No decline in cognitive function in older patients two months after a fracture of the extremities.

Abstract

To the Editor: Impaired cognition is observed frequently in older patients admitted to a hospital. Cavanaugh and Wettstein found that 28% of a random sample of hospital patients evidenced cognitive dysfunction on the Mini-Mental Status Examination (MMSE).1 Older patients with fractures of the extremities are especially at risk of developing neuropsychological problems.2,3 It is unclear whether cognitive impairment in older hospital patients with injury to the extremities will disappear over time. On the one hand, neuropsychological dysfunction may be the result of factors associated with hospitalization (e.g., psychological stress, sleep disturbances, or the use of medication acting on the Central Nervous System). This would mean that impaired cognition will disappear after discharge from the hospital. On the other hand, neuropsychological problems may also be attributable to brain damage caused by surgery and anesthesia. In this case, cognitive impairment could be more permanent. To gain more insight into the duration of cognitive dysfunction in older patients with fractures of the extremities, we decided to compare the cognitive function of older patients, measured 2 months after injury to the extremities (i.e., after discharge from hospital), with their prefracture function. This investigation is part of the Groningen Longitudinal Aging Study (GLAS).4 In 1993, more than 5000 older people from the patient panels of 12 family physicians were interviewed and administered the short version of the MMSE.5 GLAS participants who sustained injury to the extremities after the baseline, were invited for a second interview 2 months postinjury. The shortened MMSE was also administered during this interview. By the end of 1996, 166 patients had entered the study. Fifty four of them had been hospitalized because of a fracture. Baseline and postfracture cognitive function was available for 46 of these patients. Mean (SD) age of the patients was 72.9 (8.1) years. There were 32 women and 14 men. Twenty-two patients had sustained a broken hip, and the others had mainly wrist and ankle fractures. Mean (SD) baseline score on the short MMSE was 11.0 (1.1), mean (SD) postfracture score was 10.9 (1.3). A paired t test shows that this difference is not statistically significant (t = .5, df = 45, P = .622). We were unable to find a decline in cognitive function 2 months after a fracture of the extremities. This suggests that impaired cognition in older patients admitted to a hospital for injury to the extremities is often caused by factors related to hospitalization. Stress and anxiety, sleep disturbances and/or psychotropic drugs (e.g., benzodiazepines, corticosteroids, anticholinergics etc.) seem to be responsible for the high prevalence of cognitive dysfunction in this patient group. Note that our study does have one limitation. The MMSE is a somewhat crude measure for assessing cognitive function. Using more sensitive neuropsychological tests may yield evidence for lower cognitive function 2 months after a fracture of the extremities.