British drugmaker AstraZeneca said Friday it had agreed to buy US group ZS Pharma, a specialist in treating high potassium levels linked to kidney disease and heart failure, for $2.7 billion (2.5 billion euros).

"This acquisition complements our strategic focus on cardiovascular and metabolic disease by adding a potential best-in-class treatment to our portfolio of innovative medicines," AstraZeneca chief executive Pascal Soriot said in a statement.

On hyperkalaemia, or high potassium levels in the blood, he added that "the risk is underappreciated and prevalence is increasing".

ZS Pharma chief executive Robert Alexander said the deal, worth about 2.5 billion euros, would allow his company "to maximize the potential of (hyperkalaemia treatment) ZS-9, drawing on AstraZeneca's long-standing expertise in developing and commercializing medicines for cardiovascular and metabolic diseases".

AstraZeneca's announcement comes a day after it said group annual earnings were set to rise more than expected after a strong third-quarter.