However, following the introduction of the blood aldosterone/renin test, the reported values for this incidence from numerous publications in patients with or without hypokalaemia are about 10 per cent.
Therefore, the use of the word ‘unusual’ does not reflect current international opinion.
Conn himself was the first to suggest that primary aldosteronism could occur in patients without hypokalaemia and that the overall incidence for all hypertensives was relatively high. He quoted
20 per cent but recent investigators, using improved assay methods, obtain rather lower values. They are, however, still much higher [about 10 per cent] than the 1 per cent quoted by Dr Merriman.
The danger is that if this lower outdated value is generally accepted in the UK by GPs, many patients may not be successfully treated for their severe hypertension. Some clinical experts have even stated that primary aldosteronism is now the most treatable form of hypertension.
Professor James F Tait
Harrogate, North Yorkshire