Factors Associated With Variation in Long-term Acute Care Hospital vs Skilled Nursing Facility Use Among Hospitalized Older Adults

Abstract

Importance: Despite providing an overlapping level of care, it is unknown why hospitalized older adults are transferred to long-term acute care hospitals (LTACs) vs less costly skilled nursing facilities (SNFs) for postacute care.

Objective: To examine factors associated with variation in LTAC vs SNF transfer among hospitalized older adults.

Design, setting, and participants: We conducted this retrospective observational cohort study of hospitalized older adults (≥65 years) transferred to an LTAC vs SNF during fiscal year 2012 using national 5% Medicare data.

Main outcomes and measures: Predictors of LTAC transfer were assessed using a multilevel mixed-effects model adjusting for patient-, hospital-, and region-level factors. We estimated variation partition coefficients and adjusted hospital- and region-specific LTAC transfer rates using sequential models.

Results: Among 65 525 hospitalized older adults (42 461 [64.8%] women; 39 908 [60.9%] ≥85 years) transferred to an LTAC or SNF, 3093 (4.7%) were transferred to an LTAC. We identified 29 patient-, 3 hospital-, and 5 region-level independent predictors. The strongest predictors of LTAC transfer were receiving a tracheostomy (adjusted odds ration [aOR], 23.8; 95% CI, 15.8-35.9) and being hospitalized in close proximity to an LTAC (0-2 vs >42 miles; aOR, 8.4, 95% CI, 6.1-11.5). After adjusting for case-mix, differences between patients explained 52.1% (95% CI, 47.7%-56.5%) of the variation in LTAC use. The remainder was attributable to hospital (15.0%; 95% CI, 12.3%-17.6%), and regional differences (32.9%; 95% CI, 27.6%-38.3%). Case-mix adjusted LTAC use was very high in the South (17%-37%) compared with the Pacific Northwest, North, and Northeast (<2.2%). From the full multilevel model, the median adjusted hospital LTAC transfer rate was 2.1% (10th-90th percentile, 0.24%-10.8%). Even within a region, adjusted hospital LTAC transfer rates varied substantially (intraclass correlation coefficient [ICC], 0.26; 95% CI, 0.23-0.30).

Conclusions and relevance: Although many patient-level factors were associated with LTAC use, half of the variation in LTAC vs SNF transfer is independent of patients' illness severity or clinical complexity, and is explained by where the patient was hospitalized and in what region, with far greater use in the South. Even among hospitals in regions with similar LTAC access, there was considerable variation in LTAC use. Given the higher expense associated with LTACs vs SNFs, greater attention is needed to define the optimal role of LTACs in the postacute care of older adults.

Figure 1.. Adjusted LTAC Transfer Rate by Hospital Referral Region

The mean adjusted long-term acute care hospital (LTAC) transfer probability (vs skilled nursing facility) by hospital referral region among hospitalized older adults was estimated from the case-mix only multilevel model adjusted for all patient-level predictors shown in Table 2. Hospital referral regions (n = 304) are defined as regional health care markets for tertiary medical care.

Figure 2.. Hospital Variation in LTAC Use

Adjusted hospital LTAC transfer rates were estimated from the full multilevel model and shown for hospitals with 10 or more patients transferred to an LTAC or SNF (n = 1990). A, Hospitals are sorted in ascending order by their adjusted transfer rate and numbered. Mean hospital adjusted transfer rates are shown as dark blue points. The 95% CIs are shown as light gray vertical bars capped by light blue markers. The median hospital adjusted transfer rate was 2.1% (10th-90th percentile, 0.2%-10.8%). The inset shows a magnified version to better illustrate the variability of hospitals in the bottom 90th percentile of adjusted LTAC transfer rates. B, Hospitals are shown as individual markers within hospital referral regions (HRRs). The HRRs were sorted in ascending order by their case-mix adjusted LTAC transfer rates (as per Figure 1) and further categorized by tertiles of use. For each of the 304 HRRs, we estimated the HRR-specific 25th and 75th percentile values for adjusted hospital LTAC transfer rates. A low LTAC transfer hospital (blue diamond) was defined as having an adjusted transfer rate less than their HRR-specific 25th percentile hospital transfer rate. An average LTAC transfer hospital (black square) was defined as having between the 25th-75th percentile transfer rate. A high LTAC transfer hospital (orange circle) was defined as greater than the 75th percentile rate. All hospitals in HRRs with fewer than 4 hospitals were defined as average. This approach compares a hospital’s adjusted LTAC transfer rate with those of their peers within the same HRR.