The Implications of Long-Term Acute Care Hospital Transfer Practices for Measures of In-Hospital Mortality and Length of Stay

Rationale: The National Quality Forum recently endorsed in-hospital mortality and intensive care unit length of stay (LOS) as quality indicators for patients in the intensive care unit. These measures may be affected by transferring patients to long-term acute care hospitals (LTACs). Objectives: To quantify the implications of LTAC transfer practices on variation in mortality index and LOS index for patients in academic medical centers. Methods: We used a cross-sectional study design using data reported to the University HealthSystem Consortium from 2008-2009. Data were from patients who were mechanically ventilated for more than 96 hours. Measurements and Main Results: Using linear regression, we measured the association between mortality index and LTAC transfer rate, with the hospital as the unit of analysis. Similar analyses were conducted for LOS index and cost index. A total of 137 hospitals were analyzed, averaging 534 transfers to LTAC per hospital during the study period. Mean +/- SD in-hospital mortality was 24 +/- 6.4%, and observed LOS was 30.4 +/- 8.2 days. The mean LTAC transfer rate was 15.7 +/- 13.7%. Linear regression demonstrated a significant correlation between transfer rate and mortality index (R(2) = 0.14; P < 0.0001) and LOS index (R(2) = 0.43; P < 0.0001). Conclusions: LTAC hospital transfer rate has a significant impact on reported mortality and LOS indices for patients requiring prolonged acute mechanical ventilation. This is an example of factors unrelated to quality of medical care or illness severity that must be considered when interpreting mortality and LOS as quality indicators.