Cumulative effect of chronic dehydration and age on postoperative complications after total shoulder arthroplasty

Background: Dehydration is a modifiable risk factor that should be optimized prior to all surgical procedures. The aim of this study was to determine the effects of dehydration on postoperative complications following total shoulder arthroplasty (TSA). Methods: The American College of Surgeons National Surgical Quality Improvement database was queried for all patients who underwent TSA between 2015 and 2019 and a total of 16,993 patients were included in this study. The study population was subsequently classified into 3 categories: 8498 (50.0%) nondehydrated patients with blood urea nitrogen/creatinine (BUN/Cr) < 20, 4908 (28.9%) moderately dehydrated patients with 20 ≤ BUN/Cr ≤ 25, and 3587 (21.1%) severely dehydrated patients with 25 < BUN/Cr. A subgroup analysis involving only elderly patients aged > 65 years and normalized gender-adjusted Cr values was also performed. Postoperative complications within 30 days of the TSA were collected. Multivariate logistic regression analysis was conducted to explore the correlation between dehydration and postoperative complications. Results: Adjusted multivariate logistic regression analysis showed that the severely dehydrated cohort had a greater risk of postoperative transfusion, mortality, nonhome discharge, and increased length of stay (all P < .05). The moderately dehydrated cohort had a greater risk of wound dehiscence (P = .044). Among the elderly, severely dehydrated patients had a greater risk of cardiac complications, postoperative transfusion, mortality, nonhome discharge, and increased length of stay (all P < .05). Finally, the elderly moderately dehydrated cohort had a greater risk of postoperative transfusion and nonhome discharge (all P < .05). Conclusion: BUN/Cr ratio is an important preoperative diagnostic tool to identify at-risk dehydrated patients. Providers should optimize dehydration to prevent complications, decrease costs, and improve discharge planning.