Does reducing length of stay increase rehospitalization of medicare fee-for-service beneficiaries discharged to skilled nursing facilities?

Abstract

Objectives: To analyze the relationship between length of stay and rehospitalization.

Design: Retrospective cohort study.

Setting: Six thousand five hundred thirty-seven hospitals nationwide from January 1999 through September 2005.

Participants: Medicare fee-for-service beneficiaries associated with 2,101,481 hospitalizations.

Measurements: Thirty-day rehospitalization derived from Medicare hospital claims using the implementation of Medicare's post-acute care transfer policy as a quasi-experiment.

Results: Medicare's post-acute care transfer policy led to immediate declines in length of stay. A 1-day decrease in length of stay was associated with an absolute increase in 30-day rehospitalization of 1.56 percentage points (95% confidence interval (CI) = 0.30-2.82) for acute myocardial infarction (AMI) with major complications and 0.81 percentage points (95% CI = 0.03-1.60) for kidney infection or urinary tract infection (UTI) without major complications. Individuals hospitalized for AMI without major complications, heart failure, or kidney infection or UTI with major complications had no increase in 30-day rehospitalization.

Conclusion: A 1-day reduction in hospital length of stay was not consistently associated with a higher rate of rehospitalization.

Keywords: Medicare; length of stay; quality of care; rehospitalization; skilled nursing facilities.

Figure 1

Adjusted* mean lengths of stay for case DRGs. * Adjusted for policy status, age, gender, race, ICU use, Charlson Comorbidity Index, and month/year of discharge. Note: DRG 121 - Acute myocardial infarction with major complications DRG 122 - Acute myocardial infarction without major complications DRG 127 - Heart failure and shock DRG 320 - Kidney or urinary tract infections with major complications DRG 321 - Kidney or urinary tract infections without major complications

Figure 2

Risk adjusted mean length of stay for septicemia discharges pre/post implementation of Medicare’s post-acute care transfer policy. *Adjusted for age, gender, race, and Charlson Comorbidity Index.

Figure 3

Instrumental variable estimates of the effect of a one day decline in length of stay on 30-day rehospitalization (95% robust confidence intervals). Note: DRG 121 - Acute myocardial infarction with major complications DRG 122 - Acute myocardial infarction without major complications DRG 127 - Heart failure and shock DRG 320 - Kidney or urinary tract infections with major complications DRG 321 - Kidney or urinary tract infections without major complications

Figure 4

Instrumental variable estimates of the effect of a one day decline in length of stay on 30-day rehospitalization among patients with the highest Charlson Comorbidity Index (95% robust confidence intervals). Note: DRG 121 - Acute myocardial infarction with major complications DRG 122 - Acute myocardial infarction without major complications DRG 127 - Heart failure and shock DRG 320 - Kidney or urinary tract infections with major complications DRG 321 - Kidney or urinary tract infections without major complications