Table 2. Selected characteristics of those with community-onset CDI before and after matching.

	Infected subjects	Pool of uninfected subjects	Standardized differences comparing infected subjects and pool of uninfected subjects	Unmatched infected subjects	Matched infected subjects	Matched uninfected subjects	Standardized differences comparing matched infected and uninfected subjects
n	7,950	512,184	NA	1,513	6,437	6,437	NA
Hard match variablesa
Age, mean±SD	63.5±22.0	57.7±21.0	0.27	62.4±24.1	63.8±21.4	64.2±21.0	0.02
Female, %	62.7	62.2	0.01	52.2	65.1%	65.1%	0.00
First healthcare encounter, %
CDI-coded ED visit	50.2	NA	NA	47.9	50.7	NA	NA
CDI-coded non-elective hospital admission	49.8	NA	NA	52.1	49.3	NA	NA
Propensity score variables
Neighborhood income quintilea, %
1 (lowest)	22.0	20.0	0.05	22.5	21.9	20.7	0.03
2	20.5	20.4	0.00	21.1	20.4	22.2	0.04
3	19.0	19.5	0.01	18.8	19.1	19.1	0.00
4	19.2	19.7	0.01	18.5	19.3	19.2	0.00
5 (highest)	19.3	20.3	0.03	19.2	19.3	18.9	0.01
Ruralitya, %
Major urban	59.9	70.4	0.22	56.2	60.8	60.1	0.01
Non-major urban	29.0	21.9	0.16	31.7	28.4	28.2	0.00
Rural	11.1	7.7	0.12	12.1	10.8	11.7	0.03
Very high users of the healthcare systemb, %	45.0	8.8	0.90	69.7	39.2	38.4	0.02
Aggregated Diagnosis Groups- specific to infectionb, %
Time Limited: Minor- primary infections	79.2	42.3	0.82	92.1	76.2	73.6	0.06
Time Limited: Major- primary infections	35.8	9.0	0.68	66.8	28.5	28.8	0.01
Likely to Recur: Discrete- infections	42.8	19.0	0.53	52.5	40.5	39.6	0.02
Healthcare utilizationc, %	72.4	11.6	1.56	99.6	66.0	65.1	0.02
Record of an infection that may have led to an antibiotic prescriptionc, %	47.5	9.6	0.92	82.2	39.4	36.0	0.07

^aMeasured at the index date.

^bMeasure of co-morbidities (within the two years prior to the index date, see S3 Table).

^cMeasured within the previous 12 weeks before the index date.

CDI–C.difficile infection. NA—not applicable. SD—standard deviation.