2021 Annual Report for the Emerging Infections Program for Clostridioides difficile Infection

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Summary

2021 Annual Report Print Version [PDF – 7 Pages]

Surveillance data from 2021 represent the eleventh year of population-based surveillance for CDI conducted among all 10 Emerging Infections Program sites. The crude overall incidence rate of CDI in 2021 was 110.2 cases per 100,000 persons, with a slightly higher incidence of community associated cases (55.9 cases per 100,000 persons) compared with healthcare-associated cases (54.3 cases per 100,000 persons). The incidence rate of CDI increased with age and was higher in women than in men and higher in White persons than in persons of other races.

Underlying conditions were commonly reported among CDI cases, with 41 percent having a Charlson comorbidity index of ≥2. Antibiotic use in the prior 12 weeks was reported for 61 percent of CDI cases. Eighty-five percent of CDI cases were treated, with vancomycin being the most common treatment given. CDI-related complications, such as toxic megacolon and ileus, were rare.

Surveillance Catchment Areas

California (1 county San Francisco area), Colorado (5 county Denver area); Connecticut (1 county New Haven area); Georgia (8 county Atlanta area); Maryland (9 Eastern Shore and 2 western counties); Minnesota (5 counties); New Mexico (1 county Albuquerque area); New York (1 county Rochester area); Oregon (1 rural county); and Tennessee (1 county Nashville area).

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Population

The surveillance area represents 12,109,721 persons.
Source: U.S. Census Bureau, Population Division, Vintage 2021 Special Tabulation.

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Case Definition

An incident case of Clostridioides difficile infection (CDI) was defined as a C. difficile-positive stool test (toxin or molecular assay) from a person ≥1 year old with no positive test in the prior 8 weeks.

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Methods

Case finding was active, laboratory-based, and population-based. Laboratories serving the surveillance catchment areas reported positive C. difficile tests to EIP staff and were routinely audited with a goal of complete case ascertainment. An initial chart review was performed on all CDI cases in eight EIP sites and on all pediatric cases and a 1/3 random sample of cases age 18 years and older in the two remaining EIP sites with the largest surveillance catchment areas (CO and GA). A subsequent comprehensive chart review was performed on all community-onset cases and a subset of healthcare-facility onset cases.

A standardized case report form (CRF) was completed for each incident case through review of medical records. Inpatient and outpatient medical records were reviewed for information on patient demographics, clinical syndrome, outcome of illness, and relevant healthcare exposures.

A convenience sample of stool specimens or swabs was sent to reference laboratories for C. difficile isolation. Recovered isolates were sent to CDC for molecular typing and characterization.

A CDI case was classified as community-associated (CA) if the C. difficile-positive stool specimen was collected on an outpatient basis or within 3 days after hospital admission in a person with no documented overnight stay in a healthcare facility in the preceding 12 weeks. All CDI cases that did not meet the aforementioned criteria were classified as healthcare-associated (HA). HA cases with disease onset outside of a healthcare facility but with documented overnight stay in a healthcare facility in the preceding 12 weeks were classified as community-onset, healthcare-facility associated (CO-HCFA). HA cases with disease onset in a healthcare facility were classified as healthcare-facility onset (HCFO). HCFO cases were further classified into hospital onset or long-term care facility onset. Incidence rates were calculated using US Census population estimates.

CDI surveillance data undergo regular data cleaning to ensure accuracy and completeness. Patients with case data as of 05/26/2023 were included in this analysis. Because data can be updated as needed, analyses of datasets generated on a different date may yield slightly different results.

Chart showing report methodology
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Results
Table 1 – Reported Number of CDI Cases and Crude Incidence by Sex, Age Group, Race, and Epidemiologic Classification Among the 10 EIP Sites
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Sex Population ≥1 Year of Age Community Associated CDIa No.c Community Associated CDIa Incidenceb Healthcare Associated CDIa No.c Healthcare Associated CDIa Incidenceb All CDI No.c All CDI Incidenceb
Male 5,952,832 2478 41.6 3099 52.1 5577 93.7
Female 6,156,889 4291 69.7 3480 56.5 7771 126.2
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Age Group Population ≥1 Year of Age Community Associated CDIa No.c Community Associated CDIa Incidenceb Healthcare Associated CDIa No.c Healthcare Associated CDIa Incidenceb All CDI No.c All CDI Incidenceb
1-17 years 2,506,710 418 16.7 178 7.1 596 23.8
18-44 years 4,728,721 1668 35.3 839 17.7 2507 53.0
45-49 years 764,997 336 43.9 301 39.4 637 83.3
50-54 years 794,283 494 62.1 373 47.0 867 109.2
55-59 years 780,720 545 69.8 540 69.2 1085 139.0
60-64 years 732,551 651 88.9 700 95.5 1351 184.4
65-70 years 613,116 599 97.7 744 121.4 1343 219.0
70-74 years 499,997 711 142.3 881 176.2 1592 318.4
75-79 years 310,774 555 178.7 773 248.7 1328 427.3
80+ years 377,852 793 209.9 1249 330.6 2042 540.4
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Racea Population ≥1 Year of Age Community Associated CDIa No.c Community Associated CDIa Incidenceb Healthcare Associated CDIa No.c Healthcare Associated CDIa Incidenceb All CDI No.c All CDI Incidenceb
White 8,022,836 5292 66.0 4680 58.3 9972 124.3
Other 4,086,885 1477 36.1 1899 46.5 3376 82.6
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Total Population ≥1 Year of Age Community Associated CDIa No.c Community Associated CDIa Incidenceb Healthcare Associated CDIa No.c Healthcare Associated CDIa Incidenceb All CDI No.c All CDI Incidenceb
All Cases 12,109,721 6769 55.9 6579 54.3 13348 110.2

a The epidemiologic classification was statistically imputed for 3% of the CDI cases selected for medical record review, and race was statistically imputed for 15% of the CDI cases selected for medical record review. The weighted frequency of cases in Colorado and Georgia was based on 33% random sampling for cases aged ≥18 years.
b Cases per 100,000 persons.
c Subcategories may not add to total due to rounding.

Table 2 – Diagnostic Assay Results of CDI Cases (N=13348)
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Diagnostic assay N %
Toxin positive 4140 31
Nucleic acid amplification test (NAAT) positive/toxin negative 4465 33
NAAT positive/toxin result unknowna 4742 36
Unspecified assay 1 <1

a Includes cases diagnosed mainly by NAAT or multiplex PCR panel (i.e., toxin enzyme immunoassay or cell cytotoxicity assay was not performed) or by NAAT as part of a multistep algorithm where the toxin result was not readily known

Table 3 – CDI Cases by Epidemiologic Classification (N=13348)
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Epidemiologic classification N %
Hospital onset 1710 13
LTCF onset 633 5
COHCFA 1773 13
CA 4292 32
Unknowna 4940 37

a Includes 4674 non-sampled cases

Table 4 – CDI Cases by Race and Ethnicity (N=13348)
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Race/Ethnicity N %
Hispanic, any race 893 7
Not known to be Hispanica – Whiteb 6446 48
Not known to be Hispanica – Black or African Americanc 2107 16
Not known to be Hispanica – Asiand 322 2
Not known to be Hispanica – Other or multiple racese 118 <1
Non-Hispanic- Unknown race 225 2
Unknown ethnicity and race 3237 24

a Records either indicated ethnicity was non-Hispanic, or ethnicity was not known
b 531 cases with unknown ethnicity
c 99 cases with unknown ethnicity
d 47 cases with unknown ethnicity
e American Indian or Alaska Native, Native Hawaiian or Other Pacific Islander, or ≥2 races reported; 11 cases with unknown ethnicity

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Table 5 – Location of CDI Cases on the Third Calendar Day Before Incident Specimen Collection (N=8674)
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Location of patient before incident specimen collection N %
Private residence 5970 69
Long-term care facility 650 7
Acute-care hospital (inpatient) 1633 19
Long-term care acute care hospital 45 <1
Homeless 96 1
Incarcerated 7 <1
Other 7 <1
Unknown 266 3
Table 6 – Location of CDI Cases at Time of Incident Specimen Collection (N=8674)
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Location of incident specimen collection N %
Outpatient setting or emergency department 4370 50
Acute care hospital 3566 41
Long-term care facility 428 5
Long-term acute care hospital 39 <1
Other 3 <1
Unknown 268 3
Table 7 – Selected Clinical Characteristics of CDI Cases (N=6558, except where indicated)
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Clinical characteristic N %
Charlson comorbidity index – 0 2642 40
Charlson comorbidity index – 1 1254 19
Charlson comorbidity index – ≥2 2662 41
Underlying conditions – Cardiovascular diseasea,b 1382 21
Underlying conditions – Diabetes mellitusa 1407 21
Underlying conditions – Chronic pulmonary diseasea,c 1419 22
Underlying conditions – Gastrointestinal diseasea,d 1665 25
Underlying conditions – Gastrointestinal disease – Diverticular diseasea 747 11
Underlying conditions – Gastrointestinal disease – Inflammatory bowel diseasea 453 7
Underlying conditions – Gastrointestinal disease – Peptic ulcer diseasea 174 3
Underlying conditions – Gastrointestinal disease – Short gut syndromea 20 <1
Underlying conditions – Gastrointestinal disease – Liver diseasea 439 7
Underlying conditions – Chronic renal diseasea 1241 19
Underlying conditions – Neurologic condition, anya 1309 20
Underlying conditions – Malignancy (hematologic or solid organ)a 1121 17
Underlying conditions – Transplant (hematopoietic stem cell or solid organ)a 205 3
Positive test for SARS-CoV-2 during hospitalization and on or before date of incident specimen collectione 95 3

a Underlying conditions are not mutually exclusive
b Defined as myocardial infarction, congestive heart failure, congenital heart disease, stroke, transient ischemic attack, or peripheral vascular disease
c Defined as cystic fibrosis or any chronic respiratory condition resulting in symptomatic dyspnea
d Defined as diverticular disease, inflammatory bowel disease, peptic ulcer disease, short gut syndrome, or liver disease
e Among patients in the hospital on the date of incident specimen collection (N=2666). Excludes patients who were admitted to the hospital after the date of incident specimen collection. A positive SARS-CoV-2 test was defined as any positive viral test for SARS-CoV-2, including antigen and nucleic acid amplification tests.

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Table 8 – Selected Healthcare Exposures and Risk Factors of Incident CDI Cases in the 12 Weeks Before the Date of Incident Specimen Collection by Epidemiologic Classification (N=6558)
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Healthcare Exposurea CA
(N=4292),
N		 CA
(N=4292),
%		 COHCFA
(N=1773),
N		 COHCFA
(N=1773),
%		 HCFO
(N=493),
N		 HCFO
(N=493),
%
Acute care hospitalization 0 0 1734 98 244 49
Long-term care facility residence 0 0 187 11 178 36
Long-term acute care hospitalization 0 0 7 <1 9 2
Surgery 196 5 491 28 125 25
Emergency room 881 21 740 42 142 29
Observation unit 69 2 103 6 17 3
Chronic dialysis 106 2 163 9 51 10

a Healthcare exposure categories are not mutually exclusive.

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Table 9 – Antibiotic Use in the 12 Weeks Before the Date of Incident Specimen Collection (N=6558)
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Antibiotica N %
Any antibiotic 4005 61
Aminoglycosides 86 1
Beta-lactam / beta-lactamase inhibitor combinations 1283 20
Carbapenems 164 3
Cephalosporins 2062 31
Clindamycins 464 7
Fluoroquinolones 806 12
Glycopeptides 1179 18
Macrolides 262 4
Monobactam 16 <1
Penicillins 386 6
Trimethoprim or Trimethoprim/Sulfamethoxazole 366 6
Tetracyclines 276 4
Other antibiotic 1155 18

a Antibiotic use categories are not mutually exclusive.

Table 10 – Treatment of Incident CDI Cases (N=6558)
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Treatmenta N %
Any treatmentb 5604 85
Oral or rectal vancomycin (excluding vancomycin tapers)c 4724 72
Vancomycin tapers 390 6
Metronidazole 1079 16
Fidaxomicin 409 6
Bezlotoxumab 25 <1
Stool transplant 33 <1

a Treatment categories are not mutually exclusive.
b Includes any course of CDI antibiotic therapy, bezlotoxumab, or stool transplant.
c Includes 3 patients receiving vancomycin prophylaxis after treatment of incident CDI.

Table 11 – Outcomes of Incident CDI Cases (N=6558, except where indicated)
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Outcome N %
Toxic megacolona 18 <1
Ileusa 156 2
Pseudomembranous colitisa 32 <1
White blood cell count (WBC) >= 15,000/µla 1107 17
Recurrent infectiona 758 12
Hospitalization on the day of or within 6 days after the date of incident specimen collectiona,b 2868 44
ICU admission one day before, the day of, or within 6 days after the date of incident specimen collectiona 384 6
In-hospital deatha 177 3
Discharge location after acute-care hospitalization among patients who survivedc – Private Residence 2184 81
Discharge location after acute-care hospitalization among patients who survivedc – Long-term care facility 401 15
Discharge location after acute-care hospitalization among patients who survivedc – Long-term acute care hospital 12 <1
Discharge location after acute-care hospitalization among patients who survivedc – Other 75 3
Discharge location after acute-care hospitalization among patients who survivedc – Unknown 19 <1

a Outcomes, except for location of discharge from acute care hospitalization, are not mutually exclusive.
b Data include 345 cases considered to be hospital-onset
c N=2691

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Laboratory Characterization

This section will be updated once the data are available.

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Citation

Centers for Disease Control and Prevention. 2023. Emerging Infections Program, Healthcare-Associated Infections – Community Interface Surveillance Report, Clostridioides difficile infection (CDI), 2021 [PDF – 7 Pages]. Available at: https://www.cdc.gov/hai/eip/pdf/cdiff/2021-CDI-Report-H.pdf [PDF – 7 Pages].

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