This installment of osteoporosis primer for PAs will focus on the modalities used to diagnosis osteoporosis. To reiterate a diagnosis of osteoporosis could be made in an adult patient aged older than 50 years who have experienced a ground level fall resulting in a fragility hip or vertebral compression fracture.
Vertebral compression fractures
Vertebral compression fractures are the most common fragility type fracture, but clearly, the breach associated with the highest mortality are those of the hip. Any fracture, excluding toes, fingers, and skull, can be considered osteoporotic fragility type if they occur from a fall from ground level or less. However, follow-up bone density testing for these patients is indicated.
These fractures causeVertebral compression fractures disability and decreased quality of life. Besides the increased morbidity that these fractures cause, they are also expensive to the health care system resulting in 2.5 million medical visits and over 400,000 hospital admissions per year.
Osteoporosis causes most fragility fractures and is the most common disease of bone. It is associated with low bone mass and microarchitectural deterioration of bone tissue that results in increased bone fragility and fracture risk. The gold standard for the diagnosis of osteoporosis is bone density testing using dual-energy X-ray absorptiometry, or DXA. A DXA scan is a noninvasive imaging test that usually takes less than 20 minutes and is less radiation than a chest x-ray.
The World Health Organization international reference standard for osteoporosis diagnosis is a T-score of 2.5 or less at the femoral neck. The determination of osteoporosis is reserved for postmenopausal women and men aged 50 and older.
Women before menopause and men are younger than 50 with a z score less than –2.0 may be defined as “below the expected range for age” but cannot be diagnosed as osteoporotic. A normal T-score is considered anything higher than –1.0 standard deviations from the usual reference standard. The normal reference standard is the bone density of a 30-year-old white woman.
Osteopenia, or more preferably low bone mass, is defined as a T-score between 1.0 and 2.5 standard deviations from the reference. Ideally, T-score is obtained from 1 hip, femoral neck, and the lumbar spine. However, in patients who have had prior hip fractures with hardware, lumbar spine surgeries, and degenerative changes in the lumbar spine the one-third radius may be used as a testing site on DXA imaging.