Medical injuries sustained as a result of medical care affect nearly one in five older adults in receipt of Medicare, indicates research published online in the journal Injury Prevention.

Those in poorer health, or with underlying conditions or some level of disability, were most at risk, the findings suggest.

Previous research suggests that medical injury (adverse medical events) more commonly affect older adults and that the consequences tend to be more severe. But few studies have looked at the long term impact of these incidents across different healthcare providers, including hospitals; emergency departments; doctors' offices and other ambulatory care services.

The researchers analysed nationally representative claims data for more than 12500 Medicare recipients between 1998 and 2005. Their average age was 76.

At least one medical injury occurred in the care of almost one in five (19%) of the sample during the study period. Almost two thirds (62%) of these events occurred outside of hospital care.

Furthermore, the impact was relatively long lasting and was associated with higher death rates and medical costs. Almost twice as many of those who had experienced a medical injury died during the study period as did those who had not.

The risk of an injury was greater among older adults in poorer health, the findings indicated, perhaps reflecting the difficulties of managing complex healthcare needs in different services, suggest the authors.

"Overall, our findings indicate that [medical injuries] pose significant risk to the health and wellbeing of older Medicare beneficiaries, while the effects are observed long after the initial episode has concluded," they write.

The findings are particularly important, given public health efforts to improve patient safety, reduce costs, and improve transitions across healthcare settings following implementation of the Affordable Care Act, they add.