Cognitive Status at Hospital Admission: Postoperative Trajectory of Functional Recovery for Hip Fracture

BACKGROUND: Cognitive impairment is common in the hip fracture patient population, yet few studies of functional recovery include this subgroup. The objective was to determine whether baseline cognition was a determinant of the rate of functional recovery over 6 months after hip fracture. METHODS: A consecutive cohort of 383 patients 65 years or older who were treated for hip fracture within a Canadian health region were grouped on cognitive status. Participants with Mini-Mental Status Examination scores <18 at 3-5 days postoperatively were classified as cognitively impaired. Primary outcome was the Functional Independence Measure. Interviews were completed within 5 days postoperatively (baseline), 1, 3, and 6 months postoperatively. Linear mixed modeling examined the pattern of recovery and the effect of cognitive status. RESULTS: Of the 383 participants, 104 (27%) had Mini-Mental Status Examination scores of less than 18. The effect size for changes in the FIM over 6 months was large for those without cognitive impairment (effect size = 2.3) and smaller for those with cognitive impairment (effect size = 0.9). After adjusting for age, gender, proxy respondent, and fracture type, participants with impaired cognition recovered more slowly, never attaining comparable levels with those without cognitive impairment. The 6-month health status for the cohort was substantially lower than the health status of age-gender-matched, community-dwelling adults. CONCLUSIONS: Patients with cognitive impairment who fracture their hips recover more slowly and achieve less functional recovery. Recovery is not uniform nor is it linear over the initial 6 months. The diversity of patient needs should be recognized postoperatively so that long-term recovery is optimized.