Table 2.

Pretreatment clinical findings, according to treatment response.

VariableResponsive, n = 76Refractory, n = 23p
Age, average (range), yrs9.3 (2–18)10.8 (3–17)0.09
Male/female52/2416/70.99
Characteristics of early disease
  Erythema migrans, no (%)6 (8)0 (0)0.33
  Flu-like illness, no. (%)21 (28)7 (30)0.80
  Arthritis as presentation, no. (%)68 (90)22 (96)0.68
  Fevers, no. (%)25 (33)5 (22)0.44
Neurologic involvement, no. (%)1 (1)2 (9)0.13
Characteristics of arthritis
  Joint count, median (interquartile range, full range)1 (1–2, 1–6)1 (1–1, 1–2)0.16
  Duration of arthritis prior to antibiotic therapy, median (interquartile range, full range) weeks2 (1–4.5, 0–52)3 (2–6, 1–32)0.74
Initial antibiotic used, amoxicillin/doxycycline*37/3111/120.63
Additional antibiotics used, oral only/intravenous**2/48/151
  • * Missing n = 8. In these patients, the initial antibiotic was neither amoxicillin nor doxycycline, but other cephalosporins, ceftriaxone, or unspecified antibiotics.

  • ** Total n = 29, representing 23 patients with refractory arthritis who did not respond to additional antibiotic therapy and 6 patients with persisting arthritis who did respond to the additional course.