Download Reducing the risk

Anticoagulants
Reducing the risk
Sue Wooller & Amanda Powell
May 2013
Coroner highlights prescribing error after patient dies from
warfarin overdose
BMJ 2002;325:922
Failure to prescribe appropriate prophylaxis against PUD
contributes to the death of a patient from a GI bleed whilst
anticoagulated
MPS - UK Casebook 2005
Fatal outcome of Azapropazone/Warfarin interaction - INR
not checked despite early signs of bleeding.
Improving Medication Safety - DoH 2004
Delay in follow up after 20% increase in Warfarin dosage leads to
fatal haemorrhage
Improving Medication Safety - DoH 2004
Suprachoroidal haemorrhage after Clarithromycin co-prescribed
with Warfarin leaves patient with permanent visual damage
Journal of Royal Society of Medicine 2001
Patient dies of a subdural haematoma secondary to a grossly
elevated INR having been recently discharged from hospital
MPS website
Patient, post DVT, had a constantly low INR due to mistaking 0.5mg
for 5mg tablets
Local incident 2010
Patient, post DVT, given warfarin on only Saturdays and Sundays
due to poor discharge communication
Local incident 2010
Patient admitted to ITU with life threatening haematoma after
continuing on loading dose of warfarin post discharge
Local incident 2011
Anticoagulants
Reducing the risk
Sue Wooller & Amanda Powell
May 2012
NEVERMIND
THE BLOODCLOTS……….
The therapeutic "window"
Hylek EM, et al. New Engl J Med 1993;120:897-902
Adverse drug reactions as cause of admission to hospital: prospective
analysis of 18 820 patients
BMJ 2004;329:15-19
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Observational study of 18 820 patients aged > 16 years admitted
over six months and assessed for cause of admission.
There were 1225 admissions related to an ADR, giving a prevalence
of 6.5%, with the ADR directly leading to the admission in 80% of
cases.
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The median bed stay was eight days, accounting for 4% of the
hospital bed capacity.
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The projected annual cost of such admissions to the NHS is £466m
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The overall fatality was 0.15%.
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Most reactions were either definitely or possibly avoidable.
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Drugs most commonly implicated in causing these admissions
included low dose aspirin, diuretics, warfarin, and NSAIDs other
than aspirin, the most common reaction being gastrointestinal
bleeding.
National Patient
Safety Agency
88
Coroner highlights prescribing error after patient dies from
warfarin overdose
BMJ 2002;325:922
 The coroner returned a verdict of accidental death on a 79 year old
patient.
 The man died of gastrointestinal haemorrhage three weeks after
being told to take the wrong dose.
 Doctors at the surgery in south east Sheffield used to write repeat
prescriptions for the drug by hand, on the basis of the patient’s latest
blood test results.
 The card would then be handed to the receptionist, who would inform
the patient of any required change in dose.
 The patient in question was taking doses of 2 mg or 3 mg on alternate
days. His doctor wrote the word "Same" on the patient’s card and
passed it to the receptionist, who read his writing as "5mg."
Coroner highlights prescribing error after patient
dies from warfarin overdose
BMJ 2002;325:922
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Describing the incident as a "disastrous error," the doctor
concerned said the surgery has since changed its protocol for
repeat prescriptions of the drug.
Blood test results and recommended doses of warfarin are now
entered into the computer system by the doctor, the doctor
informs the patient by phone the same evening of the result, and
confirmation of the dosage is sent in writing to the patient a few
days later.
But he added that he had said in the court hearing that his own
handwriting was often difficult to read. "I accept entirely in my
own handwriting my ‘S’ and my ‘5’ are very similar and my ‘S’ can
easily be mistaken for a ‘5’”
Reducing the risks: Oral anticoagulants
Improving Medication Safety 2004, DoH
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Staff at Basildon Hospital have developed an
automatic voicemail system which calls patients at
home with their INR result, dose and clinic
appointment time.
The system has been in operation for more than 2
years, transmitting over 60,000 reports by telephone.
There were no clinical incidents.
National Patient Safety Agency
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Nursing home administered 1mg tablets instead of 3mg tablets
to a patient resulting in an INR of 1.4
Nursing home administered 2.5mg Warfarin daily instead of 21/2
tablets of 3mg (7.5mg) daily
Patient discharged from CCU with Warfarin dose written in a
booklet about medicines for the heart. Took 3 x 5mg daily
instead of 3.5mg daily
From the MPS website
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Dr L, a GP, had received notice of her requested
attendance at a coroner’s inquest into the death of
one of her patients.
Mr G had been an inpatient at the local hospital,
where he had been anticoagulated with warfarin.
After discharge, he had become unwell and been readmitted to the hospital. Unfortunately, he had died
from a subdural haematoma, secondary to a grossly
elevated INR.
There had been no opportunity to check his INR
during the short period in which he had been out of
hospital…
Local examples
Residential home called for advice:
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Patient had been discharged home from hospital a month
previously, had a DVT during admission and had been started on
warfarin.
Patient had been discharged home on a Saturday and the
discharging team advised for the patient to have 3mg of
warfarin on the Saturday and Sunday.
For the month since being discharged from hospital the nursing
home had been giving the patient 3mg of warfarin every
Saturday and Sunday, no warfarin during the week and no INR
monitoring.
Local examples
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There was a patient taking 0.5mg instead of 5mg as
the GP had issued 0.5mg and we didn't know he had
them - we kept increasing his dose and nothing was
happening.
Many patients still fail to let us know when they are
given new meds/antibiotic courses.
Anticoagulant Clinic Pharmacist, UHW
Local examples
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Patient was slow loaded for AF on 3mg daily for 7
days then re-check INR.
 Given 3mg & 1mg tablets.
 Took both despite yellow book clearly stating 3mg
(1 blue tablet) daily.
 INR on Day 8 >15
Patient given 5mg tablets instead of his usual 3mg.
 Just thought the colour had changed despite being
on warfarin for several years.
 INR >8.0 after 1 week.
Cwm Taf Anticoagulation Service
Local examples
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Patient given 2 x 10mg loading doses on the ward
 Discharged at a weekend with 1mg, 3mg & 5mg
tablets
 Continued with 10mg daily until next INR check as
thought this was correct
 Admitted to ITU with life threatening haematoma
after 5 days
Cwm Taf Anticoagulation Service
National Patient Safety Agency
Patient workshop
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Use of 0.5mg Warfarin tablets is not widespread yet
many patient and carers need to break 1mg tablets to
produce correct dose
Local policy of only using 3mg tablets and then
prescribing 2mg daily dose causes very real problems
for patients
Alternate day dosing regimes are difficult especially
for those with poor memories
National Patient Safety Agency
Patient workshop
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Problems with information not communicated to GPs
Poor communication with carers
No planning for coping during first 4 weeks postdischarge
Lack of information about effect of foods and alcohol
on anticoagulant control
Overall, discharge is the weakest yet critical stage
National Patient Safety Agency
Safer Use of Anticoagulants, 2006
Patient workshop
“They’re given a bag of tablets and a letter to take to
their GP and that’s where it stops”
“People who are discharged from hospital are given so
much information in such a short time that half of it
goes over their head. They’re not worried about what
pill they’re going to take - they’re worried about how
they’re going to manage at all”
Reducing the risks: Oral anticoagulants
Improving Medication Safety 2004, DoH
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A 66-year-old man with ischaemic heart disease was treated with
warfarin for AF.
He developed acute arthritis, diagnosed as gout by his general
practitioner, and was prescribed the anti-inflammatory drug
azapropazone.
The dose was subsequently increased in response to an
exacerbation of his arthritis.
The patient then developed signs of bleeding.
The general practitioner arranged for a full blood count, but did
not check the INR.
Before the results were available, the patient suffered a massive
intracranial haemorrhage, was admitted to hospital, and died.
On admission his INR was greater than 10.
Suprachoroidal haemorrhage after addition of
Clarithromycin
Journal of the Royal Society of Medicine 2001; 94: 583-584
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62 year old lady with AVR/MVR anticoagulated with
Warfarin target INR 3.0
Attended casualty with sudden deterioration of vision
after coughing
A week before presentation she had begun a course
of Clarithromycin for a chest infection
INR 3 days before start of course: 2.3
INR 3 days into the course: 2.9
INR on presentation: 8.2
Co-ingestion of herbal medicines and warfarin
BJGP 2004; 54 : 439-441
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Postal questionnaire
Thirty-five general practices in Devon and Somerset identified
2600 patients taking warfarin and sent postal questionnaires to
them.
Response rate = 54.2%
One or more of the specified herbal remedies thought to
interact with warfarin were taken by 8.8% of all patients.
Complementary or homeopathic treatments not specified in the
survey questionnaire were taken by 14.3% of responders.
Overall, 19.2% of responders were taking one or more such
medicines.
The use of herbal medicines had not been discussed with a
conventional healthcare professional by 92.2% of patients.
Reducing the risks: Oral anticoagulants
Improving Medication Safety 2004, DoH
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All patients taking anticoagulants should be monitored
carefully
Responsibilities of health care team should be clearly defined
There should be regular service audits
Report stresses the critical importance of effective
communications when patients move from one care setting to
another
On discharge, drug regimen /treatment plan need to be
communicated in a timely and reliable way to ensure safe and
seamless transfer
Staff should ensure that patients understand their discharge
medicines
National Patient Safety Agency
Patient Safety Alert 18 (March 2007)
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Ensure all staff caring for patients anticoagulant therapy have the
necessary work competences
Review and update procedures and clinical protocols for anticoagulant
services to ensure they reflect safe practices
Audit anticoagulant services using BSH/NPSA safety indicators as part
of the annual medicines management audit programme
Ensure that patients prescribed anticoagulants receive appropriate
verbal and written information
Promote safe practice with prescribers and pharmacists to check that
patients’ INR is being monitored regularly and that the INR level is
safe before issuing or dispensing repeat prescriptions for oral
anticoagulants
National Patient Safety Agency
Patient Safety Alert 18 (March 2007)
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Promote safe practice for prescribers co-prescribing one or
more clinically significant interacting medicines for patients
already on oral anticoagulants - make arrangements for INR
tests and inform monitoring clinic. Pharmacists to ensure
precautions have been taken.
Ensure that dental practitioners manage patients on
anticoagulants according to evidence based therapeutic
guidelines.
Amend local policies to standardise the range of anticoagulant
products used incorporating characteristics identified by
patients as promoting safer use.
Promote the use of written safe practice procedures for the
administration of anticoagulants in social care settings. Minimise
and risk assess the use of MDS.
Safety Indicators NPSA/BCSH
British Journal of Haematology (2007)
136 (1); 26-29
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Proportion of patient-time in range
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Percentage of INRs > 5·0
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Percentage of INRs > 8·0
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Percentage of INRs > 1·0 INR unit below target (e.g. percentage
of INRs < 1·5 for patients with target INR of 2·5)
Percentage of patients suffering adverse outcomes, categorised
by type, e.g. major bleed
Percentage of patients lost to follow up (and risk assessment of
process for identifying patients lost to follow up).
Safety Indicators NPSA/BCSH
British Journal of Haematology (2007)
136 (1); 26-29
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Percentage of patients with unknown diagnosis, target INR or
stop date
Percentage of patients with inappropriate target INR for
diagnosis, high and low
Percentage of patients without written patient educational
information.
Percentage of patients without appropriate written clinical
information, e.g. diagnosis, target INR, last dosing record.
Who is at risk?
BMJ 2002; 325: 828-831
Questions to ask when considering oral anticoagulation
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Is there a definite indication?
Is there a high risk of bleeding?
Will current medication/disease interfere
with control?
Is compliance/attendance at clinic a problem?
Will there be regular review of risks/benefits
of anticoagulation?
Who is at risk?
BMJ 2002; 325: 828-831
NICE CG36
Patients at high risk of bleeding with Warfarin
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Age >75 years
Uncontrolled hypertension
Alcohol excess
Poor compliance/clinic attendance
Bleeding lesions/ history of bleeds
Bleeding tendency (e.g. thrombocytopenia) or concomitant
NSAIDs and antibiotics
Instability of INR and INR above 3
Have a history of poorly controlled anticoagulation
therapy.
Are on multiple other drug treatments (polypharmacy)
Are taking antiplatelet drugs
CHADS2
CHADS2 Scoring Scheme
Condition
Points
C
Congestive
heart failure
1
H
Hypertension
1
A
Age > 75
years
1
D
Diabetes
Mellitus
1
S2
Prior Stroke or
TIA
2
Annual Stroke Risk with Respect to CHADS 2 Score (1)
Stroke Risk %
95% confidence
interval
0
1.9
1.2-3.0
1
2.8
2.0-3.8
2
4.0
3.1-5.1
3
5.9
4.6-7.3
4
8.5
6.3-11.1
5
12.5
8.2-17.5
6
18.2
10.5-27.4
CHADS2 Score
CHADS2VASC
CHA2DS2-VASc score for stroke risk in atrial fibrillation
Feature
Score
Congestive Heart Failure
1
Hypertension
1
Age >75 years
2
Age between 65 and 74 years
1
Stroke/TIA/TE
2
Vascular disease (previous
MI, peripheral arterial disease
or aortic plaque)
1
Diabetes mellitus
1
Female
1
Who is at risk?
Circulation 2012; 126: 860-865
HAS-BLED score for bleeding risk on oral anticoagulation in atrial fibrillation
Feature
Score if
present
Hypertension
(Systolic >=
160mmHg)
1
Abnormal renal
function
1
Abnormal liver
function
1
Age >= 65
years
1
Stroke in past
1
Bleeding
1
Labile INRs
1
Taking other
drugs as well
1
Alcohol intake
at same time
1
•score of 3 or more indicates increased one year bleed risk on anticoagulation sufficient to justify caution or more regular review
New Oral Anticoagulation Agents (NOACs)
– NICE Guidance
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Dabigatran (Pradaxa)▼
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Rivaroxaban (Xarelto) ▼
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Prevention of VTE after hip and knee (TA 157, September 2008)
Prevention stroke in AF (TA 249, March 2012)
Prevention of VTE after hip and knee (TA 170, April 2009)
Prevention stroke in AF (TA 256, May 2012)
VTE treatment and long-term prophylaxis (TA 261July 2012)
Apixaban (Eliquis)▼
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Prevention of VTE after hip and knee (TA 245, January 2012)
(Prevention of stroke in AF on-going) (expected imminently NICE website
states February 2013)
Dabigatran (Pradaxa) ▼
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Used in Cardiff and Vale is for prevention of stroke in AF
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Formulary status – Specialist Initiated
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Dose is:
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150mg twice a day or
110mg twice for patients > 80 years
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First prescription from secondary care
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Complete documentation prior to the first dispensing
from hospital pharmacy
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Continued prescribing by GP practices
Rivaroxaban (Xarelto) ▼
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Used in Cardiff and Vale is treating deep vein
thrombosis and preventing recurrent deep vein
thrombosis and pulmonary embolism after a diagnosis of
acute deep vein thrombosis in adults
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Formulary status – Hospital Only
Dose is 15mg twice a day for 3 weeks then 20mg daily
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Patients intolerant of warfarin on LMWH
IVDU / alcoholics
Patients with precipitated DVT (e.g. following surgery)
Apixaban (Eliquis)▼
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Used in Cardiff and Vale for prevention of VTE after hip
and knee replacements (rivaroxaban used previously for
this indication by some Cardiff and Vale orthopaedic
surgeons)
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2.5mg twice a day for 10 to 14 days post knee surgery
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2.5mg twice a day for 32 – 38 days post hip surgery
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Formulary status – Hospital Only
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Full supply from secondary care on discharge
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Not to be continued by the GP practice.