A number of themes emerged from the review of evidence. These were identified by the authors from recurrent topics in the literature, framed around the findings from successive NaDIAs. The themes have been separated into the actions DSNs take: patient education, staff education, direct patient care, psychological care and the outcomes of DSN interventions—a reduction in inpatient harm and length of stay and improved patient satisfaction. These themes are divided in this way as a reflection of the literature review questions which centred around the interventions and the outcomes of DSNs’ interventions. Challenges in practice will be identified and discussed.
Actions of DSNs
Diabetes Specialist Nurses play an increasingly crucial role in educating patients and healthcare professionals . Evidence suggests that in 97% of services in the United Kingdom, DSNs provide education to people with diabetes and staff in both primary and secondary care settings .
Much of the education given by DSNs to patients is with a view to enable self-management of diabetes at home. This education includes advice on medicine administration, for example, using insulin pumps and measuring blood glucose levels. Education most frequently occurs in one-to-one educative conversations with the patient, or additionally with family members or caregivers .
Self-management of diabetes is a challenging and complex process for patients: physically, emotionally, socially and intellectually. Patient education and self-management is essential in diabetes, combined with support from family and peers. It is widely accepted that self-management of diabetes can promote quality of life . Kousoulis’ realist review of over 5,500 individuals in six European countries showed a distinct policy shift towards patient-centred self-management of diabetes in primary care .
‘Patient education is the cornerstone of diabetes management’ according to Feddersen and Lockwood . DISNs play a pivotal role in educating patients in hospital and empowering patient self-management of their diabetes . Care and advice given by DSNs in addition to standard care has resulted in increased patient knowledge and confidence . This is essential for positive patient outcomes: patient confidence can delay complications, reduce hospitalisations, facilitate discharge and prevent readmission . Evidence suggests that education in controlling glycaemia has sustained benefits and translates to reduced associated micro and macro cardiovascular risk factors . Conversely, Kousoulis’  realist review reported that diabetes education should be regarded to have a broadly positive effect on patient outcomes, but a long-term benefit on glycaemic control cannot be assumed or expected.
Timing and location is important: patient education is particularly critical for newly diagnosed PWD  and in hospital settings . According to Davies and Davis , education is essential for diabetes inpatients to ‘make informed choices about their self-care’. Furthermore, disempowerment in United Kingdom hospitals has been regularly noted . In James et al.’s study  of 159 United Kingdom diabetes centres, 97% of services provided patient education sessions.
The delivery of appropriate care relies on adequate staff knowledge and skills, and successful coordination and cooperation between health care professionals. According to Ross et al. , diabetes specialists bridge gaps in expertise and knowledge across teams by providing staff with specific diabetes education. They increase both patient and staff self-efficacy which is connected with reduced length of stays (LOS). DSNs proactively identify and anticipate cases that need specialist attention. They respond reactively and prevent problems escalating early.
Carey et al.  suggest that health care professionals’ education is a contributing factor to medication and prescription errors in diabetes and that DSN prescribers can reduce these errors through regular patient assessment and review and individual education sessions with medical and nursing staff. Additionally, NHS England  (2016) suggests that DISNs reduce time requirements on other clinical staff due to effective and efficient management.
Due to disease complexity and new advancements in treatment, it is apparent that generalist staff cannot be expected to maintain diabetes expertise. This highlights the necessity of DSNs, who can advise and guide other staff members . A report on all identifiable diabetes centres in the United Kingdom in 2007  found that in 159 centres, 76% of DSNs deliver education sessions to both healthcare professionals and patients. Hospital DSNs provided the most education for healthcare professionals compared to community DSNs, Nurse Consultants and Paediatric DSNs, with 94% of hospital DSNs delivering professional education. How this education is delivered to health care professionals is not explicitly defined and has been purported variedly, ranging from corridor conversations to structured education sessions .
Kousoulis et al.  found that PWD often report receiving inconsistent or contradictory advice from different health care professionals. Additionally, Carey et al.  suggest that staff lack of knowledge and misperception of patients’ cases contributes to increased medication errors in hospital. These, as will be later detailed, can be reduced by DSNs.
Conversely, the presence of specialist diabetes teams has reportedly had some unintended consequences. Ross et al.  found an erosion of ward staff skills with the introduction of a specialist diabetes team. This created delays in patient treatment and often over-burdened the specialist nurses. This could perhaps be countered by further education and empowerment of ward staff to ensure they maintain the necessary diabetes confidence and knowledge to respond.
Direct patient care and medicines management
Hospital DSNs provide direct inpatient care . One of DSNs’ primary responsibilities is managing patient treatment recommendations. DISNs have a crucial role in improving glycaemic control in patients in hospital. Evans et al.  describe this role as ‘vital’. Patient care provided by inpatient diabetes specialist teams is efficient. The national ‘Think Glucose’ initiative launched in 2008 utilises a ‘traffic light’ system to guide which patients should be referred to the specialist team . This system, covering over 30 ‘red’, ‘amber’ or ‘green’ cases ensures that patients that need to be seen are being seen by a diabetes specialist, whilst also ensuring effective use of resources and DISN time.
Direct diabetes problems and complications because of diabetes include foot ulceration, renal failure, diabetic retinopathy, ischaemic heart disease, stroke and peripheral vascular disease. These complications are often the reasons for diabetes patient admission to hospital . Eighty-nine percent of DSNs deliver nurse-led clinics for patients with these complications .
Additionally, DSN telephone consultations enable outpatients that require follow-up after discharge to receive care. Evidence suggests that as of 2009, in 71% of hospital-based services, telephone helplines were offered to PWD . These were operated by hospital DSNs in 94% of cases. This ‘telemedicine’ reportedly improves ongoing diabetes care, reduces the number of acute hospital admissions and is cost-effective .
With advancements in technology playing an ever more important role in healthcare, DSNs also facilitate digital health care into diabetes treatment. Their role in enhancing the accessibility and convenience of diabetes care is well recognised .
DSNs intervene in medicines management, which reportedly has a positive effect on the delivery of medicines . Their expertise is crucial in adjusting treatment and managing comorbidities, in particular during hospital stay. The reduction of glycosylated haemoglobin (HbA1c) as a primary outcome measure has been used in a variety of studies on DSN’s effectiveness in patient health. Loveman et al.  found that specialist nurses were effective in reducing this in the short-term, with the long-term not being fully studied.
Ross et al.  reported that DSNs make more knowledge-based decisions and have more holistic views of patients than their counterparts. They also suggest that DSNs make higher-level decisions, and rather than simply following protocol, they take the clinical complexity of each case into consideration. DSNs are also reported to be responsible for the coordination of multidisciplinary responses to complex cases, in particular, in organising care plans. In this way, DISNs provide ‘continuity of care’ .
A report of specialist diabetes services in 2007 found that 49% of hospital DSNs are involved in prescribing . That is compared to the estimated 5% of the total United Kingdom nursing workforce in 2016 qualified as nurse independent or supplementary prescribers . However, the necessity of DSNs to prescribe has been contested. A comparison of prescribing and non-prescribing nurses in diabetes patient management in general practice found little difference in patient outcomes in self-care and HbA1c levels . However, there were significantly higher levels of satisfaction among prescribing nurses’ patients, and blood glucose testing was more prevalent in this group. This may have been down to longer consultations, enabling extra advice and information exchange. As not all DSNs prescribe, this can often cause delay in treatment .
Psychological care and counselling
DSNs are often seen as a pillar of knowledge during hospital stays and in primary and secondary care alike. Loveman et al.  conducted an intervention review where they found that patients often contact their DSN in preference to their GP. This review was of six trials including 1382 participants followed for six to twelve months. DSNs provide emotional, psychological and social care for both patients and their families . Loveman et al.  reported that ‘patients in contact with specialist nurses are generally satisfied with the level of care that they receive’.
This specialist role is known to have a positive effect on diabetes patients’ outcomes . DSN’s role is crucial for patients and families to establish trust and confidence in health care providers and for health promotion to be maximised . Additionally, DISNs are suggested to bridge communication gaps between clinical partners and patients, acting as an intermediate role that can prevent problem escalation .
A diabetes patient experience study at Derby Hospital Foundation Trust revealed feelings of fear and anxiety at the prospect of visiting hospital, and ‘feelings of loss of control, concerns that the staff did not have sufficient expertise in diabetes, and a lack of knowledge in the care to expect whilst in hospital.’ . It is evident that psychological care and advice is necessary for PWD, especially in inpatient settings.
Outcomes of interventions
Reduction of inpatient harm
Due to the complexity of diabetes, medication errors are common in inpatients. NaDIA 2017  reported that 31% of patients in the audit had experienced at least one diabetes medication error whilst in hospital. These included both prescription errors and medication management errors, and are much higher than errors in other diseases in hospital. As of 2014, there was an average prescribing error rate in United Kingdom hospitals of 7% and a rate of 3–8% of medicine administration . NHS England  asserts that DISNs reduce inpatient harms by reducing medication errors and hypoglycaemic events. NaDIA 2016  highlighted the need for healthcare professionals to have the knowledge, experience and confidence in managing diabetes medication to reduce medication errors. Additionally, Diabetes UK, Trend UK and RCN’s 2014  position statement presented evidence that suggests that DSNs, especially those with Nurse Prescribing skills, significantly reduce insulin error, with a consequential reduced LOS.
NaDIA 2017  revealed that around 1 in 25 inpatients with type 1 diabetes develop diabetic ketoacidosis (DKA) and around 1 in 800 inpatients with type 2 diabetes develop hyperosmolar hyperglycaemic state (HHS) during their hospital stay. These hospital-acquired emergency states are extremely serious, potentially fatal and are preventable conditions that should not occur during hospital admission. Diabetes specialist teams with sufficient knowledge, capacity and expertise are crucial in reducing inpatient harms such as DKA and HHS by using specific and tailored medicines management .
Carey et al.  found a significant reduction in the number of medication errors with a DSN study group and an overall positive effect on medicine delivery systems. Their study looked at inpatient care of a convenience sample of 56 diabetes patients over 8 months. Thompson et al.  suggest that insulin adjustment according to advice from a diabetes nurse educator is effective in improving glucose control in diabetic patients. Additionally, Vissarion et al.  suggest that DSNs play a crucial role in responding to crises.
Increasing workload and staff cuts are affecting patient care. With demand for diabetes services rising without increasing DSN numbers, 78% of DSNs have concerns that their workload is impacting on patient care and/or safety .
Reduction of length of hospital stay and prevention of hospital admissions
It has been well documented that a DISN service can help reduce the length of hospital stay for people with diabetes [23, 26, 42]. NHS England 2016  asserts that a DISN (1 nurse per 250 inpatient beds) will reduce LOS for diabetes inpatients. This is widely supported by the literature: Cavan et al.  found that the introduction of a ward-based diabetes nurse advisor was associated with significant reductions in LOS. Carey et al.  found that the median LOS of diabetes patients was reduced by three days by the presence of the DSN prescriber; analysis was made pre and post intervention by the nurse. Additionally, the savings in costs were enough to finance the post. Alabraba et al.  reported that a DISN team ensured timely and appropriate discharge and follow-up.
Mahaffey et al.  suggest that early reviews of diabetes patients by DISNs in Accident and Emergency (A&E) would prevent hospital admissions. Their study of over 3.5 years found a significant number of people attending A&E were able to be treated and discharged home without hospital admission. They estimated savings of £35,000 over 3.5 years at their service through reduced bed occupancy and patient-focused care.
Davidson et al.  found a demonstrably lower hospital resource use for patients under DSN care and significantly fewer emergency room visits and hospitalisations for preventable diabetes-related causes. Sampson et al.  also found that diabetes excess bed occupancy was notably reduced by the introduction of a DISN service in a study of 6 years.
As previously discussed, DISNs play a critical role in patient education and promotion of patient self-management. Feddersen and Lockwood’s  findings suggested that a greater awareness and knowledge of diabetes in both patients and staff can result in a shorter hospitalisation. Educational programs provided by Inpatient Diabetes Educators have been directly linked to a decrease in readmissions.
Increased patient satisfaction
DSNs have been associated with increased patient satisfaction. Courtenay et al.  reported an increase in diabetes patient satisfaction when consulted by a prescribing nurse, due to increased consultation time, and establishing relations between nurse and patient. Their study was of 214 patients in the United Kingdom. In Taylor’s  study of 169 patients, 92% reported that a DSN led care management programme was moderately to extremely helpful in preparing them to manage their condition. Cavan et al.  also found that a DSN-led programme of care for newly diagnosed type 2 diabetes patients was clinically effective with high levels of patient satisfaction and motivation. In workshops aimed at driving improvements in diabetes care and patient experience in London, people with type 1 diabetes reported that they value and would like to see more education and support for family and friends. People with type 2 reported that they would like to see more person-centered care and be seen by the same person . The evidence suggests that DSNs improve patient satisfaction through more personal and specific consultations of longer lengths, educative sessions and empowerment to self-manage.
Challenges in practice
Due to resource limitations and staff scheduling, specialist nurses are not always available to inpatients, particularly at weekends and out-of-hours. This results in ward staff taking full responsibility for diabetes inpatient’s complex care . With the increasing number of diabetes inpatients, there are restraints in DISNs’ capacity. These restraints have in some cases been alleviated by the introduction of a Diabetes Clinical Assistant post to support the Diabetes Specialist team .
Evidence has demonstrated that DSNs have an increasingly limited access to professional development and opportunity for study leave and research. This suggests that DSNs’ skill and knowledge development faces challenges [1, 10]. This has been described as ‘concerning’ and combined with a lack of long-term job security, could result in recruitment and retainment difficulties .