The risk of suffering an osteoporosis-related fracture is significantly increased with certain predisposing factors. This should be increasingly taken into account because, according to the Swiss Association against Osteoporosis (SVGO), primary and secondary prevention is currently insufficient in Switzerland. The FRAX score is suitable for multifactorial risk assessment, while densitometry using DEXA is considered the gold standard for osteoporosis diagnosis. Even in the presence of osteopenia, drug treatment of bone metabolism with antiresorptives or anabolic steroids may be useful in individual cases.
Only 10% of patients after an osteoporosis-related fracture currently receive drug therapy with antiresorptives or anabolic substances in this country, explains Dr. med. Karim El-Haschimi, Specialist in Internal Medicine, Endocrinology & Diabetology, Metabolism Center, Baden, referring to the SVGO recommendations updated in 2020 [1,2]. One in two women and one in five men aged 50 years and older can expect to suffer an osteoporosis-related fracture during the remainder of their lives [3]. After a first osteoporotic fracture, the risk of subsequent fractures increases significantly. To counteract this trend, measurements of bone metabolism are important tools for estimating fracture risk and, if necessary, initiating drug therapy. Bone is permanently broken down in the body at certain points in order to be replaced by new substance or adapted to changed loads. This is done within the framework of complex regulatory processes. In osteoporosis, the balance between bone formation and bone resorption is shifted in favor of bone resorption. The density and mass of the bones steadily decrease. Bone tissue with altered structural properties and resulting reduced load-bearing capacity develops. Decreasing bone mass becomes clinically apparent in reduced bone mineral density, which can be detected by double X-ray absorptiometry (DEXA).
In which patients is DEXA measurement indicated?
The FRAX score (“Fracture Risk Assessment Tool”) is suitable for multifactorial risk assessment in men and women over 45 years of age [4]. This is a validated tool for estimating the 10-year risk of major fractures of the hip, spine, forearm, or proximal humerus. In addition to age and gender, other risk factors are taken into account, such as BMI <20, a fracture after the age of 40 (excluding hands, feet, skull), and a fracture of the neck of the femur in one of the parents. For rough screening in clinical practice, Dr. El-Haschimi recommends the following questions (if one is answered in the affirmative, there may be an increased risk of osteoporosis);
- Did dad or mom have broken bones or hunched backs for no apparent reason?
- Have you become more than 5 cm shorter?
- Is your BMI <18 kg/m2?
- Are you bedridden or wheelchair dependent for an extended period of time (>3 months)?
- Did your menopause start before age 45 or were your ovaries removed early? (only for women)
- Do you have chronic liver or kidney disease?
- Do you suffer from recurrent diarrhea?
- Do you have a rheumatic disease?
- Have you had to take cortisone for more than 3 months in the past?
- Do you rarely consume milk, cheese and dairy products?
According to the current SVGO recommendations, bone densitometry should be performed if there is an increased risk of osteoporosis based on clinical risk factors [2]. Health insurer-approved indications for DEXA are shown in Overview 1 [1]. In addition to the above factors, earlier fracture >40 years of age (except hands, feet, skull), as well as smoking and alcohol consumption (>3 units per day*) increase the risk of osteoporosis.
* 1 unit = standard glass of beer 285 ml or single measure of spirits 30 ml or medium glass of wine 120 ml or 1 measure of aperitif 60 ml.
T value: densitometric classification according to WHO
Densitometry by dual X-ray absorptiometry(DEXA) measurement (Fig. 1) is performed on the lumbar spine (mean value of assessable vertebrae L1-L4), total femur, and femoral neck (single measurement or mean value of femur left and right) [2]. The lowest value of lumbar spine, femoral neck and total femur is decisive for estimating the 10-year fracture risk. Densitometric classification of osteoporosis is according to WHO (applies only to DEXA measurement of the spine or proximal femur). Deviations from the age-matched healthy collective are expressed as Z-score, changes related to young healthy individuals as T-score. A normal Z-value (>-1) means that the bone density corresponds to the age-typical normal range. However, this value plays a subordinate role in the indication of a therapy. The T-value is primarily used to diagnose the degree of osteoporosis. A 10% bone density loss corresponds approximately to -1 standard deviation in T-value. In addition to the DEXA measurement, a vertebral fracture assessment should be performed if possible and the trabecular bone score should be obtained.
Is there a need for therapy in osteopenia?
A T-score between -1 and -2.5 is by definition osteopenia, and a T-score below -2.5 is manifest osteoporosis. If the latter is true, the indication for antiresorptive therapy is clear, but fractures occur in many cases even in the presence of osteopenia. In its guidelines, the US National Osteoporosis Foundation recommends initiating therapy in men older than 50 years and in postmenopausal women if the 10-year risk according to the FRAX score for a hip fracture is at least 3% or for a major osteoporotic fracture is at least 20% [1]. Therapeutically, a wide range of medications is available. The pharmacological preparations currently approved in Switzerland for sequential osteoporosis therapy are shown in Table 1 [1].
Use antiresorptives or anabolic agents?
In Switzerland, anabolic substances are only prescribed to patients who have already suffered a bone fracture or when anti-resorptive therapy has not been effective or has not prevented fragility fractures. Antiresorptives are more commonly used, but tolerability and comorbidities must be considered. To promote compliance, consideration of patient preferences is critical, Dr. El-Haschimi emphasized [1]. With oral bisphosphonates, tolerance is often a problem; alternatively, corresponding active substances can be recommended i.v.: either every three months (ibandronate; Bonviva®) or every 12 months (zoledronate; Aclasta®). An example of added benefit is when a patient with too much parathyroid hormone (causes calcium to be dissolved from the bone) has calcium put back into the bones by antiresorptive therapy with a bisphosphonate or denosumab (Prolia®). Denosumab is also mostly used in breast cancer patients. Prolia® can currently be used for up to ten years, and there are data on this from the extension phase of the pivotal study, explains Dr. El-Haschimi. In contrast, the time horizon for bisphosphonates is currently limited to five years. Denosumab is an effective and safe drug, but if it is discontinued, there are a few things to keep in mind. A rebound effect can be counteracted by zoledronate (Aclasta®) i.v. 5 mg 1× per year, first administration six months after last Prolia® application; alternatively, alendronate can be used [5]. Bone remodeling markers should be measured every three to six months for follow-up [6]. Dr. El-Haschimi hardly ever uses preparations from the group of drugs known as selective estrogen receptor modulators (SERMs), as they are relatively weakly effective.
In parallel to the pharmacological influence on bone metabolism, basic measures in the area of nutrition and exercise should be implemented. Based on experience, many osteoporosis patients have low vitamin D levels, the speaker said. “We often advise our patients to take enough calcium and vitamin D, and in some cases we prescribe combination supplements.” In terms of nutrition, it would be optimal to consume three servings of dairy products** daily, emphasizes Dr. El-Haschimi [1].
** 1 serving = 2 dl milk or 180 g yogurt or 60 g soft cheese or 30 g hard cheese
Congress: Osteoporosis-Meeting
Literature:
- El-Hashimi K: Online continuing education for AIM & family physicians. Osteoporosis: The first step to treatment is diagnosis. Karim El-Haschimi, MD, Osteoporosis Meeting, September 2, 2021.
- Ferrari S, Lippuner K, Lamy O, Meier C: 2020 recommendations for osteoporosis treatment according to fracture risk from the Swiss Association against Osteoporosis (SVGO). Swiss Med Wkly 2020, 150:w20352
- Lippuner K: Epidemiology and status of osteoporosis in Switzerland, 2013, https://doi.org/10.1024/0040-5930/a000266
- FRAX® Fracture Risk Assessment Tool, www.shef.ac.uk/FRAX (last accessed Oct. 12, 2021).
- Anastasilakis AD, et al: Zoledronate for the Prevention of Bone Loss in Women Discontinuing Denosumab Treatment. A Prospective 2-Year Clinical Trial. J Bone Miner Res 2019; 34(12): 2220-2228.
- “Prolia® and Evenity®: How to prevent rebound?”, Jan. 28, 2021, www.rheumaliga.ch/blog/2021/prolia-evenity-rebound-effekt
HAUSARZT PRAXIS 2021; 16(10): 38-41 (published 10/27-21, ahead of print).
