Audit of use of ACE inhibitors and monitoring in general practice
BMJ 1999; 318 doi: https://doi.org/10.1136/bmj.318.7199.1697 (Published 19 June 1999) Cite this as: BMJ 1999;318:1697
Guidelines on monitoring, on their own, are not sufficient
- Nick Freemantle, Senior research fellow,
- James Mason, Senior research fellow,
- Martin Eccles, Professor of clinical effectiveness
- Medicines Evaluation Group, Centre for Health Economics, University of York, York YO10 5DD
- Centre for Health Services Research, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4AA
- Department of Renal Medicine, Hope Hospital, Salford M6 8HD
- Royal Preston Hospital, Preston PR2 9HT
- Department of Renal Medicine, Glan Clwyd Hospital, Rhyl LL18 5UJ
- National Primary Care Research and Development Centre, University of Manchester, Manchester M13 6PL
EDITOR—Kalra et al's paper describing an audit of monitoring renal function in general practice suggests that practice is often less than optimal, although associated with some uncertainty.1 Unfortunately, the authors do not give confidence intervals around their estimates of effect—which we provide here. The fact that only 34% (95% confidence interval 28% to 39%) of practitioners checked renal function after initiating angiotensin converting enzyme inhibitors and 15% (11% to 19%) never checked it is an important finding. We disagree, however, with the authors' conclusion that producing guidelines on monitoring, on its own, will lead to an improvement in practice.
The authors state that renal monitoring has been neglected in recent guidelines and cite the North of England evidence based guidelines on the use of angiotensin converting enzyme inhibitors in primary care (to which we contributed) as an example of this.2 They recommend that “renal function should be checked before and 7-10 days after treatment is started in all patients and thereafter regularly (for example, annually) only in those with risk factors.” Rather than neglect the issue of monitoring, the North of England Guidelines Group prioritised it. The Agency for Health Care Policy and Research also prioritised it in its guidelines on heart failure,3 on which this section of the North of England guidelines drew explicitly.
The North of England guidelines recommend that “before initiation of angiotensin converting enzyme inhibition … [patients] should have their blood pressure, renal function, and serum potassium measured. These measurements should be repeated one week after initiation of treatment and again one week after each significant increase in dosage.”2 The guidelines go on to suggest monitoring of serum creatinine concentration at least annually in all patients and describe specific criteria for patients who develop renal insufficiency. Thus they actually propose monitoring standards more stringent than those suggested by Kalra et al, although it is acknowledged that no basis for recommending one monitoring period over another could be found. The evidence base is limited, although a recent small trial suggests that complications are rare.4
Merely publishing guidelines on monitoring seems insufficient if even those citing the guidelines do not recall the recommendations. More active strategies, perhaps through computerised reminders built into prescribing systems, are required; on the basis of Kalra et al's paper they should be developed with some urgency.
Authors' reply
- P A Kalra, Consultant nephrologist (phil{at}ren.srht.swest.nhs.uk),
- P MacDowall, Specialist registrar in renal medicine,
- M Kumwenda, Associate specialist in nephrology,
- M O Roland, Director of research and development
- Medicines Evaluation Group, Centre for Health Economics, University of York, York YO10 5DD
- Centre for Health Services Research, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4AA
- Department of Renal Medicine, Hope Hospital, Salford M6 8HD
- Royal Preston Hospital, Preston PR2 9HT
- Department of Renal Medicine, Glan Clwyd Hospital, Rhyl LL18 5UJ
- National Primary Care Research and Development Centre, University of Manchester, Manchester M13 6PL
EDITOR—Although awareness of the possibility of serious uraemic complications of angiotensin converting enzyme inhibitors dates back over a decade,1 we found that such complications are still frequently encountered in certain parts of the United Kingdom and are concerned by this.
Although non-evidence based recommendations for monitoring renal function are available,2 we are worried that one key area of monitoring is often neglected, both in the literature and by doctors supervising the care of patients receiving angiotensin converting enzyme inhibitors. This concerns patients who become highly dependent on their renin-angiotensin-aldosterone axis to maintain glomerular filtration because of an intercurrent illness or event (for example, an increase in diuretic dose) accompanied by renal hypoperfusion.
The most vulnerable patients are elderly patients with heart failure (and consequent baseline renal hypoperfusion) receiving diuretics who then have a common illness such as pneumonia, gastroenteritis, or even flu.3These are the patients most likely to develop uraemia related to their angiotensin converting enzyme inhibitor and indeed are the group whom we see in the renal service. No current guidelines or recommendations emphasise the need to monitor these patients carefully at the time of their intercurrent illness; their renal dysfunction would not, therefore, be identified by the application of existing monitoring protocols.
As well as wishing to see this deficiency rectified by the development of an appropriate evidence based guideline we would echo Freemantle et al's call for more active strategies that would consolidate doctors' awareness of the need to monitor renal function more judiciously in their most vulnerable patients. Angiotensin converting enzyme inhibitors provide excellent benefits to many patients; more attention to monitoring renal function, with a consequent increase in doctors' confidence, might paradoxically lead to a desired increase in the use of these agents.