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Abstract
Background
Early in the COVID-19 pandemic, the National Health Service (NHS) recommended that
appropriate patients anticoagulated with warfarin should be switched to direct-acting
oral anticoagulants (DOACs), requiring less frequent blood testing. Subsequently,
a national safety alert was issued regarding patients being inappropriately coprescribed
two anticoagulants following a medication change and associated monitoring.
Objective
To describe which people were switched from warfarin to DOACs; identify potentially
unsafe coprescribing of anticoagulants; and assess whether abnormal clotting results
have become more frequent during the pandemic.
Methods
With the approval of NHS England, we conducted a cohort study using routine clinical
data from 24 million NHS patients in England.
Results
20 000 of 164 000 warfarin patients (12.2%) switched to DOACs between March and May
2020, most commonly to edoxaban and apixaban. Factors associated with switching included:
older age, recent renal function test, higher number of recent INR tests recorded,
atrial fibrillation diagnosis and care home residency. There was a sharp rise in coprescribing
of warfarin and DOACs from typically 50–100 per month to 246 in April 2020, 0.06%
of all people receiving a DOAC or warfarin. International normalised ratio (INR) testing
fell by 14% to 506.8 patients tested per 1000 warfarin patients each month. We observed
a very small increase in elevated INRs (n=470) during April compared with January
(n=420).
Conclusions
Increased switching of anticoagulants from warfarin to DOACs was observed at the outset
of the COVID-19 pandemic in England following national guidance. There was a small
but substantial number of people coprescribed warfarin and DOACs during this period.
Despite a national safety alert on the issue, a widespread rise in elevated INR test
results was not found. Primary care has responded rapidly to changes in patient care
during the COVID-19 pandemic.
Abstract Objectives To determine how clinicians vary in their response to new guidance on existing or new interventions, by measuring the timing and magnitude of change at healthcare institutions. Design Automated change detection in longitudinal prescribing data. Setting Prescribing data in English primary care. Participants English general practices. Main outcome measures In each practice the following were measured: the timing of the largest changes, steepness of the change slope (change in proportion per month), and magnitude of the change for two example time series (expiry of the Cerazette patent in 2012, leading to cheaper generic desogestrel alternatives becoming available; and a change in antibiotic prescribing guidelines after 2014, favouring nitrofurantoin over trimethoprim for uncomplicated urinary tract infection (UTI)). Results Substantial heterogeneity was found between institutions in both timing and steepness of change. The range of time delay before a change was implemented was large (interquartile range 2-14 months (median 8) for Cerazette, and 5-29 months (18) for UTI). Substantial heterogeneity was also seen in slope following a detected change (interquartile range 2-28% absolute reduction per month (median 9%) for Cerazette, and 1-8% (2%) for UTI). When changes were implemented, the magnitude of change showed substantially less heterogeneity (interquartile range 44-85% (median 66%) for Cerazette and 28-47% (38%) for UTI). Conclusions Substantial variation was observed in the speed with which individual NHS general practices responded to warranted changes in clinical practice. Changes in prescribing behaviour were detected automatically and robustly. Detection of structural breaks using indicator saturation methods opens up new opportunities to improve patient care through audit and feedback by moving away from cross sectional analyses, and automatically identifying institutions that respond rapidly, or slowly, to warranted changes in clinical practice.
To describe trends and geographical variation in prescribing of trimethoprim and nitrofurantoin to treat urinary tract infections, to describe variation in implementing guideline change and to compare actions taken to reduce trimethoprim use in high- and low-using Clinical Commissioning Groups (CCGs).
King's College Hospital hosts a busy anticoagulation clinic in south London within the epicentre of the COVID-19 outbreak in the UK [1]. After the UK entered a period of ‘lockdown’ from 23/03/2020, the Government advised shielding of elderly and vulnerable patients and limiting hospital visits. UK guidance for anticoagulation services was issued (Guidance for the safe switching of warfarin to direct oral anticoagulants (DOACs) for patients with non-valvular AF and venous thromboembolism (DVT / PE) during the coronavirus pandemic) with recommendations around maintaining safe anticoagulation whilst minimising exposure to COVID-19 infection [2]. These included switching to direct oral anticoagulants (DOACs) where appropriate, self-testing INRs, increasing the INR test interval for previously stable patients, and temporarily suspending anticoagulation with VKA therapy where this could no longer be safely continued. Despite implementation of these recommendations, we noted frequent high INR readings in clinical practice during this period. Routine practice at our institution is to perform root cause analysis on all INR results above >8.0. We report on the frequency of supra-therapeutic INR values during the COVID-19 pandemic compared to the previous year and during lockdown and describe the findings of the root cause analysis. Methods All INR results taken within our hospital and community anticoagulation service during a 6-week period were identified (01/03/2020–17/04/2020) centred around the lockdown date of 23/03/2020. We then compared these to the results from the same period in 2019. All cases with excessive elevation of the INR (>8.0) were selected. Data was collated from the anticoagulant clinic record and electronic patient records, which included patient characteristics, INR test frequency, drug compliance, co-medications, and changes in diet and alcohol intake as well as patient-reported events including bleeding. Bleeding events were defined by ISTH criteria [3,4]. Odds ratios (OR) with 95% confidence intervals (95% CI) were calculated to compare the incidence of high INRs during each time period. Root cause analysis was performed according to routine clinical practice, and the results reviewed by a panel of three in-house anticoagulation specialists. COVID-19 was defined as a risk factor for a high INR reading if the disease was possible or confirmed [5]. Results During the 2020 reporting period, 30/3214 (0.9%) INR samples received were > 8.0 (n = 30 patients), compared to 6/4079 (0.1%) (n = 6 patients) during the same period in the previous year (OR 6.3, 95% CI, 2.6–15.2; p 8 are described in Table 1 . Table 1 Patient characteristics for those with an INR >8 in 2019 and 2020.⁎ Table 1 Patient characteristics 2020n = 30 2019n = 6 n % n % Gender (male) 16 53 4 67 Age (years), mean [sd] 71 [14.5) – 70 [16.7] – Ethnicity White 16 53 4 67 Black 8 27 2 33 Hispanic 4 13 – – Asian 2 7 – – Care home resident 3 10 1 17 Indication for anticoagulation AF 12 40 – – APS 2 7 – – VTE 8 27 6 100 LV Thrombus 2 7 – – Aortic valve replacement 2 7 – – Mitral valve replacement 1 3 – – CVA embolic 2 7 – – Target range 2–3 26 87 3 50 2.5–3.5 2 7 3 50 3–4 2 7 – – Abbreviations: AF, atrial fibrillation; APS, antiphospholipid syndrome; VTE, venous thromboembolism; LV, left ventricular thrombus; CVA, cerebral vascular accident; SD, standard deviation. ⁎ Included DVT, PE, renal vein thrombosis, cerebral sinus vein thrombosis, portal vein thrombosis. During the pandemic, 22/30 (73%) high INRs occurred during the 3-week lockdown period (OR 3.43, 95% CI, 1.52–7.73; p < .003). Risk factors for a high INR were identified during root cause analysis. These included COVID-19 infection (10 confirmed, 6 possible, totaling 16/30, 53%), antibiotic therapy (17/30, 57%), inpatient admission (12/30, 40%), recent hospital discharge within the previous 4 weeks (5/30, 17%), missed test date (3/30, 10%), entering an end of life treatment pathway (3/30, 10%), higher target INR (3/30, 10%), other interacting drugs (2/30, 7%) and prolonged test interval (1/30, 3%). The majority (13/16, 81%) of patients with possible or confirmed COVID-19 were prescribed antibiotics. In (2/30, 7%) patients the elevated INR was unexplained. (3/30, 10%) patients experienced bleeding: 2 minor bleeding, and 1 major bleed (spontaneous retroperitoneal haemorrhage), with no recorded deaths due to bleeding. Discussion Our data reveals a significant increase in high INR results during the COVID-19 pandemic, with the majority occurring after the introduction of a lockdown. The reasons for this are likely multifactorial, however more than half of our cases had COVID-19 (possible or confirmed) and/or antibiotic use. The use of antibiotics in patients with COVID-19 appears to be common. Given the high prevalence of COVID-19 in the community, it is important to reinforce the need for prescribers of antibiotics and patients to maintain good channels of communication with anticoagulation clinics regarding co-prescribing of interacting drugs. Subclinical derangements of coagulation and liver impairment have been reported in COVID-19 which might contribute to the problem [6,7]. Reduced vitamin K status has also been reported in patients with COVID-19 [8]; this could be associated with malabsorption due to small bowel COVID-19 involvement and/or reduced dietary intake. Other potential contributory factors include decreased access to green leafy vegetables due to stockpiling [9], increased alcohol consumption [10], and increased paracetamol prescribing may too have increased warfarin sensitivity during lockdown [11]. Furthermore, the psychological impact of social distancing and bereavement may have affected adherence to regular medications during this period [12]. Prior to increasing INR test intervals or switching patients from warfarin to a DOAC during the pandemic (in keeping with UK guidance), the data highlights the importance of careful individual risk assessment, given the high incidence of elevated INRs, frequent prescribing of co-medications and unforeseen consequences of a lockdown.
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History
Date
received
: 13
July
2021
Date
accepted
: 08
October
2021
Funding
Funded by:
Health Data Research UK;
Funded by:
FundRef http://dx.doi.org/10.13039/501100000265, Medical Research Council;
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