Background Differences between populations in bone mineral density reference curve are widely reported.

The use of a reference other than its own may lead to an excessive osteoporosis diagnosis.

Objectives The purpose of this study is to determine the prevalence of misclassified post-menopausal women regarding their bone density status according to different reference peak bone masses.

Methods This is a population-based study, carried out in Douera city (50 000 inhabitants town near Algiers).

One thousand two hundred and fifty five (1255) post-menopausal women were randomly selected.

For all of them a bone mineral density was obtained using a Hologic QDR 2000 apparatus.

Both hip and spine sites were measured.

Patients were classified (normal, osteopenia or osteoporosis) according to the world health organization osteoporosis classification.

For the calculation of the T-score we used the peak bone mass of a local study and the OFELY (osteoporose femme deLyon) one.

The percentage of misclassified subjects for different bone status stages is calculated.

Results The mean study population age is: 61.7 years.

The number of misclassified women was nearly the same at both the hip and the spine sites.

When classifying the subjects by taking in account the lowest site (international society for clinical densitometry recommendation) 9% of women are misclassified.

These results are summarized in the following table.

Conclusions This study showed that there are a great number of misclassified women.

This leads to prescribe an unnecessary expensive treatment for women who have osteoporosis but who have actually osteopenia.

Disclosure of Interest None Declared