Sex-Based Differences in 90-Day Postoperative Complications Among Anemic Total Hip Arthroplasty Patients

Background Preoperative anemia is a risk factor for adverse outcomes following total hip arthroplasty (THA), disproportionately affecting females and contributing to morbidity. While both anemia and sex are independently linked to postoperative complications, few studies have examined outcomes within anemic patients stratified by sex. This study compared 90-day postoperative complication rates between anemic male and anemic female patients undergoing primary THA. Methods A retrospective cohort analysis was performed with a final matched analytic cohort of 45,788 anemic adults undergoing primary THA. Anemia was defined by the World Health Organization sex-based hemoglobin thresholds. Anemic male and anemic female patients were matched 1:1 using propensity scores based on demographics, comorbidities, and risk factors. Ninety-day postoperative complications were assessed using International Classification of Diseases, Tenth Revision and Current Procedural Terminology codes. Statistical comparisons included odds ratios, Kaplan-Meier survival analysis, and Cox proportional hazards models. Results The matched sex-based comparison revealed distinct complication profiles. Anemic females experienced higher rates of readmission, wound dehiscence, urinary tract infections, and transfusions. Anemic males had higher incidences of deep vein thrombosis and acute kidney injury. Complications such as sepsis, pneumonia, prosthetic joint infection, and mortality did not differ significantly by sex, contrasting with literature on unstratified populations. Conclusions Within anemic THA patients, postoperative complication patterns differed meaningfully by sex, supporting the need for sex-informed perioperative risk assessment. Current hemoglobin thresholds and perioperative risk models may insufficiently account for physiological and clinical sex differences. Further study is needed to determine whether sex-specific preoperative optimization strategies can improve outcomes.