What are the Optimal Age Thresholds for qCT-based Osteoporosis and Osteopenia Screening in Patients Undergoing Lumbar Fusion Surgery?

STUDY DESIGN: Secondary analysis of two prospective single-center studies.

OBJECTIVE: To evaluate the effectiveness of guideline-recommended osteoporosis screening age cutoffs in lumbar fusion surgery (LFS) patients and identify optimized thresholds for osteoporosis and osteopenia detection.

BACKGROUND: Poor bone quality impacts lumbar fusion surgery (LFS) outcomes. Current general population screening guidelines recommend starting at 65 years for women and 70 years for men in the absence of other risk factors. This study evaluates their effectiveness and refines age-based screening strategies for LFS patients.

METHODS: This post-hoc analysis included patients ≥50 years of two prospective studies enrolling patients undergoing LFS for degenerative conditions. Patients with unsuitable imaging for quantitative CT (qCT) bone mineral density measurements were excluded. Osteoporosis and osteopenia status was determined by medical history and qCT in all patients. Uni- and multivariable logistic regression and ROC analysis to optimize age cut-offs for BMD screening were performed. The number needed to screen (NNS) for age cut-offs to detect one case was calculated.

RESULTS: Among 515 patients (56% female, median age 66 years), impaired bone quality was present in 70%. Osteoporosis was found in 34%, with 38% of cases previously undiagnosed. Age was the only significant risk factor for low BMD for both sexes. Guideline age cutoffs yielded a sensitivity of 78% in females (NNS 1.8) and 58% in males (NNS 2.4) for osteoporosis and 68% (NNS 1.2) and 39% (NNS 1.2), respectively, for impaired bone status. Sensitivity-optimized screening for osteoporosis required lowering the age threshold to 58 for men (NNS 4) and 62 for women (NNS 2). Screening all patients for impaired bone status had an NNS of 1.4.

CONCLUSIONS: General population age cutoffs inadequately detect osteoporosis in LFS patients. We propose individualized osteoporosis screening with sensitivity-optimized age thresholds and osteopenia screening for higher-risk procedures in patients aged ≥50 years.