Length of Stay for Hip or Knee Replacements and Hospital Readmission Rates

Reducing readmission rates for total hip and knee replacements is a topic of much interest to Virginia hospitals. At present, Virginia readmission rates ranks 49th out of 50 states and Washington, D.C. What’s more, readmission penalties for hip and knee replacements are forecast to account for more than 50 percent of the total penalties Virginia hospitals incur as part of the Centers for Medicare and Medicaid Services Hospital Readmissions Reduction Program in 2016. VHHA concurrently is conducting a series of statewide analyses to identify possible trends involving Hip and Knee readmissions. Length of hospital stay is often viewed as a potential predictor for a readmission. Hospitals that discharge patients too early may be at increased odds of releasing patients who may later incur post-discharge complications attributable to inadequate preparation for leaving inpatient care. In its analysis, VHHA used logistic regression to test each hospital’s average length of stay for hip and knee replacements compared to a facility’s risk-adjusted standardized rate (RSRR). No statistically significant correlation was found (see Figure 1). So what does this mean for clinicians? While more readmissions can be anticipated involving patients with conditions that are significant in the total joint replacement readmission model, predicting readmission based solely on length of stay appears statistically unsound. The majority of readmitted patients have three or more chronic diseases that also need to be managed during recovery (see Figure 2). This suggests that even when controlling for length of stay, other contributing health factors can play a substantial role in whether a patient will be readmitted. One reasonable conclusion to draw is that managing transitions from home to hospital to home (or another site) for recuperation is one key to keeping readmissions low. (2/19)

2-19 A










Figure 2: Top Comorbidities for Total Hip/Knee Replacements

Top Comorbidities (TJR) Odds Ratio
Cellulitis 3.01
Hematological 2.55
Major Psych 1.92
History of Infection 1.57
Disorders of Fluid Balance 1.52
COPD 1.52
Other injuries 1.44
Major Symptoms (Neurological) 1.44
Morbid Obesity 1.32
Chronic Atherosclerosis 1.30
Pneumonia 1.29
Polyneuropathy 1.28
ESRD Dialysis 1.27
Stroke 1.26
Rheumatoid Arthritis 1.25
Vascular Disease (W Comp) 1.25
Renal Failure 1.25
Chronic Heart Failure 1.24
Hypertension 1.22