Table 1.

The definitions of the different algorithms used for identifying when antibiotic prophylaxis has been prescribed in large administrative data sets.

PARAMETER*	ALGORITHM A	ALGORITHM B	ALGORITHM C
Antibiotics	Any systemic antibiotic	Oral amoxicillin, clindamycin, cephalexin azithromycin, or clarithromycin	Oral amoxicillin, clindamycin, cephalexin azithromycin, or clarithromycin
Dosage†	Any	2 grams for amoxicillin, 600 milligrams for clindamycin, 2 g for cephalexin, 500 mg for azithromycin, or 500 mg for clarithromycin	2 g for amoxicillin, 600 mg for clindamycin, 2 g for cephalexin, 500 mg for azithromycin, or 500 mg for clarithromycin
Days’ Supply	≤ 2	≤ 3	≤ 5
Time (Days) Between	≤ 7	≤ 30 when days’ supply = 1	≤ 73 when days’ supply = 1
Fill Date and Visit Date		≤ 60 when days’ supply = 2	≤ 146 when days’ supply = 2
		≤ 90 when days’ supply = 3	≤ 219 when days’ supply = 3
			≤ 292 when days’ supply = 4
			≤ 365 when days’ supply = 5

^*Data parameters available for each prescription included drug name, fill date, number of days’ supply, metric quantity, strength, and refill number.

^†Dosage = metric quantity / 1-day supply × strength.