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Table 5 Proposed mechanisms and mediators for the mortality effect of patient factors

From: Patient and system factors of mortality after hip fracture: a scoping review

Factor Mechanism Mediator
Age Aging reduces the reserve capacity necessary to cope with a double trauma of hip fracture and surgery [22, 37]. Hypothesis only
The number of chronic conditions increases with age [47, 70]. Extent of comorbidity
Sex Men present with more comorbidity than women [47, 54, 65, 68]. Extent of comorbidity
Men develop delirium [60], lung infection, pneumonia, and septicemia more often than women [54, 68]. Complications
Prefracture function Patients with poorer pre-fracture ambulatory status often have reduced cardiorespiratory function compared to those with better status [68]. Cardiorespiratory function
Patients with a high degree of dependency are more often delayed to admission than patients with a low degree of dependency [50]. Hospitalization delay
Patients with poor pre-fracture ambulatory status are quickly placed in nursing homes while patients with better status wait in hospital for rehabilitation beds [36]. Length of stay
Preadmission residence Institutionalized patients develop pneumonia and pressure ulcer more often than patients from community [54, 60]. Complications
Socioeconomic status Patients with low socioeconomic status are more often delayed to admission than patients with high socioeconomic status [50]. Hospitalization delay
Clinical stability Patients who are acutely unstable on admission are delayed to surgery more often than those who are stable [25, 39]. Surgical delay
Extent of comorbidity Multiple comorbidities diminish reserves for stresses of surgery and delays recovery [37, 38]. Hypothesis only
Patients with more comorbidity are delayed to surgery more often than those with less comorbidity [25, 48]. Surgical delay
Patients with more comorbidity are quickly placed in nursing homes while patients with less comorbidity wait in hospital for rehabilitation beds [36]. Length of stay
Body composition Patients with low BMI are more likely to develop adverse cardiac event post hip fracture surgery [66]. Complications
Patients with low BMI are more likely to be frail [66] and have diminished reserves to cope with the stress of surgery [38]. Hypothesis only
Patients with low BMI often have reduced cardiorespiratory function and a supressed immune system [38]. Immune response, Cardiorespiratory function
History of cerebrovascular accident Patients with hemiplegia often have more comorbidity and poor pre-fracture ambulatory status [68]. Extent of comorbidity, Pre-fracture function
Dementia Patients with dementia often have more comorbidity and poor pre-fracture ambulatory status [68]. Extent of comorbidity, Pre-fracture function
Diabetes Diabetes may lead to poor bone remodeling post hip fracture [52]. Bone remodeling [77]
Diabetes may lead to poor wound healing post hip fracture surgery [52]. Hypothesis only
Patients with diabetes may have poor glycemic control leaving the body prone to infections and complications after surgery [52]. Glycemic control [78] Complications
Malnutrition Patients with malnutrition often present with more comorbidity and poor pre-fracture ambulatory status.(16;38) Extent of comorbidity, Pre-fracture function
Myocardial infarction Patent foramen ovale allows procoagulant cell conjugates and fragments to pass directly from the venous to the arterial blood [37]. Hypothesis only
Secondary hyperparathyroidism Patients with secondary hyperparathyroidism often have more comorbidity [51]. Extent of comorbidity
Secondary hyperparathyroidism leads to severely altered calcium homeostasis [32]. Calcium homeostasis