BACKGROUND: Hypoalbuminemia (serum albumin < 3.5 g/dL) is associated with increased morbidity and mortality in patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA). However, costs associated with hypoalbuminemia remain unknown. This study investigated the effect of serum albumin on direct treatment costs, length of stay (LOS), and readmissions for primary and revision THA and TKA patients. METHODS: All adult patients at a single institution undergoing primary or revision THA or TKA between January 2014 and December 2016 were retrospectively reviewed. Patients were stratified by preoperative serum albumin level. The primary outcome was total direct costs at index hospitalization. Secondary outcomes included LOS and readmission within 30 days. Multivariable regressions were utilized to adjust for demographics and comorbidities. RESULTS: Of 3,785 patients, 114 (3.0%) had hypoalbuminemia. After adjustment, hypoalbuminemia was associated with a 16.2% increase in costs (β = 0.162; 95% confidence interval [CI], 0.112 to 0.213; p < 0.001), representing an average cost increase of $3,383 (95% CI, $2,281 to $4,485) relative to costs for serum albumin > 4.5 g/dL. The increased total costs were significantly higher in revision ($4,322, p = 0.034) than in primary ($3,446, p < 0.001) procedures. In adjusted regression, each 1.0 g/dL increase in serum albumin yielded a 6.6% reduction in costs (β = −0.066; 95% CI, −0.090 to −0.042]; p < 0.001), for average savings of $1,282 (95% CI, $759 to $1,806) per unit albumin. Adjusted regressions demonstrated that a 1-point increase in serum albumin reduced readmissions by 53% (odds ratio, 0.47; 95% CI, 0.31–0.73; p = 0.001) and LOS by 0.6 days (β = −0.60; 95% CI, −0.76 to −0.44; p < 0.001). CONCLUSIONS: Hypoalbuminemia is associated with increased total direct costs, LOS, and readmissions following primary and revision THA and TKA. Future efforts to predict and address total costs should take into consideration the patient's preoperative serum albumin levels.
Adult ; Arthroplasty, Replacement, Hip ; Arthroplasty, Replacement, Knee* ; Comorbidity ; Demography ; Health Care Costs* ; Hip* ; Hospitalization ; Humans ; Hypoalbuminemia ; Income ; Knee* ; Length of Stay ; Mortality ; Retrospective Studies ; Serum Albumin*

PURPOSE: Total knee arthroplasty (TKA) is increasing in frequency and cost. Optimization of discharge location may reduce total expenditure while maximizing patient outcomes. Although preoperative illness rating systems—including the American Society for Anesthesiologists Physical Classification System (ASA), severity of illness scoring system (SOI), and Mallampati rating scale (MP)—are associated with patient morbidity and mortality, their predictive value for discharge location, length of stay (LOS), and total costs remains unclear. MATERIALS AND METHODS: We conducted a retrospective analysis of 677 TKA patients (550 primary and 127 revision) treated at a single institution. The influence of ASA, SOI, and MP scores on discharge locations, LOS, and total costs was assessed using multivariable regression analyses. RESULTS: None of the systems were significant predictors of discharge location following TKA. SOI scores of major or higher (β=2.08 days, p < 0.001) and minor (β=−0.25 days, p=0.009) significantly predicted LOS relative to moderate scores. Total costs were also significantly predicted by SOI scores of major or higher (β=$6,155, p=0.022) and minor (β=−$1,163, p=0.007). CONCLUSIONS: SOI scores may be harnessed as a predictive tool for LOS and total costs following TKA, but other mechanisms are necessary to predict discharge location.
Arthroplasty ; Arthroplasty, Replacement, Knee ; Classification ; Health Expenditures ; Humans ; Knee ; Length of Stay ; Mortality ; Osteoarthritis ; Retrospective Studies