Delirium motor subtypes in elderly hip fracture patients: risk factors, outcomes and longitudinal stability

Delirium is often accompanied by changes in motor activity but the longitudinal expression of these features and etiological and prognostic significance of clinical subtypes defined by motor activity is unclear.

This is a prospective cohort study of elderly patients undergoing hip fracture surgery. Baseline characteristics were assessed preoperatively. During hospital admission presence of delirium was assessed daily according to CAM criteria. This study compared baseline characteristics and outcomes according to a longitudinal pattern of motor subtype expression (predominantly hyperactive, predominantly hypoactive, predominantly mixed, no motor subtype and variable). Motor subtype categorization was performed with the DRS-R98. We also investigated the longitudinal stability of motor subtypes across the delirium episode.

62 patients had experienced in-hospital delirium postoperatively. The full course of the delirium episode could be defined for 42/62 (67.7%) patients. Of the patients with multiple days of delirium only 4/30 (13.3%) patients had a consistent motor subtype profile throughout the delirium episode, while 26/30 (86.7%) patients had a variable course. Of the patients with multiple days of delirium, 5/30 (16.7%) were predominantly hypoactive in profile, 7/30 (23.3%) predominantly hyperactive, 6/30 (20%) predominantly mixed, 1/30 (3.3%) had no motor subtype and 11/30 (36.7%) had a variable profile. Baseline characteristics and outcomes did not differ between the groups.

The majority of elderly hip fracture patients in this homogenous sample experienced variable expression of motor subtype over the course of their delirium episodes. The subtype categorization according to dominant motor subtype across the delirium episode identified groups with similar characteristics and outcomes.