Incidence, clinical features and subtypes of delirium in elderly patients treated for hip fractures

OBJECTIVE: To describe the incidence, risk factors and clinical features (subtypes) of delirium during the postoperative period after hip fracture surgery in elderly patients. DESIGN: Prospective study. METHODS: Thirty-four consecutive patients (9 men and 25 women) were included in this study between June 16 to July 14, 2003. All patients underwent surgery for a fractured neck of femur and were pre- and postoperatively cared for at a combined geriatric/orthopedic ward. ASSESSMENT: The diagnosis of delirium was based on the criteria of the DSM-IV and the Confusion Assessment Method Scale. Subtypes of delirium were classified according to the criteria proposed by Lipowski: hyperactive-hyperalert (or agitated), hypoactive-hypoalert (somnolent) and mixed delirium. Results: Fifty-five percent (n = 19) of the 34 patients developed delirium after surgery. The development of delirium was associated with the medication midazolam taken perioperatively. Nine (47%) of the delirious patients had a hyperactive type of delirium; 5 (26%) developed a hypoactive delirium, and 5 (26%) had a mixed type. We did not find any association among subtypes of delirium and clinical features. CONCLUSIONS: Delirium is a common complication in the postoperative period of elderly patients treated for hip fractures. The use of midazolam in the perioperative period increased the risk of developing postoperative delirium. The hyperactive type of delirium was the most common subtype of delirium.