Osteoporosis is markedly underdiagnosed: a nationwide study from Denmark.

Aim: To compare the number of patients diagnosed with osteoporosis and osteoporotic fractures in Denmark, with the number of subjects expected to have osteoporosis.

Subjects And Methods: From the National Hospital Discharge Register, records for all patients diagnosed with osteoporosis and/or with osteoporotic fractures between 1995 and 1999 were retrieved. Based on normal Danish values for BMD, the expected number of subjects aged 50 years or more with osteoporosis according to the WHO definition was calculated.

Results: The estimated prevalence of osteoporosis was 40.8% of women aged >or=50 years and 17.7% among men. The expected annual incidence was 58,658/million inhabitants in women >or=50 years of age and 23,648/million in men >or=50 years. However, the observed incidence was only 4,823 and 862/million per year, respectively (8.2% and 3.6% of the expected). In 1999, a total of 34,691 hip, spine, and forearm fractures were reported in subjects >or=50 years, and of these, 18,566 were potentially attributable to osteoporosis (14,240 fractures in women and 4,326 in men equaling 14,976 and 5,297/million per year). Only 0.3% of men >or=50 years were receiving a bisphosphonate, while 2.2% of women received a bisphosphonate or raloxifene. Among women >or=50 years, 27.7% received hormone replacement therapy.

Conclusions: Osteoporotic fractures of the hip, spine, and forearm are rather frequent in Denmark, but the diagnosis of osteoporosis is rarely used. It seems that osteoporosis is markedly underdiagnosed and undertreated in Denmark as probably also elsewhere. This may have significant implications for the prevention of osteoporotic fractures.