Diagnosis and therapy of osteoporosis in geriatric trauma patients: an update

Background

Demographic changes confront clinicians with an increasing number of orthogeriatric patients. Aged trauma patients present with various comorbidities, and these have to be addressed to secure the results of surgical intervention. Thus, fractures associated with a low-energy trauma are frequently the first sign indicating an underlying osteoporosis [1], [2]. Given the high prevalence of osteoporosis in combination with frailty, patients are at a high risk for secondary fractures. Within 5 years after an osteoporotic index fracture, 14.7% of these patients suffer another hip fracture and 32.5% another osteoporotic fracture [3].

Thus, it is crucial to screen orthogeriatric patients for an underlying osteoporosis to initiate adequate therapy, adjust the surgical procedures, and prevent subsequent fractures in these patients.

Epidemiology

In female patients older than 75 years, the prevalence of osteoporosis is 59.2% [4]. Approximately 6.3–7.8 million of German inhabitants are affected by osteoporosis [5]. However, there is a huge treatment gap, as 77% of these patients are not treated adequately [6]. Even after fragility fractures, only 16%–21% of female patients and 3.4% of male patients receive specific osteoporosis therapy [5], [7]. Given the high risk of secondary osteoporotic fractures, prevention is of great importance in the treatment of these patients.

Identification

At a first glance, the identification of patients at risk of osteoporosis appears complicated. However, there are fractures such as thoracic and lumbar vertebral fractures, proximal femur fractures, proximal humerus fractures, and fractures of the distal radius in which the prevalence of an underlying osteoporosis remains high. Osteoporosis was diagnosed in 56.2% of women older than 50 years with fragility fractures and men ages 60 years [4]. Patients with typical osteoporosis-related fractures should be screened for osteoporosis [8].

According to the guidelines for osteoporosis by the Dachverband Osteologie e.V. (DVO) 2014, patients without any fracture should generally be assessed at the age of 70 years in women and at the age of 80 years in men; in high-risk patients, a clarification in younger age might already be useful [9].

When orthogeriatric patients with fractures are admitted to hospital, risk factors for osteoporosis should be assessed by standardized questionnaires. Thus, standardized questionnaires and algorithms based on the osteoporosis guidelines of the DVO 2014 for prevention, diagnostics, and treatment of osteoporosis [9] can help to estimate the risk of a secondary fracture (downloads available at http://www.klinikum.uni-muenchen.de/Klinik-fuer-Allgemeine-Unfall-und-Wiederherstellungschirurgie/de/fach/alterstraumatologie/downloads/index.html). Internationally acknowledged to identify the osteoporosis-associated fracture risk are the FRAX- or Q-factor score [10], [11]. A diagnostic assessment in postmenopausal women and men older than 60 years is recommended as soon as a fragility fracture or an increased risk of fractures is present [12].

Osteoporosis diagnostics

The new guidelines of the DVO 2014 recommend five diagnostic steps to confirm the diagnosis of osteoporosis.

Taking the medical history should already identify risk factors for osteoporosis as mentioned above. The following subjects are important to include in the medical history: tendency to fall, medication (especially glucocorticoids, aromatase inhibitors, and the long-term intake of proton pump inhibitors, which are a potential risk factor still under discussion), and preexisting conditions such as diabetes mellitus, ankylosing spondylitis, chronic obstructive pulmonary disease (COPD), and endocrine disorders (such as hypothyroidism).

Also, a detailed clinical examination helps finding indicators for osteoporosis. Especially, the Tannenbaum phenomenon is common. In addition, a loss of height over 2 cm may indicate further diagnostics [13].

A basic blood testing consists of calcium and phosphate in serum, alkaline phosphatase, γ-glutamyltransferase (γ-GT), creatinine, C-reactive protein (CRP), thyroid-stimulating hormone (TSH), 25-OH-vitamin D3, a serum electrophoresis, and a complete blood count.

Dual X-ray absorptiometry (DXA) is the gold standard to determine bone density. Radiation exposure and costs are relatively small [8]. The lower bone density is, the higher is the risk for osteoporotic fractures [14]. Density measurements of the lumbar spine, femur, and femoral neck are set in relation to bone density values of a normal population (T-value). Treatment is based on the t-value, age of patients, and the individual risk factors. Risk factors, such as glucocorticoid therapy or multiple fractures in the past 3 years, increase the treatment threshold.

According to the DVO 2014 [9], in some cases, bone density scans are not necessary to obtain the diagnosis of an underlying osteoporosis. Thus, in patients having suffered a fragility fracture that shows radiographic signs of an osteoporosis within the spine or proximal femur (i.e. Figures 1 or 2), an underlying osteoporosis can be diagnosed without bone density measurements. Also, multiple low-graded fractures of the vertebral spine, such as a singular grade II impression of the vertebrae according to the Genant classification, go in line with an underlying osteoporosis (Figure 1) [15].

Figure 1:

Preoperative CT scan with an atraumatic lumbar vertebral fracture.

In this case, the diagnosis of an underlying osteoporosis can be secured without further bone density scans.

Figure 2:

Preoperative X-ray with a pertrochanteric fracture of the proximal femur on the left side.

Degenerative changes (i.e. of the spine) can increase the t-value. If, in these cases, bone density scans of the hip cannot be applied, quantitative computed tomography (CT) scans are recommended [16], [17].

Osteoporosis treatment

Vitamin D deficiency is widely spread among elderly patients. It is associated with muscle weakness and therefore with a tendency to fall. Aged trauma patients are at high risk to develop vitamin D deficiency because of malnutrition, reduced sunlight exposure, impaired intestinal absorption, and impaired hydroxylation in the liver and kidneys [18]. In elderly patients with hip fractures, only approximately 10% of the patients have an adequate vitamin D level [19].

Treatment algorithms can be helpful for the decision of the individual osteoporosis therapy (Figure 3).

Figure 3:

LMU algorithm for the treatment of osteoporosis.

Basic treatment aims on a compensation of vitamin D level and a sufficient calcium intake. A balanced calcium homeostasis is required for the initiation of a specific osteoporosis treatment and crucial to secure fracture healing [20].

According to the DVO guidelines, a dose of approximately 1000 IU/day vitamin D is needed to maintain a normal to high vitamin D level. Vitamin D application should be adjusted to the laboratory results (Table 1). A 25-OH-vitamin D level above 75 μg/L is not recommended, as it has been shown to be associated with an increased risk of falls [21].

The intake of calcium should be up to 1000 mg/day. Raising the calcium level can be achieved through diet, for example, with calcium-rich mineral water (about 400 mg/L) or dairy products such as milk, cheese, cottage cheese, or yogurt. During a therapy with glucocorticoids, calcium supplements with a dose of 1000 mg/day calcium are recommended.

As supplement, calcium carbonate is recommended. However, a high percentage of elderly patients have proton pump inhibitors among their daily medication. In these patients, calcium citrate or calcium gluconate is recommended for an adequate resorption of calcium [22].

Depending on laboratory findings, specific therapy can be initiated during hospitalization. Considering contraindications and comorbidities, a specialized physician should initiate specific therapy.

Oral bisphosphonates are the first-line medication in postmenopausal osteoporosis. In patients older than 75 years, alendronate and risedronate show a reduced risk for vertebral fractures [23]. Also, intravenously applied bisphosphonates such as ibandronate or zolendranate show a reduction of vertebral fractures and zolendronate also decreases the total fracture risk.

An intravenous therapy with bisphosphonates should not be started before 14 days after surgery to prevent accumulation around the internal fixation [24]. To avoid hypocalcemia, vitamin D levels should be normal before starting with a specific osteoporosis therapy. In some cases, an intravenous bisphosphonate therapy is recommended 6 weeks after fracture.

Studies show that intravenous therapy with bisphosphonates is not inferior to the therapy with oral bisphosphonates concerning fracture risk. The compliance of the patients might be even higher in monthly intravenous applications than in taking it orally [25], [26].

The osteoanabolic therapy with recombinant parathyroid hormone (teriparatide) is effective but costly. It can be an option when, despite adequate pretreatment, osteoporosis progresses or causes further vertebral fractures. Teriparatide received the recommendation level B of the DVO due to the superior effect compared to alendronate in treating glucocorticoid-induced osteoporosis and reducing peripheral postmenopausal osteoporotic fractures [27].

Depending on the risk profile of the patient, monoclonal antibodies, such as denosumab, are also considered as an option. Studies with denosumab show a reduction of vertebral fractures and peripheral fractures such as proximal femur fractures. Especially, in orthogeriatric patients with limited compliance associated with cognitive disorders such as dementia or patients who refuse taking more oral medication, denosumab offers advantages. Thus, a specific osteoporosis therapy with denosumab, which has to be applied only twice a year, can be secured easily, as it is injected subcutaneously, which could be handled, for example, by the nursing staff and monitored by their general practitioners [28], [29], [30].

Due to the increased risk of thrombosis, strontium ranelate, selective estrogen receptor modulators (SERMs; raloxifene and bazedoxifene), and estrogens (optionally in combination with a progestin) are not suitable for orthogeriatric patients [10], [31].

Calcitonin plays no role in first-line therapy. Only in cases with severe renal insufficiency, it might be applied because other agents are contraindicated.

Prevention

An effective prevention of subsequent fractures includes also fall prevention with muscle training, physiotherapy, and critical adjustment of the preexisting medication.

Training should concentrate on an integration of general movement, improvement of coordination, balance, posture, and flexibility [32].

Medication, which causes vertigo or dizziness, should be reduced [33]. Also, medication that reduces bone quality (e.g. glucocorticoids) or bone healing [e.g. nonsteroidal antirheumatics (NSAR)] should be avoided.

A big problem is also the compliance of these elderly patients. The literature shows that the percentage of compliant patients decreases to 50% over a period of 1 year after initiation of treatment and even to only 30% over time [34]. Women and patients with DXA were more likely to follow their doctors’ instructions, whereas older or multimorbid patients and those with a preexisting high amount of medications are more likely to not continue with their medication.

Secondary prevention via fracture liaison service (FLS) is another additional organization to comanagement to reduce subsequent fractures and postoperative complications. First mentioned in 1999, the “UK National Health Service” in Glasgow, Scotland, established one of the first FLS. Today, clinics can apply to certify through the International Osteoporosis Foundation (IOF) for FLS.

A specially trained fragility fracture nurse is taking care of the coordination of the patients’ treatment after admission to the hospital. Besides identifying patients of high risk and initiation of adequate diagnostics and osteoporosis therapy, the fragility fracture nurse is also monitoring the patients’ compliance after discharge.

This network also increases compliance by close supervision in rehabilitation and outpatient clinics [35], [36].

The rate of subsequent fractures in patients with untreated osteoporosis increases significantly within the first 2 years after the first fracture [37]. Patients with fragility fractures have an increased risk of 86% for subsequent fractures [38]. In patients with vertebral fractures, the risk of another fracture is doubled and after proximal femur fractures even trebled [39]. Recent studies show that establishing an FLS can reduce subsequent fractures by approximately 30%. Axelsson et al. stated that even a minimal resource FLS was effective in increasing investigation and treatment (Figure 4). Patients treated in an FLS setting had a re-fracture risk reduction of 51%. This indicates that an FLS can improve secondary prevention of fractures [40], [41].

Figure 4:

Re-fracture rate with and without treatment of osteoporosis in an FLS setting from 2011 to 2014 [40].

To prevent one re-fracture in 3 years, the number needed to treat (NNT) with FLS is 20 [42]. For the widely spread angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), the NNT is 80 and 338 over a period of 4.3 years to prevent one myocardial infarction.

Allowing an early initiation of appropriate treatment, the rate of subsequent fracture can be significantly reduced [41], [43]. Another positive effect lays in the reduction of health economic cost [44], [45]. The literature shows that introducing an orthogeriatrician-led or a nurse-led FLS is cost-effective compared to usual care.

Conclusion

The management of orthogeriatric patients should not only focus on the surgical aspects of treatment but also include diagnosis and treatment of an underlying osteoporosis. Decisions should be based on the risk profile of the patients. Treatment is more complicated because of comorbidities limiting the therapy options. It is also difficult to convince these patients to follow through with their therapy even if they have already reached a high age. Therefore, it is important to involve their general practitioners and the patients themselves as an attempt to increase compliance. Thus, precise patient information about their therapy and risk of subsequent fractures is of importance. Especially, aged trauma patients tend to concentrate on their return to daily activities following fracture and neglect the necessity of osteoporosis therapy. Therefore, it is important to follow up on these patients and secure secondary fracture prevention.

FLS is a new approach that can significantly increase the efficiency of osteoporosis treatment by coordinating osteoporosis treatment during hospitalization and after discharge. It helps avoiding subsequent fractures and therefore is an effective service to secure secondary fracture prevention.