Patients who suffered low-level traumatic injuries were at greatest risk of dying two to three weeks after being injured, according to study of European patients.

Published in the journal Computers in Biology and Medicine, mathematics professor Evgeny Mirkes and emergency medicine professor, T.J. Coates, MD, both of the University of Leicester, along with co-authors, examined more than 165,000 trauma cases.

The authors said for most trauma cases, the mortality risk decreases over time, but for less severe traumatic injuries, the risk increases with a longer hospital stay.

“This means that while the probability of dying for all trauma cases consistently decreases over time, there are peaks in the probability of death for those with less severe trauma who remain in a hospital at around 14 days and 21 days after admission,” Mirkes and Coates wrote.

The researchers said their examination of records found more than 19,000 trauma cases labeled “unknown outcome.” While Mirkes and Coates wrote that patients in those cases most likely alive, they stressed the need to develop methods to accurately include those results in studies in order to maintain accuracy in future studies.

“One of the reasons for data incompleteness is fragmentation, which is unavoidable due to the diverse structure of the health service,” the researchers said in a press release. “Although the problem of handling missed values in large healthcare datasets is not yet completely solved, the approach developed by the team of Leicester academics can be applied to various healthcare datasets which have the problem of lost patients, inter-hospital transfer, and missing outcomes.”