United Kingdom. A group of doctors in the UK conclude that monitoring of renal function in patients treated with angiotensin-converting enzyme (ACE) inhibitors remains inadequate and cases of uraemia still commonly occur.

They suggest that guidelines for appropriate monitoring of renal function may help to minimize the problem.

The doctors undertook three separate studies to investigate the adequacy of renal function monitoring in patients taking ACE inhibitors in primary care and the impact of hospital admission for uraemia related to use of the drugs: 1) a postal questionnaire sent to 400 general practitioners; 2) 162 patients treated with ACE inhibitors in a general practice; and 3) 135 patients admitted to a regional renal unit with uraemia.

1) 277 of the 400 general practitioners replied to the questionnaire, of whom 235 (85%) checked renal function before initiating ACE inhibitor treatment, but only 93 (34%) checked it after treatment had started. Forty-two general practitioners admitted not having assessed renal function at any stage.

2) In 122 of the 162 patients treated with ACE inhibitor in a general practice, the treatment had been initiated by the general practitioner. 55 patients had renal function monitoring before treatment and 35 had repeated monitoring after starting treatment.

3) During a 12-month period, the researchers found that of 135 patients admitted with uraemia to a regional renal unit, ACE inhibitors were causally implicated in 9 cases (7%). Eight patients had received ACE inhibitors for more than six months, but only four had renal function checked before treatment. No patients had renal function monitored after treatment was started. Although 8 patients survived, the mean hospital stay was 21 days.

The researchers recommend that patients should be screened for risk factors predisposing them to uraemia (e.g. old age, peripheral vascular disease, low cardiac output, or concomitant treatment with NSAIDs or high dose diuretics). Renal function should be checked before and seven to ten days after treatment is started in all patients and thereafter regularly (e.g. annually) only in those with risk factors. Most importantly, renal function should be assessed in all patients, especially the vulnerable, at times of relevant intercurrent illness.

References:

1) The Pharmaceutical Journal 262, p. 149, 30 January 1999.
2) Kalra PA, Kumwenda M, MacDowall P et al. Questionnaire study and audit of use of angiotensin converting enzyme inhibitor and monitoring in general practice: the need for guidelines to prevent renal failure. British Medical Journal 318: 234, 1999.