In 2016, registered dietitians in the UK gained the right to train as supplementary prescribers (gov.uk, 2016). Supplementary prescribing is a voluntary partnership between an independent prescriber and a supplementary prescriber to implement an agreed patient-specific clinical management plan (CMP) with the patients' agreement (Baird, 2003). A CMP is an agreed, defined plan of treatment for a named patient, which sets the legal boundaries of the medication and the parameters of prescribing responsibility for the supplementary prescriber (Baird, 2003). The CMP must be in place before prescribing can occur. Dietitians working in specialist roles where the interplay of diet and medication is important to patient understanding, concordance and treatment outcome are in an ideal position to train and practice as supplementary prescribers as other healthcare professionals have limited knowledge of diet and nutrition (Crowley et al, 2019). Currently, there are 193 registered dietitians with the annotation supplementary prescriber on the Health and Care Professions Council (HCPC) register.
The author is a nutrition support dietitian specialising in intestinal failure (IF) working in a national intestinal rehabilitation unit within a specialist bowel hospital in England. The author is a qualified non-medical prescriber and at the time was the only supplementary prescriber in the hospital. Patients with IF fall into three main categories. Type 1 IF includes patients who require parenteral nutrition (PN) short term, usually less than 28 days, often as the result of surgery including post-operative ileus or bowel obstruction. Type 2 IF includes patients who require PN with complex metabolic and nutritional requirements who require multidisciplinary care from surgeons, gastroenterologists, radiologists, microbiologists, dietitians, pharmacists, psychologists and specialist nursing including nutrition and stoma care. These patients often require ICU and high dependency unit (HDU) support before transfer to a specialist unit for rehabilitation. It may be the result of abdominal trauma, volvulus or mesenteric ischaemia resulting in resection of the intestine causing a high output stoma or the development of enterocutaneous fistulae (Pironi et al, 2016). Type 2 can last for several months until reconstructive surgery is performed to restore normal intestinal function.
Type 3 IF is a chronic condition in which patients require parenteral support (either PN or parenteral fluid and electrolytes) for years including HPN. This includes patients with a short bowel, intestinal fistula, extensive small bowel mucosal disease, mechanical bowel obstruction and intestinal dysmotility (Pironi et al, 2016).
The national intestinal rehabilitation unit receives complex referrals with significant physical, metabolic and psychological needs. The role of the Dietitian is to complete a nutritional assessment, estimate requirements and formulate PN suitable for hospital and ultimately home. The dietitian is responsible, as part of the multidisciplinary team (MDT), for monitoring patients regarding the efficacy of treatment and managing any short and/or long-term complications such as refeeding syndrome, hypo and hyperglycaemia, abnormal liver function, catheter-related bloodstream infections, deranged electrolytes and fluid balance issues. Patients with IF require close monitoring to identify and treat potential complications (Tables 1 and 2).
Table 1. Clinical monitoring requirements for patients receiving parenteral nutrition
| Parameter | Frequency | Rationale | Consequence | |
|---|---|---|---|---|
| Anthropometry | Mid arm circumferenceTricep skinfold thickness | Monthly | Assess body composition | Loss of muscle mass not recognised |
| Weight | Daily | Monitor hydration | Risk of overload and dehydration | |
| Biochemistry | Capillary blood glucose | Every 4-6 hours until stable | Risk of hypo and hyperglycaemia | Increased risk of infection, dehydration |
| Urinalysis | Daily | Ketones and glucose | Refeeding and glycosuria | |
| Urine sodium | Twice a week | Monitor hydration | Dehydration | |
| Clinical | Fluid balance | Hourly/daily | Monitor hydration | Risk of overload and dehydration |
| Temperature | Every 4-6 hours | Risk of catheter related bloodstream infection | Infection goes undetected | |
| Clinical condition | Daily | Altered requirements | Under and overfeeding | |
| Catheter assessment | Daily | Risk of infection/displacement | Interruption in PN delivery | |
| Dietary | Food chart/enteral feeding regimen | Daily | Assess oral/enteral intake | Transition to oral/enteral feeding |
| Environment | Medications | Daily | Effects and side effects | Side effects eg increased GI losses, nausea, abnormal electrolytes |
| Functional | Hand grip | Weekly | Measure of functional capacity | Effect of PN unknown |
Table 2. Blood biochemical monitoring requirements for patients receiving parenteral nutrition
| Parameter | Frequency | Rationale | Consequence |
|---|---|---|---|
| Sodium | Daily until stable then 1-2 times a week | Assessment of hydration and fluid balance | Risk of dehydration and overload |
| Urea | Daily until stable then 1-2 times a week | Assessment of hydration and stress response | Risk of dehydration and overload |
| Creatinine | Daily until stable then 1-2 times a week | Assessment of renal function | Acute kidney injury and chronic kidney disease |
| Potassium, Magnesium and Phosphate | Daily if refeeding risk. 3 times a week until stable then weekly | Depletion common | Clinical symptoms |
| Corrected Calcium | 3 times a week until stable then weekly | Hypocalcaemia secondary to ↓ Magnesium | Clinical symptoms |
| Albumin | Daily until stable then 1-2 times a week | Disease severity | Risk of oedema |
| Liver function tests | Twice weekly until stable then weekly | Abnormalities common in sick patients | Liver diseasePN delivery compromised |
| C-reactive protein | 2-3 times a week until stable | Presence of inflammation | Inflammation unrecognised |
| White cell count | Daily until stable then 1-2 times a week | Presence of infection | Infection unrecognised |
Previous work has demonstrated that it is the dietitian who is responsible for assessing nutritional status, estimating requirements and risk of refeeding syndrome and formulating the PN prescription but was then asking junior doctor colleagues to sign the legal prescription (Culkin, 2015). This lack of professional accountability was one of the reasons that non-medical prescribing was introduced. The Crown report stated that ‘One professional should not be expected to take responsibility for clinical decisions that are actually taken by a colleague’ (Crown, 1999). Joint dietitian and pharmacy decision making regarding PN has been successfully implemented with no harmful effects although at this time prescribing rights were only available to pharmacists (Farrer et al, 2009).
The prescribing practice of dietitians is currently unknown due to limited published work in this area (Culkin and Gabe, 2018) as the profession is relatively new to prescribing. In addition, the COVID-19 pandemic is likely to have had an impact on dietitians completing the non-medical prescribing course as many dietitians were redeployed to ICU where supplementary prescribing can be problematic.
It is a requirement that all non-medical prescribers audit their practice yearly as part of the hospital's non-medical prescribing policy.
Aim
This work aimed to describe the prescribing practice of a nutrition support dietitian working within intestinal rehabilitation and to identify how long after qualification the first prescription was issued.
Methods
The prescribing practice of a nutrition support dietitian was evaluated over a six-month period from August 2017 to January 2018. Patient data included demographics, aetiology (Pironi et al, 2016), medications prescribed, route and dose administered and any adverse events. Data were collected at the time of prescribing from patient records and transferred to the hospital's non-medical prescribing audit proforma and then an Excel spreadsheet.
Findings
During the six-month period, 24 patients were prescribed medications by the dietitian of whom 13 were female and 11 were male. The mean age was 57±15 years and aetiologies included short bowel (n=9), mechanical obstruction (n=6), intestinal fistula (n=5), intestinal dysmotility (n=3) and extensive small bowel mucosal disease (n=1). The different types of medications and the frequency of prescriptions are shown in Table 3. The medications prescribed related to the nutritional management of patients with PN and IV fluids and electrolytes being the most prescribed medications. The following medication was deprescribed; 2L of 0.9% sodium chloride, codeine phosphate, loperamide, lansoprazole, sytron, forceval and folic acid. The first prescription was issued four months post qualification. None of the patients approached declined consent and no adverse events were observed. The benefits of supplementary prescribing were faster access to medications for patients. For example, when the dietitian identified a patient had a micronutrient deficiency, the appropriate micronutrient could be prescribed and administered by the nursing staff without delay. The dietitian had superior knowledge of micronutrient requirements and treatment compared to the medical team as members of the dietetic and pharmacy department created the hospital policy for the management and prescribing of micronutrients in patients with intestinal failure. The main barriers to prescribing were the creation of the CMP and the logistics of asking the designated medical prescriber to sign and agree with the CMP in a timely manner. Other barriers included a lack of national guidance on the creation and implementation of CMP.
Table 3. Medications prescribed by the registered dietitian
| Medication and route | Dose | Number of times prescribed (n) |
|---|---|---|
| 5% Dextrose (IV) | 1L | 61 (+8 mmol MgS04)1 (+4 mmol MgS04) |
| 0.9% Sodium Chloride (IV) | 1L | 364 (+4 mmol MgS04)2 (+8 mmol MgS04)3 (+40 mmol KCL) |
| 0.18% Sodium Chloride/4% Dextrose (IV) | 1L | 131 (+8 mmol MgS04)1 (+20 mmol KCL)1 (+40 mmol KCL) |
| Parenteral Nutrition (IV) | 1-4.5L | 52 |
| Pabrinex (IV) | 1 pair bd | 1 |
| Selenium (IV) | 500 mcg | 1 |
| Vitamin A (IM) | 100 000 IU | 1 |
| Vitamin D (IM) | 300 000 IU | 5 |
| Vitamin D (oral) | 800 IU od | 1 |
| 30% Sodium Chloride (Enteral) | 10 ml | 1 |
| Forceval (Oral) | One tablet od | 1 |
| Thiamine (Oral) | 100 mg bd | 2 |
| Sandoz Phosphate (Oral) | Two tablets od | 2 |
| Adcal D3 (Oral) | One tablet bd | 1 |
| Diarolyte (Oral) | 8 sachets in 1 L | 2 |
IU = International Units, MgS04 = magnesium sulphate, KCL= Potassium chloride
Discussion
A nutrition support dietitian specialising in IF was able to prescribe a range of different medications including PN, IV fluids and electrolytes, micronutrients and oral rehydration solutions. All these medications play an integral part in the management of IF either by providing life-sustaining PN and IV fluid and electrolytes or by reducing the volume from a high output stoma/fistula or correcting electrolyte and micronutrient deficiencies.
A case study of a patient with abdominal tuberculosis resulting in bowel obstruction demonstrated supplementary prescribing by a registered dietitian in practice. This included reviewing the patient's past medical and surgical history, current medications and allergies. An assessment of nutritional status indicated severe malnutrition with a body mass index of 14.5 kg/m2 and a 34% weight loss in the last 3-6 months plus low muscle mass (mid-arm muscle circumference <5 th centile). Dehydration was identified as reflected by a raised urea and negative fluid balance due to high gastrointestinal aspirates from a nasogastric tube. The patients' requirements for energy, nitrogen, fluid, sodium, potassium, calcium, magnesium and phosphate were assessed using national guidelines (Cope et al, 2018; The National Institute of Health and Care Excellence [NICE], 2017) and PN was prescribed after the creation of a patient-specific CMP. The case study demonstrated that the registered dietitian specialising in nutrition support prescribed safely and effectively with good clinical outcomes. The close monitoring the patient received (Tables 1 and 2) ensured that any potential complications associated with IF and PN were identified and corrected to prevent deterioration in clinical status. A full micronutrient screen identified selenium and vitamin D deficiency and then subsequent appropriate supplementation via the correct route treated these deficiencies, which if not treated would have been detrimental to the patient's outcome (Culkin, 2019). Therefore, dietitians are in an ideal position to prescribe for patients with IF due to their expertise and knowledge in nutrition and hydration.
Dietitians are experts in nutrition and under and postgraduate courses include all aspects of nutrition, fluid and electrolytes requirements and it is for this reason that dietitians working in nutrition support were included in the case of need for supplementary prescribing for dietitians which supported the change in the law (gov.uk, 2016). Other areas suitable for supplementary prescribing by dietitians include renal disease, diabetes, cystic fibrosis, pancreatic disease, oncology, gastroenterology, paediatrics, obesity management and other chronic conditions where the interplay of diet and medication is key.
The number of patients included in this work may appear low during a six-month period. The intestinal rehabilitation unit is a 22 bedded unit and patients can remain in the unit for several months. Once they are established on PN they may remain on the same prescription until discharge unless changes are required based on clinical need. Supplementary prescribing is ideal for the treatment of patients with chronic conditions and therefore works well in patients who require the expertise of a dietitian over several months or years.
Renal dietitians have expert knowledge in the management of bone biochemistry for patients with chronic kidney disease on dialysis and have previously used patient group directions (PGD) to tailor eating patterns and dietary phosphate intake to adjust phosphate binders and alfacalcidol. A retrospective review of prescribing by a renal dietitian over 9-months identified 34 prescriptions (27 new and seven adjustments). Twenty-nine were for phosphate binders and five were for alfacalcidol and an improvement in at least one bone biochemistry marker was found in 76% of cases, one-month post-intervention (Rai, 2019).
Another aim of supplementary prescribing is timely access to medications to prevent delays in treatment. A service evaluation in a cohort of 16 patients on haemodialysis investigating the time taken for a prescription to be dispensed following dietetic recommendation pre and post supplementary prescribing found a reduction from 13 days to 1 day. One month post-intervention, improvements in serum calcium, phosphate and/or parathyroid hormone concentrations as a result of the prescription were seen in 63% pre prescribing compared to 92% post prescribing. This work demonstrated timely intervention improved the management of chronic kidney disease-mineral and bone disorder and supported the extended role of the specialist renal dietitian (Brice and Pugh, 2020).
Non-medical prescribing has evolved over the decades and started with nurses prescribing from an extended formulary to now nurses, pharmacists, physiotherapists, therapeutic radiographers, optometrists, podiatrists and paramedics becoming independent prescribers. Currently, dietitians are limited to supplementary prescribing but there is limited evidence to demonstrate that supplementary prescribing by dietitians is effective.
A Cochrane systematic review demonstrated that independent and supplementary prescribing by nurses and pharmacists was as effective as usual care provided by doctors (Weeks et al, 2016). Nurses and pharmacists were initially given supplementary prescribing rights before independent prescribing and whilst independent prescribing is now established practice for these and other professions, there is evidence to suggest that difficulties were experienced with supplementary prescribing. In the early implementation of supplementary prescribing, pharmacists were positive, describing it as ‘a stepping stone’ and ‘a step forward’ but also noted it was bureaucratic and limited freedom in decision making (Dawoud et al, 2011). In 2010 a study of 47 pharmacists who participated in a focus group about prescribing found that three-quarters were not actively prescribing due to logistics and organisational barriers (Lloyd et al, 2010). A pre- and post-interview with eight pharmacists completing the supplementary prescribing course documented delays from qualification to prescribing in practice needed to be reduced to maintain motivation for prescribing (Tulley et al, 2007).
The dietitian took 4 months post qualification to issue their first prescription. This was despite a significant amount of preparation work before starting the course to gain approval to attend and to ensure the logistics would not hinder prescribing by the dietitian. This is less than other professions which showed that 15% of nurses and pharmacists took longer than 6 months to issue their first prescription (Latter et al, 2010). A large survey investigating the prescribing practices of nursing staff found 87% of nurses (n=1107) had used independent prescribing with 44% (n=568) using supplementary prescribing. The requirement and time required to set up a CMP was the biggest hurdle with 50% of respondents identifying this as an issue. In addition, access to doctors, hospital policy or difficulties accessing records was stated as a barrier to prescribing (Courtenay and Carey, 2008).
Similar issues have been highlighted regarding the CMP within renal dietetics due to a lack of clear national guidelines on supplementary prescribing with different Trusts endorsing different practices (Ruddock and Stevens, 2020).
Due to the difficulties faced by other professions with supplementary prescribing and from anecdotal evidence from the British Dietetic Association supplementary prescribing forum it appears that there is a need for dietitians to be granted independent prescribing rights. However, research is required to support this to ensure it is safe and effective. The TraDip study from the University of Surrey is currently underway, which aims to investigate the effect of dietitian supplementary prescribing on patients, staff and services.
Conclusion
A nutrition support dietitian was able to prescribe a range of medications for patients with IF. More evidence is essential to demonstrate that dietitians are safe and effective prescribers. Future research is required to assess patient satisfaction, economic impact and attitude of other healthcare professionals.
Key Points
- Registered dietitians are qualifying and practicing as become supplementary prescribers
- A Dietitian specialising in nutrition support had the skills and knowledge to prescribe parenteral nutrition, intravenous
- uids, electrolytes and micronutrients to patients with intestinal failure
- Other areas suitable for supplementary prescribing include renal disease, diabetes, cystic fibrosis, pancreatic disease, oncology, gastroenterology, paediatrics, obesity management and other chronic conditions where the interplay of diet and medication is crucial
- Registered dietitians are encouraged to publish evidence of safe and effective prescribing.
CPD reflective questions
- Which healthcare professional has the knowledge and skills to prescribe medications where the interplay of diet and medicine is crucial to patient understanding and concordance?
- What monitoring is required for patients receiving parenteral nutrition?
- Do you think dietitians should be granted independent prescribing rights?