the recommended repeat testing frequency .

Results (contd.)Results (contd.)

GP42GP42

A

B

© Copyright 2009 by the American Association for Clinical Chemistry

Results - QuestionsResults - Questions

What are the potential causes of under- and over- requesting? What do the data presented suggest in this regard?

National guidance appears ineffective. How, therefore, might these causes be addressed?

Does it matter? If so, how & to whom?

© Copyright 2009 by the American Association for Clinical Chemistry

Take home messagesTake home messagesInappropriate testing is common and varies considerably between requestors

>Under-testing as well as over-testing

National guidance is ineffective at influencing behaviour on testing frequency

Changing behaviour (and releasing healthcare savings) requires:

>A multi-system approach>Inclusion of all the stakeholders>Assessment of the whole patient pathway

© Copyright 2009 by the American Association for Clinical Chemistry

Thank you for participating in this month’sClinical Chemistry Journal Club.

Additional Journal Clubs are available atwww.clinchem.org

Follow us