The Scottish Government said an assessment of patient safety was to take place at NHS Lanarkshire, led by NHS watchdog Healthcare Improvement Scotland (HIS).
It comes after the latest statistics on deaths – the hospital standardised mortality ratios or HSMR – were published, showing an 11.6 per cent drop in death rates across Scotland in the past five years.
But the statistics also revealed that Monklands Hospital in Airdrie and Wishaw Hospital had high rates at the start of this year.
Professor Jason Leitch, NHS Scotland’s clinical director, said he had now asked the watchdog to work with NHS Lanarkshire to examine its approach to patient safety.
“We expect all health boards to ensure patient safety is their top priority and the Scottish Patient Safety Programme (SPSP) has been working for over five years to deliver ways to make healthcare safer,” he said.
“Although a high HSMR is not by itself a definitive measure of the quality and safety of care, it serves as an important prompt for further investigation.
“Where HSMR suggests a potential issue, a health board must be able to demonstrate it is taking appropriate action to investigate and resolve any problems found to be causing a higher than expected HSMR, and it is reassuring that NHS Lanarkshire is already working on an action plan to address this.”
Mortality ratios are calculated by dividing the number of deaths within 30 days of admission to hospital by the predicted number of deaths, based on factors such as a patient’s age and severity of illness.
Overall, the mortality ratio for Scotland stood at 0.92 in January to March, up from 0.89 a year ago.
But at Monklands the rate rose from 0.94 to 1.38 in a year, while at Wishaw it went up from 0.89 to 1.10.
The Scottish Government said the review would help clarify if there were “any underlying issues which require additional support to be resolved”.
It said NHS Lanarkshire was already working on an action plan to improve patient safety, and would work closely with HIS on its assessment.
Although Monklands and Wishaw were the sites identified as having an above average HSMR rate, the assessment will also look at Hairmyres hospital in East Kilbride.
Dr Iain Wallace, medical director for NHS Lanarkshire, said: “Our priority is for patients to receive the highest quality of care every time and we have a clear focus on the provision of safe and effective patient care.
“We very much welcome the support and involvement of HIS to undertake an assessment of the local action plans we are progressing, along with their detailed review to identify any further improvement measures that can be implemented.”
Robbie Pearson, director of scrutiny and assurance at HIS, added: “We will carry out a rigorous and independent review of NHS Lanarkshire. Our work will be driven and underpinned by a commitment to improving the safety and quality of care for patients, and patient interests will be placed first at all times.”
The investigation is due to publish its findings before the end of the year.
Margaret Watt, chair of the Scotland Patients’ Association, said patients may be worried when they heard their hospital was being investigated for high death rates.
“We should be taking this much more seriously as these are lives that might have been saved,” she said.
“The buck has got to stop somewhere as this should not really be happening.”
The SPSP was set up with the aim of reducing hospital mortality by 15 per cent by December 2012. This was then extended to a 20 per cent reduction by December 2015.
Hospital mortality has shown a sustained reduction between 2009 and 2011, but ISD Scotland, which publishes the statistics, said the level since had remained “relatively constant”.