Problem

The coronavirus pandemic brought vitamin D into focus due to its potential role in reducing severity of respiratory tract infections.1–5 There is currently no conclusive evidence that vitamin D deficiency predisposes to coronavirus, however, evidence supports the role of vitamin D in prevention of acute respiratory infections.6 The alcohol care team (ACT) were alerted to a health-promotion intervention at South London and Maudsley National Health Service Foundation Trust (SLaM) at the start of the pandemic, where vitamin D replacement was provided to inpatients with schizophrenia, who are at high risk of vitamin D deficiency.7 This prompted the team to investigate whether their patient group may be similarly at risk.

We defined vitamin D status in table 1.

We found evidence to support vitamin D deficiency being prevalent in patients with substance use disorders (SUD). Cross-sectional studies of non-cirrhotic patients with alcohol dependence in addiction services in France demonstrate that between 41% and 90% have vitamin D levels below 12 nmol/L.8–10 In those with fatty liver or liver fibrosis, the prevalence of severe deficiency is 60.4%.11 Alcohol dependence is an independent risk factor for adult respiratory distress syndrome and may worsen outcome.12 Many opioid dependent patients smoke and a large proportion (30.3%) have chronic obstructive pulmonary disease which makes them more vulnerable to COVID-19.13 US data indicate that patients with opioid dependence have high rates of deficiency (36%) and insufficiency (52%)14 with some populations reporting a mean vitamin D level of 5.2 nmol.15 We found no UK data on vitamin D deficiency prevalence in SUD.

A UK study published in October 2021 on mortality in people with mental disorders, showed elevated standardised mortality ratios (SMR) for all mental disorders (including SUD) with COVID-19.16 For all other causes of death (not due to COVID-19), the SMR increased for patients with SUD to 5.1 (95% CI 4.3 to 5.9) during the pandemic (second quarter of 2020) when compared the same quarter of 2019 (SMR 3.7, 95% CI 3.2 to 4.7).16 A US study suggests that individuals with SUD are both more at risk of becoming infected with COVID-19 (OR of 8.7 with CI of 8.4 to 9.0) and more at risk of worse outcomes after becoming infected than the general population.17

It is clear that vitamin D is vital for maintaining bones and muscle function. Complications of low vitamin D in adults result in increased risk of fractures, secondary to osteomalacia and proximal muscle weakness (an independent risk factor for frailty, falls and fractures),18 likely contributors to frequent attendances at emergency departments (ED) and hospital admissions.

In light of significant morbidity resulting from vitamin D deficiency, the addictions management group decided to evaluate how we are investigating and treating vitamin D deficiency. This was less feasible in the community where face to face contact was minimised but more actionable in the general hospital setting.

Background

A recent review of evidence assessing vitamin D status and vulnerability to coronavirus infection found no direct evidence related to vitamin D deficiency predisposing to coronavirus.11 However, it did state that current advice is that the whole population of the UK should take vitamin D supplements to prevent vitamin D deficiency, irrespective of any possible link with respiratory infection. The review concluded that clinicians should treat patients with vitamin D deficiency regardless of any link with respiratory infection.11

Our hospital guidelines state that individuals at particular risk of vitamin D deficiency should be offered routine replacement treatment. They also advise that patients with the combination of one or more risk factors for vitamin D deficiency as well as symptoms/signs of vitamin D deficiency should be offered a vitamin D level check. Local and national guidelines suggest that everyone living the UK should take daily over-the-counter vitamin D supplements of 10 µg/400 IU between October and March.19 20

Risk factors for vitamin D deficiency listed in the local guidelines are numerous, including deranged liver function and ‘mental health conditions’. Nevertheless, they do not explicitly mention SUD. This omission is contrary to evidence already referenced, in that being a patient in addictions services is itself a risk factor for vitamin D deficiency.

Symptoms and signs of vitamin D deficiency are non-specific and can be easily missed. Vitamin D levels are easy to check with a simple blood test. Replacement of vitamin D is straightforward, safe and inexpensive.

Measurement

To establish a baseline measurement of current practice around vitamin D level checks and replacement, we carried out a pilot project of 50 patients. This sample of 50 patients was taken from our team’s current handover list and recent patient discharge list, in the order in which they were referred to us. A spreadsheet was kept with patient details and hospital clinical records were reviewed. It allowed us to ascertain whether patients were already being offered vitamin D checks or replacement in line with local hospital guidelines.

The results of our baseline measurement showed that none of the 50 patients in the pilot study were offered vitamin D level checks or replacement during their inpatient admission, despite often meeting criteria on local guidelines for vitamin D replacement and/or level checks.

We started our first cycle of quality improvement (QI) by raising awareness of vitamin D testing within our own team and on hospital wards, as well as actively requesting vitamin D levels checks by immunoassay. We extracted patient data and recorded vitamin D level results on a spreadsheet. We used the patient total number of 95 as an arbitrary cut-off point to analyse our results.

Six months later, in our second cycle of QI, we collected data on 62 patients. This final sample of 62 patients was selected as a representative sample of patients on our current handover list and list of recently discharged patients, again in the order which they were referred to us. The risk of bias in selection of patients was reduced by taking patients directly from team patient lists sequentially.

We listened to feedback and decided not to include patients who were in the acute phase of illness for vitamin D testing. We also noted that it was not practical to include patients who were in the ED and not admitted to hospital wards. The following inclusion and exclusion criteria were established after learning from our pilot study:

Design

We undertook data collection in conjunction with patients referred to our team between June–August 2020 and November 2020–January 2021. We initially planned to advocate universal prescription of a loading dose of vitamin D in a similar manner to that advocated by our partnering mental health trust. Significant differences existed between the two trusts however, for example, the acute hospital had experienced recent incidences of hypervitaminosis, had a more physically acutely unwell patient population and had easy access to vitamin D testing. In contrast, the mental health trust had patients who were generally more physically well, frequently declined blood tests on admission and had no laboratory on site to carry out vitamin D tests. We agreed that all patients admitted to our acute hospital site could have a vitamin D level check, with vitamin D replacement, if required.

Advice was sought from junior doctors on the logistics of requesting routine vitamin D level checks. Vitamin D status was added to our team’s handover list, which involved all team members in requesting and chasing results of vitamin D levels.

Medical colleagues from a range of specialties were involved in discussions about this QI project. We took into account their views that vitamin D intervention was more appropriate for general practice rather than acute hospital admission. However, patients with SUD often struggle to attend generic services, to the extent that screening for other health conditions, for example, Hepatitis C is conducted in addictions services and at needle exchanges.

We did not include patients who had a low chance of surviving the admission. We also excluded patients who were referred to our team for review in ED only, as patients had often left ED by the time vitamin D level results were ready. The opportunity to issue outpatient prescriptions from the ED is limited.

Strategy

Our stages for improvement began with assessing current clinical practice with respect to vitamin D checks and replacement. We found that 0 out of 50 patients had a vitamin D level check and no patients were offered routine vitamin D replacement. This was not concordant with our local guidelines, which advise vitamin D level checks be offered to all patients with risk factors for low vitamin D and symptoms or signs of low vitamin D. Routine maintenance dose vitamin D replacement, without vitamin D level checks was also not being offered to patients with risk factors for low vitamin D, which was also not in keeping with local guidelines.

We adapted our handover list to include a column on vitamin D, stating if a level had been requested, when the level was due and if replacement was needed.

We reflected on the issues of patients being discharged before the vitamin D level could be checked. We decided to omit patients who only attended ED who were not admitted to wards.

In order to increase awareness of vitamin D testing and start further discussion, we ran teaching sessions within our team. We discussed vitamin D levels regularly at our team handover meetings and team members began requesting vitamin D levels and raising awareness of vitamin D deficiency and its consequences with ward teams.

Six months after the outset of this project, we collected another round of data from 62 patients. This was to assess if QI had been sustained and gauge whether vitamin D level checks and replacement had been embedded into routine clinical practice by both our own team and, more broadly, to acute hospital ward teams.

Lessons and limitations

A limitation of this project was the lack of linking our discharge template to the patient’s GP requesting appropriate follow-up blood tests at 4 weeks (patients who received vitamin D loading)21 and 3–6 months21 22 with each patient’s hospital discharge letters. This did not happen routinely within our team due to time constraints and fast patient turnover. A lesson learnt, and which should form the basis of a follow-up project is the need to audit discharge letters of patients prescribed vitamin D during inpatient stays and assess if the information in our template is present on hospital discharge summaries. Patients not admitted for the duration of vitamin D loading doses should have been discharged with vitamin D ‘to take away’. We do not have any data on how many of our patients attended for follow-up blood tests.

The research published to date on vitamin D deficiency and substance use has mainly focused on people with alcohol23,8 9 or opioid dependence.13 We accept that our patient sample is heterogeneous, incorporating a range of SUD, including polysubstance use.

The initial approach of blanket checks of vitamin D levels for all of our patients with hindsight was not the correct approach. It emerged during the project that some patients were not appropriate for vitamin D levels checks. We addressed these issues by reviewing case notes briefly prior to requesting vitamin D level check (to rule out hyperacute phase of illness) and excluded patients in ED, as there was not enough time to test and prescribe for these patients.

Initially, some vitamin D results were not pursued due to different team members being present on different days. A lesson learnt was to add a column to our team handover list which allowed all team members to be aware if there were outstanding vitamin D level checks to be followed up on.

The cost of vitamin D checks (≈£25 each) is significant. When the test is more expensive than the treatment, it must be questioned whether blind prescription of vitamin D is a better course of action. If we had adopted an initial strategy of prescribing and dispensing a loading regimen at first contact without testing, it is likely that our coverage would have been wider. The workload was undoubtedly higher because of the need to request testing and check the results.

Knowing a patient’s exact vitamin D level is useful as it informs clinicians on the optimum vitamin D dose for each individual patient. There is a stark contrast between the high dose needed to comprehensively treat very low vitamin D levels and the more modest supplementation for patients with milder vitamin D insufficiency.

The risk of overtreating patients is slim, but still must be considered in light of the potentially serious and irreversible cardiovascular and renal toxicity that can result from hypervitaminosis. One patient was found to have a high level of vitamin D and it later emerged that he had been taking over-the-counter supplements prior to admission. We cannot be sure that harm (damage from hypercalcaemia) would not have resulted from blindly loading this one patient with vitamin D. Safety could be improved by asking patients directly if they are taking over-the-counter vitamin supplements.

This QI project was carried out prior to the current UK national blood specimen bottle shortage. In August 2021, NHS England issued advice on reducing non-clinically urgent blood tests and specifically recommended that vitamin D testing is temporarily stopped, except in ‘very exceptional circumstances’.24

There was some disagreement between colleagues whether inpatient general hospital was the appropriate setting to address vitamin D deficiency, proposing that the responsibility for this should instead lie with general practice. A lesson learnt is for us all to recognise that, for this disadvantaged patient population who frequently have poor relationships with healthcare, hospital admission provides a rare opportunity to address these common physical health issues. Indeed, the patients we see are often poorly engaged with community services.