Safety of direct oral anticoagulants (DOACs) vs. warfarin for people aged ≥ 75 years with atrial fibrillation: a cohort study

Introduction

Warfarin significantly reduces the risk of stroke in people with atrial fibrillation (AF), but historically has been underused in older people due to complicated dosage regimens. DOACs offer an attractive alternative to warfarin and were shown to be non-inferior in randomised controlled trials, however older people were underrepresented in these trials and there have been few studies investigating outcomes specifically in this high risk group (1).

Aim

To compare the risk of major, non-major, gastrointestinal, and intracranial bleeding between warfarin and DOACs in people aged ≥ 75 years with AF.

Methods

A cohort of patients aged ≥ 75 years with a diagnosis of AF was extracted from the Clinical Practice Research Datalink (CPRD). Patients could enter the study on the date of their first prescription for warfarin or a DOAC between 1/1/2013 and 27/12/2017. Patients were censored on the date of the outcome, death, or leaving the general practice. Switching between anticoagulants and unexposed periods were measured using prescription mapping. Crude and adjusted hazard rates of the risk of bleeding were calculated using a Cox proportional hazards model with oral anticoagulant prescribing as a time varying covariate.

Results

The cohort included 10,149 patients in the warfarin group and 10,237 in the DOAC group. The groups had similar characteristics and the average age was 81 in the warfarin group and 82 in the DOAC group. The table summarises the results. Whilst major and non-major bleeding was similar between all DOACs and warfarin, rivaroxaban was associated with higher risk and apixaban lower risk when analysed separately. Risk of gastrointestinal bleeding was higher with all DOACs and rivaroxaban than warfarin but apixaban was not significantly different. Few intracranial events occurred (n=131).

Conclusion

The results indicate that DOACs as a group are not significantly different to warfarin, however when analysed separately, apixaban may be safer. While the study relies on prescription data and hence it is not known if patients were taking the medications, the large cohort studied is representative of older people who are prescribed these medications in UK primary care.

Reference

(1) Mitchell A, Watson MC, Welsh T, McGrogan A. Effectiveness and safety of direct oral anticoagulants versus vitamin K antagonists for people aged 75 years and over with atrial fibrillation: A systematic review and meta-analyses of observational studies. Journal of Clinical Medicine. 2019; 8 (554).

Low carbon footprint inhalers in England: a review of dispensing data

Introduction

Due to propellants, metered dose inhalers (pMDIs) have a higher carbon footprint than low carbon footprint inhalers (LCFIs), such as dry powder or soft mist inhalers (1). Consequently, pMDIs contribute 3.5% of the NHS’s CO2 equivalent emissions (2). Local and national guidelines (NICE, British Thoracic Society) have attempted to increase use of LCFIs, but their effects and factors influencing success are unknown.

Aim

To investigate temporal and geographical variation in LCFI dispensing in England over five years.

Methods

Clinical commissioning group (CCG) dispensed items (March 2016-February 2021) were obtained from openprescribing.net for five classes of inhaler where a choice between pMDIs and LCFIs is available: short-acting beta-agonists (SABAs), long-acting beta-agonists (LABAs), inhaled corticosteroids (ICS), ICS plus LABA inhalers (ICS/LABA) and ICS/LABA plus long-acting muscarinic antagonist inhalers (ICS/LABA/LAMA). CCG population age profiles were obtained from the Office for National Statistics. CCG emergency hospital admission and mortality rates were obtained from Public Health England. CCG formularies and guidelines were reviewed to identify where guidance is available to prescribers.

To control for total inhaler dispensing, the key measure used is the %LCFI: the number of LCFI items dispensed relative to the total number of pMDI and LCFI items. Multivariate regression models were used to investigate geographical variation.

Results

The total annual %LCFI increased from 19.5% to 26.3% over the study period. This was driven by the introduction of ICS/LABA/LAMA inhalers in 2018, as %LCFI decreased for SABA, ICS and ICS/LABA inhalers. %LCFI varied between classes. In the final year, it ranged from 6% for both SABA and ICS inhalers, to 41.2% and 43.9% for ICS/LABA and ICS/LABA/LAMA inhalers, respectively. Interestingly, the cost per item for ICS/LABA and ICS/LABA/LAMA inhalers was similar for both pMDIs and LCFIs, but for SABA and ICS inhalers LCFIs were more expensive.

%LCFI in the final year varied between CCGs (10.7% to 30.9%). The North West, and Birmingham and London areas had consistently higher %LCFI for all classes. For SABA and ICS inhalers, both the presence of advice on climate change in CCG guidelines or formularies, and greater CCG asthma prevalence, were significantly associated with higher %LCFI (p<0.05). The proportion of CCG population <15 years had a significant negative association with %LCFI for ICS and ICS/LABA inhalers (p<0.05). There were no clinically significant associations between %LCFI and either emergency hospital admission or mortality rates.

Conclusion

Current initiatives have not been successful in increasing the use of LCFIs, indicating limited implementation of guidelines for unknown reasons. Further action is required to reduce the carbon footprint of inhaler prescribing. Actions to address the financial disincentives to LCFI prescribing, CCG leadership (e.g. guidelines) and the appropriate use of LCFI in young people should be considered. Research into facilitators and barriers to LCFI use would support this. An important limitation is the use of dispensed items data rather than the number of inhalers, although there is no evidence that the number of inhalers per item varies between pMDIs and LCFIs. In addition, the Covid-19 pandemic disrupted prescribing patterns and long-term NHS projects.

References

(1) Wilkinson AJK, Braggins R, Steinbach I, Smith K. Costs of switching to low global warming potential inhalers. An economic and carbon footprint analysis of NHS prescription data in England. BMJ Open. 2019; 9:e028763.

(2) Environmental Audit Committee. UK progress on reducing F-Gas emissions inquiry: Fifth report of session 2017-19. London (UK): House of Commons Environmental Audit Committee; 25 April 2018. Available from https://publications.parliament.uk/pa/cm201719/cmselect/cmenvaud/469/469.pdf: [Accessed 27 September 2021].

Sensitivity of the UK Clinical Practice Research Datalink to Detect Neurodevelopmental Effects of Medicine Exposure in Utero: Comparative Analysis of an Antiepileptic Drug-Exposed Cohort

Introduction

Electronic healthcare data have several advantages over prospective observational studies, but the sensitivity of data on neurodevelopmental outcomes and its comparability with data generated through other methodologies is unknown.

Objectives

The objectives of this study were to determine whether data from the UK Clinical Practice Research Datalink (CPRD) produces similar risk estimates to a prospective cohort study in relation to the risk of neurodevelopmental disorders (NDDs) following prenatal antiepileptic drug (AED) exposure.

Methods

A cohort of mother–child pairs of women with epilepsy (WWE) was identified in the CPRD and matched to a cohort without epilepsy. The study period ran from 1 January 2000 to 31 March 2007 and children were required to be in the CPRD at age 6 years. AED exposure during pregnancy was determined from prescription data and children with an NDD diagnosis by 6 years were identified from Read clinical codes. The prevalence and risk of NDDs was calculated for mother–child pairs in WWE stratified by AED regimen and for those without epilepsy. Comparisons were made with the results of the prospective Liverpool and Manchester Neurodevelopment Group study which completed assessment on 201 WWE and 214 without epilepsy at age 6 years.

Results

In the CPRD, 1018 mother–child pairs to WWE and 6048 to women without epilepsy were identified. The CPRD identified a lower prevalence of NDDs than the prospective study. In both studies, NDDs were more frequently reported in children of WWE than women without epilepsy, although the CPRD risk estimate was lower (2.16 vs. 0.96%, p < 0.001 and 7.46 vs. 1.87%, p = 0.0128). NDD prevalence differed across AED regimens but the CPRD data did not replicate the significantly higher risk of NDDs following in utero monotherapy valproate exposure (adjusted odds ratio [OR_adj] 2.02, 95% confidence interval [CI] 0.52–7.86) observed in the prospective study (OR_adj 6.05, 95% CI 1.65–24.53).

Conclusion

It was possible to identify NDDs in the CPRD; however, the CPRD appears to under-record these outcomes. Larger studies are required to investigate further.

Electronic supplementary material

The online version of this article (doi:10.1007/s40264-017-0506-5) contains supplementary material, which is available to authorized users.

Pregnancy losses in women with Type 1 or Type 2 diabetes in the UK: an investigation using primary care records

AIM

This study aims to investigate pregnancy losses in women with Type 1 or Type 2 diabetes and compare this with the general population.

METHODS

Pregnancies ending between 1993 and 2006 in those with Type 1 or Type 2 diabetes were identified on the General Practice Research Database. Pregnancy losses were identified from medical records and the cohort described by their characteristics and prescribing for diabetes.

RESULTS

Of 2001 pregnancies identified in women with Type 1 diabetes, 678 ended in a pregnancy loss: 19.6% were spontaneous, 9.6% were induced and 4.3% were losses for unknown reasons. In women with Type 2 diabetes, there were 240 losses in 669 pregnancies: 21.1% were spontaneous, 10.3% induced and 4.0% were losses for unknown reasons. The proportion of spontaneous losses in women with diabetes was higher than in the general population (13.2%). Women with Type 1 diabetes treated with human and analogue insulins were 60% more likely to have a delivery than a loss (odds ratio 1.6, 95% CI 1.18-2.18) compared with human insulin treatment alone, although numbers were small.

CONCLUSION

We found that the proportions of spontaneous losses in women with Type 1 or Type 2 diabetes were similar at approximately 20%, which is higher than in the general population and also higher than previous studies have reported. While much emphasis has been placed on pre-conception care for women with Type 1 diabetes, the same is now needed for those with Type 2 diabetes, given the similarity in outcomes and increasing prevalence of this condition.