The benefits of establishing or expanding outpatient parenteral antimicrobial therapy (OPAT) services

Outpatient parenteral antimicrobial therapy (OPAT) services treat patients with intravenous antimicrobials in out-of-hospital settings. They can be provided by healthcare professionals or administered by patients or carers themselves.

They can increase productivity by:

• supporting the recovery and restoration of NHS services
• providing opportunities to streamline and integrate with new service changes, including same day emergency care expansion, virtual wards and hospital@home services
• addressing the increasing length of stay of non-elective admissions seen post-pandemic
• improving patient flow through hospitals and reducing discharge delays due to the need for intravenous treatment
• addressing the increasing burden of antimicrobial resistance seen in England, which can limit the use of simple oral treatment options and necessitate a hospital admission and inpatient stay
• addressing the burden of antimicrobial resistance, which falls more heavily on deprived areas than more affluent areas, and therefore reducing health inequalities
• providing treatment options for patients who are accessing primary and community services in higher volumes and who need more complex physical healthcare
• shifting care to less intensive settings such as the patient’s home
• supporting partnership working to support the right capacity being in the right place to care for patients effectively.

OPAT services can deliver high quality, convenient patient care that achieves similar outcomes to inpatient treatment. They can help appropriate patients with infections to return to normal lives, allowing adults to return to work, children to return to school and older patients to maintain their independence. This benefits them, wider society and the economy. Avoidable healthcare-associated infections and the resulting morbidity and costs can be minimised.

OPAT represents a more efficient use of resources. Infection management via an OPAT service can be between 23-56% cheaper than the equivalent inpatient treatment (Dimitrova et al, 2021).

OPAT services support the NHS operational priorities, freeing up acute bed capacity to support improved ambulance response and A&E waiting times, and help with elective admissions by avoiding admissions and allowing early hospital discharges. For example, for an integrated care board (ICB) with a population of 1 million people, it is estimated that an OPAT service could treat 1000 patients a year with an estimated saving of between 16,000-28,000 bed days.

OPAT is good clinical practice and is aligned with antimicrobial stewardship. Discharge of patients on OPAT is one of the nationally recommended treatment decisions when considering the 48-72 hour review of antimicrobial therapy as set out in the ‘Start Smart then Focus’ guidance. The 2024-29 National Action Plan for Antimicrobial Resistance states that ensuring equitable access to OPAT services is important to optimise the efficient use of NHS resources and reduce the risk of prolonged hospital stay.

Developing and commissioning OPAT services addresses the health inequalities and variation in care identified in a survey of OPAT services in England in 2022.  Access to OPAT services varied both geographically and by patient population. While most services were equipped to support ambulatory adults, there was less equitable access for housebound patients, children and young people.

Despite this variation, OPAT services in 2020-21 were reported to have treated almost 16,000 patients in England, avoiding an estimated 280,000 bed days and generating efficient improvements to the value of £35-45 million.

Which OPAT service model?

ICBs can choose from different OPAT service models based on healthcare infrastructure, available resources, and patient needs. OPAT can be delivered:

• in a clinic
• in an intermediate care setting (for example, a nurse-led walk-in treatment centre or a community hospital)
• in the patient’s home by a healthcare professional
• in the patient’s home (by the patient themselves or a relative who has been trained in line care and drug delivery).

Delivery of OPAT in a clinic is usually the easiest to set up and can be the most convenient for the service provider if dedicated clinic space or a dedicated area of an inpatient ward can be identified. It is geared towards ambulatory patients. However, patient transport may be an additional cost, so consideration should be given to encouraging delivery of OPAT in the patient’s home, where possible.

Infections that can be managed via an OPAT service can vary significantly in complexity. At the less complex end, patients can require intravenous treatment for relatively simple infections such as lower urinary tract infections, when there is no suitable oral option available. More complex cases might include, for example, a chronic infection of implantable prosthetic material that cannot not be removed and requires lifelong suppression of infection.

OPAT can help with avoiding admissions of patients with low complexity infections such as:

• ambulatory cellulitis
• multi-resistant lower UTI with no oral treatment options
• exacerbations of bronchiectasis with no oral treatment options.

OPAT can support early hospital discharge for a range of more complex infections. Data from the British Society for Antimicrobial Chemotherapy (BSAC) National Outcomes Registry System for OPAT for 2015-19 on the 30 most commonly treated infections for adult and paediatric patients included:

• prosthetic joint infections
• diabetic foot infections
• endocarditis (heart valve infection).

Implementing an OPAT service or expanding an existing OPAT service

As part of a broader strategic needs assessment of infection management pathways for integrated care systems, OPAT service provision should be a key focus. While many acute trusts and some community providers already have established OPAT services, there may be opportunities to enhance and expand provision to tackle health inequalities.

In any local NHS system, the initiative to introduce a new OPAT service or expand an existing one could come from the ICB as a commissioner, an existing provider, or a partnership of providers.

Ultimately, both the ICB and provider(s) will need to be involved in discussions. Any agreed arrangements for providing new or different OPAT services will need to be referenced in the NHS Standard Contracts between them. The ICB will need to ensure that contracts are awarded (or varied, as applicable) in accordance with the requirements of the NHS Provider Selection Regime (PSR).

Whether the initiative comes from the ICB or a provider, a sensible starting point will be to undertake a stocktake of what OPAT services are already in place locally, what future needs for them exist and how they should best be configured. This could include consideration of:

• the workforce currently delivering, or available to deliver, OPAT services and future requirements for expanding existing services
• what groups of patients or types of infections are currently being included?
• what groups of patients or types of infections are currently being excluded?
• equity of service provision to adults and children, including neonates, hard-to-reach groups, groups subject to health inequalities
• what treatment options are available to support current OPAT service models and what might be required to deliver an expansion of an OPAT service or introduction of a new service model (for example, access to ready-to-administer antimicrobials in elastomeric devices)?
• benchmarking of existing OPAT services against the Good Practice Recommendations for OPAT services
• the governance, infection management expertise and antimicrobial stewardship oversight in place for the provision of intravenous antimicrobial therapy in out of hospital settings within the ICB (for example, virtual wards).

Depending on the findings of the stocktake, a local business case may need to be developed to set out the clinical and financial arguments for establishing or further expanding a service and seek approval to proceed from the ICB or trust boards as appropriate. See Appendix 1 for a business case toolkit for OPAT services that can support this.

The procurement and contracting implications will depend on the proposed approach.

• at the simplest level, the ICB and acute trust may agree that the trust should provide services for certain groups of patients requiring intravenous antimicrobials in an outpatient clinic setting rather than in bed-based ward facilities. This may need a variation to the existing ICB or trust NHS Standard Contract to describe the new service model in a specification and to make any agreed adjustments to how the trust will be paid. (Note that moving from an inpatient bed-based service to an outpatient one may have implications for the way in which the trust is paid for the relevant activity under the NHS Payment Scheme).
• in a more complicated scenario, the ICB might propose a new community- or home-based OPAT service and award an NHS Standard Contract to a provider to deliver it

It is, of course, mandatory for ICBs to use the NHS Standard Contract when they commission healthcare services. NHS England publishes technical guidance on the use of the NHS Standard Contract. This gives general advice on drafting service specifications (paragraph 36) and local quality standards (paragraph 39). More specific suggestions for possible content for OPAT service specifications and local quality standards are set out below in Appendix 2 and 3 respectively. 

Appendix 1: Preparing a business case

We’ve created a flexible business case template to help develop or expand OPAT services which provides useful information, published evidence on costs and analysis of different service models. This should be adapted to fit local circumstances.

Appendix 2: Writing an OPAT service specification

The purpose of developing a service specification for OPAT is to define the requirements for an integrated outpatient parenteral antimicrobial therapy (OPAT) and complex oral or parenteral antimicrobial therapy (COPAT) service for use in NHS organisations in England which is suitable for both adults and children. These services can be described, for convenience, as OPAT services in this service specification but with the understanding that complex oral-parenteral antimicrobial is a core element of an OPAT service.

The ICB and provider should agree the service specification based on the good practice recommendations for OPAT services. This should include:

• a detailed description of the service, including the scope of the service
• the responsible service provider, and model of service delivery
• referral and patient selection criteria
• provision for patient populations known to experience health inequalities and those with poor health literacy to ensure equitable access
• patient assessment and clinical management processes
• the types of treatment regimen that will be used (for example, bolus injection, short infusions, continuous infusions using elastomeric devices) and how or where these treatments will be sourced from and supplied to patients
• monitoring and follow-up plans
• documentation and reporting processes
• governance, accountability, quality and safety assurance frameworks
• benchmarking
• education and training of healthcare staff delivering the service

The ICB should identify the patient populations that would benefit from the OPAT service. This can be done by conducting a needs assessment of the local population, reviewing hospital discharge data, and consulting with healthcare professionals and patient representatives, in addition to an Equality and Health Inequalities Impact Assessment.

Consideration should be made to ensure that OPAT services are linked to patient records, such that a treatment episode will be visible in a patient’s history.

The ICB should review and update the OPAT service specification regularly based on feedback from healthcare professionals, patients, and the service provider. The service specification should be revised periodically to reflect changes in clinical practice, patient needs, population demographics and relevant national standards.

Service description

The OPAT service should be led by infection management experts that allow patients to receive intravenous antimicrobial therapy in an ambulatory setting (for example, clinic or home environment). Patients may be on short courses of intravenous antibiotics administered by a peripheral cannula, or on a longer course that may require central venous accessIntravenous-to-oral antimicrobial switch is common in OPAT services and patients may transition from an OPAT to a COPAT (complex oral-parenteral antimicrobial therapy) service. Regardless of the route of administration of the antimicrobial agent, the principles are the same and the service should be designed to ensure that patients receive safe, effective and efficient care, and that there is a seamless transition between care settings as required.

Scope of the OPAT service

ICBs and providers should agree the scope of the service provided. The overlap between OPAT or COPAT services and the evolving landscape of virtual wards (acute respiratory wards, frailty wards etc.), acute respiratory infection hubs and acute infection hubs is still being defined and should be subject to local discussion. The same principles of antimicrobial stewardship (AMS) must be applied to patients (adults or children) being managed within such services as they do to in-patients. Local review is recommended to decide whether patients on intravenous antimicrobials within such services are best managed within a formal OPAT service or whether the OPAT team should maintain oversight into the antimicrobial management of such patients via another mechanism.

The service should be available 7 days a week, with access to clinical advice and support for patients outside of normal working hours. The service should accept referrals from hospital and community healthcare professionals based on agreed referral and selection criteria. Patients should be assessed for suitability for OPAT, taking into account their clinical condition, comorbidities, home circumstances, and preferences. Provision of treatment in a location that is the most convenient and safe for the patient (taking into account wherever possible of patient or carer preferences) by utilising an appropriate range of treatments, administered by the most appropriate route and over the most convenient time period, that meets clinical and antimicrobial stewardship requirements, should be prioritised. This may require access to aseptically prepared ready to administer preparations, or provision of intravenous antimicrobials dispensed from community pharmacies, so appropriate arrangements should be put in place to ensure timely access.

Care should be taken to ensure that the service is accessible and equitable for all patient cohorts. Paediatric and neonatal access to OPAT services is limited in England, with the majority of services and funding being directed to adult patients. Patients who suffer from health inequalities, or who have poor health literacy and limited agency to demand more convenient care may be overlooked by or excluded from traditional models of care delivery. ICBs must consider the needs of all patient cohorts and conduct Equality and Health Inequality Impact Assessments when establishing or reconfiguring OPAT services.

Staffing and clinical governance

The service provider should have the appropriate healthcare professional and administrative staff, infrastructure, and clinical governance frameworks in place to ensure that the service is safe, effective and responsive to patient needs. The British Society of Antimicrobial Chemotherapy’s good practice recommendations for OPAT services should be consulted when considering the workforce required to deliver the OPAT service.

Service delivery

OPAT services may be delivered in a variety of locations such as outpatient departments, admissions units, same day emergency care (SDEC) units or emergency departments within the hospital campus, or in geographically distant settings such as community clinics, in the patient’s own home or usual domiciliary setting.

The OPAT service should be delivered by a multi-disciplinary team which includes healthcare professionals such as microbiologists, infectious diseases physicians, antimicrobial stewardship pharmacists and nurses, with appropriate levels of administrative support. The team should have the necessary expertise to manage patients with complex medical needs and patients who may be on complex treatment regimens which require close monitoring and regular adjustment, as well as ensuring the principles of antimicrobial stewardship are adhered to. The OPAT team should have identified time for OPAT in their job plans.

Referral and selection criteria

Patients who may be suitable for treatment via an OPAT service should be referred to that service, wherever possible on a proactive basis as routine medical practice or as identified by an antimicrobial stewardship service. This allows sufficient time for assessment by the OPAT team, an appropriate management plan to be developed and agreed, for any required medication to be obtained and maximises the effective use of provider resources.

Referrals to the OPAT service should be made by healthcare professionals, and patients should be selected based on inclusive and equitable, locally agreed criteria which could include (but is not limited to) the following:

• the patient being clinically stable and able to receive OPAT safely in an ambulatory setting
• the patient having suitable vascular access for administration of OPAT
• the patient being able to attend the OPAT clinic as required, or an appropriate monitoring service being provided virtually
• the patient being able to receive a visit from a healthcare professional in their usual residence to have treatment administered
• the patient or their parent/carer having passed the competencies for self-administration or parent/carer-administration and being able to administer intravenous antimicrobials
• the patient being willing and able to comply with the treatment regimen.

Care should be taken to ensure there is provision for patient populations known to experience health inequalities and those with poor health literacy to ensure equitable access; this should include effective inclusive communications and patient information available in languages other than English and provision of translation services for patients who do not speak English.

Patient assessment and management processes

Prior to starting OPAT, patients should be assessed by the OPAT team to ensure that they are suitable for the service. The assessment should include a review of the patient’s past medical history, the nature of the current infection requiring OPAT, concurrent medications, allergies, laboratory results (including relevant microbiology culture results), any relevant radiology or imaging reports and social history. Patients (or their carers or representatives) must consent to be treated by the OPAT service and provided with all the relevant information in a format suitable for their individual needs. Patients should also be provided with information on the OPAT service, the treatment regimen, and any potential side effects. The service should ensure that patients receive appropriate education and training on the administration of the treatment, self-monitoring, and the management of adverse effects. Medicines adherence support should be provided to patients, for either oral or self-administered intravenous medication in accordance with good practice, including competency assessment prior to discharge from secondary care for aseptic no touch technique and medication preparation. Local escalation policies should be made clear to patients or carers as part of safety-netting so they know how to report deterioration and where to go (for example, emergency department versus OPAT in-hours or out-of-hours service where available).

Lead clinical responsibility for patients receiving OPAT should be agreed between the referring clinician and the OPAT clinician. This should be documented in the patient’s medical records.

Treatment regimen

The OPAT team should develop a treatment regimen in conjunction with the patient that is tailored to the patient’s clinical needs and has a defined treatment goal. The regimen should specify the antimicrobial agent, the dose, the frequency of administration, and duration of treatment, monitoring requirements and any parameters that might indicate the need for escalation or de-escalation of treatment, immediate clinical review etc. The regimen should also take into account any co-morbidities, allergies, or drug interactions. Appropriate oral step down should be actively considered and included where appropriate into the treatment and management plan.

The OPAT service should have a range of antimicrobial regimens available, based on local or national antimicrobial guidelines, and should select the most appropriate regimen for each patient. The service should have arrangements in place for the timely supply of antimicrobial agents, including contingency plans for emergencies. The service should have timely access to ready to administer aseptic products (for example, elastomeric devices to deliver continuous infusions or pre-filled syringes) to ensure that patients receive their medications on time and without delay. Issues relating to capacity within NHS or commercial providers of ready to administer products should be considered by the OPAT service and mitigated against; the OPAT service should be a key stakeholder in local or regional plans for aseptic service transformation.

To ensure the timely supply of antimicrobial agents, the OPAT service should have a service level agreement in place with a local hospital pharmacy department (where the OPAT service provider is not from the same organisation), which is responsible for ordering, dispensing, and delivering medications. The pharmacy department should have a system in place for ordering and stocking the necessary antimicrobial agents or arranging their supply from a local or regional aseptic unit, as well as a process for monitoring medication supplies and ensuring that they are replenished in a timely manner.

The OPAT service should also have a process for reviewing and monitoring antimicrobial use to ensure that appropriate regimens are selected and that antimicrobial stewardship principles are followed. This may include regular reviews of prescribing practices, antimicrobial utilisation, therapeutic drug monitoring and treatment outcomes. The service should also have a process for reporting adverse drug reactions and other safety concerns related to antimicrobial use.

Overall, timely access to appropriate antimicrobial agents is critical for the successful management of patients in the OPAT setting. Therefore, it is important for the service to have robust systems and processes in place to ensure the timely supply of antimicrobial agents and to monitor and review antimicrobial use to ensure the safe and effective use of these medications, including timely access to the microbiology laboratory for therapeutic drug monitoring when required.

Monitoring and follow-up

Patients receiving OPAT should be monitored closely by the OPAT team to ensure that the treatment is effective and well-tolerated. The team should monitor the patient’s clinical status, laboratory results, and any potential side effects. Patients should also be provided with appropriate follow-up care, including any necessary laboratory tests, review of symptoms, and medication adjustments (for example, based on therapeutic drug monitoring results). The service should have a clear monitoring and follow-up plan in place for each patient receiving OPAT. This should include regular clinical and laboratory monitoring, including the monitoring of adverse effects, and the provision of advice and support to patients and healthcare professionals. The service should have clear escalation pathways for patients who develop complications or require additional support, such as direct admission to an inpatient setting if required. The service should ensure that patients who are self-administering their treatment receive appropriate education and training on the administration of the treatment, self-monitoring, and the management of adverse effects.

Documentation and reporting

All aspects of the OPAT service should be documented in the patient’s medical record. Wherever possible, electronic records should be used, and the records should be visible to and accessible by all healthcare providers within the ICB subject to interoperability and access limitations.

The documentation should include the diagnosis, reason for referral, the assessment, results of investigations and clinical parameters, the treatment regimen, and the monitoring and follow-up plan.

The service should have clear documentation and reporting processes in place, including the timely and accurate recording of patient information, treatment administration, adverse effects, and clinical outcomes. The service should provide regular reports to healthcare professionals involved in the patient’s care, including the primary care physician and the referring hospital team.

The OPAT service provider should also submit regular reports to the relevant NHS commissioning body and relevant local antimicrobial stewardship committee, outlining the number of patients treated, key patient demographics, inpatient bed days saved, the types of infection treated, the antimicrobial agents used, intravenous to oral switch metrics, treatment outcomes, adverse events or incidents and any other relevant metrics to demonstrate equity of access to and provision of the service. The ICB should monitor and evaluate the OPAT service regularly to ensure that it meets the agreed service specification and NHS standards. This should include regular performance reviews, clinical audits, and patient feedback.

Benchmarking

OPAT services should benchmark themselves against a number of metrics to ensure they are achieving good outcomes for patients, are efficient and cost-effective. This should include monitoring of trends over time and comparison with other OPAT services in neighbouring ICBs/regionally/nationally according to the availability of applicable and valid comparator data. This benchmarking process should feature in regular reports required for local governance processes and be used for service improvement.

There should be an annual review of the service to measure compliance against the national good practice recommendations (see here for an example of a self-assessment toolkit), with an action plan developed to address any gaps in compliance. Progress with this action plan should be reviewed regularly and reported via the governance framework for the service.

Education and training of healthcare staff delivering the service

The service provider should have in place an appropriate regular education and training offer to healthcare professionals involved in the delivery of the service, including the administration of antimicrobial agents, the monitoring of patients, and the management of adverse effects. The service provider should also provide education and training to patients and their carers where appropriate, including the administration of the treatment, self-monitoring, and the management of adverse effects.

Interdependencies with other services or providers

The landscape of care provided by the NHS is changing, with a relative shift to community-based care based on decentralising acute care and building the provision and capacity of acute level care in a community setting, such as virtual wards. While hospital@home has been operating in England for a number of years, new models such as virtual wards are continuing to become established. Within the sphere of infection management, virtual wards for acute respiratory infections and acute respiratory hubs have been operating. Given the uncertainty of the funding landscape and the need to develop integrated infection management pathways that are based on an understanding of local needs, it is beyond the scope of this document to outline what interdependencies are likely to be relevant or important for OPAT services. Beyond the infection management sphere, it is likely that OPAT services will need to be integrated with and available to ambulance services, urgent and emergency care, social care services and primary care services, and potentially other services available and relevant locally but not specified here.

Appendix 3: Applicable service standards

Applicable obligatory national standards:

• NICE Systems and Processes for antimicrobial stewardship (NG15)
• Health and Care Act 2008: code of practice on the prevention and control of infections
• Royal Pharmaceutical Society/Royal College of Nursing Professional guidance on the administration of medicines in healthcare settings
• Start Smart then Focus: antimicrobial stewardship toolkit for inpatient care settings

Other applicable national standards to be met by commissioned providers:

• BSAC Good Practice Recommendations for outpatient parenteral antimicrobial therapy (OPAT) in adults and children in the UK
• a standard protocol for deriving and assessment of stability. Part 1 – Aseptic Preparations (Small Molecules)
• Guidance on the Pharmaceutical Issues concerning Outpatient Parenteral Antibiotic Therapy (OPAT) and other Outpatient INTRAVENOUS Therapy Services 1^st Edition, January 2018
• Insertion and care of intravascular devices – RCN Standards for infusion therapy

Other applicable local standards:

• local OPAT policies, procedures and guidelines
• local antimicrobial prescribing guidelines and antimicrobial formulary.
• local infection prevention and control guidelines or policies.
• local central intravenous access and central venous access device policies
• medicines management and medicines administration policies
• visual inspection of phlebitis (VIP) scoring policy
• service level agreements with third party organisations providing elements of the OPAT service (for example, community nursing or ready to administer aseptically prepared medication)

The OPAT service will adhere to the following local service standards as a minimum, but ICBs will be free to specify additional service standards as appropriate.

• patients will receive a comprehensive multi-disciplinary team assessment within 24 hours of referral to assess suitability for OPAT
• treatment and management plans will be developed within 48 hours of assessment
• patients will receive education and training on self-administration or have a caregiver trained within 72 hours of assessment where appropriate
• patients will receive ongoing monitoring and support throughout their treatment
• patients will have access to support and advice
• weekly multidisciplinary meeting or virtual ward rounds to review patients on the OPAT service
• regular blood tests, where appropriate, for patients who are on prolonged courses of antimicrobials
• clear pathway for 24-hour immediate access to advice/review/admission for OPAT patients, including access to relevant diagnostic investigations such as ultrasound, X-ray as appropriate, whether patients are on the OPAT service via early supportive discharge or admission avoidance routes
• the service will meet all relevant regulatory and quality standards

Publication reference: PRN01192_i