The speed with which hospitals operate on patients with broken hips can have an "enormous" bearing on their chances of survival, suggests new figures.
Hip operations are common, but many patients die soon after
In some English hospitals patients can be four times more likely to die than in others, said the report, published in The Times.
An analysis of Department of Health data found many hospitals failed to operate within the target of 48 hours.
Patients were 60% more likely to die if they waited more than 24 hours.
One tenth of the 30,000 people who broke a hip every year died within a month, and one quarter within six months.
The cause of death was usually pneumonia or infection, according to the report.
But the Department of Health rejected the claim that waiting times had the impact on death rates the analysis claimed.
It argued patients with broken hips were often made to wait because they were too frail to undergo immediate operations.
It claimed the research - in which health company Dr Foster looked at hospital performance in England between April 1999 to March 2002 - did not take into account more recent improvements.
According to the Times, the safest place to break a hip was Weston-super-Mare in Somerset and the most risky were Southampton, and St Helens in Merseyside.
Surgery should ideally take place within 24 hours, according to the guidelines, but only a few hospitals manage it within two days.
Help the Aged told the newspaper the report provided yet more proof of a "postcode lottery" in the NHS.
Dr Tricia Woodhead, medical director at Weston General Hospital - which operates on 86 of its hip patients within 48 hours - said they had a system of fast-tracking people through the emergency department and up to the wards.
She said: "We tried to streamline how patients come in through A&E.
"There is a pretty rapid diagnosis - has this patient a broken hip or not?"
More than a third of hip break patients in Southampton waited longer than two days for an operation.
The Southampton trust said it was working hard to improve, by appointing more specialist medical and nursing staff, introducing a system to prioritise highest-risk patients and expanding operating theatre capacity and opened extra beds.
The Department of Health told the Times it had set up a programme to look at hip fractures, and was already seeing improvements.