Pre-operative factors associated with increased mortality in elderly patients with a hip fracture: A cohort study in a developing country

Abstract

Background: Hip fractures are a public health problem worldwide, and several factors are involved with post-operative mortality. The aim of this study was to identify the pre-operative factors associated with increased mortality in elderly patients with hip fractures in a developing country during the first post-operative year.

Methods: An ambidirectional cohort study was conducted with patients ≥ 65 years of age who underwent hip surgery due to a hip fracture caused by a fall from a standing position. Socio-demographic data, time to surgery, and comorbidities measured by the Charlson Comorbidity Index (CCI) were recorded. One-year mortality from all causes was the primary outcome, and 30-day and 6-month mortality were the secondary outcomes. Log-rank test was used to evaluate survival, and Cox's proportional hazard regression was used to detect the factors associated with increased mortality.

Results: 478 patients who underwent hip surgery were included in this study. The mean age was 80.2 ± 9.9, and 297 (62%) were females. There were 150 (31.4%) deaths at the end of the first follow-up year, and the mean of surgical delay was 8.8 days ± 6.4. Patients who underwent surgery during the first 4 days (Log-rank test < 0.001) after hip fracture occurred and patients with a CCI ≤ 2 (Log-rank test < 0.001) showed better survival (90%), comparing to mortality (52%) of patients with a CCI ≥ 3 and surgical delay > 4 days. The age ≥ 80 years (Hazard ratio 2.55 (HR), 95% confidence interval (CI) 1.70 to 3.84, p < 0.001), CCI ≥ 3 (HR 1.61, 95% CI 1.14-2.26, p 0.006), surgical delay > 4 days (HR 2.41, 95% CI 1.38-4.21, p 0.006), and haemoglobin < 10 g/dl (HR 1.51, 95% CI 1.06-2.15, p 0.02) were associated with increased 1-year mortality. In addition, 30-day mortality was associated with age ≥ 80 years (HR 4.15, 95% CI 1.98-8.70, p < 0.001), CCI ≥ 3 (HR 1.80, 95% CI 1.08-2.99, p 0.023), pre-surgical time >48 h (HR 3.0, 95% CI 1.58-5.92, p 0.001), and surgical delay > 4 days (HR 3.0, 95% CI 1.33-6.81, p 0.008); and 6-month mortality was associated with surgical delay > 4 days (HR 2.72, 95% CI 1.42-5.23, p 0.003), and haemoglobin < 10 g/dl (HR 1.56, 95% CI 1.04-2.33, p < 0.028).

Conclusions: Surgical delay greater than 4 days and Charlson Comorbidity Index ≥ 3 were found as factors associated with increased mortality, along with anaemia < 10 g/dl and age ≥ 80 years. A similar mortality rate was found in this study compared to the rates reported by the literature, despite a surgical delay of 8.8 days.

Keywords: Developing country; Elderly; Hip fracture; Mortality; Multiple comorbidities; Surgical delay.