1 10 points. AF & Warfarin practice Profile 2011

2 QOF 2009/10 CHADS2 and GRAPS data from systemone Admissions – Bradford HES data 2009/10 Data used

3 Order of slides 1.Incidence 2.Prevalence – diagnosed 3.Undiagnosed cases – opportunistic case finding 4.Risk profile of AF population in NHSBA – CHADS2 5.Anticoagulation 6.Potentially avoidable strokes 7.INR Control 8.Patients who might be taken off warfarin 9.Secondary care – admissions. – General non elective admissions – Stroke with AF – GI bleed

4 Point 1 New incident cases of AF

5 A practice with 10,000 patients would expect to diagnose 7-8 new AF patients per year. This would vary depending on age profile, CV and other risk profile. The increase might be attenuated through improved CV risk management. This would mean approximately. 395 new incidents a year in Bradford (ranging between 1 and 15 new cases per practice).

6 Point 2 Prevalence of AF

7 09/10 prevalence of AF was 1.2% (95%CI 1.23 – 1.17) 6,411 cases. Older practices (proportion register >65+yrs) showing higher prevalence – linear relationship between age profile and prevalence

8 Prevalence of AF varies widely across NHSBA practices and is closely correlated with age structure Prevalence varies between 0.1% of registered population and 2.6%

9 Point 3 Underdiagnosis opportunistic case finding might warranted this should be structured and targeted. Opportunistic pulse check is as good as any (Fitzmaurice / SAFE study)

10 There are undiagnosed cases. We don’t know the true number, but can estimate it. Estimated true prevalence is 1.3% (nationally thought to be about 1.7 to 1.8%) Expected cases (compared to an age standardised population) 7,134 (diff+ 723) or 1.3% The majority of unfound cases can be found in City Care alliance (n=381).

11 Number of unfound cases ranges between -49 and 58 per practice (mean = 9)

12 Estimated that 90% of true prevalent cases have been diagnosed through QOF. This proportion varies across practices – helpful in informing case finding. Practices with small list sizes are, as a rule, have a low proportion of cases that are diagnosed. Practices with a large list size have a high proportion of expected that is diagnosed – or have diagnosed more than the expected prevalent pop

13 Positive (but weak) correlations between list size, age of practice and % of population that is diagnosed. Practices with older populations tend to have higher proportion of cases that are diagnosed, as do practices with larger populations.

14 Point 4 CHADS2 profile – as a measure of risk. Patients with a CHADS2 score and who appear on the AF register

15 Profile of all CHADS2 scores available for each practice. CHADS2=2 = 29%, CHADS2 = 6 = 1%. Practices generally have a similar CHADS2 profile as district average. There are no significant differences. Differences are due to small numbers and random variation

16 Point 5 Anticoagulation GRASP in NHSBA Practices Numbers who need to be on Warfarin who are currently not Numbers currently on warfarin that might not need to be

17 Based on CHADS2≥1, number of patients who need to be on Warfarin = 2,804. Based on CHADS2≥2, number of patients who need to be on Warfarin = 1,813.

18 40% of prevalent AF patients have CHADS2 of ≥ 1 and are not prescribed warfarin. This varies from practice to practice

19 Point 6 Potentially avoidable strokes.

20 We know there are avoidable strokes through putting people on OAC who need to be What is the impact of getting those who need to be on Warfarin on to Warfarin

21 Annually - an extra 107 strokes would potentially avoided if patients with a CHADS2≥ 2 went onto Warfarin 134 strokes if patients with CHADS2 ≥ 1 were prescribed OAC. NNT taken from AFA - Anticoagulation and Bleeding risk – Guidelines for Medical Professionals, 2009 and applied to local CHADS2 scores. OAC threshold is an issue still under discussion – Treat at CHADS2 = 2 annual relative risk:-4% (Gage) however many now treat at 1 (annual relative risk:-2.8%). With the move to CHADSVASc treatment is recommended at scores of 2 (annual relative risk of 1.9%) and suggested at a score of 1 (annual relative risk of 0.7%). Even at CHADS score of 0 the annual relative risk is 1.9% compared with a relative risk of 0% with a CHADSVASc score of 0.

22 Point 7 % with good INR control

23 NICE guidance states that a30% of patients on Warfarin have poor control (therefore assumed 70% have good). The estimated number of CHADS2≥ 2 patients on the AF register and on Warfarin with good control is approximately 1,831, with 2,341 for CHADS2 ≥ 1.

24 Estimated that 10% -15% of patients would be unable to attain good control with improved warfarin use. Ie half of the 30% of currently diagnosed cohort who have poor INR control now - might be candidates for new OACs

25 Point 8 Patients who need to be taken off Warfarin

26 Based on CHADS2=0 and on AF register and on Warfarin. 398 patients need to be taken off Warfarin – 10.6% of patients with a CHADS2 score on the AF register and on Warfarin. Ranges from 0 to 29 patients per practice (mean = 5).

27 A mean of 6% prevalent AF patients ARE prescribed Warfarin and might not need to be

28 Point 9 Non elective AF admissions Dataset is based on extracts from local admissions, 2009/10 ICD-10 code I48X used in either a primary or secondary position

29 09/10 – Approximately 3,347 admissions (average 42 per practice) to hospital where AF was a primary or secondary diagnosis. Of these, 453 were recorded as a primary diagnosis. Variation between practices in admission rates, between 0.4 and 13.6 per 1,000 population (Bradford mean = 6.4 per 1,000).

30

31 Reasons for admits – where AF is in primary or secondary diagnosis + CV admit (ie excluding ingrowing toenails) – top 15

32 A proportion of non elec admits might be avoided with better rate and rhythm control

33 AF Strokes What of AF strokes that are admitted. Strokes with AF in a secondary diagnosis position NB – this tells us nothing about AF strokes that died.

admissions where primary diagnosis Stroke (ICD 10 code I60-I67) and secondary diagnosis AF (ICD 10 code I48X). Estimated that the majority of these (>90%) NOT taking OAC. Low practice numbers (mean = 2 per practice) therefore issues around reliability and further use. Possible low numbers due to miscoding / undercounting of secondary diagnosis codes. 45 admits for TIA where AF is secondary dx

35 Important point to remember (1) Approx 15% of all strokes are due to / in AF pt In NHSBA – 920 strokes admitted in 09/10 AF strokes are more serious - more likely to end in death and disability With anticoagulation AF strokes are significantly less likely (though not completely avoidable)

36 Important point to remember (2) RCP Stroke Audit, 2010 Factors, Medication Pre-Admission Vascular risk factors were present in 81% of patients with previous stroke/TIA (29%) and hypertension (57%) being the most frequent conditions. Only 27% of patients known to have atrial fibrillation (AF) prior to admission with their stroke (21%) were on anticoagulants. Comment: 81% of patients admitted with stroke have a history of known vascular risk factors, with 29% having had previous stroke or TIA and 57% with hypertension. Only (27%) who were recorded as having atrial fibrillation (AF) prior to stroke were taking warfarin which indicates again the failure to provide large numbers of people at risk of stroke because of AF with effective prevention. Patients are dying and having disabling strokes because of our failure to anticoagulate people appropriately stroke-audit-2010-public-report-and-appendices_0.pdf stroke-audit-2010-public-report-and-appendices_0.pdf

37 Important point to remember (3). BTH 2010 audit of AF patients in AntiCoag clinic. Key points: 950 patients with AF in the clinic in BTH In 2008 there were 4 ischeamic strokes (chance of avoiding a stroke while anticoagulated in the clinic 99.6%) In 2009 there were 6 ischeamic strokes and 2 haemorrhagic strokes. The haemorrhagic strokes were both in patients with mechanical heart valves not AF (hence high range INR) Of the 2009 cohort of the 6 ischeamic strokes – 2 had INRs of 1 (i.e. Not complying with therapy) – 2 had INR in a sub therapeutic range – 1 was in therapeutic range – 1 was above therapeutic range (3.8 so with in a range which has been previously studied and found to be effective) In the 2009 cohort of the 2 haemorrhagic strokes ( recall - the annual incidence of intracranial haemorrhage is 0.1 per 1000 ( 0.06 in males and 0.13 in females)- Nilsson OG et al 2000): – 1 had an INR in range – 1 had an INR of 14 and died In 2009 the audit considered patients who had been taken off Warfarin as it was ‘too dangerous to continue) – 9 patients who had been taken off anticoagulants due to this risk suffered an ischeamic stroke In 2010 the audit also considered the AF related stroke (this has also been looked at with larger number in St Mary’s and Imperial Hospital London): – 67 patients had an ischeamic stroke with AF – 59 patients had a CHADS2 score of 2 or greater – 4 were taking warfarin

38 Point (3) reinforced - Summary of BTH audit Asprin doesn’t work. Of the AF strokes admitted, almost all were taking asprin. Warfain is effective in preventing 99% of strokes 9 strokes in the BTH cohort who were taken off warfarin because it was too dangerous. Dozens of AF strokes in patients not taking warfarin. Many fear risk of OAC At Lukes cohort, the risks of being on warfarin are far outweighed by the risks of NOT being on it if the patient is at medium / high risk of stroke.

39 Bleed Risk Many are concerned about bleed risk of patients when on OAC How common IS a bleed? NB – more work to be done on bleed risk. Chang et al.

40 38 admissions where primary diagnosis is GI haemorrhage (ICD 10 code K92.2) and upper GI bleed (K22, K25-29) or AF and a secondary diagnosis of AF or GI bleed. Very low practice numbers (mean = 0.5 per practice) therefore issues around reliability and further use.

41 Summary

42 Summary in numbers 534k pt registered 6411 pt on AF register 1.2% 7134 estimated true number – 1.3% est 723 missing pt 90% of population diagnosed.

have CHADS2 of 1 or more, of which 2804 not currently prescribed warfarin – 46% not px 4429 have CHADS2 of 2 or more, of which 1813 not currently prescribed warfarin – 41% 398 have CHADS2 of 0 and are prescribed warfarin – might be taken off

avoidable strokes if currently non anticoagulated patients with CHADS2 of 2 or more get anticoagulation 134 if the threshold for anticoag is CHADS2 of 1 or more

45 Estimated that 10% of current anticoagulated CHADS2 of 2 or more might be eligible for new OAC – 262 patients. Drug cost of c£900 – minus INR clinic cost.

46 c190 AF strokes admitted (from c900 overall) – mostly not taking OAC. Doesn’t take into account deaths. c38 admissions due to bleed in AF

47 And so what Issues to consider in determining “what next”

48 For a start Targeted case finding – opportunistic pulse checks. GP education Longitudinal dataset needed. How have things changed over time. How might it change in the future Continued push for improved OAC Careful and measured introduction of new agents? Quality improvement project. Primary care focused. Area of emphasis – case finding, OAC, INR. Q measures being determined.