SỰ PHÙ HỢP CỦA Z-SCORE TRONG ĐÁNH GIÁ MẬT ĐỘ XƯƠNG Ở NỮ GIỚI CHƯA MÃN KINH TẠI VIỆT NAM

Abstract

In the context where Z-score is recommended for diagnosis in younger individuals and premenopausal women, determining the appropriateness of the -2.0 threshold according to the ISCD (International Society for Clinical Densitometry) in interpreting bone mineral density (BMD) results among Vietnamese premenopausal women, compared with T-score, is of significant importance for providing evidence in clinical practice. 

Methods: A cross-sectional study was conducted on 8,367 premenopausal women from 2018 to 2025 at Hanoi Medical University Hospital. 

Results: When using T-score, the proportions of patients at risk of overdiagnosis and underdiagnosis were 0.18-1.49% (T-score ≤ -2.5 and Z-score > -2) and 0.12- 1.79% (T-score > -2.5 and Z-score ≤ -2), respectively. In contrast, the use of Z-score almost eliminated the risk of overdiagnosis (0-0.02%) (Z-score ≤ -2 and T-score > -1.1), while maintaining a low underdiagnosis rate (0.18-1.49%) (Z-score > -2 and T-score ≤ -2.5), thereby confirming the appropriateness of Z-score in evaluating bone mineral density in premenopausal women. Conclusion: The use of Z-score helps reduce the risk of age-inappropriate and clinically inconsistent classification, aligning with international recommendations and the clinical context in Vietnam.