Hospital readmissions measure how often people return to a hospital after an earlier admission, commonly within 30 days. AHRQ HCUP statistics show that the national pattern varies substantially by year, diagnosis, payer, location, and patient group. In 2018, there were 3.8 million 30-day all-cause adult readmissions, equal to 14 readmissions per 100 index admissions. In 2020, the overall rate was similar at 13.9 per 100 index admissions, while the average readmission cost rose to $16,300.
Hospital readmission statistics at a glance
- National counts, rates, and costs
- Readmissions by payer
- Conditions with the most readmissions
- Conditions with the highest rates
- Earlier diagnosis-level statistics
- Differences by location and patient group
National counts, rates, and costs
The AHRQ HCUP Statistical Brief #278 reports 2018 adult hospital readmissions. The all-cause total was 3.8 million, and the overall readmission rate was 14.0 per 100 index admissions. The same report gives an average readmission cost of $15,200. These figures describe 30-day all-cause adult readmissions in the United States during 2018.
The 2020 figures in AHRQ HCUP Statistical Brief #304 show 3,850,413 total readmissions and an overall rate of 13.9 per 100 index admissions. Average costs were $16,300 for readmissions and $14,500 for index admissions, a reported 12.4 percent difference. The cost figures are averages for the report’s 2020 measures, not a price for every hospital or patient.
The two years provide a compact comparison:
| Measure | 2018 | 2020 |
|---|---|---|
| Overall readmission rate | 14.0 per 100 index admissions | 13.9 per 100 index admissions |
| Total readmissions | 3.8 million | 3,850,413 |
| Average readmission cost | $15,200 | $16,300 |
Source: [AHRQ HCUP Statistical Brief #278] and [AHRQ HCUP Statistical Brief #304].
Readmissions by payer
Insurance category is associated with large differences in the reported rates. In 2018, Medicare accounted for 60.3 percent of adult readmissions, or 2.3 million readmissions. Medicare stays had a 16.9 percent readmission rate. Medicaid accounted for 19.0 percent, or 721,300 readmissions. Privately insured stays had the lowest reported 2018 rate at 8.7 percent.
The 2020 payer figures were 17.0 per 100 index admissions for Medicare, with 2,198,000 readmissions, and 13.6 per 100 for Medicaid, with 791,000 readmissions. Self-pay or no-charge stays had an 11.9 per 100 rate, compared with 8.5 per 100 for private insurance.
Condition-specific payer figures also show variation. In 2018, chronic kidney disease had a 28.6 percent readmission rate among Medicare stays, 32.5 percent among Medicaid stays, and 19.7 percent among privately insured stays. For Medicare’s condition mix, septicemia represented 9.3 percent of readmissions and heart failure represented 7.8 percent.
Older AHRQ HCUP data show similar payer differences for particular diagnoses. In 2010, congestive heart failure had readmission rates of 30.1 percent for Medicaid, 25.0 percent for Medicare, 19.5 percent for privately insured patients, and 17.1 percent for uninsured patients. Schizophrenia and other psychotic conditions had rates of 24.0 percent for Medicaid, 23.7 percent for Medicare, 16.1 percent for privately insured patients, and 15.1 percent for uninsured patients.
For acute and unspecified renal failure in 2010, the rates were 25.0 percent for Medicaid, 22.7 percent for Medicare, 17.0 percent for privately insured patients, and 13.3 percent for uninsured patients. Diabetes with complications had rates of 23.6 percent for Medicare, 23.5 percent for Medicaid, 13.6 percent for privately insured patients, and 14.1 percent for uninsured patients.
Conditions with the most readmissions
The 2018 diagnosis counts identify septicemia as the leading principal diagnosis at index admission, with 314,600 readmissions, or 8.3 percent of all adult readmissions. Heart failure generated 233,100 readmissions. Diabetes mellitus with complication generated 122,400, while chronic obstructive pulmonary disease and bronchiectasis generated 106,300.
Pneumonia generated 97,500 readmissions, and acute and unspecified renal failure generated 96,900. The four leading diagnoses—septicemia, heart failure, diabetes, and COPD—accounted for 20 percent of adult readmissions. The 20 leading principal diagnoses together accounted for 48.5 percent.
The 2020 diagnosis mix was led by circulatory system diseases, which accounted for 16.8 percent of all readmissions, or 647,861 of 3,850,413. Infectious and parasitic diseases accounted for 12.4 percent, and digestive system diseases accounted for 11.6 percent.
Conditions with the highest rates
Counts and rates measure different aspects of readmission. A condition can produce many readmissions because it is common, while another can have a higher rate among a smaller number of admissions.
In 2018, sickle cell trait or anemia had the highest overall readmission rate in the reported diagnosis group at 36.1 percent. Its rate was 37.2 percent among Medicare stays and 39.4 percent among Medicaid stays. Hepatic failure had a 34.9 percent overall rate, cirrhosis of the liver had a 30.8 percent rate, diseases of white blood cells had a 29.3 percent rate, and chronic kidney disease had a 28.1 percent rate.
The leading rate varied by payer. Hepatic failure had the highest rate among privately insured stays at 31.9 percent. Cirrhosis of the liver had the highest rate among self-pay or no-charge stays at 26.7 percent. In the 2020 broad disease categories, blood diseases had the highest rate at 23.8 per 100 index admissions, followed by neoplasms at 19.0 per 100.
The 2016 AHRQ HCUP figures also identify blood diseases as the highest-rate broad category, at 25.3 percent and 104,800 readmissions. Circulatory system diseases produced 754,900 readmissions at a 16.4 percent rate, while neoplasms produced 226,900 at a 17.9 percent rate.
Earlier diagnosis-level statistics
AHRQ HCUP Statistical Brief #153 provides diagnosis-level figures for 2010. Pneumonia had 924,160 index stays and 144,894 readmissions, for a 15.7 percent rate. Congestive heart failure had 847,073 index stays and 209,017 readmissions, for a 24.7 percent rate. Septicemia had 696,122 index stays and 145,896 readmissions, for a 21.0 percent rate.
COPD and bronchiectasis had 606,186 index stays and 126,443 readmissions, for a 20.9 percent rate. Schizophrenia and other psychotic disorders had 397,166 index stays and 88,629 readmissions, for a 22.3 percent rate. Acute and unspecified renal failure had 326,586 index stays and 70,756 readmissions, for a 21.7 percent rate.
Several less common diagnoses had high percentages. Sickle cell anemia had 87,326 index stays and 27,837 readmissions, for a 31.9 percent rate. Gangrene had 33,786 index stays and 10,693 readmissions, for a 31.6 percent rate. Hepatitis had 37,480 index stays and 11,593 readmissions, for a 30.9 percent rate. Disease of white blood cells had 54,861 index stays and 16,771 readmissions, for a 30.6 percent rate. Chronic renal failure had 17,394 index stays and 4,766 readmissions, for a 27.4 percent rate.
The same 2010 report recorded a 25.5 percent readmission rate for children aged 1–17 with a complication of a device, implant, or graft. The rate for that complication was 25.4 percent among Medicaid patients.
Differences by location and patient group
The 2020 statistics also separate rates by metropolitan status and race or ethnicity. Patients in large central metropolitan areas had a 14.6 per 100 index admissions rate and 989,000 readmissions. Rural patients had a 13.0 per 100 rate and 586,000 readmissions.
Among the reported racial and ethnic categories, non-Hispanic Black patients had a 16.0 per 100 index admissions rate in 2020. Non-Hispanic Asian or Pacific Islander patients had an 11.7 per 100 rate. These figures describe differences in the measured readmission rates for the specified groups and year; they do not by themselves identify the causes of those differences.
Pregnancy and childbirth had the lowest 2020 readmission rate among the listed broad categories, at 3.6 per 100 index admissions. That rate is not directly comparable with a diagnosis-specific percentage unless the admission definitions and category level are kept in view.
Source labels: AHRQ HCUP Statistical Brief #153 reports the 2010 figures; AHRQ HCUP Statistical Brief #248 reports the 2016 figures; AHRQ HCUP Statistical Brief #278 reports the 2018 figures; and AHRQ HCUP Statistical Brief #304 reports the 2020 figures. The 2010, 2016, and 2018 figures are historical report values and are presented with their original measurement years.