Current guidelines from the UK National Institute for Health and Clinical Excellence (NICE 2011) and the European Society of Hypertension and European Society of Cardiology (ESH/ESC 2013) recommend the use of ambulatory blood pressure measurement (ABPM) in the diagnosis and management of hypertension.^1,2

We aimed to follow up a previously undertaken study that reviewed ABPM use by one general practice over a three-year period from January 1, 2010 to December 17 2012.³ We reviewed the practice one year later, from November 1, 2013 to 31 October 2014, to identify improvements in practice adherence to NICE guidelines for clinical management of primary hypertension, and to understand why non-adherence persists in some cases.

All patients who had an ABPM recording were included in the study. We analysed practice ABPM records using NICE guidelines and identified all abnormal results. We then reviewed how patients with abnormal ABPM results were managed. Where management did not adhere to guidelines, we quantified the variance above guideline limits in millimetres of mercury (mmHg). Finally, we reviewed whether the clinical rationale for non-adherence to guidelines was documented in patient notes. 

A total of 110 patients were included in the review with 113 ABPMs performed in total. We found that 54.9% (n = 62) of ABPM results were abnormal; patient management was subsequently changed in 75.8% (n = 47) of these.  Thus, there was no change in management in 24.2% (n = 15) of abnormal cases. This represents a significant improvement over the original study, where 247 ABPMs were reviewed, 59.5% (n = 147) of results were abnormal, and no change in management was found in 45.6% (n = 67) of abnormal cases.³

Ambulatory blood pressure measurement

Ambulatory blood pressure measurement (ABPM) has become a cornerstone in clinical diagnosis and management of hypertension. We reviewed ABPM use in a large inner-city general practice in Dublin over a one-year period. Our aims were to identify improvements in adherence to NICE guidelines, following a previous study of practice ABPM use, and to identify reasons for non-adherence to guidelines, where this was the case.

Methods

We conducted an audit of patient records. The practice uses Meditech ABPM-04 hardware and Meditech software for 24-hour blood pressure monitoring and Socrates software for patient record management. We generated a report of all patients who had an ABPM carried out during the period November 1, 2013 to October 31, 2014. This included patient names and addresses, dates of birth, GMS eligibility, ABPM date and average daytime and night-time systolic and diastolic blood pressures.  

We interpreted ABPM data using NICE guidelines and identified all abnormal results. We then reviewed patient electronic records and reviewed the clinical decisions taken in cases of abnormal ABPM results.

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Results

A total of 113 patients had 117 ABPM measurements in the review period. Four ABPMs referring to three patients were excluded (less than 12 hours of data recorded n = 3; no results recorded n = 1). Thus, 110 patients and 113 ABPM measurements were eligible for the study. The male:female ratio was 45:55. The net GMS patient population was 54.5% (n = 60), the net GP visit card population was 5.5% (n = 6), with the remaining 40% being private patients (n = 44). The age profile is analysed in Table 2. Table 3 summarises ABPM results by age. Table 4 summarises how each of these cases was subsequently managed.

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Discussion

A comparison of results between our original audit and this review is shown in Table 5.

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While we were pleased with the increase in the number of patients who had a change in management following an abnormal ABPM (original audit: 54.4%; this review: 75.8%), we were initially disappointed with our finding that 24.2% of abnormal ABPM results were not managed in line with guidelines, and were curious to understand why this non-adherence should persist. 

With this in mind, we re-analysed our data to quantify the extent to which abnormal ABPM readings fell outside the accepted guideline range. 

Table 6 analyses the cases of abnormal ABPMs with no subsequent change in management, in mmHg above the upper limit of normal (NICE guidelines).

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In the < 80-year-old population, the variance was less than 10mmHg above the upper limit of normal in 93.3% (n = 14) of cases. The highest recorded variance was 10mmHg. In the high-risk elderly group (≥ 80 years old), all patients were managed in line with guidelines.

Thus, while there remained a significant (24.2%) subset of patients whose management did not adhere to guidelines, deeper analysis revealed that in each of these cases the variance was ≤ 10mmHg above the guideline upper limit. Furthermore, the clinical rationale justifying non-adherence was documented in the notes in 93.3% (n = 14) of cases.  

Our original audit discussed the prevalence of ‘clinical inertia,’ defined by Phillips et al as a ‘failure of healthcare providers to initiate or intensify therapy when indicated’.⁴ We recommended that clinicians should aim to minimise the influence of this phenomenon in their practice. The results above highlight the effect of actively employing clinical judgement when formulating patient management plans, as distinct from the more passive phenomenon of ‘clinical inertia’.

We noted that, in cases where the clinician did not adhere to guidelines, the abnormal ABPM result was described as ‘normal’ in the patient records in 53.3% (n = 8) of cases. This phrase reflects the fact that the variance was ≤ 10mmHg. We would suggest a more accurate descriptor such as ‘tolerable variance’ in such cases.

Value of clinical audit

This follow-up study of one general practice in Dublin examined whether management of patients with abnormal ABPM results adhered to NICE guidelines for clinical management of primary hypertension.

We found that 75.8% (n = 47) of abnormal ABPM results were managed in accordance with guidelines, an improvement of 21.4% over the original study, where 54.4% (n = 80) of cases adhered to guidelines.

Notably, where management did not adhere to guidelines, the variance above the upper limit of normal was never greater than 10mmHg, and the clinical rationale justifying non-adherence was documented in 93.3% of cases. All cases in the ≥ 80-year-old group were managed in accordance with guidelines.

This study highlights the value of a clinical audit in bringing about improvements in patient care. It also highlights how clinicians use clinical judgement to tailor guidelines to individual patient need. Quantifying the use of clinical judgement, as opposed to clinical inertia, is worthy of further study. 

References

1. National Institute for Health and Care Excellence. The clinical management of primary hypertension in adults. London: NICE, 2011. http://guidance.nice.org.uk/CG127/Guidance (accessed 30 March 2015).
2. Mancia G, Fagard R, Narkiewicz K, et al. 2013 ESH/ESC Guidelines for the management of arterial hypertension: Eur Heart J 2013; DOI: 10.1093/eurheart/eht151.
3. Maher J, Bates M, Carmody P. The effect of clinical inertia on the management of blood pressure. Br J Gen Pract 2014; DOI: 10.3399/bjgp14X680053
4. Phillips LS, Branch WT, Cook CB et al.  Clinical ine tia. Ann Intern Med 2001 Nov 6;135(9):825-34