Influence of demographic and clinical characteristics of elderly patients with a hip fracture on mortality: A retrospective, total cohort study in North-East Spain

Importance: The increased mortality after hip fracture (HF) is caused by multiple factors, and large samples are needed to assess the weight of each factor. To date, few studies have investigated these factors through a total cohort approach, and the complexity of underlying medical conditions has not been considered. Objective: To investigate the influence of demographic and clinical characteristics on increased mortality risk in elderly patients with hip fracture (HF). Design: Retrospective, total cohort study collecting 4-year data. Setting: All hospitals and primary care units owned by, or associated with, Catalonia's local health department (CatSalut) (north-east Spain). Participants: All patients aged >= 65 years, admitted to Catalan hospitals from CatSalut because of a HF between 1st January 2012 and 31st December 2015. Exposure: Hip fracture. Main outcome measures: The main outcome was survival. Measures regarding demographic and clinical characteristics at the moment of hospital admission included age, sex, osteoporosis treatment, previous fractures, type of intervention, nutritional status, and comorbidities. Patients were stratified using the Adjusted Morbidity Groups (GMA) risk assessment tool. Results: Of the 30,552 patients included in the study sample, 10,439 (34%) died during follow-up, 6821 (22%) within the first year after hospital admission. Mean (SD) age was 84 (7) years; 75% were female. Baseline factors with greater influence on survival were age (HRs 1.44 [95% CI 1.22-1.70], 2.38 [2.03-2.79], and 4.38 [3.73-5.15] for age groups 70-79, 80-89, and > 89, respectively), underweight (HR 1.65 [1.36-2.01]), lack of surgical intervention (HR 2.64 [2.47-2.83]), and very high risk stratum of GMA risk (HR 1.58 [1.45-1.73]). Vitamin D/calcium supplementation and osteoporosis treatment showed a significant but moderate influence on mortality (HRs 0.84 (0.79-0.88) and 0.92 [0.85-0.99], respectively). Conclusions and relevance: In elderly patients with HF, age and health status factors at hospital admission have the greatest impact on mortality risk after hospital admission. Our findings encourage a comprehensive intervention aimed at improving underlying medical conditions of HF patients.