NPiD includes: process and treatment target measures of preparation for pregnancy, and antenatal care; maternal complications and delivery measures; foetal and infant complications measures. Pregnancy in women with diabetes is high risk but uncommon (3,500 to 4000 per year in England & Wales).
Approximately equal numbers of women have Type 1 and Type 2 diabetes. The principal location of usual, non-pregnancy diabetes care is specialist for Type 1 and General Practice for Type 2. Typically a specialist service will have around 10 women with Type 1 diabetes becoming pregnant each year while an individual general practice might have one pregnant diabetic woman every 2 to 3 years.
Specialist diabetes services in collaboration with high risk obstetric services manage the antenatal care and delivery of women with diabetes and lead the design and implementation of pre-pregnancy pathways and services in their locality.
Choice of performance indicator
All the scientific evidence reflected in NICE Guidance and corroborated by NPiD analyses is that foetal and maternal outcomes are most influenced by preparation for pregnancy and very early antenatal management.
A composite indicator comprising percent achieving pre-pregnancy NICE glucose control, antenatal folic acid supplementation and early first specialist antenatal review is recommended.
This applies to every woman and even though it is a ‘whole pathway’ measure (specialist and primary care, doctors, midwives nurses) it is advocated by the advisory group as the best single performance measure. Because of small numbers it would have to be cumulated over 3 years for each specialist joint diabetes-antenatal team to be statistically valid.
Secondary measures that would be Diabetes-Antenatal team specific could be glucose control in the third trimester and rate of admission to Neonatal Intensive Care by Type of Diabetes again cumulated over 3 years.
Choice of target (expected performance)
The expected performance would be less than 2SD from mean indicator achievement rate of all providers. More than 2SD but less than 3SD below the mean would raise an alert. More than 3SD below the mean would be an alarm.
Data quality
Three aspects of data quality must be considered and reported:
- case ascertainment: very few women decline to participate so close to 100% case ascertainment for each participating unit, and from 2018 no need to consent women for England due to direction
- data completeness: patient characteristics are linked from the Core NDA so completeness is close to 100%; the three measures that form the ‘bundle’ have a more than 95% data completeness in NPiD
- data accuracy: tested using consistency and range checks, and if possible external sources
Case-mix (risk) adjustment
Modeling includes age, ethnicity, IMD and type and duration of diabetes.
Detection of a potential outlier
Statistically derived limits around the case-mix adjusted mean performance will be used to define if a provider is a potential outlier: more than 2 standard deviations from the target will be deemed an ‘alert’; more than 3 standard deviations deemed an ‘alarm’.
It will then be determined whether there are similar or radically different patterns for women with Type 1 Diabetes (for whom pre-pregnancy diabetes management responsibility usually rests with specialist services) and women with Type 2 Diabetes (for whom pre-pregnancy management responsibility usually rests with General Practice).
In the event of divergence Specialist services will be assessed on their Type 1 diabetes data.
In the event of the problem applying to both Type 1 and Type 2 or just to Type 2 then a ‘whole system’ approach will be applied as noted below.
Management of a potential outlier
The NDA and NPiD clinical lead and the team responsible for managing and running the audit in partnership with HQIP will follow the 8step process specified in the national outlier (appendix).
If the issue is restricted to Type 1 diabetes the usual lines of accountability (clinical team, clinical director, executive clinical director, CEO/Trust Board, CCG) will apply.
If it is restricted to or also includes Type 2 Diabetes because of the ‘whole system’ footprint of responsibility the first action will be to establish in the relevant locality who will assume lead responsibility and who will be the group members of the local investigating team (drawn from clinical team, clinical director, executive clinical director, CEO/Trust Board, CCG). For CCGs the line of responsibility would probably be (diabetes clinical lead, medical director, Chair/Director of Quality, CEO/Board, NHSE) (appendix).