Predictors for shorter and longer length of hospital stay outliers: a retrospective case-control study of 8247 patients at a university hospital trauma department.

BACKGROUND: Providing efficient healthcare is important for hospitals. Shorter and longer length of hospital stay (LOS) outliers influence financial results and reimbursement. The objective of this study was to identify independent diagnosis related group (DRG)-related risk factors for shorter and longer LOS outlier status.

METHODS: A retrospective case-control study was conducted at a Swiss level 1 trauma centre between January 2012 and December 2014. The study included all patients with available information on LOS based on DRG. Many predictor variables were tested. The outcome variable was the DRG-based LOS. Logistic regression models were fitted for shorter and longer LOS outliers, with a significance level of <1%.

RESULTS: A total of 8247 patients were analysed, of whom inliers were more frequent than shorter and longer LOS outliers (n = 5838 [70.8%] vs n = 1996 [24.2%] vs n = 413 [5.0%]). Predictors for shorter LOS outliers were death (odds ratio [OR] 4.89, 95% confidence interval [CI] 3.27-7.31), concussion (OR 4.87, 95% CI 4.20-5.63) and psychiatric disease (OR 1.85, 95% CI 1.46-2.34). Predictors for longer LOS outliers were age ≥65 years (OR 1.74, 95% CI 1.31-2.30), number of diagnoses ≥5 (OR 2.07, 95% CI 1.52-2.81), comorbidity (OR 1.75, 95% CI 1.28-2.40), number of surgical procedures (OR 1.76, 95% CI 1.36-2.28), complication perioperatively (OR 1.69, 95% CI 1.24-2.30), infection (OR 2.66, 95% CI 1.57-4.49]), concussion (OR 1.52, 95% CI 1.14-2.01) and urinary tract infection (OR 2.34, 95% CI 1.61-3.41).

CONCLUSION: This large study showed that LOS outliers, especially shorter LOS outliers, are relatively common. Patients who died, or had concussion or psychiatric disease were more commonly discharged early. Patients weremore often discharged late if they were aged ≥65 years, had more diagnoses, were comorbid, had more surgical procedures, complications perioperatively, infection, concussion and urinary tract infection. For hospitals, this can help raise awareness and lead to better management of specific diagnoses in order to avoid monetary deficits. For the public health sector, this information may be considered in future revisions of the DRG.