Hip fracture in patients with cognitive impairment : Epidemiology and Patient-Reported Outcome Measures. Data from the Norwegian Hip Fracture Register

Abstract

Norway has one of the highest incidences of hip fractures in the world. Every year around 9000 persons are operated for a hip fracture. The mean age of the patients is over 80 years and this injury is often accompanied by important consequences and sequelae for the patient. There are different types of hip fractures and there are different methods of surgery. The Norwegian Hip Fracture Register (NHFR) has registered most hip fractures operated in Norway since 2005. The orthopaedic surgeon fills in a form reporting fracture type, operation method, operation time, complications, choice of implants and information on the patient, including cognitive function. Any reoperation is registered using the same form. The NHFR receives information on deaths from the National Population Register and analyses end with emigration or death (or at the end of a study). After four, 12 and 36 months, the NHFR sends questionnaires to the patients with questions on health-related quality of life. About a quarter of hip fracture patients have cognitive impairment. Cognitive impairment is defined as a decline in cognitive functioning beyond normal ageing. Cognitive impairment is more common with older age. The aim of this thesis was to compare hip fracture treatment in patients with and without cognitive impairment, using data from the NHFR. In Paper I we validated orthopaedic surgeons’ assessment of cognitive impairment of hip fracture patients, using information in quality databases where geriatricians had assessed cognitive function, as the gold standard. We found that the orthopaedic surgeons had an acceptable assessment of hip fracture patients with cognitive impairment. In Paper II we found the prevalence of cognitive impairment in hip fracture patients to be 27%. There were no differences in types of hip fractures or in treatment of the different types according to cognitive function. However, when analysing reoperations, we found differences based on cognitive function. There were more reoperations due to dislocation of hemiarthroplasty in patients with cognitive impairment, particularly when a posterior approach was used. Uncemented hemiarthroplasties had a higher risk of revision due to periprosthetic fracture in patients with cognitive impairment than in those without cognitive impairment. There were few revisions to total hip arthroplasty (THA) in patients with cognitive impairment. Mortality was higher in patients with cognitive impairment. After 30 days, 13% of patients with cognitive impairment had died compared to 4.6% of non-cognitively impaired patients. After one year, 38% of cognitively impaired patients had died compared to only 16% of the patients without cognitive impairment. In Paper III we analysed data on health-related quality of life in hip fracture patients according to cognitive impairment. Most hip fracture patients had a decrease in health-related quality of life after the hip fracture. There were large differences in quality of life both before the fracture and four and 12 months postoperatively. In hip fracture patients with cognitive impairment there was an increase in those confined to bed from 2% preoperatively to 14% 12 months postoperatively. In patients without cognitive impairment, the corresponding increase was from 0.8 to 1.9%. We found that only 28% of hip fracture patients with cognitive impairment returned to pre-fracture functioning, compared to 33% of patients without cognitive impairment, one year after surgery. The conclusions of our studies were that orthopaedic surgeons had an acceptable ability to identify and report cognitive impairment in hip fracture patients. Presence of cognitive impairment did not influence the choice of surgical treatment of these patients. The reoperation rates varied according to cognitive impairment. Mortality was higher in patients with cognitive impairment and health- related quality of life lower.