Baseline serum PINP is associated with early lumbar spine bone mineral density gains during twice-weekly teriparatide treatment: the OASIS cohort study

Baseline serum PINP was significantly and independently associated with achieving a ≥ 8% increase in lumbar spine (LS) bone mineral density (BMD) after 12 months of twice-weekly teriparatide therapy. PURPOSE: Early predictors of the BMD response to twice-weekly teriparatide remain poorly defined. This study aimed to identify clinical and biochemical determinants of early LS BMD improvement under this regimen. METHOD: In this retrospective multicenter cohort study, 242 osteoporosis patients at high fracture risk completed 12 months of twice-weekly teriparatide (28.2 μg). At baseline, 88.0% were female, mean age was 80.0 years, 83.5% had a history of osteoporotic fracture, and 72.3% were treatment-naïve. Multivariate regression was performed to identify independent predictors of LS BMD change, and receiver operating characteristic (ROC) analysis was used to determine the optimal cutoff value for predicting an LS BMD increase ≥ 8% at 12 months. RESULTS: The percent change (mean ± standard deviation) in LS BMD was 7.0 ± 8.6%, and 41.3% of patients achieved an LS BMD increase ≥ 8% at 12 months. In the multivariate model, baseline total procollagen type I N-terminal propeptide (PINP) was significantly and independently associated with percent LS BMD change (standardized coefficient = 2.73, p < 0.001). ROC analysis identified a baseline PINP cutoff of 53.1 μg/L for predicting ≥ 8% LS BMD increase (sensitivity 74.4%, specificity 60.5%, area under the curve = 0.67). CONCLUSION: Baseline serum PINP represents one of the clinically relevant independent predictors of early LS BMD response to twice-weekly teriparatide.