Conversion of osteoporotic vertebral fracture severity score to osteoporosis T-score equivalent status: a framework and a comparative study of Hong Kong Chinese and Rome Caucasian older women

Summary We explored how the severity of radiological osteoporotic vertebral fracture (OVF) can be converted to the equivalent T-score values. Introduction To perform a study to define what portion of older community women with what severity of radiographic OVF correspond to what low T-score status. Methods There were age-matched 301 Italian community women and 301 Chinese community women (sub-group A, age, 73.6 ± 6.1 years). In addition, Chinese sub-groups B and C included 110 community women (age, 68.9 ± 5.5 years) and 101 community women (age: 82.2 ± 4.3 years), respectively. For each vertebra in women, a score of 0, − 0.5, − 1, − 1.5, − 2, − 2.5, and − 3 was assigned for no OVF or OVF of < 20%, ≥ 20 ~ 25%, ≥ 25% ~ 1/3, ≥ 1/3 ~ 40%, ≥ 40%–2/3, and ≥ 2/3 vertebral height loss, respectively, OVFss was defined as the summed score of vertebrae T4 to L5. OVFss and T-scores were ranked from the smallest to the largest values. Results For the Chinese total group (sub-groups A, B, and C together), OVFss = − 1 corresponded to lowest T-score (lowest T-score of lumbar spine, femoral neck, and total hip) of − 3.4 ~ − 3.2. OVFss ≤ − 1.5 corresponded to femoral neck T-score ≤ − 2.5. OVFss = −1.5 corresponded to a mean femoral neck T-score of − 3.0, − 2.6, and − 2.4, among Chinese sub-groups B, A, and C subjects, respectively. For Italians, all cases with OVFss ≤ − 1 had lowest T-score ≤ − 2.5. For cases with femoral neck T-score = − 2.5, 41.7% had OVFss = − 1.5, and 58.3% had OVFss = − 1. Conclusion For older women, statistically OVFss ≤ − 1 suggests this subject is osteoporotic according to lowest T-score. If using femoral neck T-score, OVFss ≤ − 1.5 qualifies osteoporosis diagnosis.