Table 2:

Definitions of Clostridioides difficile infection cohort and matched control groups^*

Cohort	Cohort definition	Control groups
Cohort	Cohort definition	Hard-match criteria	Propensity-score–match criteria
ACH-associated/ACH-onset	ICD-10-CA diagnosis code for C. difficile infection (A04.7) during inpatient hospital stay, coded as postadmission comorbidity of clinical significance	Age ± 2 yr Sex Hospital admission date ± 90 d Most responsible diagnosis at hospital admission^‡	Urban/rural score^§ Local Health Integration Network Elixhauser score^¶
LTCF-associated/LTCF-onset^†	LTCF resident with ICD-10-CA diagnosis code for C. difficile infection (A04.7) during inpatient hospital stay, coded as most responsible diagnosis or preadmission comorbidity AND no hospital admission in 12 wk before onset	Age ± 2 yr Sex LTCF resident in 12 wk before matched patient’s date of hospital admission ± 90 d	Urban/rural score^§ Local Health Integration Network Elixhauser score^¶
Community-associated/community-onset^*	Community resident with ICD-10-CA diagnosis code for C. difficile infection (A04.7) during inpatient hospital stay, coded as most responsible diagnosis or preadmission comorbidity AND no hospital admission in 12 wk before onset	Age ± 2 yr Sex Non-LTCF resident in 12 wk before matched patient’s date of hospital admission ± 90 d No hospital admission in 12 wk before matched patient’s date of hospital admission ± 90 d	Urban/rural score^§ Local Health Integration Network Elixhauser score^¶
ACH-associated, community-onset	ICD-10-CA diagnosis code for C. difficile infection (A04.7) during inpatient hospital stay, coded as most responsible diagnosis or preadmission comorbidity AND did not reside in LTCF in 12 wk before onset	Age ± 2 yr Sex Community-dwelling but admitted to hospital in 12 wk before matched patient’s index date of hospital admission ± 90 d for same most responsible diagnosis^‡	Urban/rural score^§ Local Health Integration Network Elixhauser score^¶

Note: ACH = acute care hospital, ICD-10-CA = International Statistical Classification of Diseases and Related Health Problems, 10th Revision, enhanced Canadian version, LTCF = long-term care facility.
↵* Adapted from reference 19 (Oxford University Press).
↵† People in this control group had not necessarily been admitted to hospital at the index date.
↵‡ Matched on the first 3 digits of the ICD-10-CA code.
↵§ A measure of a community’s rurality based on its population and population density, travel time to nearest basic referral centre and travel time to nearest advanced referral centre.20
↵¶ Comorbidity score based on ICD-10-CA coding.21