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

Abstract

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.

Keywords: Bone mineral density; Osteoporosis; Osteoporotic vertebral fracture; Spine; T-score.