Most hospitals could increase the amount of day surgery they do by up to 15 per cent, according to health data analysts.

The claim comes out of a new research by healthcare information company CHKS, which found trusts that take on more day surgery cases do not end up with higher rates of patients staying overnight in hospital.

The analysis turns the common assumption that more day cases always mean more inpatients on its head and shows there is scope to increase day surgery in English hospitals.

“The assumption is that higher day case rates mean higher conversion rates because you’re taking on more marginal day cases and end up having to keep people in overnight,” said Paul Robinson, head of market intelligence for CHKS.

“But what the data shows is that the opposite is true. My interpretation is that those hospitals that have put a lot of effort into improving day case rates have worked hard on the whole pathway so actually end up with less conversions.

“This is about both clinicians and managers working hard to get the pathway right and shows the benefits of giving this some focus and attention.”

CHKS carried out the analysis as part of its 2012 Top Hospitals programme using data from the British Association of Day Surgery’s directory of day surgery.

It found trusts with higher than average day surgery rates yet lower than expected numbers of conversions.

At the other end of the scale one trust with a relatively low day case rate had three times as many conversions than the norm.

“The majority of trusts could increase their day case rate by 10 to 15 per cent without increasing conversions if they did it as well as the good performing ones,” Mr Robinson told HSJ.