Albumin as a Predictor of Periprosthetic Joint Infection Following Total Joint Arthroplasty: Identifying a New Data-Driven Threshold Utilizing a Continuous Variable Analysis.

BACKGROUND

Albumin is a preoperative risk stratification tool for patients undergoing primary total knee arthroplasty (TKA) and total hip arthroplasty (THA). However, existing literature predominantly evaluates serum albumin levels as a categorical variable using predetermined cut-off values, limiting our ability to identify a data-driven risk threshold. Our study addresses this gap by analyzing albumin as a continuous variable, aiming to establish a more clinically relevant preoperative threshold for identifying patients at increased risk of postoperative complications.

METHODS

A healthcare database was used to retrospectively identify all primary TKA and THA patients between 2016 and 2021 with available preoperative albumin values within a 28-day window. The primary outcome of interest was the 90-day periprosthetic joint infection (PJI) risk. Utilizing logistic regression, restricted cubic splines were employed to model the relationship between preoperative albumin as a continuous variable and PJI risk. Bootstrap simulation was used to determine a cutpoint indicative of an albumin level, below which a significant increase in PJI risk was observed. Similar analyses were performed for aggregate medical and surgical complications. In total, 32,952 total patients (THA: 37.9%; TKA: 62.1%) who had preoperative albumin were identified. Of these, 184 (0.56%) individuals developed PJI.

RESULTS

For both TKA and THA, bootstrap analysis identified a preoperative albumin cutpoint of 3.1 g/dL, below which the risk of PJI and medical complications significantly increased. While hypoalbuminemia was not associated with a higher risk of surgical complications following TKA, the risk of surgical complications significantly increased for THA patients with albumin levels below 3.1 g/dL.

CONCLUSIONS

Patients undergoing TKA or THA who had a preoperative albumin < 3.1 g/dL are at increased risk of PJI, medical complications, and surgical complications. Patients who have hypoalbuminemia should be counseled regarding the increased risk of infection, and attempts should be made to enhance these patients' nutritional status.