Osteoporosis Case Of The Month

This month I will discuss a clinical question that is often asked when I lecture about osteoporosis and bone densitometry. The question is when should a clinician obtain a bone densitometry study? To answer the question I will present 2 cases.

Case 1

Mrs. P.B. is a 54 years old Caucasian woman who recently developed amenorrhea associated with severe hot flashes and vaginal dryness. She is a sexually active woman with no medical problems who does not smoke or drink excessively and exercises regularly. Over the years she has had yearly examinations which have been normal except for an occasional vaginal infection. There is no family history of osteoporosis or breast cancer and her physical examination is within normal limits. She wishes to have hormone replacement therapy (HRT).

A common situation that many practitioners encounter is that of the menopausal woman who presents to her physician complaining of recent amenorrhea. Some of the patients may have already made a decision to proceed with estrogen replacement therapy (ERT) while others may have chosen to avoid it. A third group of women may present undecided, confused or misinformed about the issue. They hope that their physician will assist them in making a sound decision that, on one hand, is individually appropriate given their health history and, on the other hand, they will feel comfortable with.

Usually, those who choose to be replaced with estrogen will have experienced disturbing vasomotor symptoms or, if that is not the case, are intent in taking the hormone because of the potential benefits that have been associated with its use in many organs. The organ systems that can benefit from postmenopausal estrogen replacement are the cardiovascular, the skeletal, the central nervous, the integumentary, the genitourinary, the gastrointestinal, the dental and the ocular.

In the group of patients committed to the use of hormones, the performance of a bone densitometry study would mostly benefit the limited number of individuals (estimated to be 3%-10%) who are destined to continue to lose bone mass at an accelerated rate despite the hormone replacement. It is difficult to identify this group of "non-responders" from the larger group of women for whom HRT will help retard the accelerated bone loss observed when estrogen levels are low. Nonetheless, patients who have demonstrated to be poorly compliant, smokers, heavy drinkers and those nutritionally deficient are likely to be the ones who could benefit the most from initial evaluation and follow up of their bone mineral density status. Another strategy in those patients would be to obtain a baseline measurement of a bone marker and repeat it six to eight weeks later in order to assess response to therapy. Some bone marker measurements can be obtained from urine samples making it clinically convenient.

Mrs. P.B. was started on a cyclical HRT regimen without obtaining a bone density evaluation. She was seen again eight weeks after the initiation of her therapy to reassess any potential concerns that she may have and that might affect compliance. The HRT had relieved her hypoestrogenic symptoms and her vaginal bleeding was regular and timed appropriately in relation to the ingestion of the hormones. She was reassured and encouraged to call if any new concerns presented.

Case 2

Mrs. E. A. is a 63 years old Caucasian female who underwent a total abdominal hysterectomy and bilateral salpingo-oophorectomy at age 37 because of severe endometriosis. She was never placed on HRT and except for the first couple of years after the surgery she has no hot flashes. She presents for a consultation after having heard on a television program that women such as her are at high risk for osteoporosis. Her history is significant for gastroesophageal reflux treated with antacids. Her mother died of breast cancer. Her father died from coronary heart disease. She is still active and involved in many social activities. Does not smoke and drinks socially. Adamantly opposes the use of ERT because of concerns about increased risk of breast cancer. The physical examination was significant for some kyphosis. Her fasting lipid profile shows an adverse risk for cardiovascular disease. The mammogram was normal.

Many of the women who choose to avoid estrogen replacement may have decided against it because of the side effects associated with the hormone replacement therapy (HRT). These commonly, but not exclusively, include: bleeding, the concern for a potential increased risk of breast cancer and the side effects caused by the addition of a progestin to the estrogen regimen. The progestin is almost uniquely added to the ERT of postmenopausal women who have a uterus in order to greatly minimize the risk of endometrial neoplasia observed in such women when they receive unopposed estrogen.

For women opposed to HRT the performance of a bone densitometry study can be beneficial since, if osteopenia or osteoporosis is documented, these patients are likely to adopt some changes in their lifestyle that will promote bone health. Some may change their mind about HRT while others will quit smoking, increase their intake of calcium and vitamin D, or engage in a new exercise routine. For these patients as well as for those who hope to make a decision about their menopausal care with the assistance of their physician, the professional encounter should be a unique opportunity. The physician should educate and evaluate the health issues that are going to bear on the patient’s longevity and quality of life.

In the United States there are several pharmacological agents, which like ERT, work to retard the bone resorption after menopause. Bisphosphonates and nasal calcitonin are available for the prevention and treatment of osteoporosis. Among the bisphosphonates, the Food and Drug Administration (FDA) have approved only alendronate for this purpose. Calcitonin is only effective in the spine and has a unique analgesic advantage for pain associated with vertebral fractures. Recently raloxifene, a selective estrogen receptor modulator, was approved for the prevention of osteoporosis. In addition to its benefits in bone health it has some protective benefits in the cardiovascular system. This agent has also not demonstrated adverse effects on the breast and the endometrium. In contrast to ERT, it has no effect on the central nervous system and in fact may cause an exacerbation of severe hot flashes when compared to placebo. In addition, the drug circular warns about a potential increased risk of venous thromboembolism that is more common during the first month of intake. The drug should also be discontinued for 72 hours before prolonged inactivity is anticipated such as in the immediate postoperative period.

Mrs. E. A. had a dual X-ray absorptiometry (DEXA) study performed. Her T-score in the spine was 2.7 standard deviations below the mean and in the left hip it was 2.3 standard deviations below the mean thus confirming the diagnosis of osteoporosis. She was counseled at length about the potential benefits of ERT, in particular to her cardiovascular and skeletal systems. She was informed that these benefits far outweigh the potential risk for breast cancer and that many patients with a family history of breast cancer die from cardiovascular disease, which ERT can prevent. She was also counseled about the appropriate amounts of calcium and vitamin D that she requires, and warned about possible accidents that can increase her risk of fracture. Nevertheless, she refused to take ERT and was placed on daily raloxifene. She was also advised to have her DEXA scan repeated in a year.

Most authorities feel that ERT is the preferred approach for the prevention and treatment of deficient bone mass because of its more global benefits. Yet compliance with this therapy is poor because of side effects. Given the many different available therapeutic options for the management of patients at high risk of fracture, bone densitometry should be obtained at any time when there is uncertainty about the bone mass status of any patient. Even in the older woman who has been postmenopausal for many years the use of bone densitometry can be helpful in identifying those patients whose bone loss is accelerated because of reasons other than age. The bone density study would indicate that their bone mineral density is significantly lower when compared to that of other individuals similar in age (the % aged matched or Z score). Proper diagnosis and treatment of the underlying condition causing the accelerated bone loss can improve the patient’s quality of life.

As of July 1998, in the United States, Medicare will cover the expenses related to assessment of bone mass in all its subscribers. Similarly, some states such as Florida have passed legislation that mandates such coverage by entities that market and provide health care services in the state. At our center we charge $170.00 for a scan that includes assessment of the spine and the non-dominant hip. The price also includes the interpretation of the study.