The study looked at areas such as patient rights and information, IT, waiting times, outcomes, the range and reach of services and access to new drugs.
NHS Confederation policy director Nigel Edwards said: "The Euro Consumer Health Index should carry its own health warning pointing out that anything but the broadest comparison using their figures is meaningless.
"The figures take different data collected in different ways from health services that do not even offer the same range of services."
"At the same time, no account is taken of whether people have to pay for some services or not."
Mr Edwards said: "Everyone involved in the NHS knows that it needs to improve but these figures have little to add in helping that process."
While the UK performs well on patients' rights and information, unlike Denmark and the Netherlands there has not been improvement across the board.
Euro Health Consumer Index director Dr Arne Bjornberg said the UK risks "raising expectations that the healthcare system cannot deliver".