Mortality in cancer patients after a fall-related injury: The impact of cancer spread and type

Abstract

Background

Cancer patients are at an increased risk of dying following an injury, of which among the elderly is predominately caused by falling. In addition, patients with certain types of cancer are more prone to bone injury. However, studies are needed that examine the role of cancer site and metastasis on the relationship between cancer and death following traumatic injury.

Methods

A total of 4201 cancer patients from 2000 to 2009 in the Illinois Hospital Discharge and Illinois Trauma Registry, and 4201 patients without cancer met eligibility criteria (e.g., fell and were injured; 50–96 years old). A multivariable logistic regression analysis was conducted to assess the relationship between cancer and death following traumatic injury, including models stratified by cancer site and metastasis.

Results

The demographic characteristics, prevalence of comorbid conditions, and injury severity and type did not differ substantially between patients with and without diagnoses for cancer. In the main adjusted model, patients with cancer were more likely to die during the course of hospitalization after a fall than those without cancer (OR = 2.58; CI 95%: 1.91–3.49). Patients with metastatic malignancies had a higher risk of in-hospital death than patients without metastasis (adjusted OR = 3.59 and OR = 2.18, respectively). Patients with diagnoses for all specific cancer sites, except prostate and breast, were also significantly more likely to die.

Discussion

Cancer patients with and without spread over the age of 50 years are more likely to die in-hospital after a fall than elderly patients without cancer. However, this relationship may exist only for patients with specific cancer types.

Introduction

Approximately one in three community-dwelling elderly fall each year, with reoccurrence rates between 15% and 25% [1], [2], [3]. Of those that seek medical treatment, 20–30% suffer moderate to severe injuries [4]. Nonfatal unintentional fall-related injuries are increasing dramatically [5], as are fall-related deaths. From 1999 to 2009 falls were the most common cause of death from unintentional injury in people 50 and older, and are the cause of 60–80% of all injuries in the elderly—increasing in proportion with age [5]. During this time the adjusted mortality rate increased 64% from 15.1 to 24.8 deaths per 100,000 people in this age group [6], [7]. Falls increase mortality through a variety of pathways including: pulmonary embolisms resulting from deep venous thrombosis (DVT) at the site of fractured bone, infection (e.g., from the injury, surgery, or hospital-acquired), or from surgical complications [8], [9]. Furthermore, risk of injury and death from falling increases with age, as does the incidence of many chronic conditions, which may also increase the risk of injury or complicate recovery [4], [5], [7], [10].

Cancer patients may be particularly vulnerable to decreased bone density from cancer treatments and the disease itself. Radiation can damage bone blood supply. The pelvic/hip region is one of the most vulnerable regions to suffer radiation damage, significantly increasing fracture risk [11], [12]. Hormone therapies, chemotherapy, and bone cancer (or bone cancer metastasis) can also disrupt bone-cell homeostasis leading to bone loss [13], [14], [15]. Chemotherapies and hormone therapies that can decrease bone density are used to treat a variety of cancers [14], [16]. Several studies indicate that cancer patients are at an increased risk for fracture, particularly patients with primary lung, prostate, breast, multiple myeloma, and bone cancer or patients with metastasis to the bone or other types of metastasis excluding bone [12], [17], [18], [19].

In addition to an increased fracture risk, having cancer increases the risk of in-hospital mortality after an injury from a trauma [20], [21], [22], [23], [24], [25]. Only one of these studies assessed mechanism of injury [20] and found that the relationship between cancer and in-hospital mortality was only significantly higher when the cause of the injury was a fall (OR = 2.35, 95% CI: 1.67–3.25).

The association between cancer and in-hospital morality after a trauma (e.g., a fall) may be attributed to: a disruption of normal clotting, immunodeficiency from chemotherapy, and/or an overall decrease in the patient's physical reserve [22], [24]. However, studies completed in this area have not examined the role of cancer metastasis [20], [21], [22], [23], [24], [25]. Most people that die of cancer have cancer metastasis [26] and 85–90% have delirium in the days and hours before death [27], which significantly increases the risk of falling [28], [29]. Therefore, the relationship between cancer and in-hospital mortality after a fall may only exist for patients with advanced cancer, and the fall injury is simply a marker in the causal pathway of the final terminal phase of the illness.

As patients with specific cancer types are more prone to fracture, cancer type may also be an effect modifier in the relationship in question, which has not been examined in previous work [20], [21], [22], [23], [24], [25]. In addition, these past studies have relied on data solely from trauma registries, which focuses on patients with more severe injuries, as patients with less severe injuries are generally not taken to trauma centers [30].

Studies are needed that include a comprehensive patient population treated in facilities with and without specialised trauma teams that is large enough to adequately assess the risk of in-hospital mortality after a fall-related injury in patients with a malignancy, as well as evaluate the role of two potentially important risk modifiers: (1) the role of advanced cancer (i.e., cancer spread) and (2) cancer type. This study, a retrospective cohort study of patients treated in hospitals with and without specialised trauma units addresses these research gaps.