Risk stratification and proactive care in NHS Sussex

Summary

Health Innovation Kent Surrey Sussex (Health Innovation KSS) supported NHS Sussex [1] to evaluate the implementation of the Johns Hopkins Adjusted Clinical Groups (ACG) risk stratification tool in Sussex. Working with our evaluation partner, Unity Insights, the evaluation explored how the tool could better identify people living with frailty and high complexity needs at risk of acute adverse outcomes – namely emergency admissions. We then examined how this information could support the proactive care programme for primary care and neighbourhood teams.

Compared with the electronic Frailty Index plus (eFI+), early findings suggest the Johns Hopkins ACG tool offers greater positive predictive value for emergency admissions and meaningfully identifies a different set of priority patients to previous approaches. Optimising the size of prioritisation lists to service capacity is important to maximise efficiency. This work provides early evidence to inform future approaches to proactive care, admissions avoidance, and management of long term conditions.

Challenge

Primary care and neighbourhood teams in Sussex need reliable ways to identify people at greatest risk of unplanned hospital admission and A&E attendance and offer proactive and preventative care. Existing approaches, including the electronic Frailty Index (eFI) and pre-built searches built by GP system providers, are widely used, but these tools are not built around the risk of future healthcare utilisation and there is interest in whether alternative tools could improve precision and support more targeted, proactive care.

The Johns Hopkins ACG risk stratification tool has been deployed within the Sussex Integrated Dataset to support the identification of people living with frailty and those with high complexity needs (labelled Patient Notification Groups (PNG) 10 and 11 within the tool). The aim is to help teams focus proactive and preventative interventions on those most likely to benefit, with the intention of preventing avoidable emergency admissions and Accident and Emergency (A&E) attendances.

Our approach

Health Innovation KSS and Unity Insights worked with NHS Sussex to carry out a rapid evaluation of the Johns Hopkins ACG risk stratification tool. The work focused on understanding how the tool performs in a real world system context and what it could add to existing approaches.

Key evaluation questions

1. How does the predictive value of the JHU ACG tool compare to the alternative strategy for identifying high risk people used in 2024-2025?
2. What is the business case for the JHU ACG tool? What is the size of the economic opportunity presented by the tool compared to the 2024-2025 strategy?
3. What has been the impact of the proactive care programme on emergency and avoidable admissions?

Methods

The predictive value of the JHU ACG tool and the business case were assessed using real world data from the 2024-2025 proactive care programme applying the tool retrospectively to enable direct comparison with eFI+. Follow-up data through the following six months was available to assess actual emergency admission activity exhibited by the patient cohorts.

The data was sourced from the Sussex Integrated Dataset (SID), which provides pseudonymised data linked across care providers in the Sussex region. The dataset was invaluable for tracking the outcomes of patients receiving a primary care intervention in other areas of care, allowing precise measurement of system and patient impact for measures such as emergency admissions.

The effectiveness of the proactive care programme was assessed for a particular intervention strategy, to explore the relationship between the intervention and emergency or avoidable admissions and compared it against high-risk patients who did not receive the same intervention strategy. The follow-up period was up to six months post-identification, with a risk of right censoring.

The treatment strategy or intervention examined was an initial primary care appointment where a Structured Medication Review or Rockwood frailty assessment occurred prior to follow-up referrals or treatment plans across a variety of providers.

Impact

Evidence from the evaluation suggests:

• The Johns Hopkins ACG tool in 2024-2025 identified a cohort that went on to experience 2,612 emergency admissions over 6 months post-identification, presenting a total economic opportunity of £7.1m if these could be prevented.
• Conversely, the previous strategy positively identified 1,777 and £4.8m worth of activity, for a net gain of up to 835 emergency admissions and £2.3m in additional economic opportunity from using the Johns Hopkins ACG tool over the previous strategy.
• Approximately 25% of the emergency admissions identified for the cohort were ambulatory or urgent care sensitive, indicating preventability.
• Following identification, the timing of the proactive care intervention is critical.  Approximately half of short-term adverse outcomes occurred during the period between identification and treatment.
• Lags between identification and the start of treatment (approximately 40 days on average for the first care contact) were due to a range of data, patient, and service-related factors.
• The lags for starting treatment, the likelihood for patients to remain in PNG11 over several months, and the potentially long lag period for observing outcomes all indicate that the proactive care programme can shift activities earlier than the immediate winter.
• The studied interventions are not well-suited to short-term outcomes, which may be a consideration when planning schemes to support, for example, winter pressures. A further follow-up study is required to examine the effect on longer term outcomes and to examine other intervention strategies.
• The main benefits from the studied intervention strategy are expected to be in relation to ongoing management of long-term conditions, which requires longer term follow-up.

Jack Feintuck, Director of Digital, Data, Analysis and Technology, NHS Surrey and Sussex said:

“The ICB is committed to supporting neighbourhood teams to proactively manage patients, with the aim of keeping appropriate people out of hospital. While we are utilising the Johns Hopkins risk stratification tool to help identify these patients, our partnership with Health Innovation Kent Surrey Sussex and the independent evaluation delivered by Unity Insights have been critical in ensuring we are getting the best from both the tool and our overall approach.

 

The evaluation has shown that the tool is more effective than previous approaches at identifying those most at risk of deterioration, giving us greater confidence in its use. It has also highlighted the importance of timing – both in acting on the insights and delivering interventions at the right point in a patient’s pathway.

 

We are pleased with the results so far and the clarity the evaluation has provided on where to focus our efforts moving forward, helping us maximise the value of this approach for patients, staff and the wider system.”

Spread and scalability

The work has focused on building evidence to inform decisions about future procurement and deployment of risk stratification tools, alongside proactive and preventative care. To support spread and scale, working in partnership with Unity Insights, we propose:

• Working with clinicians and key stakeholders to gather a deeper understanding of the interventions and their expected outcomes.
• A longer-term follow-up to provide a more complete picture of the outcomes realised by the existing interventions.
• A deeper understanding and horizon scan of intervention strategies and their outcomes to enhance these initial findings.
• Further development of the evaluation framework to support efficient ongoing monitoring and evaluation for the proactive care programme.
• Working closely with clinicians, patients and their carers to explore and analyse opportunities for personalised care and support prioritisation activities, matching patients with the most appropriate interventions.

Find out more

For more information about this work, please contact Lisa Devine.

References

[1] This work was delivered with NHS Sussex before its merger with NHS Surrey Heartlands to form NHS Surrey and Sussex ICB (1 April 2026).