There was a large disparity in A&E attendances
Separate health policies within England, Wales, Scotland and Northern Ireland are leading to wide differences for patients, it is claimed.
A Health Service Journal analysis found differences in emergency and planned hospital admissions and A&E visits.
However, the NHS Confederation - which represents managers - said it was not clear whether the NHS was better or worse in any of the nations.
The Department of Health said devolved administrations had to set priorities.
The handover of NHS control from Whitehall to the Welsh and Northern Irish assemblies and the Scottish Parliament led to obvious differences in health policy.
In Scotland, the government moved to make personal social care free; in Wales, prescription charges were scrapped, while in England the focus was heavily on waiting times for appointments, operations, and even in A&E.
The latest statistics, compiled by healthcare information firm CHKS, suggest that the differences now run deep, affecting some of the most basic indicators of health service performance.
In England, there was an increase of 37% in A&E attendances between 2004 and 2007, while this rose by only 3% elsewhere.
The rate of emergency admissions to hospital - used by some analysts as a sign of issues with access to primary healthcare - was higher in Wales than the other nations, and continues to rise.
In Northern Ireland, far fewer of these emergency admissions were discharged in less than one day, compared with England.
Overall, however, the number of planned admissions to hospital in Northern Ireland was high - 51% higher than the rate in Wales.
However, the devolved governments were quick to point out that the underlying causes of these statistics might be far more complex than simple policy differences.
The Welsh Assembly said a high rate of emergency admissions was due partly to a long history of chronic ill-health among the population, in an area dominated by heavy industry.
In Scotland, a government spokesman said a fall in patients given their surgery and discharged the same day might be the result of a shift of less complex procedures in community surgeries and clinics.
And the Northern Ireland health department said that its higher rate of planned surgery was aimed at reaching "challenging" waiting time targets.
A spokesman for England's Department of Health said: "It is right and proper for each NHS to use its own policies and standard operational procedures to meet the differing needs of their national populations."
Jo Webber, from the NHS Confederation, said the statistics did not give the whole picture of the "NHS experience" across the UK.
"It shows that the systems are different, but not necessarily better or worse."
The most important ingredient was overall quality of care, and this was not covered by this research, she said.
"We have four diverging systems, but they are still trying to deliver the same thing.
"If you were to look at similar statistics within England, you would find differences in the way the NHS worked in different areas, for example in an urban and a rural area."