INTRODUCTION: Proximal femoral fractures are critically associated with increased risk of mortality and secondary fractures. Identifying prognosis predictors related to sagittal imbalance that are known to have negative impact on fracture risk and mortality is crucial. This study aimed to explore the relationship between various sagittal imbalance parameters and the prognosis of proximal femoral fractures to identify the most important prognostic indicators. MATERIALS AND METHODS: This multi-center prospective cohort study included patients with proximal femoral fractures treated surgically from April 2020 to March 2021. Spinal standing radiographs were obtained to measure various sagittal spine parameters. Postoperative follow-ups were conducted at 6, 12, 18, 24, and 36 months to assess mortality and secondary fracture rates and examine the predictors and their effects. RESULTS: Among the 137 patients who underwent spinal standing radiographs, 22 died and 23 developed secondary fractures. Multivariate analyses identified the number of previous vertebral fractures and thoracolumbar kyphosis (TLK) as significant risk factors for mortality and secondary fractures. Survival analysis revealed that patients with TLK <
20° had significantly higher survival rates than those with TLK ≥ 20° (P = 0.002 and P <
0.002 for mortality and secondary fractures, respectively). In addition, serum albumin was associated with mortality, and the intake of sleeping pills and antidepressants was associated with secondary fractures. CONCLUSION: TLK after surgery and the number of previous vertebral fractures affected both mortality and secondary fractures. When each risk factor, such as low serum albumin levels, intake of sleeping pills and antidepressants, was also considered, it was found that comprehensive postoperative care is essential.