Diagnoses and timing of 30-day readmissions after hospitalization for heart failure, acute myocardial infarction, or pneumonia

Abstract

Importance: To better guide strategies intended to reduce high rates of 30-day readmission after hospitalization for heart failure (HF), acute myocardial infarction (MI), or pneumonia, further information is needed about readmission diagnoses, readmission timing, and the relationship of both to patient age, sex, and race.

Objective: To examine readmission diagnoses and timing among Medicare beneficiaries readmitted within 30 days after hospitalization for HF, acute MI, or pneumonia.

Design, setting, and patients: We analyzed 2007-2009 Medicare fee-for-service claims data to identify patterns of 30-day readmission by patient demographic characteristics and time after hospitalization for HF, acute MI, or pneumonia. Readmission diagnoses were categorized using an aggregated version of the Centers for Medicare & Medicaid Services' Condition Categories. Readmission timing was determined by day after discharge.

Main outcome measures: We examined the percentage of 30-day readmissions occurring on each day (0-30) after discharge; the most common readmission diagnoses occurring during cumulative periods (days 0-3, 0-7, 0-15, and 0-30) and consecutive periods (days 0-3, 4-7, 8-15, and 16-30) after hospitalization; median time to readmission for common readmission diagnoses; and the relationship between patient demographic characteristics and readmission diagnoses and timing.

Results: From 2007 through 2009, we identified 329,308 30-day readmissions after 1,330,157 HF hospitalizations (24.8% readmitted), 108,992 30-day readmissions after 548,834 acute MI hospitalizations (19.9% readmitted), and 214,239 30-day readmissions after 1,168,624 pneumonia hospitalizations (18.3% readmitted). The proportion of patients readmitted for the same condition was 35.2% after the index HF hospitalization, 10.0% after the index acute MI hospitalization, and 22.4% after the index pneumonia hospitalization. Of all readmissions within 30 days of hospitalization, the majority occurred within 15 days of hospitalization: 61.0%, HF cohort; 67.6%, acute MI cohort; and 62.6%, pneumonia cohort. The diverse spectrum of readmission diagnoses was largely similar in both cumulative and consecutive periods after discharge. Median time to 30-day readmission was 12 days for patients initially hospitalized for HF, 10 days for patients initially hospitalized for acute MI, and 12 days for patients initially hospitalized for pneumonia and was comparable across common readmission diagnoses. Neither readmission diagnoses nor timing substantively varied by age, sex, or race.

Conclusion and relevance: Among Medicare fee-for-service beneficiaries hospitalized for HF, acute MI, or pneumonia, 30-day readmissions were frequent throughout the month after hospitalization and resulted from a similar spectrum of readmission diagnoses regardless of age, sex, race, or time after discharge.

Figure 1

The percentage of 30-day readmissions by day (0–30) following hospitalization for heart failure, acute myocardial infarction, or pneumonia. The denominators used to calculate the percentage of 30-day readmissions on each day after hospitalization were 329,308 30-day readmissions following HF hospitalization, 108,992 30-day readmissions following AMI hospitalization, and 214,239 30-day readmissions following pneumonia hospitalization.

Figure 2

The percentage of patients readmitted with common readmission diagnoses during cumulative time periods following hospitalization for heart failure, acute myocardial infarction, or pneumonia. The denominators used to calculate the percentage of 30-day readmissions due to common readmission diagnoses during each cumulative time period after hospitalization for HF were 44,257 readmissions for days 0–3, 104,362 readmissions for days 0–7, 201,005 readmissions for days 0–15, and 329,308 readmissions for days 0–30. Analogously, following AMI hospitalization, the denominators used were 20,801 readmissions for days 0–3, 43,687 readmissions for days 0–7, 73,641 readmissions for days 0–15, and 108,992 readmissions for days 0–30. Following pneumonia hospitalization, the denominators used were 32,829 readmissions for days 0–3, 71,995 readmissions for days 0–7, 134,033 readmissions for days 0–15, and 214,239 readmissions for days 0–30.

Figure 2

The percentage of patients readmitted with common readmission diagnoses during cumulative time periods following hospitalization for heart failure, acute myocardial infarction, or pneumonia. The denominators used to calculate the percentage of 30-day readmissions due to common readmission diagnoses during each cumulative time period after hospitalization for HF were 44,257 readmissions for days 0–3, 104,362 readmissions for days 0–7, 201,005 readmissions for days 0–15, and 329,308 readmissions for days 0–30. Analogously, following AMI hospitalization, the denominators used were 20,801 readmissions for days 0–3, 43,687 readmissions for days 0–7, 73,641 readmissions for days 0–15, and 108,992 readmissions for days 0–30. Following pneumonia hospitalization, the denominators used were 32,829 readmissions for days 0–3, 71,995 readmissions for days 0–7, 134,033 readmissions for days 0–15, and 214,239 readmissions for days 0–30.

Figure 3

The percentage of patients readmitted with common readmission diagnoses during consecutive time periods following hospitalization for heart failure, acute myocardial infarction, or pneumonia. The denominators used to calculate the percentage of 30-day readmissions due to common readmission diagnoses during each consecutive time period after hospitalization for HF were 44,257 readmissions for days 0–3, 60,105 readmissions for days 4–7, 96,643 readmissions for days 8–15, and 128,303 readmissions for days 16–30. Analogously, following AMI hospitalization, the denominators used were 20,801 readmissions for days 0–3, 22,886 readmissions for days 4–7, 29,954 readmissions for days 8–15, and 35,531 readmissions for days 16–30. Following pneumonia hospitalization, the denominators used were 32,829 readmissions for days 0–3, 39,166 readmissions for days 4–7, 62,038 readmissions for days 8–15, and 80,206 readmissions for days 16–30.

Figure 3

The percentage of patients readmitted with common readmission diagnoses during consecutive time periods following hospitalization for heart failure, acute myocardial infarction, or pneumonia. The denominators used to calculate the percentage of 30-day readmissions due to common readmission diagnoses during each consecutive time period after hospitalization for HF were 44,257 readmissions for days 0–3, 60,105 readmissions for days 4–7, 96,643 readmissions for days 8–15, and 128,303 readmissions for days 16–30. Analogously, following AMI hospitalization, the denominators used were 20,801 readmissions for days 0–3, 22,886 readmissions for days 4–7, 29,954 readmissions for days 8–15, and 35,531 readmissions for days 16–30. Following pneumonia hospitalization, the denominators used were 32,829 readmissions for days 0–3, 39,166 readmissions for days 4–7, 62,038 readmissions for days 8–15, and 80,206 readmissions for days 16–30.