Association between Pan-Immune-Inflammation Value and Bone Turnover Markers in Chinese Pat ients with Osteoporotic Fractures: A Retrospective Cross-Sectional Study

Jiahao Wang¹Meng-Cheng Zhu¹Chong Li¹Guo-Hua Wang²Ke Lu^1*Yan-ming Hao^1*

• ¹First People's Hospital of Kunshan, Kunshan, China
• ²Qiandeng First People's Hospital of Kunshan, Kunshan, China

Background Systemic inflammation has been linked to impaired bone remodeling and may contribute to the risk of ost eoporotic fractures (OPFs). This study examined the relationship between baseline pan-immune-inflamma tion value (PIV) and bone turnover markers (BTMs) in patients hospitalized for surgical treatment of OPF s. Methods In this retrospective cross-sectional study, 839 patients aged ≥50 years who were treated for osteoporotic f ragility fractures between 2017 and 2024 were analyzed. PIV was calculated as (neutrophils × platelets × monocytes) / lymphocytes. BTMs included serum β-C-terminal telopeptide of type I collagen (β-CTX) an d procollagen type I N-terminal propeptide (P1NP). Associations between log₂-transformed PIV and BT Ms were assessed using multivariable generalized estimating equations (GEE), adjusting for demographic, clinical, and biochemical factors. Smoothing spline models and threshold effect analyses were used to ex plore potential nonlinear relationships. Subgroup analyses were conducted to examine effect modification. Results The mean age of participants was 69.4 ± 10.9 years, with 70.9% being female. Mean β-CTX and P1NP le vels were 0.54 ± 0.29 ng/mL and 58.1 ± 35.3 ng/mL, respectively, and the mean log₂PIV was 8.24 ± 1.28. Higher PIV levels were independently associated with lower BTMs. Specifically, each doubling of PIV was associated with a 4.46 ng/mL reduction in P1NP and a 0.05 ng/mL reduction in β-CTX (both P < 0.0 01). An inverted J-shaped association was observed, with the relationship plateauing at log₂PIV levels bet ween approximately 8.3 and 10.3. The inverse association was more pronounced in individuals with hype rtension or impaired renal function. Conclusion Elevated PIV is independently and nonlinearly associated with suppressed bone turnover, underscoring th e role of systemic inflammation in the pathophysiology and management of osteoporosis.