Modifiable and non-modifiable risk factors in hip fracture mortality in Norway, 2014 to 2018

Abstract

Aims This study aimed to identify risk factors (patient, healthcare system, and socioeconomic) for mortality after hip fractures and estimate their relative importance. Further, we aimed to elucidate mortality and survival patterns following fractures and the duration of excess mortality. Methods Data on 37,394 hip fractures in the Norwegian Hip Fracture Register from January 2014 to December 2018 were linked to data from the Norwegian Patient Registry, Statistics Norway, and characteristics of acute care hospitals. Cox regression analysis was performed to estimate risk factors associated with mortality. The Wald statistic was used to estimate and illustrate relative importance of risk factors, which were categorized in modifiable (healthcare-related) and non-modifiable (patient-related and socioeconomic). We calculated standardized mortality ratios (SMRs) comparing deaths among hip fracture patients to expected deaths in a standardized reference population. Results Mean age was 80.2 years (SD 11.4) and 67.5% (n = 25,251) were female. Patient factors (male sex, increasing comorbidity (American Society of Anesthesiologists grade and Charlson Comorbidity Index)), socioeconomic factors (low income, low education level, living in a healthcare facility), and healthcare factors (hip fracture volume, availability of orthogeriatric services) were associated with increased mortality. Non-modifiable risk factors were more strongly associated with mortality than modifiable risk factors. The SMR analysis suggested that cumulative excess mortality among hip fracture patients was 16% in the first year and 41% at six years. SMR was 2.48 for the six-year observation period, most pronounced in the first year, and fell from 10.92 in the first month to 3.53 after 12 months and 2.48 after six years. Substantial differences in median survival time were found, particularly for patient-related factors. Conclusion Socioeconomic, patient-, and healthcare-related factors all contributed to excess mortality, and non-modifiable factors had stronger association than modifiable ones. Hip fractures contributed to substantial excess mortality. Apparently small survival differences translate into substantial disparity in median survival time in this elderly population. Cite this article: Bone Joint J 2022;104-B(7):884–893.

Change in 1-year mortality after hip fracture surgery over the last decade in a European population

“…An English report found a 30-day mortality risk of 1.2% during 2009-10 [25]. Like us, some of these more recent studies reported a higher 30-day mortality risk in males compared with females between 2010 and 2017 [11,24,26], while others found that male was not significant predictor in 2014 [20]. In the present study, the 30-day mortality decreased significantly from 2010 to 2020, despite an increase over time in the mean age of patients and their comorbidities.…”

“…The 1-year mortality is high over time in the literature, with risks about 29% in the 1960s [3], 23% in the 1980s [29], and 26% in the 1990s [7,28]. In the most recent studies, no significant changes in the last 20 years have been reported with risks maintained about 22% [2,6,11]. Like us, the most common predictors reported were male, age > 80 years, and Charlson index > 2 [30].…”

“…Nevertheless, mortality risks are influenced by various factors. Kjaerevik et al [11] included 18 factors in a study of mortality after hip fracture. Sheehan et al [31] identified 39 patient-factors that could be associated with mortality after hip fracture.…”

“…Sheehan et al [31] identified 39 patient-factors that could be associated with mortality after hip fracture. Compared with the general population of similar age and gender, hip fracture patients had 1-year mortality risk 16 times higher in females, and 12 times higher in males during the 1990s [32], with a SMR of 2.4 increased risk in females and 3.5 in males in 2010 [33], and of 3.5 for both genders in 2018 [11]. However, this decrease did not translate into increased survival as compared with that in the general population of similar gender and age.…”

“…Trevisan et al [6] reported no significant change in 1-year mortality from 2000 to 2016. Likely, Gjertsen et al [10] reported no significant change from 2005 to 2014, and Kjaervik et al [11] found small survival differences from 2014 to 2018. Conversely, Nordstrom et al [12] reported that short-term mortality increased during 1998-2017.…”