Elsevier

Bone

Volume 117, December 2018, Pages 123-129
Bone

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

https://doi.org/10.1016/j.bone.2018.09.002Get rights and content

Abstract

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.

Introduction

Proximal femoral fracture, or hip fracture (HF), is a major worldwide public health issue, with high incidence in the elderly [[1], [2], [3]]. Although age has been considered a major independent risk factor for HF, world age-standardized rates show a >10-fold range between countries, suggesting that the probability of experiencing a HF depends on environmental rather than genetic factors [2]. Like other First World countries, Spain has experienced a progressive increase in HF incidence over the last decades, with over 35,000 cases in 2012, and its regions (autonomous communities) have shown remarkable differences in HF incidence that cannot be explained by age, sex, and rurality [4,5].

In addition to causing functional disability, HF is associated with a greater mortality risk, particularly in patients over 60 years old [[6], [7], [8]]. Several observational trials have shown that the risk of death for patients with HF is 3–8 times greater than for age-matched subjects in the general population. In Spain, in-hospital mortality rate of HF patients aged 65 or more—accounting for nearly 90% of all HF—ranges from 2% to 8%, depending on specific regions [9]; similar variability has been found when comparing mortality rates between countries [10,11].

Differences in the mortality risk reported in various trials have prompted the investigation of factors influencing mortality after HF. Besides age, identified as the primary predictor of mortality 3–12 months after HF [12], the patient's comorbidity burden has been postulated as a key factor determining mortality risk following HF [[13], [14], [15], [16], [17]]. Individual conditions such as low body mass index (BMI), dementia, cardiovascular disease, diabetes, and liver disease appeared to have a remarkable influence on mortality risk during the years following the HF [[12], [13], [14]]. In addition to patient's clinical, nutritional and functional statuses before the fracture, variables related to HF management such as type of surgical intervention and osteoporosis treatment may also influence the patient's survival odds [18,19].

Taken together, these data suggest that the mortality risk after HF is caused by multiple factors. However, addressing the influence of various clinical and demographic factors on mortality risk requires large study samples to gain enough statistical power to clearly assess the weight of each individual factor. In countries with public healthcare systems covering the whole population, large administrative datasets provide clinical data from a massive number of patients, allowing for a whole-population approach to healthcare issues. Using this approach—commonly regarded as total cohort studies—some authors have provided relevant information regarding the impact of measures taken after hospital admission on mortality of HF patients [10,11,20]. In an attempt to provide new insights regarding the influence of patients characteristics on mortality after suffering HF, we have analyzed a database of a public healthcare entity that provides healthcare services to virtually the entire population of Catalonia (north-east of Spain) to describe the HF incidence in the elderly, and to dissect the components of a multivariate model of HF mortality risk.

Section snippets

Study design and population

In this observational, retrospective study we have gathered socio-demographic and clinical data from the local health department (CatSalut) dataset of Catalonia (north-east Spain). CatSalut provides free healthcare services to the entire population of Catalonia through a network of 62 public hospitals and 369 primary care units. Since 2011, the CatSalut surveillance system collects detailed information on healthcare usage for the entire population of Catalonia. As part of this surveillance

Characteristics of the study population

Between 2012 and 2015, 30,552 patients aged 64 years or more were admitted to public health centers (either owned by, or associated with CatSalut) with a HF diagnosis. Overall, 10,439 (34.2%) of HF patients included in our analysis died during the entire study period; 6821 (22.3%) within the first year after hospital admission.

Table 1 shows the main demographic and clinical characteristics of the study population, as well as the survival associated with each subgroup. Mean (SD) age of the study

Discussion

In this retrospective analysis of a public health dataset, which included most cases of HF in a population of over 7.5 million people, we found that age and health status (characterized by the patient's nutritional status and comorbidity burden) at the moment of experiencing the HF were the two factors with greater influence on mortality for a few years after hospital admission. Other baseline factors such as type of fracture, type of intervention, or osteoporotic treatment showed either lesser

Conclusion

In summary, our analysis of 30,552 HF patients—all cases of HF treated within the framework of public health care in a population of over 7.5 million people—confirmed age as the factor with the greatest influence on survival during the years following a HF. Furthermore, our results suggest that, rather than pharmacological treatment, the general health status and the complexity of underlying diseases at the moment of experiencing the HF have an important influence on mid-term mortality in HF

Funding sources

Amgen Inc. provided financial support to hire medical writing services.

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