TABLE 1.
CHARACTERISTICS OF PARTICIPANTS AT ENROLLMENT ACCORDING TO COUGH AEROSOL SAMPLING SYSTEM RESULTS
| Characteristic* | All† (N = 101) | Aerosol Negative‡ (N = 73) | Aerosol Positive‡ (N = 28) | P Value§ |
| Age, yr | 32 (27–38) | 31 (28–38) | 32 (27–41) | 0.74W |
| Sex | ||||
| Male | 71 (70) | 50 (70) | 21 (30) | 0.63E |
| Female | 30 (30) | 23 (77) | 7 (23) | |
| Body mass index, kg/m2 | 17.6 (16.2–19.5) | 17.6 (16.2–19.5) | 17.6 (16.4–19.6) | 0.89W |
| Karnofsky score | 90 (80–90) | 80 (80–90) | 90 (80–100) | 0.016W |
| HIV status | ||||
| Uninfected | 35 (42) | 25 (71) | 10 (29) | 0.61E |
| Infected | 49 (58) | 38 (78) | 11 (22) | 0.11W |
| CD4 count (HIV+ only), cells/μl | 112 (33–274) | 69 (31–253) | 159 (100–594) | |
| TB treatment category | ||||
| New | 26 (27) | 20 (77) | 6 (23) | 0.61E |
| Retreatment | 71 (73) | 49 (69) | 22 (31) | |
| Any smoking history | ||||
| Yes | 36 (44) | 30 (83) | 6 (17) | 0.20E |
| No | 46 (56) | 32 (70) | 14 (30) | |
| Days of cough before enrollment | 80 (45–120) | 90 (60–90) | 60 (38–120) | 0.86W |
| Albumin, g/L | 33.7 (29.8–36.9) | 33.7 (29.6–36.6) | 32.2 (30.8–39.1) | 0.56W |
| Chest X-ray findings | ||||
| Extent of disease | ||||
| Normal | 5 (6) | 5 (100) | 0 | 0.71E |
| Minimal | 9 (11) | 7 (78) | 2 (22) | |
| Moderate | 16 (20) | 11 (69) | 5 (31) | |
| Advanced | 51 (63) | 38 (75) | 13 (25) | |
| Cavitations | ||||
| Absent | 36 (37) | 28 (78) | 8 (22) | 0.35E |
| Present | 60 (63) | 40 (67) | 20 (33) | |
| Sputum characteristics | ||||
| Volume, ml | 7.5 (4–12) | 6.5 (4–12) | 9 (5–12.5) | 0.32W |
| Appearance | ||||
| Salivary/mucosalivary | 59 (70) | 21 (36) | 38 (64) | 0.077E |
| Purulent/mucopurulent | 23 (28) | 3 (13) | 20 (87) | |
| Bloody | 2 (2) | 1 (50) | 1 (50) | |
| Acid-fast bacilli smear | ||||
| Negative | 11 (11) | 11 (100) | 0 | 0.007T |
| 1+ | 5 (5) | 4 (80) | 1 (20) | |
| 2+ | 11 (11) | 8 (73) | 3 (27) | |
| 3+ | 24 (24) | 20 (83) | 4 (17) | |
| 4+ | 50 (50) | 30 (60) | 20 (40) | |
| Middlebrook 7H10 agar culture, cfu | ||||
| 0 | 1 (1) | 1 (100) | 0 | 0.13T |
| 20–100 | 3 (3) | 3 (100) | 0 | |
| 101–200 | 2 (2) | 2 (100) | 0 | |
| >200 | 92 (94) | 64 (70) | 28 (30) | |
| Days to positive BACTEC 460 culture | 8 (4–12) | 8 (5–14) | 5 (3–9) | 0.004W |
| Drug susceptibility testing | ||||
| Sensitive to I and R | 84 (86) | 63 (75) | 21 (25) | 0.16E |
| Resistant to I or R | 6 (6) | 3 (50) | 3 (50) | |
| Resistant to I and R (MDR) | 8 (8) | 4 (50) | 4 (50) | |
| CASS characteristics | ||||
| Ambient temperature, °C | 23 (22.1–24.2) | 23 (22.1–24.3) | 22.6 (21.6–23.2) | 0.13W |
| Relative humidity, % | 70.9 (66–74.4) | 70.4 (65.4–73.7) | 73 (68.2–77.4) | 0.068W |
| Cough assessment (subjective) | ||||
| Weak | 43 (43) | 35 (81) | 8 (19) | 0.016T |
| Moderate | 44 (44) | 31 (70) | 13 (30) | |
| Strong | 13 (13) | 6 (46) | 7 (54) | |
| Days on TB treatment before enrollment | ||||
| Non-MDR only (n = 75) | 4 (3–6) | 4 (3–6) | 3 (2.5–4) | 0.047W |
| MDR only (n = 6) | 4 (1–69) | 5 (0–132) | 3 (1–69) | >0.99W |
| Aerosol cfu | 0 (0–2) | 0 (0–0) | 16 (5–30) | – |
Definition of abbreviations: CASS = Cough Aerosol Sampling System; cfu = colony forming units of Mycobacterium tuberculosis; I = isoniazid; IQR = interquartile range; MDR = multidrug resistant; R = rifampicin; TB = tuberculosis.
Missing data as follows: age (n = 4), BMI (19), Karnofsky score (14), HIV status (17), CD4 (2), TB status (4), smoking history (19), days of cough before enrollment (19), days on TB treatment before enrollment (20), albumin (24), chest X-ray extent of disease (20), cavitations (5), drug susceptibility testing (3), cough assessment (1). Middlebrook culture results were missing (1) or contaminated (2).
Values are n (column %) or median (IQR).
Values are n (row %) or median (IQR).
Categorical variables compared using exact (E) or Cochran Armitage trend (T) tests and continuous variables using a Wilcoxon (W) test.