By RONI CARYN RABIN

  NYT - March 8, 2010

Older people are more likely to suffer a decline in their cognitive abilities after being hospitalized for an illness than they would otherwise, a new study reports.

The study, published last month in The Journal of the American Medical Association, followed almost 3,000 people 65 and older for more than a decade. All of the participants lived in the Seattle area; none had dementia at the start of the study.

Those who were hospitalized for a critical condition like severe infection or cardiac arrest experienced a statistically significant drop in scores on a cognitive performance test given later, when compared with people who had not been hospitalized.

Those who had been hospitalized for a noncritical illness faced a statistically significant 40 percent increase in dementia after the hospitalization, when compared with those who had not been hospitalized.

While some of the cognitive impairment could stem from the illness itself, the researchers said, side effects of hospitalization and treatment could also play a role.

Low blood pressure, drugs like morphine, infections and systemic inflammation are among the many possible causes of decline after hospitalization, said the lead author, Dr. William J. Ehlenbach, senior fellow in pulmonary and critical care medicine at the University of Washington.