Clinical features

• renal failure, and look at recent electrolytes, urea and creatinine
• heart failure
• current medication: specifically ACE inhibitors, infusions, diuretics, NSAIDs, trimethoprim
• use of salt substitutes 

Why?

Abnormal renal function, ACE inhibitors and heart failure increase the risk of hyperkalaemia

Outcome b	Risk Factor	PEER	OR (95% CI)	NNH (95% CI)
K > 5.0 mmol/l	creatinine 137 µmol/l or more independent	11%	4.6 (1.8 to 12)	4 (2 to 14)
K > 5.0 mmol/l	use of long-acting ACE inhibitor (e.g. lisinopril or enalapril) independent	11%	2.8 (1.3 to 6.0)	7 (3 to 36)
K > 5.0 mmol/l	urea 6.4 mmol/l or more independent	11%	2.5 (1.5 to 4.4)	8 (4 to 22)
K > 5.0 mmol/l	congestive heart failure independent	11%	2.6 (1.4 to 5.1)	8 (4 to 27)
K > 6.0 mmol/l	aged > 70 independent	0.2%	5.4 (1.5 to 19)	140 (35 to 1200)
K > 6.0 mmol/l	urea 8.9 mmol/l or more independent	0.2%	4.5 (1.5 to 15)	170 (44 to 1200)

• Patients on loop or thiazide diuretics are at reduced risk of developing hyperkalaemia

Diuretic use reduces the risk of hyperkalaemia

Outcome b	Risk Factor	PEER	OR (95% CI)	NNH (95% CI)
K > 5.0 mmol/l	use of loop diuretic independent	11%	0.4 (0.2 to 0.8)	-16 (-51 to -12)
K > 6.0 mmol/l	use of thiazide diuretic independent	11%	0.4 (0.2 to 0.9)	-16 (-100 to -12)