Table 2.

Antibiotic utilization and treatment-associated adverse events among children with and without ARLA

Treatment characteristic, N (%)	Resolve <3m (N=188)	ARLA (N=49)	P- value1
Antibiotics
Oral antibiotics	185 (98%)	49 (100%)	0.992
Amoxicillin	109 (58%)	24 (49%)	0.26
Doxycycline	91 (48%)	43 (88%)	<0.001
Cefuroxime	8 (4%)	6 (12%)	0.052
Other	2 (1%)	0	0.992
Days of oral antibiotics, median (IQR)	28 (28, 30)	57 (56, 72)	<0.0013
IV antibiotics	13 (7%)	28 (57%)	<0.001
Ceftriaxone	13 (7%)	28 (57%)	<0.001
Days of IV antibiotics, median (IQR)4	28 (21, 28)	28 (21, 28)	0.303
Total days of antibiotics, median (IQR)	30 (28, 35)	76 (58, 88)	<0.0013
Prescribed non-steroidal anti-inflammatories	57 (30%)	39 (80%)	<0.001
Adverse events during antibiotic treatment period
Any recorded treatment-associated adverse event5	29 (15%)	18 (37%)	0.001
Fever	3 (2%)	2 (4%)	0.282
Rash	8 (4%)	9 (18%)	0.0022
Non-rash allergic reactions	0	2 (4%)	0.042
Heartburn	1 (1%)	2 (4%)	0.112
Abdominal pain	7 (4%)	3 (6%)	0.442
Vomiting	8 (4%)	3 (6%)	0.702
Diarrhea	5 (3%)	0	0.592
Headache	2 (1%)	4 (8%)	0.022
Dizziness	1 (1%)	0	0.992
Altered mental status	0	1 (2%)	0.212
C. difficile or other infection	0	0	-
Thrombosis	0	0	-
Mechanical IV problem	0	2 (4%)	0.042
Hospitalization for any treatment-associated adverse event6	1 (1%)	3 (6%)	0.032

ARLA, antibiotic-refractory Lyme arthritis; IQR, interquartile range; IV, intravenous

¹P-value calculated from chi-square testing except where indicated

²P-value calculated from Fisher’s exact test

³P-value calculated from Wilcoxon rank-sum testing

⁴Calculated among subjects who received ceftriaxone

⁵Some subjects had more than 1 adverse event

⁶Excluding hospitalization for worsening disease (e.g., leg swelling from popliteal cyst rupture)