Venous thromboembolism (VTE) is a major cause of death and morbidity in hospital patients. The first step in preventing death and disability is to identify those who are at risk so that preventative treatments can be used. The VTE risk assessment was formally a national Commissioning for Quality and Innovation (CQUIN) indicator and is a National Quality Requirement in the NHS Standard Contract 2020/21. It sets a threshold rate for acute providers to undertake risk assessments for at least 95% of inpatients each month.
Here we look at how the rate of VTE risk assessment has changed over time. We also examine how deaths from VTE-related events within 90 days post-discharge from hospital have changed over time, and how the UK’s deep vein thrombosis (DVT) rate after hip or knee replacement surgery compares internationally.
To free up capacity across the NHS to respond to the coronavirus (Covid-19) outbreak, NHS England and NHS Improvement have suspended data collection and publication for some of their performance statistics, including VTE risk assessment. The latest data presented here is from Q3 2019/20 (October to December 2019).
Since quarter 2 (Q2) of 2010/11, there has been an increase in the proportion of adult inpatients aged 18 and over admitted to NHS-funded acute care (NHS trusts, NHS foundation trusts and independent sector providers) who are risk assessed for venous thromboembolism (VTE). The 95% target was introduced in 2013/14 as part of the national VTE CQUIN goal, and the 95% threshold has been exceeded since 2013/14 Q1.
From April 2019, the target was expanded to include all inpatients aged 16 and over, so rates pre- and post- 2019/20 Q1 are not comparable, although the target has been exceeded in both time periods. In 2019/20 Q3, the proportion of adult inpatients who were risk assessed for VTE on admission to hospital was 95.3% for acute providers and 97.6% for independent sector providers.
This indicator measures VTE-related deaths within 90 days post-discharge from hospital – a key measure of patient safety. Between 2007/08 and 2018/19, the rate of patients who were admitted to hospital with any cause and died from a VTE-related event within 90 days of their last discharge decreased from 72 to 57 deaths per 100,000 adult hospital admissions. The absolute number of VTE-related deaths for people whose last hospital episode ended within 90 days of death increased by 3%, from 8,025 in 2007/08 to 8,301 in 2018/19 (data not shown). However, since the total number of adult hospital admissions increased by 31% over the same time period, the rate of VTE-related deaths per 100,000 hospital admissions has decreased.
In the UK, the post-operative deep vein thrombosis (DVT) rate after hip or knee replacement surgery is relatively low compared to other countries. Between 2011 and 2017, the post-operative DVT rate in the UK decreased by 18% from 240 per 100,000 hospital discharges to 198 per 100,000 hospital discharges. In France, the rate is much higher, reaching 1,328 per 100,000 hospital discharges in 2015. The DVT rate is lowest in Portugal, at 24 per 100,000 hospital discharges in 2017.
However, the OECD's Health at a Glance 2019 suggests that some of the observed variations in DVT rates may be due to differences in diagnostic practices across countries. For example, routine ultrasound screening can significantly increase the detection of DVT. Furthermore, caution is needed in interpreting the extent to which the data accurately reflects international differences in patient safety rather than differences in the way that countries report, code and calculate rates of adverse events. Higher rates may indicate more developed safety monitoring systems and a stronger patient safety culture.
About this data
NHS Improvement data:
The data presented relates to the proportion of adult hospital admissions admitted during the analysis period who are risk assessed for VTE on admission to hospital according to the Department of Health/NICE National VTE Risk Assessment Tool. All providers of NHS-funded acute hospital care (including foundation and non-foundation trusts and independent sector providers) are required to complete the data collection, which was mandated in June 2010.
NHS Digital data:
This indicator measures the number of adults (19 years or over) who were admitted to hospital for any reason (not just episodes where VTE had been diagnosed) and subsequently died up to 90 days post-discharge according to the Medical Certificate of Cause of Death (MCCD) and where VTE was one of the conditions leading to, or directly causing death. This is measured per 100,000 adult hospital admissions.
Definitions and comparability for the international indicator are taken directly from the OECD report Health at a Glance 2019: OECD indicators. Detailed information about the definitions and the source and methods for each country can be found here.
The surgical admission-based method uses unlinked data to calculate the number of discharges with ICD codes for deep vein thrombosis in any secondary diagnosis field, divided by the total number of discharges of patients aged 15 and older.
A fundamental challenge in international comparison of patient safety indicators centres on differences in the underlying data. Variations in how countries record diagnoses and procedures and define hospital admissions can affect calculation of rates. In some cases, higher adverse event rates may signal more developed patient safety monitoring systems and a stronger patient safety culture rather than worse care. There is a need for greater consistency in reporting of patient safety across countries and significant scope exists for improved data capture within national patient safety programmes.