Diagnostic codes for GDPs in the UK

Diagnostic codes

Diagnostic codes are a means to record the findings and diagnoses for patients in a standardised manner and have been used in electronic health records for some time in the medical world. But dentistry has lagged behind with the only items being recorded those that are related to treatment.

Why record diagnostic codes? 

If we want to assess the suitability of patient management decisions - whether we are talking about diagnostic tests, prevention regimes, treatments or prognoses - we need to know what the decisions relate to.

Say a dentist writes in their notes that they have prescribed Amoxicillin 500mg TDS for 5 days and writes nothing else. We have no idea whether this is the appropriate way to manage whatever it was the patient walked in with. We need to know what diagnosis led to this prescription. Some dentists prescribe only when there is a risk of spreading infection or when incision and drainage of an abscess is impossible. Others prescribe when a patient has an irreversible pulpitis without opening the pulp chamber despite the lack of evidence to support this approach.

So we generally expect that a dentist will record a presenting complaint, the results of any investigations and their diagnosis. This is better note keeping but because we each come up with different terms and have different short hand ways of writing our notes it can be difficult to gather comparable information from many dentists.

So diagnostic codes have developed as a means to standardise the diagnoses given by clinicians to a limited set of terms. International organisations have come together to map these terms in different languages too, so that international comparisons can be made.

So what?

Well, it means that one can audit the practice of many hundreds of clinicians using computer records rather than wading through text trying to understand what people have done. QResearch in the UK now gathers data from 600 general medical practices in the UK, anonymises the data and allows researchers to assess, for example, the number of patients being prescribed the best medication for a given condition. This is possible because all the practices use the same set of terms for their diagnoses and for the treatment they prescribe. My understanding is that all the medical practice management systems use one terminology or another.

Unfortunately, though, the dental software companies in the UK don't seem to be doing this apart from EMIS Dental. (If I'm wrong please tell me as I'd love to know). A group of US dental schools are developing and using a terminology set and a recent conversation with a visiting American dental student suggests this is a routine of his practice.

SNOMED CT is the international terminology that last year incorporated the American Dental Association's dental terminology. This presentation identifies some others being developed in the US. If you want to have a look at how SNOMED CT works there are various free browsers that let you see, such as SNOFLAKE. The terminology can be incorporated into any software with a licence which, I believe, is free in the UK as a member of the International Health Terminology Standards Development Organisation.

I find this quite exciting - if we could persuade dental software companies in the UK to use the codes. It would mean that our dental electronic health records could be used to easily audit our own practice and to potentially create a massive research data set from general dental practice. This in turn could form the basis of large studies to inform us about the prognosis of teeth, the success or otherwise of common interventions and the efficacy of prevention when delivered in primary dental care.

A call to action

The NHS Connecting for health will require SNOMED CT to be part of any electronic health record used in NHS practice. I believe we should go further in dentistry as much of our work is being conducted outside of the NHS. So I call on UK dentists to begin pestering software developers to incorporate SNOMED CT into their systems and allow general dental practitioners to contribute not only to their own practice improvement but to more meaningful research conducted in primary dental care.

Diagnosing pulpal pathology

I spend a lot of time discussing diagnosis of pain originating from the pulp with students. We have mostly been brought up on making diagnoses of irreversible or reversible pulpitis based on signs and symptoms - spontaneous pain, length of pain, reaction to thermal stimuli, percussion, electric pulp testers, ethyl chloride, bladebladebla. And what I realised a while ago was that some of those teeth - based on these criteria - that I had determined as irreversibly damaged or non-vital actually turned out to respond well to simple temporary dressings without going anywhere near the pulp i.e. the inflammation in the pulp was actually reversible.

So I was pleasantly surprised to come across a systematic review that looks at the sensitivity and specificity of signs, symptoms and diagnostic tests commonly used to make decisions about whether a pulp is alive and well or ailing.

Diagnosis of the condition of the dental pulp: a systematic review

Of 18 studies, none were high quality according to pre-specified criteria, 2 were moderate and the rest were low quality.

Regarding signs and symptoms as indicators of the inflammatory status of pulp the authors concluded: "there is insufficient evidence to determine whether the presence, nature and duration of toothache offer accurate information about the extent to which dental pulp is inflamed. The evidence base is also insufficient to assess the accuracy of other commonly used clinical markers of pulp inflammation "

and with regard to sensibility and vitality testing they conclude: "there is insufficient evidence to determine the diagnostic accuracy of tests used to assess pulp vitality".

I think this is borne out by my experience and suggests that, with plenty of discussion with the patient, we take a conservative view in deciding whether a tooth needs to be opened up or extracted. It may be that, in the absence of a clear diagnosis, we are best temporising and warning the patient the pain may get worse.

One thing, however, is that this review did not take into account the use of radiographs. We often don't see apical changes with irreversible pulpitic teeth but a tooth that does not respond to sensitivity testing and that has an apical radiolucency plus a potential cause for pulpal necrosis (deep filling, caries, fracture) may be diagnosed more confidently as being non-vital.

Swans and differential diagnoses

Sir Karl Popper, swans, and the general practitioner -- Berghmans and Schouten 343 -- bmj.com

This BMJ article raises a really important point for all clinicians involved in making a diagnosis: we need to question our quick diagnoses and think of differential diagnoses if we are to be better able to help our patients. And we need to accept that we can be wrong, like all other humans, but be willing to change our decisions.

Diagnosis

What is a diagnosis? This question comes up regularly on the clinic.

I see this as the beginning of the management of a patient - an essential step in determining not only treatment but also prognosis. It is a label that categorises a patient to help us help them.

As such, I don't necessarily see a diagnosis as only something relating to what we would normally recognise as a 'disease', that is, caries, perio, apical abscess, etc. A diagnosis may relate to other problems the patient has:

1. orthodontic problem (e.g. crowding or increased overjet) 
2. aesthetic problem (e.g. a median diastema that causes this particular patient concern - a problem others might not see as such)  
3. functional problem (e.g. a lack of alveolar ridge, which results in problems retaining a denture)

A diagnosis does not necessarily mean we have to - or be able to - treat. There are pros and cons to most things and we would need to explain each to the patient. But by having a diagnosis we identify the problem and can agree it with the patient. Then we can work out how to manage it with the patient.