Table 1. Association of selected pretreatment characteristics with Borrelia skin culture positivity and with Borrelia skin PCR positivity.
| Characteristic | Culture result 65/118 a (55.1%) | PCR result 94/121 b (77.7%) | ||||||
|---|---|---|---|---|---|---|---|---|
| Positive (N = 65) | Negative (N = 53) | P value c | P adj d | Positive (N = 94) | Negative (N = 27) | P value c | P adj d | |
| Male sex | 30 (46%) | 18 (34%) | 0.25 | 0.92 | 43 (46%) | 7 (26%) | 0.10 | 0.57 |
| Comorbidities e | 29 (45%) | 26 (49%) | 0.77 | >0.99 | 43 (46%) | 12 (46%) | 1.00 | >0.99 |
| Immunocompromised f | 2 (3%) | 4 (8%) | 0.50 | >0.99 | 4 (4%) | 2 (7%) | 0.87 | >0.99 |
| Tick bite g | 29 (45%) | 23 (43%) | 1.00 | >0.99 | 41 (44%) | 13 (48%) | 0.84 | >0.99 |
| Days since EM first observed | 7 (5–10) | 7 (4.3–13) | 0.83 | >0.99 | 7 (5–10) | 7 (4–14) | 0.89 | >0.99 |
| EM with central clearing | 33 (51%) | 18 (34%) | 0.10 | 0.56 | 47 (50%) | 6 (22%) | 0.02 | 0.13 |
| Diameter of EM, cm | 14 (10–21) | 14 (9–20) | 0.47 | >0.99 | 14 (10–20) | 10 (5.5–17) | 0.01 | 0.04 |
| Systemic symptoms h | 17 (26%) | 11 (21%) | 0.64 | >0.99 | 26 (28%) | 3 (11%) | 0.13 | 0.64 |
| Fatigue | 9 (14%) | 6 (11%) | 14 (15%) | 2 (7%) | ||||
| Headache | 4 (6%) | 7 (13%) | 10 (11%) | 1 (4%) | ||||
| Myalgia | 2 (3%) | 4 (8%) | 5 (5%) | 1 (4%) | ||||
| Arthralgia | 4 (6%) | 1 (2%) | 5 (5%) | 0 (0%) | ||||
| Number of symptoms i | 1 (1–2) | 2 (1–4) | 0.15 | >0.99 | 1 (1–2) | 2 (1.5–3) | 0.40 | 0.19 |
| Symptoms at EM site | 23 (35%) | 23 (43%) | 0.49 | >0.99 | 35 (37%) | 13 (48%) | 0.42 | >0.99 |
| Seropositive j | 48 (75%) | 32 (62%) | 0.17 | 0.82 | 71 (76%) | 71 (76%) | <0.01 | 0.01 |
| Treated with amoxicillin | 35 (54%) | 24 (45%) | 0.46 | >0.99 | 48 (51%) | 12 (44%) | 0.70 | >0.99 |
Data are median (interquartile range) or number (%) of patients.
Abbreviations: adj, adjusted; EM, erythema migrans.
a Number of Borrelia-positive skin culture results out of the 118 analyzable biopsies.
b Number of Borrelia-positive PCR results out of 121 biopsies.
c P value for comparison between culture positive vs culture negative and between PCR positive vs PCR negative patients.
d Adjusted P value for multiple comparisons.
e Patients with underlying chronic illness such as arterial hypertension, hyperlipidemia, osteoporosis, diabetes mellitus, thyroid disease, cardiac rhythm abnormality, psychiatric illness, ischemic heart disease, osteoarthritis, asthma.
f 11 patients had active malignancy, one patient had Crohn’s disease.
g Patients with history of a tick bite at the site of the EM skin lesion.
h Patients with EM who reported new or increased systemic symptoms (NOIS). Some patients had more than one NOIS.
i Number of NOIS in patients who reported NOIS.
j Immunoglobulin M and/or immunoglobulin G to B. burgdorferi sensu lato positive at enrollment. Serological testing was done for 64 culture-positive patients and for 52 culture-negative patients, for 93 PCR-positive, and for 25 PCR-negative patients.