National Diabetes Inpatient Safety Audit 2022-23

The National Diabetes Inpatient Safety Audit (NDISA) is part of the National Diabetes Audit (NDA) portfolio within the National Clinical Audit and Patient Outcomes Programme (NCAPOP), commissioned by the Healthcare Quality Improvement Partnership (HQIP) and funded by NHS England and the Welsh Government.

The NDISA has 2 main strands:

Firstly, NDISA undertakes a continuous collection of serious inpatient harms that can affect people with diabetes. This collection was previously known as the National Diabetes Inpatient Audit (NaDIA) harms audit. Data collection began on 1 May 2018. All acute hospitals in England and Wales with inpatients with diabetes are eligible to participate. The Welsh government initially decided not to participate in the NDISA harms collection. Welsh providers were invited to submit to NDISA in November 2022 and 1 of 7 Welsh local health boards (LHBs) have since participated.

Secondly NDISA reviews the provision of inpatient services using the Integrated Specialist Services Survey (ISS), an NDA questionnaire which asks healthcare providers whether they have put in place structures and systems of care for people with diabetes recommended by the Getting It Right First Time (GIRFT) programme. The GIRFT report was itself informed by recommendations made in previous NaDIA publications (both the NaDIA snapshot audit and the NaDIA harms collection), the NHS Long Term Plan (2019), the Diabetes UK 2018 publication on Making Hospitals Safe For People With Diabetes and the National Confidential Enquiry into Patient Outcome and Death (NCEPOD) Report into Perioperative Diabetes (2018). The ISS was distributed to healthcare providers in England and Wales in October 2023.

The NDISA collects data on occurrences of the following serious inpatient harms that can affect people with diabetes:

• hypoglycaemia requiring rescue treatment
• diabetic ketoacidosis (DKA)
• hyperglycaemic hyperosmolar state (HHS)
• new diabetic foot ulceration

The main objective of the NDISA harms collection is to help reduce the rates of these serious inpatient harms by providing case-mix adjusted benchmarked feedback and identifying patients at risk to hospital trusts and inform quality improvement work. Monitoring and improving participation are important first steps towards meeting this objective.

The NDISA 2022-23 release is a detailed analysis file with information on the inpatient questions from the October 2023 Integrated Specialist Services Survey (ISS) and inpatient harms collected in NDISA between November 2018 and October 2023. Results are split into 7 sections:

1. ISS 2023: Submitters
2. ISS 2023: NDISA eligibility and coverage
3. ISS 2023: NDISA results for England and Wales
4. ISS 2023: NDISA results by nationality and region
5. NDISA: Inpatient harms participation
6. NDISA: Inpatient harms counts
7. NDISA: Inpatient harms rates

Sections 1 to 4 use data from ISS 2023. Sections 5 to 7 use NDISA harms data linked to the core NDA and Hospital Episode Statistics (HES).

The NDISA 2022-23 release will be of interest to the public, especially to people with diabetes. Health planners and policy makers, as well as acute NHS Trusts, integrated care boards (ICBs), LHBs, integrated care systems (ICSs), sustainability and transformation partnerships (STPs), clinical networks (CNs; formerly strategic clinical networks or SCNs) and other providers and commissioners of specialist diabetes services will also make use of the information in this report.

Patients in the NDISA harms collection were linked to data items recorded in the core NDA, including NDA data up to 30 September 2023. Linkage included data from the incomplete core NDA audit year 2023-24 for England only (1 January 2023 to 30 September 2023). NDA data covering January to September 2023 is therefore provisional and does not include Welsh data, except Welsh data for 1 January 2023 to 31 March 2023 submitted to core NDA audit year 2022-23.

The core NDA collects data on patient demographics, care processes and treatment targets amongst those registered with participating GP practices and secondary care organisations in England and Wales. GP practice participation in England and Wales was 97% in the latest core NDA Report 1 for 2022-23, covering 1 January 2022 to 31 March 2023. An additional 123 specialist services in England submitted data to the collection.

94% of patients in the NDISA harms collection were found in the core NDA. Age at start of NDA year, sex, ethnicity, diabetes type and diabetes duration at start of NDA year were taken from the core NDA demographics table. Smoking status, body mass index (BMI), renal function and deprivation quintile took the value in NDA closest to the inpatient harm date (in the corresponding NDA year or 1 of the preceding 3 years). NDA treatment targets and care processes were taken from the NDA year preceding the inpatient harm year (defined as April to March). Note that not all core NDA data items were used in the NDISA 2022-23 release.

HES is a database containing details of all admissions, outpatient appointments and accident and emergency attendances at NHS hospitals and NHS-funded private providers in England. NDISA harms patients were linked to hospital admissions data in HES, with admissions data available up to 30 November 2023. HES data covering April to November 2023 is provisional.

Hospital admissions covering the date of the inpatient harm were found for 94% of episodes in the NDISA 2022-23 harms collection period (November 2018 to October 2023).

Data in the inpatient harms section of the NDISA 2022-23 report are derived from inpatient harms that occurred between 1 November 2018 and 31 October 2023 (the cohort), covering 60 months of data collection. The data was extracted from the NDISA harms collection database on 11 December 2023, just over 1 month after the end of the audit period.

Results in the inpatient service provision section of the NDISA 2022-23 report are derived from ISS data for 1 October 2023. The ISS data was extracted from the ISS data collection tool in December 2023, following the close of the ISS submission window.

The NDISA 2022-23 report was published on 13 June 2024. The time lag to the publication of the main report was therefore 8.5 months after the inpatient services snapshot (1 October 2023), 7.5 months after the end of the NDISA harms cohort (31 October 2021) and 6.5 months after the respective inpatient harms and ISS data extracts were taken (early December 2023).

Participation in the NDISA harms collection is voluntary, but encouraged, for all acute NHS trusts admitting patients with diabetes in England and Wales. The Welsh government initially decided not to participate in the NDISA harms collection. Welsh providers were invited to submit to NDISA in November 2022 and 1 of 7 Welsh local health boards (LHBs) have since participated.

118 healthcare providers registered for the NDISA harms collection between 1 May 2018 and 15 December 2023. 114 of these 118 healthcare providers participated in the NDISA harms collection between 1 May 2018 and 31 October 2023. A healthcare provider is classed as having participated if they either:

1. Submitted 1 or more inpatient harm; or
2. Confirmed a nil submission for 1 or more month

during the stated period.

For comparison, 139 healthcare providers in England and Wales are known to be eligible for NDISA: 132 acute NHS trusts in England (excluding 3 acute children's trusts) and 7 LHBs in Wales. 96 of the 139 NDISA-eligible providers participated in the latest NDISA audit year (November 2022 to October 2023), suggesting a participation rate of around 69%.

10,585 inpatient harms were recorded in the NDISA harms collection during the 5 year report period (November 2018 to October 2023). Case ascertainment for each type of inpatient harm has previously been calculated using estimates derived from the 2019 National Diabetes Inpatient Audit (NaDIA) snapshot. Results were published in the 2019 NaDIA harms audit report (p. 32). Case ascertainment for DKA was estimated at 20% (DKA), with the other inpatient harms estimated at 6-8% (others).

However, the true case ascertainment is likely to be higher than the above estimates for 2 reasons:

1. The expected number of inpatient harms may be inflated by the increased likelihood of longer stay patients both experiencing an inpatient harm and being present on the NaDIA snapshot audit day; and
2. Because the latest NaDIA snapshot was undertaken in September 2019, any reduction in the number of inpatient harms since this period will not be reflected in the baseline figures.

Both of the factors above will inflate the expected number of inpatient harms, consequently reducing the case ascertainment.

Analysis covering April to October 2023 uses provisional data from both HES and core NDA. Further analysis will be required to get a complete picture of hospital activity during this period.

It should be noted that different NDISA harms cohorts are used in different parts of the NDISA 2022-23 report:

• Results are aggregated by NDISA audit year (November to October) to review NDISA participation and inpatient harms counts in sections 5 and 6.
• To review hypoglycaemic rescue trends over time in figures 7a and 7b, results are aggregated by quarters based on the calendar year (e.g. 2020 Q1 covers 1 January 2020 to 31 March 2020), starting in 2018 Q3 and ending in 2023 Q2.
• To review DKA, HHS and diabetic foot ulcer trends over time in figures 7c and 7e, results are aggregated by calendar year (2019 to 2023). Note that 2023 is a partial year, covering 1 January to 31 August 2023.

The ISS is a survey that looks at diabetes service provision as of 1 October each year. The ISS covers both English and Welsh providers. The first ISS collection was undertaken in October 2020, although the questions were different to those asked in the 2023 survey.

158 sites and 1 provider in England and Wales responded to the 2023 ISS. The NDISA 2022-23 report includes data from 142 of the 158 ISS site responses from NDISA-eligible providers. Of the 139 NDISA-eligible providers, 94 submitted 1 or more site-level response to ISS 2023, so the overall ISS response rate is 68% (94 of 139).

Table 1: Number of ISS 2023 responses by organisation type, England and Wales, October 2023

Notes:

1. ISS 2023 responses should be at site-level (e.g. hospital) rather than at provider-level (e.g. NHS trust or local health board).

Table 2 below shows that the number of participants per NDISA audit year has remained fairly static since audit inception (between 93 and 98).

Table 2: Number of NDISA participants per NDISA audit year, England and Wales¹, November 2018 to October 2023

Notes:

1. Welsh providers were invited to submit to NDISA in November 2022 and 1 of 7 Welsh LHBs have since participated.

Looking at the latest NDISA audit year (November 2022 to October 2023) in table 3 below:
On a monthly basis, the number of participants is always substantially less than the 98 total for the full NDISA audit year, ranging from 66 to 77. This means that not all participants submit NDISA returns every month.

Table 3: Number of NDISA participants per month, by submission type, England and Wales, November 2022 to October 2023

Table 4 shows that, overall, the participation rate amongst NDISA-eligible providers was 69% (96 of 139). Coverage by region ranged from 52% of NDISA-eligible providers in the Midlands to 94% in the South East of England. Welsh organisations were invited to submit to NDISA in November 2022 and 1 of 7 Welsh LHBs have since participated (14%).

Table 4: Number of NDISA-eligible providers that submitted to NDISA, by country and region, England and Wales, November 2022 to October 2023

Notes:

1. 132 acute NHS trusts, excluding 3 acute children's trusts, and 7 LHBs.

From 2010 to 2019 the NaDIA snapshot audit collected information on the incidence of inpatient harms during a specified week in September, including the 4 inpatient harms collected in the continuous NDISA harms collection. The latest NaDIA snapshot was carried out by hospital teams in England on a nominated day between 23 and 27 September 2019 and published in the 2019 NaDIA report published on 13 November 2020.

Inpatient harms in the NaDIA snapshot are reported as a proportion of inpatients experiencing the inpatient harm during their hospital stay (DKA, HHS, new diabetic foot ulceration) or in the previous 7 days of their hospital stay (hypoglycaemia requiring rescue treatment).

Direct comparison between the collections is difficult due to the different methodology and collection periods of the 2 collections. Comparative analysis was done for the 2020 NaDIA harms report to produce estimated case ascertainment for each inpatient harm. The results and limitations of this comparison are discussed above (in Accuracy, reliability and limitations).

No other data source provides equivalent information about the incidence of inpatient harms in England.

From 2010 to 2019 the NaDIA snapshot ran a Hospital Characteristics (HC) survey as part of the annual NaDIA snapshot undertaken in September, providing information on the hospital’s resources and staffing structure. The latest results from the NaDIA HC survey were published as part of the 2019 NaDIA report.

However, direct comparison with the care structures captured in the 2023 ISS collection is not possible. Firstly, the questions in the NaDIA HC are different from those in the 2023 ISS collection. Where there are similarities in subject matter, the impact of differences in wording should be considered before comparing. For example, the questions below around the provision of specialist foot teams are superficially similar, but the exact wording needs to be reviewed carefully before comparisons are made:

• 2019 NaDIA report: Is there an established Multi-disciplinary Diabetic Foot care Team (MDFT)?
• 2023 ISS collection: Does the hospital have a dedicated multi-disciplinary team of specialist diabetes inpatient practitioners as indicated in the NHS Long Term Plan?

A secondary issue to consider is that the units used in the NaDIA HC (a mixture of hospitals, multi-hospital groupings and providers) differ from those used in the ISS (provider), again presenting an obstacle to comparability.

Audit information is held securely and with restricted access.

It is expected that, through the audit collection, all organisations will continue to follow existing NHS codes of practice about patient confidentiality, information security management, record management and other legal obligations.

A risk assessment has been carried out on the audit publication to identify risks to patient confidentiality. Rounding has been used for numbers derived from inpatient harms records to reduce the risk of patient identification; numbers between 1 and 7 (inclusive) are shown as 5, while all other numbers are rounded to the nearest 5. Percentages will be calculated using rounded numerators and denominators. The calculated value will not be shown in cases where the denominator is less than 20. Statistical calculations (e.g. significance tests) are performed on unrounded numbers.

The NDISA 2022-23 release is a detailed analysis file in Excel format. Below are links to additional material relevant to this publication:

• The NDISA 2018-21 report. 
• Further information about the NDISA harms collection.
• Information about the superseded NaDIA harms collection. 
• The final NaDIA harms audit report from 2021.
• Information about the closed NaDIA snapshot.
• The final NaDIA snapshot report from 2019. 

The NDISA advisory group (consisting of patient representatives, healthcare professionals, administrators, researchers and analysts, including representation from Diabetes UK and NHS England) provide advice on the content of the reports as well as the direction and development of the audit.

The wider NDA team has an active role in the National Cardiovascular Intelligence Network (NCVIN) workshops to gain a better understanding of how commissioners and localities use the data and how we can improve the NDA programme’s publications and supporting information.

The NDISA harms collection is designed to be a low-burden collection, with only 4 data items required from submitters:

• NHS number: for data validation and linkage
• Inpatient harm type: hypoglycaemia requiring rescue treatment, DKA, HHS, new diabetic foot ulceration
• Date the inpatient harm occurred
• Hospital site at which the inpatient harm occurred

The audit team acknowledges that participation in the audit involves costs in both time and organisation for the providers that take part, and thanks them for their efforts. The audit continues to look at ways in which to reduce respondent burden and increase ease of participation and welcomes comments and suggestions.

NHS England are currently reviewing the routine production of NDA State of the Nation reports. Please note that data will still be released via dashboards and standalone data files whilst this review is being conducted.

To help inform this review we would be grateful if users can provide feedback on their use of the State of the Nation reports using the feedback survey available in the ‘Related links' section of this page.