A NEW study has revealed significant regional differences across Scotland in patients undergoing hip and knee replacements and cataracts surgery on the NHS.

Patients living in Inverclyde, covered by NHS Greater Glasgow and Clyde health board, were the least likely to undergo an elective primary hip replacement last year.

Rates were also significantly below the Scottish average in the Glasgow city area.

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Overall, residents of the Western Isles - which had the highest rate of hip replacements - were around twice as likely as people living in Greater Glasgow and Clyde health board area to undergo the procedure.

Knee replacements were least common among people living in East Renfrewshire, which also falls within the NHSGGC umbrella, with fewer than one for every 1000 residents.

However, the breakdown by health board shows that NHS Grampian had the lowest overall rate for the procedure at 102.4 per 100,000 compared to 106.2 per 100,000 in NHSGGC.

Rates for cataracts surgery varied from a peak of around five for every 100 people in Inverclyde to a low of around two per 100 people in Moray, which is covered by NHS Grampian.

The health board had the second lowest rate of cataracts surgery provision in Scotland, after NHS Shetland.

All figures were standardised to take into account variations in age and other demographic factors.

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The findings emerged in the first ever 'Atlas' examining the so-called postcode lottery in the provision of some routine health services, published by the Scottish Government statistics body ISD Scotland.

The research was commissioned as part of the Realistic Medicine agenda in order to identify pockets of potential over- and under-treatment.

It was stressed, however, that significantly lower or higher than average rates are not necessarily bad, nor that the Scottish average is necessarily ideal.

A summary of the Atlas review states: "Data which show variation in interventions do not tell us whether services are good or bad.

"No one knows the right rate of hip replacements, cataract operations, MRI examinations or antidepressant prescriptions, for example.

"The right level of an intervention, sometimes called the 'warranted level', must be determined by clinicians discussing variation to understand the reasons for it.

"Only by discussing variation together can we decide whether that variation is warranted or not.

"Where clinicians agree that the variation is unwarranted, they must seek to find, agree and implement solutions to tackle it."

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The data will be used to identify "unwarranted variation" and steps to tackle it.

It added that over-treatment should be avoided as much as under-treatment, stating: "When we talk about 'harm' in healthcare we tend to focus on harm from missed diagnoses or under-intervention.

"Although this is very important, we must not lose sight of the fact that there may be 'hidden harm' involved in over treatment and excessive interventions."

An NHS Grampian spokesman said: “We are aware that some people have to wait longer than we would like for some procedures and we apologise for that. We would like to reassure patients that those in need of urgent treatment will always be seen as a matter of priority."