Malnutrition in Elective Shoulder Arthroplasty: A Multi-Institutional Retrospective Study of Preoperative Albumin and Adverse Outcomes.

BACKGROUND Malnutrition is associated with poor postoperative outcomes following knee, hip, and spine surgery. However, whether albumin labs should be part of the routine preoperative workup for shoulder arthroplasty remains understudied. This study investigated the role of preoperative albumin levels in predicting common postoperative adverse outcomes in patients undergoing shoulder arthroplasty. METHODS All shoulder arthroplasty cases performed at two tertiary referral centers between July 2013 and May 2019 (Institution 1) and between June 2007 and Feb 2020 (Institution 2) were reviewed. 421 primary and 71 revision elective shoulder arthroplasty cases had preoperative albumin levels recorded. Common demographic variables and relevant Elixhauser comorbidities were pulled. Outcomes gathered included extended (>3d) postoperative inpatient length of stay (eLOS), 90-day readmission, and discharge to rehab or skilled nursing facility (SNF). RESULTS The prevalence of malnutrition (albumin <3.5 g/dL) was higher in the revision group compared to the primary group (36.6% vs. 19.5%, P = 0.001). Reverse shoulder arthroplasty (P = 0.013) and increasing ASA score (P = 0.016) were identified as independent risk factors for malnutrition in the primary group. In the revision group, liver disease was associated with malnutrition (P = 0.046). Malnourished primary shoulder arthroplasty patients had an increased incidence of eLOS (26.8% vs 13.6%, P = 0.003) and discharge to rehab/SNF (18.3% vs 10.3%, P = 0.045). On univariable analysis, low albumin had an odds ratio of 2.34 for eLOS (P = 0.004), which retained significance in a multivariable model including age, ASA, gender, and BMI (OR 2.11, P = 0.03). On univariable analysis, low albumin had an odds ratio of 1.94 for discharge to SNF/rehab (P = 0.048), but this did not reach significance in the multivariable model. Among revisions, malnourished patients had an increased incidence of eLOS (30.8% vs 6.7%, P = 0.014) and discharge to rehab/SNF (26.9% vs 4.4%, P = 0.010). In both the primary and revision groups, there was no difference in 90-day readmission rate between patients with low or normal albumin. CONCLUSION Malnutrition is more prevalent among revision shoulder arthroplasty patients compared to those undergoing a primary procedure. Primary shoulder arthroplasty patients with low preoperative albumin levels have an increased risk of eLOS and may have an increased need for post-acute care. Low albumin was not associated with risk of 90-day readmissions. Albumin level merits further investigation in large, prospective cohorts to clearly define its role in preoperative risk stratification.