Equalis user meeting Protein HbA1c the mean patient values might have been constant since 2007!

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1 Equalis user meeting Protein HbA1c the mean patient values might have been constant since 2007! Gunnar Nordin Marie Lundberg 14 april 2015

2 How true are the mean HbA1c values in the national diabetes register (NDR)? 2

3 patientmedelvärde, mmol/mol How true are the mean HbA1c values in NDR? Grupp Medicinkliniker, diabetes typ 1 Medicinkliniker, diabetes typ 2 Primärvården data från NDR År IFCC calibration Sept-Dec 2009

4 Deviation from target (mmol/mol) Deviation from target in EQA for the major HbA1c method groups Increase due to transition to IFCC calibration? Yearly mean bias in Equalis EQA for the major method groups BioRad D10 BioRad Variant Turbo BioRad Variant Turbo (Mono S cal) Mono S Roche Tina-quant Siemens DCA Vantage Tosoh G5-G8 Tosoh G5-G8 (Mono S cal) Decrease due to adjustment of major method groups? Mono S target IFCC SRM (ERL) target

5 Deviation from target (mmol/mol) Deviation from target in EQA for the major method groups Yearly mean bias in Equalis EQA for the major method groups BioRad D10 BioRad Variant Turbo BioRad Variant Turbo (Mono S cal) Mono S Roche Tina-quant Siemens DCA Vantage Tosoh G5-G8 Tosoh G5-G8 (Mono S cal) aritm mean of main methods Mono S target IFCC SRM (ERL) target

6 Deviation from target (mmol/mol) Deviation from target in EQA for the major method groups Yearly mean bias in Equalis EQA for the major method groups BioRad D10 BioRad Variant Turbo BioRad Variant Turbo (Mono S cal) Mono S Roche Tina-quant Siemens DCA Vantage Tosoh G5-G8 Tosoh G5-G8 (Mono S cal) estimated weighted mean bias aritm mean of main methods Weighted mean according to estimated number of patient results Mono S target IFCC SRM (ERL) target

7 Deviation from target (mmol/mol) All methods seem to have reduced the bias since 2012 an active adjustment? Roche: reduced lot-variation BioRad: improved calibration procedure Tosoh: improved calibration procedure Siemens: no changes [Alere (Axis Shield): calibration changed No data presented] Yearly mean bias in Equalis EQA for the major method groups BioRad D10 BioRad Variant Turbo BioRad Variant Turbo (Mono S cal) Mono S Roche Tina-quant Siemens DCA Vantage Tosoh G5-G8 Tosoh G5-G8 (Mono S cal) estimated weighted mean bias aritm mean of main methods

8 patientmedelvärde, mmol/mol Can a calibration bias for HbA1c influence the mean patient HbA1c? Grupp Medicinkliniker, diabetes typ 1 Medicinkliniker, diabetes typ 2 Primärvården Results from Primary Health Care (type 2) data från NDR År

9 patient mean value, mmol/mol Mean HbA1c for diabetes patients (type 2) in Primary Health Care Data from NDR 55 PHC mean value in NDR yr 2007 yr 2008 yr 2009 yr 2010 yr 2011 yr 2012 yr 2013 yr 2014

10 patient mean value, mmol/mol deviation from target (mmol/mol) Changes in mean HbA1c are almost parallel with changes in estimated mean deviation from target in EQA PHC mean value in NDR weighted mean bias in EQA Probably no change in true mean patient HbA1c during ! 55 Unexplained 55 diff of 1 mmol/mol ,0 0,5 0,0-0,5-1,0-1,5-2,0-2,5 51 yr 2007 yr 2008 yr 2009 yr 2010 yr 2011 yr 2012 yr 2013 yr ,0 Mono S target IFCC SRM (ERL) target

11 Equalis will use a new (=old) procedure for target value in EQA scheme from 2015 Equalis EQA scheme for HbA1c is accredited (ISO 17043) Target values in accredited schemes must be set by accredited methods Target values as mean values of three IFCC SRM (at ERL) does not meet the accredition critera The Mono S dedicated comparison method participate in IFCC Monitoring program and is accredited The Mono S DCM performed at Malmö University hospital until 2011, from 2012 at Sahlgrenska University hospital

12 Equalis will use a new (=old) procedure for target value in EQA scheme from 2015 The results from Mono S are currently slightly lower than the results from ERL, but the correlation is good. From 2015 the Mono S DCM will be presented as the target value, after conversion to values on the IFCCscale by the equation: HbA1c (mmol/mol) = HbA1c (Mono S %) x The ERL-values will be given for information.

13 patient mean value, mmol/mol deviation from target (mmol/mol) Can we find the reason for a possible 1 mmol /mol discrepancy? A true increase in patient mean values? PHC mean value in NDR weighted mean bias in EQA ,0 0,5 1 mmol/mol? ,0-0,5-1,0-1,5-2,0-2,5 51 yr 2007 yr 2008 yr 2009 yr 2010 yr 2011 yr 2012 yr 2013 yr ,0 13

14 patient mean value, mmol/mol deviation from target (mmol/mol) Can we find the reason for a possible 1 mmol /mol discrepancy? Or maybe a negative method bias?? PHC mean value in NDR weighted mean bias in EQA ,0 1,5 1, ,5 0,0-0,5-1,0-1,5 1 mmol/mol? 51 yr 2007 yr 2008 yr 2009 yr 2010 yr 2011 yr 2012 yr 2013 yr ,0

15 : : : :01 Deviation, mmol/mol The difference between IFCC SRM (ERL) and the Mono S level 2007: 0 mmol/mol 2014: 1 mmol/mol 3 IFCC SRM (ERL) deviation from Mono S DCM mmol/mol

16 Some speculations.. 1. Can the IFCC SRL methods have developed a bias of 1 mmol/mol since 2007? To gain further information the EQA samples for 2014 have been measured with IFCC reference method (mass spectrometry) at Instand, Germany The results indicate a positive bias for both Mono S and for IFCC SRL (ERL)! Mono S DCM: IFCC SRM (ERL): ± 0.5 mmol/mol ± 0.4 mmol/mol The difference ERL Mono S is approximately 1 mmol/mol...

17 Some speculations mmol/mol IFCC 1 sept - 31 dec 2009 Medicinkliniker, diabetes typ 1 Medicinkliniker, diabetes typ 2 Primärvården Diabgrupp1_3_namn Mean HbA1c in NDR can have been constant for the whole period ! A calibration drift for the major HbA1c methods in use in Sweden might have appeared since 2007 Since 2012 the drift has been compensated For reasons not yet known, these changes might have been unattended in the EQA schemes Investigations will continue År