Superoxide Dismutase and Glutathione Reductase as Indicators of Oxidative Stress Levels May Relate to Geriatric Hip Fractures' Survival and Walking Ability: A Propensity Score Matching Study

Abstract

Background: Oxidative stress status may affect bone metabolism and regeneration. However, few studies reported whether oxidative stress could impact the outcomes of hip fractures. This study aimed to explore if superoxide dismutase and glutathione reductase, the critical antioxidant enzymes, correlated with the prognosis of hip fractures.

Methods: Patients with hip fractures were extracted from our database, and those who met the inclusion criteria were analyzed. Propensity score matching was used to reduce the influence of confounding factors, and ROC curves based on matched populations were created to determine the optimal cutoff points of SOD and GR. Then, outcomes between SOD or GR and outcomes of hip fractures were compared.

Results: Out of 301 patients enrolled in this study, 50 patients died within one year. After a 1:1 PSM, the patients with less than 1-year survival had significantly lower SOD (p = 0.026) and GR (p = 0.021) than those who were still alive at one year. Logistics analysis showed that low SOD and low GR may be independent risk factors for 6-month survival, 1-year survival, 6-month free walking ability, and 1-year free walking ability.

Conclusion: SOD and GR may be the independent risk factors for survival and walking abilities of hip fractures.

Keywords: glutathione reductases; hip fractures; oxidative stress; prognosis; superoxide dismutase.

Figure 1

Flowcharts of our study.

Figure 2

Serum levels of SOD and GR in the patients with Hip fracture after surgery grouped by one-year survival (A and B), and ROC curves of SOD and GR for one-year survival (C and D). (A and B) The patients who survived more than one year had significantly higher SOD levels (p = 0.026) than those who survived less than one year in the PSM population, as well as GR (p = 0.021); (C and D) Both SOD (AUROC: 0.635) and GR (AUROC: 0.640) were able to predict the 1-year survival according to the ROC curves.

Figure 3

Kaplan–Meier analyses of one-year survival based on optimal serum levels of SOD (112.5 U/mL) and GR (52.5 U/L). (A) Kaplan–Meier analysis showed that SOD values of 112.5 U/mL significantly differentiated patients who died within one year and survived more than one year (p < 0.001), (B) SOD values of 52.5 U/L significantly differentiated patients who died within one year and survived more than one year (p < 0.001).