Modified criteria for identifying elevated bone mass

This study used modified criteria to exclude osteoporosis and osteopenia from elevated bone mass (EBM) to avoid a diagnostic paradox and demonstrated that diffuse idiopathic skeletal hyperostosis (DISH), severe lumbar degenerative disease (LDD), elevated body mass index (BMI), and diabetes are key risk factors for super EBM (SEBM).

The current criteria classify individuals with both EBM and osteopenia/osteoporosis. To avoid this contradiction, we used a modified criterion to exclude osteoporosis or osteopenia from EBM and to examine the clinical impact and risk factors of EBM.

In this retrospective study, bone mineral density (BMD) data from participants aged 18 years or older collected at a tertiary hospital between 2021 and 2023 were analyzed. Inclusion criteria were complete Z-scores and T-scores for the lumbar spine, femoral neck, and total hip. Participants with a history of lumbar spine surgery or hip arthroplasty prior to BMD measurement were excluded. Normal bone mass (NBM) was defined as T-scores ≥ –1.0 at all sites and Z-scores < 2.5 at any site. EBM was defined as NBM plus Z-scores ≥ 2.5 at any site. EBM was further subdivided into moderate EBM (MEBM) with Z-scores between 2.5 and 4.0, and SEBM with Z-scores ≥ 4.0. Demographic data, medical history, and comorbidities were collected and analyzed.

Of the 33,479 eligible participants, 1,472 (4.4%) were identified with EBM. The EBM group was divided into 1,267 (3.8%) with MEBM and 205 (0.6%) with SEBM. SEBM group had a significantly higher proportion of men and a higher BMI than the MEBM group (p < 0.001). In addition, SEBM group had a higher prevalence of conditions such as DISH, ankylosing spondylitis (AS), LDD, and diabetes (p < 0.001). Different correlation trends between BMI, T-scores, and Z-scores were observed in the SEBM and MEBM groups. Chi-squared Automatic Interaction Detection (CHAID) analysis identified DISH as the strongest predictor of SEBM, while severe LDD, increased BMI, and diabetes were contributing factors for SEBM.

Using the modified criteria for EBM, which exclude cases of osteoporosis and osteopenia, SEBM has a higher rate of comorbidities compared to MEBM. The presence of DISH, higher severity of LDD, increased BMI, and diabetes were identified as strong risk factor of SEBM.