Dr Nigel Watson explains how he identified hypertensive patients in his practice audit, in response to a reader's query


I was very disappointed to read the article about a hypertension audit carried out by Dr Nigel Watson (Guidelines in Practice, August/ September 2000, Vol 3).

It would appear that simply checking his computerised records for patients with the code for hypertension is enough for Dr Watson to accept that his practice has 100% of patients with hypertension registered. He is fortunate that in his practice less than 6.5% of the population suffer from hypertension and that the rule of halves does not apply to his patients.

I would recommend a slightly more difficult exercise – such as the one we used in our practice when trying to find out how the rule of halves applied to us. We looked for patients on diuretics and then went through the notes to find out how many of them were on the medication because they suffered from hypertension, how many had the diagnosis in the summary and how many were checked and well controlled.

It was amazing to see how many patients took diuretics without knowing what they were taking them for, and how the diagnosis was not even made by the prescribing doctor in some medical records.

Dr P Millares-Martin, GP, Leeds

Dr Nigel Watson replies:

My article contained only the essential information for the audit. Perhaps some of the background information would reassure Dr Millares-Martin.

The audit looked specifically at patients aged 75 years or less. This identified 810 patients. If patients aged more than 75 years are included, the total number of hypertensive patients is 1488.

With a total list size of 12400, this would mean that approximately 12% of the practice population have been identified as having hypertension, which is consistent with published data.1,2

The practice has used computerised patient records exclusively for more than 10 years. All medications added to the computer are linked to a diagnosis. I was therefore able to identify the condition for every prescribed medication.

As part of the first audit I looked through all 810 sets of computerised patient records. By doing this I was able to identify the reason for the medications and also to confirm the diagnosis of hypertension.

I am certain that a number of our patients are walking around with undiagnosed hypertension. We are trying to identify as many of these as possible by checking blood pressure readings whenever we can.

Dr Nigel Watson, GP, Hampshire

  1. Whelton PK. Epidemiology of hypertension. Lancet 1994; 344: 101-6.
  2. Ramsay LE, Williams B, Johnston GD et al. British Hypertension Society Guidelines for Hypertension Management 1999: summary. Br Med J 1999; 319: 630-5.

I was very impressed by Dr Nigel Watson's hypertension audit. I am preparing a similar audit for my practice and would be grateful if Dr Watson could send me his hypertension protocol to assist my audit.

Dr VR Patel, GP, Sheffield

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Guidelines in Practice, November 2000, Volume 3
© 2000 MGP Ltd
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