Background: While advanced age is a known risk factor for postoperative complications following hip arthroplasty, its role as an independent predictor versus a surrogate for comorbidity remains unclear, particularly in developing countries. This study aimed to investigate the independent impact of age on postoperative outcomes and explore the mediating role of key comorbidities in a resource-limited setting. Methods: We retrospectively reviewed 769 adult patients undergoing hip arthroplasty at a Vietnamese tertiary hospital (2021–2024), categorized into three groups: younger adults (18–64 years), older adults (65–79 years), and oldest old (≥80 years). The primary outcome was a composite of major postoperative complications. Multivariable logistic regression and structural equation modeling were used to identify independent predictors and assess mediation effects. Results: Among 769 patients, 363 were younger (47.2%), 241 older adults (31.3%), and 165 oldest old (21.5%). Complication rates increased significantly with age (18.7%, 36.9%, and 60.0%, respectively; p<0.001). However, multivariable adjustment showed that age was not an independent predictor. Instead, heart failure (adjusted odds ratio [aOR]=5.49, 95% confidence interval [CI] 2.19–13.74) and preoperative anemia (aOR=1.77, 95% CI 1.21– 2.59) were identified as independent risk factors. Mediation analysis revealed that the effect of age on complications was significantly mediated through preoperative anemia. Conclusion Increased postoperative risk in older adults is driven by comorbidity burden rather than chronological age. Preoperative anemia and heart failure are critical, independent predictors, with anemia acting as a key mediator for the effects of age. Individualized correction of modifiable comorbidities may be more beneficial than using age alone to assess surgical risk.

Objective To evaluate the impact of plant growth regulators including kinetin (KN), benzyl adenine and naphthalene acetic acid, yeast extract and casein hydrolyzate on biomass accumulation of Vietnamese ginseng Panax vietnamensis (P. vietnamensis) in cell suspension culture. Methods Cell suspension cultures were established from friable calluses derived from leaves and petioles of 3-year-old in-vitro P. vietnamensis plants. The cell suspension cultures were grown in Murashige and Skoog basal media supplemented with various concentrations of KN, benzyl adenine, naphthalene acetic acid, and yeast extract and casein hydrolyzate. Results All tested factors generated an increase in the cell biomass of P. vietnamensis in suspension culture, but the impact of each varies depended on the factor type, concentration, and incubation period. Addition of 2.0 mg/L KN resulted in the largest biomass increase after 24 d, (57.0 ± 0.9) and (3.1 ± 0.1) mg/mL fresh and dry weight, respectively, whereas addition of benzyl adenine or naphthalene acetic acid produced optimum levels of Panax cell biomass at 1.0 and 1.5 mg/L, respectively. Addition of the elicitor yeast extract led to a 1.4–2.4 fold increase in biomass of P. vietnamensis, while addition of casein hydrolyzate enhanced biomass accumulation 1.8–2.6 fold. Conclusions The addition of each factor causes significant changes in biomass accumulation of P. vietnamensis. The largest biomass accumulation is from cultures grown in MS media containing 2.0 mg/L KN for 24 d. The outcome of the present study provides new insights into the optimal suspension culture conditions for studies on the in vitro cell biomass production of P. vietnamensis.