2020 Annual Report for the Emerging Infections Program for Clostridioides difficile Infection

Note: The COVID-19 pandemic caused significant delays in 2020 case identification, data collection, data entry, data cleaning, and isolate collection and submission in all EIP sites. However, overall completeness of data collection for Clostridioides difficile infection cases in 2020 was similar to pre-pandemic years.

Summary

2020 Annual Report Print Version [PDF – 8 Pages]

Surveillance data from 2020 represent the tenth year of population-based surveillance for CDI conducted among all 10 Emerging Infections Program sites. The crude overall incidence rate of CDI in 2020 was 101.3 cases per 100,000 persons, with a slightly higher incidence of community associated cases (51.2 cases per 100,000 persons) compared with healthcare-associated cases (50.1 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-four 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).

Population

The surveillance area represents 12,104,962 persons.
Source: U.S. Census Bureau, Population Division, Vintage 2020 Special Tabulation.

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.

Methods

Case finding was active, laboratory-based, and population-based. Laboratories serving the surveillance catchment areas reported all positive C. difficile tests to EIP staff and were routinely audited to ensure 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-associated 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 were 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 complete case report form data as of 12/07/2022 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.

12264 cases in 10 sites, 7971 selected for medical record review, 1588 with partial CRF, 191 without medical record access, 6192 with full CRF, 4293 not sampled (CO and GA)
Results
Table 1 – Reported Number of CDI Cases and Crude Incidence by Sex, Age Group, Race, and Epidemiologic Classification Among the 10 EIP Sites
Caption Goes Here
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 5,921,841 2314 39.1 2827 47.7 5141 86.8
Female 6,183,121 3883 62.8 3240 52.4 7123 115.2
Caption Goes Here
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 2,497,437 351 14.1 153 6.1 504 20.2
18-44 years 4,755,297 1551 32.6 791 16.6 2342 49.3
45-49 years 780,305 360 46.1 271 34.8 631 80.9
50-54 years 776,740 456 58.7 328 42.2 784 100.9
55-59 years 783,418 501 63.9 521 66.5 1022 130.5
60-64 years 720,234 619 85.9 609 84.6 1228 170.5
65-70 years 597,748 555 92.9 750 125.4 1305 218.3
70-74 years 480,445 588 122.3 810 168.7 1398 291.0
75-79 years 309,638 506 163.5 616 198.9 1122 362.4
80+ years 403,700 711 176.2 1217 301.4 1928 477.6
Caption Goes Here
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 8,052,023 4879 60.6 4456 55.3 9335 115.9
Other 4,052,939 1318 32.5 1611 39.7 2929 72.3
Caption Goes Here
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 12,104,962 6197 51.2 6067 50.1 12264 101.3

a The epidemiologic classification was statistically imputed for 2% of the CDI cases selected for medical record review, and race was statistically imputed for 16% 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=12264)
Caption Goes Here
Diagnostic assay N %
Toxin positive 3901 32
Nucleic acid amplification test (NAAT) positive/toxin negative 3788 31
NAAT positive/toxin result unknowna 4560 37
Other methodsb 15 <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
b Includes cases diagnosed by culture or unspecified assay

Table 3 – CDI Cases by Epidemiologic Classification (N=12264)
Caption Goes Here
Epidemiologic classification N %
Hospital onset 1465 12
LTCF onset 726 6
COHCFA 1675 14
CA 3914 32
Unknowna 4484 37

a Includes 4293 non-sampled cases

Table 4 – CDI Cases by Race and Ethnicity (N=12264)
Caption Goes Here
Race/Ethnicity N %
Hispanic, any race 879 7
Not known to be Hispanica – Whiteb 6003 49
Not known to be Hispanica – Black or African Americanc 1811 15
Not known to be Hispanica – Asiand 262 2
Not known to be Hispanica – Other or multiple racese 156 1
Non-Hispanic- Unknown race 176 1
Unknown ethnicity and race 2977 24

a Records either indicated ethnicity was non-Hispanic, or ethnicity was not known
b 635 cases with unknown ethnicity
c 134 cases with unknown ethnicity
d 36 cases with unknown ethnicity
e American Indian or Alaska Native, Native Hawaiian or Other Pacific Islander, or ≥2 races reported; 68 cases with unknown ethnicity

Table 5 – Location of CDI Cases on the Third Calendar Day Before Incident Specimen Collection (N=7971)
Caption Goes Here
Location of patient before incident specimen collection N %
Private residence 5536 69
Long-term care facility 743 9
Acute-care hospital (inpatient) 1373 17
Long-term care acute care hospital 38 <1
Homeless 83 1
Incarcerated 5 <1
Other 1 <1
Unknown 192 2
Table 6 – Location of CDI Cases at Time of Incident Specimen Collection (N=7971)
Caption Goes Here
Location of incident specimen collection N %
Outpatient setting or emergency department 4056 51
Acute care hospital 3167 40
Long-term care facility 514 6
Long-term acute care hospital 41 <1
Other 1 <1
Unknown 192 2
Table 7 – Selected Clinical Characteristics of CDI Cases (N=6192, except where indicated)
Caption Goes Here
Clinical characteristic N %
Charlson comorbidity index – 0 2487 40
Charlson comorbidity index – 1 1136 18
Charlson comorbidity index – ≥2 2569 41
Underlying conditions – Cardiovascular diseasea,b 1319 21
Underlying conditions – Diabetes mellitusa 1395 23
Underlying conditions – Chronic pulmonary diseasea,c 1280 21
Underlying conditions – Gastrointestinal diseasea,d 1461 24
Underlying conditions – Gastrointestinal disease – Diverticular diseasea 579 9
Underlying conditions – Gastrointestinal disease – Inflammatory bowel diseasea 459 7
Underlying conditions – Gastrointestinal disease – Peptic ulcer diseasea 164 3
Underlying conditions – Gastrointestinal disease – Short gut syndromea 19 <1
Underlying conditions – Gastrointestinal disease – Liver diseasea 377 6
Underlying conditions – Chronic renal diseasea 1182 19
Underlying conditions – Neurologic condition, anya 1126 18
Underlying conditions – Malignancy (hematologic or solid organ)a 1081 17
Underlying conditions – Transplant (hematopoietic stem cell or solid organ)a 215 3
Positive test for SARS-CoV-2 during hospitalization and on or before date of incident specimen collectione 94 4

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.

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=6192)
Caption Goes Here
Healthcare Exposurea CA
(N=3914),
N
CA
(N=3914),
%
COHCFA
(N=1675),
N
COHCFA
(N=1675),
%
HCFO
(N=603),
N
HCFO
(N=603),
%
Acute care hospitalization 0 0 1646 98 305 51
Long-term care facility residence 0 0 159 9 231 38
Long-term acute care hospitalization 0 0 10 <1 16 3
Surgery 155 4 446 27 172 29
Emergency room 764 20 666 40 191 32
Observation unit 55 1 80 5 33 5
Chronic dialysis 112 3 137 8 61 10

a Healthcare exposure categories are not mutually exclusive.

Table 9 – Antibiotic Use in the 12 Weeks Before the Date of Incident Specimen Collection (N=6192)
Caption Goes Here
Antibiotica N %
Any antibiotic 3760 61
Aminoglycosides 76 1
Beta-lactam / beta-lactamase inhibitor combinations 1242 20
Carbapenems 186 3
Cephalosporins 1889 31
Clindamycins 461 7
Fluoroquinolones 792 13
Glycopeptides 1204 19
Macrolides 262 4
Monobactam 21 <1
Penicillins 320 5
Trimethoprim or Trimethoprim/Sulfamethoxazole 364 6
Tetracyclines 256 4
Other antibiotic 1046 17

a Antibiotic use categories are not mutually exclusive.

Table 10 – Treatment of Incident CDI Cases (N=6192)
Caption Goes Here
Treatmenta N %
Any treatmentb 5228 84
Oral or rectal vancomycin (excluding vancomycin tapers) 4401 71
Vancomycin tapers 331 5
Metronidazole 1170 19
Fidaxomicin 192 3
Bezlotoxumab 9 <1
Stool transplant 26 <1

a Treatment categories are not mutually exclusive.
b Includes any course of CDI antibiotic therapy, bezlotoxumab, or stool transplant.

Table 11 – Outcomes of Incident CDI Cases (N=6192, except where indicated)
Caption Goes Here
Outcome N %
Toxic megacolona 20 <1
Ileusa 142 2
Pseudomembranous colitisa 29 <1
White blood cell count (WBC) >= 15,000/µla 1071 17
Recurrent infectiona 659 11
Hospitalization on the day of or within 6 days after the date of incident specimen collectiona,b 2808 45
ICU admission one day before, the day of, or within 6 days after the date of incident specimen collectiona 407 7
In-hospital deatha 163 3
Discharge location after acute-care hospitalization among patients who survivedc – Private Residence 2114 80
Discharge location after acute-care hospitalization among patients who survivedc – Long-term care facility 423 16
Discharge location after acute-care hospitalization among patients who survivedc – Long-term acute care hospital 39 1
Discharge location after acute-care hospitalization among patients who survivedc – Other 61 2
Discharge location after acute-care hospitalization among patients who survivedc – Unknown 8 <1

a Outcomes, except for location of discharge from acute care hospitalization, are not mutually exclusive.
b Data include 408 cases considered to be hospital-onset
c N=2645

Laboratory Characterization

This section will be updated once the data are available.

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