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Review BP drug monitoring guidelines, say researchers

NICE guidance on the monitoring of renal function in patients prescribed ACE inhibitors/angiotensin II reception antagonists (ARB) may need to be revised as they are not followed and adverse events are rare, concludes a new analysis.

The study

NICE and SIGN guidelines recommend that renal function should be checked before – and within – one to two weeks of initiation for ACE-inhibitors and ARBs. UK researchers looked at 4,056 patients with type 2 diabetes (mean age of 65.2 years) prescribed ACE inhibitors/ARB for the first time during a five-year period. For each patient, four outcomes were measured: pre-monitoring of renal function (measuring urea and electrolytes), post-initiation monitoring (measuring urea and electrolytes 5-14 days after drug initiation), and two adverse renal outcomes – hyperkalaemia and a rise in serum creatinine.

The results

Some 3,606 (89%) of patients were prescribed an ACE inhibitor at initiation, and the remaining 450 (11%) patients were prescribed an ARB. Urea and electrolytes were measured in 69% of patients during the 90 days preceding treatment and 27% of patients had their urea and electrolytes measured five to 14 days after drug initiation. The mean duration between drug initiation and first monitoring of urea and electrolytes was 68.8 days, with patients significantly less likely to have post-initiation monitoring if prescribed an ARB, compared with an ACE inhibitor. Of the 61% patients who had serum potassium measured after initiation, less than 2% patients developed hyperkalaemia. Of the 52% of patients who had serum creatinine measured after initiation, less than 2% patients developed a =30 increase in serum creatinine.

What this means for GPs

The researchers said ‘81% of patients initiated on ACE inhibitors/ARBs and considered to be at high renal risk by virtue of having diabetes were sub-optimally monitored compared to national guideline’ and suggest that ‘the low incidence of significant renal complications may be one reason why monitoring is relatively poor’. They added: ‘perhaps now is the time to consider whether current monitoring guidelines appropriately balance cost and benefit to both patient and the health service’ and that future large-scale studies should be conducted to assess this.

Scott Med J 2013 58: 69