Participant subgroup comparisons across demographic, clinical laboratory and psychosocial characteristics*
| Subgroup 1 n=125 | Subgroup 2 n=40 | Subgroup 3 n=47 | q value 1 versus 2 | q value 1 versus 3 | q value 2 versus 3 | |
| Demographic | ||||||
| Age at study visit (years) | 49.00 (40.00, 61.00) (18.00, 82.00) | 51.00 (40.75, 56.00) (25.00, 70.00) | 42.00 (27.00, 52.00) (18.00, 82.00) | 0.887 | 0.126 | 0.219 |
| Male gender | 75 (60.0%) | 23 (57.5%) | 26 (55.3%) | 1.000 | 0.887 | 1.000 |
| White, non-Hispanic | 111 (88.8%) | 34 (85.0%) | 45 (95.7%) | 0.887 | 0.528 | 0.370 |
| Years of education | 16.00 (14.00, 18.00) (10.00, 25.00) | 16.00 (14.00, 18.00) (12.00, 30.00) | 16.00 (14.25, 18.00) (12.00, 22.00) | 0.937 | 0.887 | 0.859 |
| Annual household income >US$100K | 78/117 (66.7%) | 23 (57.5%) | 18/46 (39.1%) | 0.697 | 0.014 | 0.370 |
| Currently out of work on disability | 2 (1.6%) | 4 (10.0%) | 6 (12.8%) | 0.126 | 0.035 | 0.887 |
| Body mass index (kg/m2) | 25.72 (22.71, 29.42) (16.47, 38.88) | 26.78 (22.59, 30.50) (19.80, 41.74) | 26.15 (23.47, 29.29) (18.99, 45.70) | 0.615 | 0.849 | 0.887 |
| Clinical/physical examination | ||||||
| Duration from Lyme disease onset to study visit (years) | 1.45 (0.59, 3.84) (0.15, 28.59) | 1.30 (0.71, 2.14) (0.06, 13.13) | 2.23 (1.03, 5.56) (0.13, 18.67) | 0.720 | 0.309 | 0.086 |
| Centers for Disease Control and Prevention ‘confirmed’ initial Lyme disease presentation16 | 77 (61.6%) | 21 (52.5%) | 26 (55.3%) | 0.707 | 0.849 | 1.000 |
| Initial late Lyme arthritis | 15 (12.0%) | 3 (7.5%) | 1 (2.1%) | 0.849 | 0.249 | 0.615 |
| Initial neurologic Lyme disease | 7 (5.6%) | 2 (5.0%) | 7 (14.9%) | 1.000 | 0.299 | 0.404 |
| Time to initial recommended antibiotic treatment (days)† | 23.00 (0.00, 110.00) (0.00, 10000.00) | 14.50 (0.00, 181.25) (0.00, 757.00) | 14.00 (2.50, 128.00) (0.00, 3700.00) | 0.887 | 0.887 | 0.715 |
| Total antibiotic exposure from Lyme disease onset to study visit (weeks) | 8.00 (4.43, 13.00) (2.00, 112.86) | 7.64 (4.29, 19.21) (3.00, 130.00) | 9.00 (5.64, 14.71) (2.86, 168.57) | 0.923 | 0.566 | 0.863 |
| Intravenous antibiotic use | 26 (20.8%) | 7 (17.5%) | 20 (42.6%) | 0.923 | 0.035 | 0.092 |
| Non-recommended antibiotic exposure prior to recommended antibiotic exposure† | 17 (13.6%) | 4 (10.0%) | 8 (17.0%) | 0.909 | 0.887 | 0.831 |
| Steroid exposure after disease onset, prior to recommended antibiotic treatment† | 10 (8.0%) | 7 (17.5%) | 4 (8.5%) | 0.391 | 1.000 | 0.615 |
| Systolic blood pressure (mm Hg) | 125.50 (114.00, 137.50) (92.00, 171.00) | 133.00 (121.75, 144.25) (106.00, 173.00) | 126.00 (115.00, 138.00) (99.00, 179.00) | 0.091 | 0.937 | 0.288 |
| Diastolic blood pressure (mm Hg) | 80.82±9.36 (63.00, 103.00) | 85.53±9.34 (64.00, 110.00) | 82.47±8.93 (63.00, 100.00) | 0.035 | 0.597 | 0.358 |
| Pulse (beats per minute) | 68.00 (61.50, 73.00) (48.00, 120.00) | 70.50 (64.00, 81.00) (52.00, 106.00) | 70.00 (64.00, 80.25) (51.00, 104.00) | 0.199 | 0.402 | 0.859 |
| Vibratory sense abnormal‡ | 34/124 (27.4%) | 15/39 (38.5%) | 10/45 (22.2%) | 0.566 | 0.882 | 0.402 |
| Comorbidities | ||||||
| Thyroid disease | 9 (7.2%) | 4 (10.0%) | 4 (8.5%) | 0.816 | 0.887 | 1.000 |
| Heart disease or hypertension | 20 (16.0%) | 5 (12.5%) | 7 (14.9%) | 0.916 | 1.000 | 1.000 |
| Migraine headaches | 17 (13.6%) | 10 (25.0%) | 18 (38.3%) | 0.386 | 0.007 | 0.566 |
| Carpal tunnel syndrome | 13 (10.4%) | 5 (12.5%) | 4 (8.5%) | 0.901 | 1.000 | 0.887 |
| Neuropathy/neuromuscular disorder | 8 (6.4%) | 3 (7.5%) | 6 (12.8%) | 0.887 | 0.597 | 0.797 |
| Laboratory | ||||||
| Absolute lymphocyte count (103/µL) | 1.96 (1.56, 2.19) (0.68, 3.82) | 1.89 (1.59, 2.26) (1.09, 4.29) | 1.87 (1.63, 2.29) (0.82, 3.26) | 1.000 | 0.711 | 0.887 |
| C reactive protein abnormal | 6/119 (5.0%) | 8/38 (21.1%) | 3/43 (7.0%) | 0.035 | 0.887 | 0.309 |
| Reactive IgG bands on two-tier testing for antibodies to Borrelia burgdorferi | 5.00 (2.00, 8.00) (0.00, 10.00) | 4.00 (2.00, 7.00) (0.00, 10.00) | 4.00 (2.00, 6.50) (0.00, 10.00) | 0.720 | 0.391 | 0.887 |
| Psychosocial | ||||||
| Beck Depression Inventory-II Cognitive/Affective subscale Score18 | 5.00 (1.00, 8.00) (0.00, 20.00) | 6.00 (4.00, 8.00) (0.00, 17.00) | 13.00 (9.00, 19.00) (3.00, 39.00) | 0.528 | <0.001 | <0.001 |
| Stanford Chronic Diseases Self-Efficacy total Score21 22 | 7.50 (5.30, 8.50) (1.00, 9.80) | 6.00 (4.30, 7.55) (1.00, 9.80) | 5.30 (4.25, 6.80) (1.00, 9.70) | 0.068 | <0.001 | 0.597 |
| Life Events Checklist total Score20 | 2.00 (1.00, 4.00) (0.00, 13.00) | 2.00 (0.00, 3.25) (0.00, 8.00) | 2.00 (0.50, 4.00) (0.00, 9.00) | 0.615 | 0.879 | 0.887 |
| Big Five Inventory: Extraversion Score24 | 3.38 (2.75, 3.88) (1.38, 5.00) | 3.44 (3.00, 3.91) (1.63, 4.88) | 3.13 (2.56, 3.63) (1.75, 5.00) | 0.797 | 0.527 | 0.355 |
| Big Five Inventory: Agreeableness Score | 4.00 (3.67, 4.44) (2.44, 5.00) | 4.22 (3.97, 4.56) (2.33, 5.00) | 3.89 (3.38, 4.38) (2.33, 5.00) | 0.299 | 0.408 | 0.084 |
| Big Five Inventory: Conscientiousness Score | 4.00 (3.56, 4.44) (2.22, 5.00) | 4.05 (3.67, 4.44) (2.22, 4.89) | 3.67 (3.28, 4.11) (1.56, 4.89) | 0.887 | 0.020 | 0.035 |
| Big Five Inventory: Emotional Stability Score | 3.63 (3.13, 4.10) (1.38, 5.00) | 3.75 (3.22, 4.25) (2.50, 5.00) | 2.63 (1.82, 3.25) (1.00, 4.63) | 0.668 | <0.001 | <0.001 |
| Big Five Inventory: Openness Score | 3.70 (3.30, 4.20) (2.30, 5.00) | 3.90 (3.40, 4.32) (2.70, 4.90) | 3.80 (3.30, 4.10) (1.20, 4.80) | 0.495 | 1.000 | 0.615 |
*Data from categorical variables are presented as count (%). Data from normally distributed continuous variables are presented as mean±SD (range) and from continuous variables not normally distributed as median (25th percentile, 75th percentile) (range). Proportions were calculated based on non-missing data and may not add to 100% because of rounding. Missing data are as follows: years of education, 1 (0.5%); annual household income, 9 (4.2%); body mass index, 18 (8.5%); systolic blood pressure, 5 (2.4%); diastolic blood pressure, 4 (1.9%); pulse, 3 (1.4%); vibratory sense, 4 (1.9%); absolute lymphocyte count, 2 (0.9%); C reactive protein, 12 (5.7%); IgG reactive bands, 1 (0.5%); Beck Depression Inventory-II Cognitive/Affective Score, 1 (0.5%); Stanford Chronic Diseases Self-Efficacy Score, 1 (0.5%); Big Five Inventory, 3 (1.4%).
†Recommended antibiotic regimens were considered any of the following: Doxycycline 100 mg two times per day for ≥10 days, tetracycline 500 mg three times a day for ≥14 days, ceftin 500 mg two times per day for ≥14 days, ceftriaxone 2 g/ day for ≥14 days. Other drugs, or lower doses or durations were considered non-recommended antibiotic regimes.
‡Below age-adjusted normal vibration threshold values in either upper (distal interphalangeal joint of the index finger) or lower (interphalangeal joint of the hallux) extremities on either right or left side using a Rydel-Seiffer 64 Hz tuning fork.26