Table 1.
Characteristics of the study cohort
| Characteristic | Result (n = 6455) |
|---|---|
| Age, years [IQR] | 24 [17, 37] |
| Female (%) | 4457 (69.0) |
| APAP ingestion type (%): | |
| Acute ingestion at single, known time | 3496 (54.2) |
| Acute ingestion at inconsistently reported time | 1739 (26.9) |
| Chronic ingestion (ingestion over > 8 h) or time unknown | 1220 (18.9) |
| Peak (highest measured) APAP concentration, μg/mL [IQR] | 126 [50.8, 197] |
| First post-4 h APAP concentrationa, μg/mL [IQR] | 103 [37.8, 175] |
| Time from ingestion to above APAP concentrationa, h [IQR] | 8.4 [5.0, 18] |
| Equivalent 4 h APAP concentrationa, μg/mL [IQR] | 244 [154, 606] |
| Rumack-Matthew nomogram risk zone (%): | |
| ≥ 500 μg/mL | 477 (7.4) |
| 400 μg/mL to < 500 μg/mL | 233 (3.6) |
| 300 μg/mL to < 400 μg/mL | 477 (7.4) |
| 200 μg/mL to < 300 μg/mL | 899 (13.9) |
| 150 μg/mL to < 200 μg/mL | 715 (11.1) |
| < 150 μg/mL | 798 (12.4) |
| Not measured between 4 and 24 h | 1636 (25.3) |
| Not applicable (chronic/time unknown) | 1220 (18.9) |
| Time from ingestion to start of NAC, h [IQR] | 9.3 [6.2, 19] |
| Dose of APAP reportedly ingested, g [IQR] | 15 [6.5, 30] |
| Ethanol co-ingested (%) | 1848 (28.6) |
| Alcoholic (%) | 1417 (30.0) |
| Total duration of NAC therapy (%): | |
| Less than 20 h | 516 (8.0) |
| 20 to 21 h | 4872 (75.5) |
| Greater than 21 h | 1067 (16.5) |
| NAC therapy interrupted (%): | 274 (4.2) |
| Peak aminotransferase (AST or ALT) recorded, IU/L | 31 [20, 87] |
Continuous measures are shown as the median and interquartile range [IQR]
APAP acetaminophen, NAC N-acetylcysteine
aFirst post-4-h APAP concentration, times from ingestion, and subsequent nomogram-based transformations are undefined for chronic/time unknown ingestions or when obtained outside the 4- to 24-h window post ingestion