Doctors have to tell police when they see gunshot victims
Victims of knifings and shootings may be covering up how they got their injuries because of fears police will be called to hospitals, doctors say.
A group of A&E doctors told the Lancet about two cases when patients denied being shot despite scans showing bullets inside the body.
They said some inner-city A&Es were seeing knife and gunshot victims daily.
The medics also urged caution over compelling doctors to tell police when they treat victims of violence.
Doctors are currently required to alert the police when a gunshot victim is admitted to hospital.
Regulators are currently consulting over what to do over knife victims. The favoured option is leaving it to the judgement of medics on whether to call the police.
The three doctors featured in the Lancet, who work in hospitals in London and Glasgow, believe it is probably the right balance, but describe the issue of lying about injuries as worrying.
In one case outlined, a patient arrived at an A&E department with a chest injury saying he had fallen onto a blunt object.
A scan of the chest showed a bullet, but again the patient denied a firearm had caused his injury.
The patient was kept in overnight and the police alerted, but when the patient realised what was happening, he fled.
Dr Hazem Fallouh, who works at St Thomas' Hospital in central London, said: "I am not saying we should not alert the police when we treat these patients - in some cases there is a clear public interest in doing so.
"However, I think it is something we should be aware of and take into consideration where we can. We do not have to identify the person when we call the police and we should perhaps stress this to the patient."
But he also warned the practice was putting people at risk.
"An injury may look benign but we do not know what is going on inside. If patients do not feel they can be honest with us, then there is a problem and it could risk their health," he said.
"And that is before we consider the people who do not even come to hospital."
Martin Shalley, of the College of Emergency Medicine, said he had heard of similar cases.
"Knife and gun crime is something hospitals do find themselves dealing with, and when the victims behave like this it makes it much harder for hospitals.
"We have to be careful how we manage these situations. I would always talk to the patient and explain what and why I am doing something."
A spokeswoman for the General Medical Council, which issues guidance to doctors on when to alert police, said: "Patients have a right to expect that information about them will be held in confidence by their doctors.
"That duty is not absolute, however, and information may be disclosed in the public interest without consent."
The latest figures from both the British Crime Survey, which measures public experience of crime, and the police's recorded figures show violent crime is falling.
Nonetheless, the numbers of assault-related admissions hospitals have been dealing with have been rising and now stand at nearly 34,000 cases a year.