Outpatient parenteral antimicrobial therapy (OPAT) services enable patients who require intravenous (IV) antimicrobial therapy, but who are well enough to receive care outside of a hospital environment, to receive their treatment in the community. This may include self-administration of IV antimicrobials by the patient or a family member/carer or a nurse administering treatment in the patient's home or in a clinic setting.
Across the UK, the number of OPAT services is increasing (Durojaiye et al, 2019), helping to reduce hospital admissions, facilitate early discharge, reduce length of hospital stays, and provide cost-effective care closer to home (Chapman, 2013; Chapman et al, 2019). OPAT features in the NHS strategy for strengthening antimicrobial stewardship (Ashiru-Oredope et al, 2012) and the British Society for Antimicrobial Chemotherapy (BSAC) has a number of workstreams related to OPAT, including drug stability testing and a framework for practice (BSAC, 2021).
The University Hospitals of Leicester NHS Trust (UHL) is one of the largest NHS trusts in the UK, with three hospitals across Leicester serving approximately 1 million residents and increasingly providing specialist services over a much wider area. The infectious diseases department in UHL had previously treated small numbers of patients through an ad-hoc OPAT system (Wiselka and Nicholson, 1997) and subsequently initiated a formal pilot service in 2012, open to taking referrals from all specialties within the Trust. Over a 6-month period, the service treated 65 patients and saved a total of 1316 hospital bed days, which can otherwise be considered as inpatient beds released for further use (Sahota, 2012). Since then, the service has evolved into a multidisciplinary team, led by an infectious diseases consultant and with virtual ward round input from a microbiology consultant, 4.6 full-time equivalent specialist nurses and a specialist antimicrobial pharmacist.
In this service review, the authors present findings of a retrospective study conducted between 1 July 2014 and 31 December 2019 to evaluate the impact of expansion of the OPAT service on the number of hospital inpatient bed days saved, clinical efficacy and the patient experience. The authors have concentrated on the increasing use of self-administration by patients and the adverse event rate associated with OPAT care.
Methods
Patient selection
Adult patients were eligible for OPAT if they were current inpatients or outpatients under the care of a hospital consultant who provided shared clinical care and responsibility for OPAT. All referrals were considered individually, but the broad criteria are detailed below.
OPAT inclusion criteria
OPAT exclusion criteria
OPAT patient process pathway
All eligible patients were assessed by the OPAT nurses, who made the decision with the patient and their family/carers as to whether antimicrobials would be administered by the nurses or whether the patient/family/carer would train to administer. (Figure 1) In reaching this joint decision, a variety of patient factors were taken into consideration. These included:
The OPAT self-administration infusion system
Patients/carers who were unable to mix their antimicrobials in the traditional way, but who were considered otherwise suitable for self-administration, were trained to use aseptically filled pre-mixed elastomeric devices. External pharmaceutical providers supplied the pre-mixed devices, for which appropriate stability data were available.
In October 2016, continuous 24-hour infusion devices of flucloxacillin, benzylpenicillin and piperacillin with tazobactam also became available. Prior to this, these beta-lactam antibiotics were either self-administered in the standard manner of divided doses throughout the day by the patient (but only a minority felt they could manage this), or an alternative class of antimicrobial was used, if considered appropriate. Individuals for whom these beta-lactam antibiotics were considered the best treatment choice, but where self-administration was not possible, had previously had to remain in hospital for the duration of their therapy.
Individuals for whom pre-mixed products were considered particularly appropriate included elderly people or those with dexterity issues, patients on complex, multidrug regimens and those for whom continuous beta-lactam antibiotics were the preferred treatment. These patients were supplied with an elastomeric device, which contains an elastomeric ‘balloon’: as this deflates over time, it gently pushes the antimicrobial through the IV infusion set that carries the medication from the device into the catheter/port, providing a consistent, reliable and accurate flow rate.
Data collection
The OPAT Patient Management System (PMS) was developed by the OPAT initiative arm of the BSAC and enables patient-level data to be entered into an electronic database for use during care. Until recently, anonymised data from the PMS were sent to the National OPAT Registry System (NORS, www.opatregistry.com) to enable national data to be collected. Activity and outcomes between 1 July 2014 and 31 December 2019 were collated from these systems. The following data were extracted:
Other events, including leaking or misplaced VADs or medical adhesive-related skin injuries (MARSI), were not recorded.
The BSAC OPAT initiative requires two outcomes to be allocated to each patient before their data can be uploaded to the PMS and NORS. The first is the infection outcome comprising clinical cure, clinical improvement or failure. The authors amalgamated the first two categories and slightly modified the latter definition to include cases in which there was progression or non-response of infection despite OPAT, or where the patient required unplanned admission, unplanned surgical intervention, or unexpectedly died.
The second outcome is the OPAT outcome related to the overall OPAT process, and comprises success, partial success, failure or indeterminate (readmission due to an event unrelated to the infection or treatment). The authors amalgamated the first two categories in their service review.
Simple statistics in the form of percentages were used to analyse data.
Patient satisfaction questionnaire
Anonymous patient satisfaction questionnaires were sent to 105 patients who were treated by the OPAT team in 2016. Patients were asked if they agreed, disagreed or had a neutral opinion towards a series of questions relating to the OPAT service, including the self-administration training and support provided to them by the OPAT team.
Results
Patient episodes
Over the study period, 1084 completed patient episodes were recorded in 958 patients. The number of patient episodes and bed days saved increased year by year. Over the study period, the proportion of patients referred for OPAT in order to facilitate early discharge from hospital was significantly higher than those referred for admission avoidance (Table 1), and patients were predominantly referred from within the University Hospitals of Leicester NHS Trust or from the corresponding community Trust, the Leicestershire Partnership Trust. A small proportion of patients were accepted directly from hospitals outside the region. This occurred mainly when the patient lived within the area served by the Trust and had been receiving care in another hospital within the UK, but was considered well enough to be discharged home to complete their IV antimicrobial therapy.
| 2014 n (%) | 2015 n (%) | 2016 n (%) | 2017 n (%) | 2018 n (%) | 2019 n (%) | |
|---|---|---|---|---|---|---|
| Number of patients receiving OPAT | 39 | 124 | 156 | 208 | 217 | 265 |
| Total completed patient episodes | 40 | 130 | 174 | 221 | 233 | 286 |
| Total bed days saved | 828 | 3524 | 4340 | 5858 | 5661 | 8462 |
| Episode referral type | ||||||
| Early discharge from hospital | 37 (92.5) | 122 (93.8) | 165 (94.8) | 201 (91.0) | 206 (88.4) | 255 (89.2) |
| NHS hospital admission avoidance | 3 (7.5) | 8 (6.2) | 9 (5.2) | 20 (9.0) | 27 (11.6) | 31 (10.8) |
| Episode referral location | ||||||
| Leicester hospitals | 40 (100) | 129 (99.2) | 174 (100) | 219 (99.1) | 229 (98.3) | 282 (98.6) |
| Regional hospitals | 0 (0) | 1 (0.8) | 0 (0) | 2 (0.9) | 4 (1.7) | 4 (1.4) |
Primary infective diagnoses
The most frequent primary infective diagnoses were diabetic foot infections, with or without osteomyelitis (117/1084, 10.8%), upper and lower urinary tract infections (110/1084, 10.1%), prosthetic knee-joint infections (105/1084, 9.7%), and osteomyelitis (100/1084, 9.2%). Other infections treated varied and included, among others, intra-abdominal infections, septic arthritis, other prosthetic joint infections, bacterial meningitis, malignant otitis externa, skin and soft-tissue structure infections, vascular graft infections and tuberculosis. For the full range of diagnoses, see the Appendix at the end of the article.
Antimicrobial administration method
The percentage of bed days saved due to patients and their relatives or carers learning to administer IV antimicrobials significantly increased over the study period (Figure 2). Administration in the OPAT clinic stayed relatively static, but there was a decrease in the number of nurse-administered antimicrobials at home.
Infection outcome
The percentage of patient episodes where the patient's infection was considered to have been cured or improved during their OPAT treatment ranged between 84.6% and 92.8% (Table 2), and remained relatively stable over the study period.
| 2014 n=40 (%) | 2015 n=130 (%) | 2016 n=174 (%) | 2017 n=221 (%) | 2018 n=233 (%) | 2019 n=286 (%) | |
|---|---|---|---|---|---|---|
| Infection outcome | ||||||
| Cured/improved | 34 (85.0) | 110 (84.6) | 148 (85.1) | 205 (92.8) | 204 (87.6) | 261 (91.2) |
| Failed | 6 (15.0) | 20 (15.4) | 26 (14.9) | 16 (7.2) | 29 (12.4) | 25 (8.7) |
| Outcome of OPAT processes | ||||||
| Success/partial success | 30 (75.0) | 112 (86.2) | 147 (84.5) | 202 (91.4) | 202 (86.7) | 256 (89.5) |
| Failure | 7 (17.5) | 14 (10.8) | 19 (10.9) | 9 (4.1) | 13 (5.6) | 17 (5.9) |
| Indeterminate | 3 (7.5) | 4 (3.1) | 8 (4.6) | 10 (4.5) | 18 (7.2) | 13 (4.5) |
OPAT outcome
The percentage of patient episodes where the OPAT outcome was deemed to have been successful or partially successful ranged between 75% and 91.4% (Table 2). The trend was an increase in successful/partially successful outcomes over time, with a corresponding reduction in failures.
Serious vascular access device events
The number of serious events related to VADs was low overall (range 0–3.15% patient episodes each year) (Table 3). There were 11/1084 (1.01%) cases of thrombus and 2/1084 (0.18%) cases of catheter-related bloodstream infection (CRBSI).
| 2014 n=40 (%) | 2015 n=130 (%) | 2016 n=174 (%) | 2017 n=221 (%) | 2018 n=233 (%) | 2019 n=286 (%) | |
|---|---|---|---|---|---|---|
| Catheter-related bloodstream infection (CRBSI) | 0 (0) | 1 (0.77) | 0 (0) | 0 (0) | 0 (0) | 1 (0.35) |
| Line-related infection (local) | 0 (0) | 0 (0) | 0 (0) | 1 (0.45) | 2 (0.86) | 1 (0.35) |
| Thrombus (deep and superficial) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 4 (1.72) | 7 (2.45) |
| Total complications | 0 (0) | 1 (0.77) | 0 (0) | 1 (0.45) | 6 (2.58) | 9 (3.15) |
Patient experience
Of the patients who were sent the questionnaire, 32/105 (33.6%) responded. The response was generally positive, with 29 patients (90.6%) agreeing that receiving antibiotic treatment at home was better than receiving it while in hospital (Figure 3).
Discussion
The study set out to assess the impact of expansion of the authors' OPAT service on the number of hospital beds available for further utilisation (bed days) and clinical efficacy and, in particular, to evaluate the increasing use of self/family-administered drug delivery. The authors have demonstrated that, as patient numbers increased, they were able to maintain high levels of infection cure/improvement, and there was a reduction in failures of the OPAT process over the years. The data recorded by the authors support the national recommendations which indicate that OPAT is a safe alternative to hospitalisation for selected patients (Chapman et al, 2019).
| Question | Response |
|---|---|
| How can patients be trusted to self-administer intravenous (IV) medicines when even registered nurses need special training to do this? |
|
| How safe is it? What if they get it wrong? |
|
| What support is there for patients who are self-administering IV antimicrobials at home? |
|
| How do you reduce the risk of line infections? |
|
| How do you assess competence in IV administration by patients or carers? |
|
| Do you experience any resistance from clinical staff on the wards who may be sceptical of the safety of patients giving their own IV antibiotics? |
|
The subsequent patient survey, albeit small, is encouraging, in that it indicates support for the service among the patients treated. Formal cost-effectiveness analysis was beyond the scope of this article, and is a complex issue, which would need to take into consideration tariffs and trim points associated with inpatient admissions, cost of drugs and nursing services, and the income generated from home visits and outpatient attendances.
The increasing implementation of nurse-led training for patients and their carers/families to administer IV antimicrobials at home, where appropriate, has been significant, ranging from around 25% of patients in 2014 to around 75% in 2018 and 2019. This has allowed the service to increase the number of patients who can benefit from it, because it frees up the OPAT nursing staff to concentrate on administering antimicrobials to patients who are unable or unwilling to train to self-administer. The authors' service previously relied on nurses from a private provider to assist with drug administration at home, which was costly, but have not needed to use such providers for several years, dramatically reducing the costs associated with running the service and allowing the service to employ additional nurses directly through the implementation of a successful business case.
This empowerment of patients is an excellent example of nurses being supported by the national nursing framework to lead change and adding value to the services provided by the NHS, through resource management and innovation (NHS England, 2016). The nurses have developed a competency-based assessment tool to determine whether patients/families are competent to self-administer, together with step-by-step instructions on administration technique, which are given to each patient on discharge to guide them through each drug administration.
Alongside low levels of both clinical failure and failure of the OPAT processes, it is reassuring to see that the number of serious VAD events was low overall across the study period and, in particular, there were very low numbers of CRBSIs. It is important that constant monitoring of this is undertaken and reviewed as part of clinical governance processes. In relation to thrombi resulting from the placement of VADs, the authors' department has undertaken a review of cases that have occurred, and they are creating a guideline on management of these events, in conjunction with haematology colleagues. The patients experiencing CRBSIs were reviewed carefully and alterations made to the mode of their subsequent antimicrobial delivery, where appropriate.
The advances in technological design of antimicrobial delivery systems has contributed towards the service being able to increase the number of patients self-administering therapy at home, through the use of easy-to-use elastomeric devices, including 24-hour infusors of beta-lactam antibiotics. The latter have pharmacokinetic advantages over multiple daily doses, translating into clinical benefit (Vardakas et al, 2018), and enable narrower spectrum agents to be used in line with antimicrobial stewardship guidelines (Ashiru-Oredope et al, 2012). Drug stability testing, such as that undertaken by the BSAC, will potentially enable more antimicrobials to be administered via elastomeric devices in the future. This is an exciting area of development and heralds the inclusion of patients with very complex infections within OPAT services.
The nurses and antimicrobial pharmacists in the authors' Trust are all independent medical prescribers, which further empowers them to take ownership of the clinical management of patients and makes OPAT processes more efficient. Future work in this area could include expansion of the nursing and pharmacy roles to become advanced clinical practitioners, which would allow them to take on some of the management of some clinical cases such as cellulitis, and the monitoring of patients on complex oral stepdown regimens.
Over the years, the authors have encountered a number of concerns from other clinicians over the training of patients and families to self-administer, and these anxieties sometimes were communicated to patients prior to or during their training (Box 1). Patients themselves were sometimes fearful of being taught to self-administer, although their anxieties were often allayed following a detailed discussion and demonstration of the technique. A future initiative planned is to identify ‘OPAT link nurses’ in order to empower nursing colleagues in the management of midlines on the hospital wards and instil confidence in patients, families and staff, allowing rapid training and smooth discharge processes.
Conclusion
The expansion of the OPAT nursing team at the Trust has been an exciting journey, and over 5 years has led the authors from a situation in which they relied on private nursing providers to administer antibiotics to patients to one where 75% of patients and their families are trained to self-administer IV antibiotics at home. Nurse empowerment, coupled with innovative antimicrobial delivery system technology, has enabled the authors' OPAT service to provide a patient-centred service with stable clinical outcomes. The hope is that this may give other OPAT services the confidence to consider increasing the proportion of their patients who undertake self or family/carer-administered therapy.