Rise in baby deaths on Letby’s ward was ‘not surprising at all’
THE spike in baby deaths at the hospital where Lucy Letby worked was not surprising, a leading statistician has said.
Letby, 35, was convicted of murdering seven babies and the attempted murders of seven others at the Countess of Chester hospital between 2015 and 2016. The investigation began after doctors noticed an uptick in “inexplicable” deaths in the neonatal unit, with nine deaths in 2015 rather than the usual average of two. There was also a rise the following year.
This spike, combined with a chart showing Letby was on shift when every child died at the unit over a 13-month span, was critical evidence in her trial. She is serving 15 whole life terms in prison. Statisticians have since questioned the veracity and validity of both of these pieces of evidence.
Prof Sir David Spiegelhalter, emeritus professor of statistics at the University of Cambridge, told the Thirlwall Inquiry yesterday that a spike in neonatal deaths of the scale which occurred at the Countess of Chester hospital in 2015 would be expected to happen around once a year nationally.
He was involved in the analysis for the inquiry into deaths of babies with heart disease at Bristol Royal Infirmary and he was also part of the statistics team for the Harold Shipman inquiry.
Prof Spiegelhalter told the inquiry that data from the MBRRACE-UK system which monitors maternal deaths, stillbirths and neonatal deaths showed the Countess of Chester hospital’s neonatal ward to be the worst of its kind in 2015, which was when Letby was working on the ward.
There are about 150 neonatal units in the UK and around 39 which are of the same size as the Countess of Chester hospital, with between 2,000 and 4,000 births a year.
The Countess of Chester experienced nine deaths in 2015 according to MMBRACE data, Prof Spiegelhatler told the inquiry, with a crude death rate of 2.96 deaths per 1,000 births.
“It was the highest in its tier of centres,” he said. “But only just, Blackpool has eight deaths compared to the Countess of Chester’s nine.”
His analysis of data also showed that when accounting for other factors such as ethnicity and prematurity of the birth, the Countess of Chester unit was also the highest among similar units. “MBRRACE identified the Countess of Chester as having higher rates [of neonatal deaths] in 2015 and 16,” he said.
“It was highest in its tier but that would not be considered generally an outlier, but it would be sufficient to generate a signal and alert warranting investigation.”
He added: “Numbers have gone up but just because numbers have gone up does not mean, necessarily, that there’s a special cause for it. It’s important to give it that context. This is a surprising event within the Countess of Chester but from a national level, this is not very surprising at all. We would expect this to happen every year somewhere.”
The public inquiry, chaired by Lady Justice Thirlwall, is hearing its final week of evidence.
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