Table 2.
Input Parameter Estimates for the Agent-Based Model
| Parameter | Mean | Distribution (Range) | Sourcea | |
|---|---|---|---|---|
| Agent parameters | ||||
| Patient | Length of stay, d | 4.8 | Lognormal (SD = 4.8) | [51–54] |
| CDI attributable length of stay increase, d | 2.3 | Exponential (mean = 2.1–2.4) | [55] | |
| Arrival rate per day | 26 | … | [51, 56] | |
| Nursing visits per 6 h | 5 | … | [21, 57–59] | |
| Doctor visits per 6 h | 1 | … | [21, 57–59] | |
| Proportion on high CDI risk antibiotics | 20% | Triangular (15–25) | [60–62] | |
| Vancomycin treatment time, d | 14 | … | [39] | |
| Vancomycin success rate | 81% | Triangular (78–83) | [63–66] | |
| Nurse | Number per ward | 4 | … | [58, 67–69] |
| Service time, min | 4.7 | Exponential (mean = 3–7) | [58, 59, 70, 71] | |
| Doctor | Number per ward | 2 | … | [51, 58] |
| Service time, min | 10.8 | Exponential (mean = 4–14) | [58, 59, 70, 71] | |
| Visitor | Daily probability of receiving visitors | 0.5 | Triangular (0.3–0.7) | [72, 73] |
| No. of visitors per visit | 2 | Triangular (1–3) | [73, 74] | |
| Service time, min | 15 | Exponential (mean = 10–30) | [58, 73–75] | |
| Admission parameters | ||||
| Proportion of susceptible patients | 39.7% | Triangular (30%–50%) | [52, 76–79] | |
| Proportion asymptomatic colonized patients | 6.1% | Triangular (4%–10%) | [40, 80–89] | |
| Proportion of patients with CDI | 0.29% | Triangular (0.25%–1%) | [80, 86, 90, 91] | |
| Proportion of nonsusceptible patients | 53.9% | … | … | |
| Transmission parameters | ||||
| Probability patient:patient contact | 5% per 30 min | Triangular (1%–15%) | EO | |
| Probability patient:nurse contact | 36% per 4.7 min | Triangular (26%–46%) | [58] | |
| Probability patient:doctor contact | 69% per 10.8 min | Triangular (59%–79%) | [58] | |
| Probability patient:visitor contact | 65% per 15 min | Triangular (55%–75%) | [58] | |
| Probability environment:nurse contact | 70% per 4.7 min | Triangular (60%–80%) | [58] | |
| Probability environment:doctor contact | 90% per 10.8 min | Triangular (80%–100%) | [58] | |
| Probability environment:visitor contact | 93% per 15 min | Triangular (83%–100%) | [58] | |
| Probability environment:patient contact | 100%; constant | … | … | |
| C. difficile transfer efficiency person:person | 30% | Triangular (15%–45%) | [92] | |
| C. difficile transfer efficiency environment:person | 44% | Triangular (29%–59%) | [93] | |
| Contamination parameters | ||||
| Colonized patient contaminated | 38% | Triangular (15%–60%) | [94–96] | |
| Active CDI patient contaminated | 70% | Triangular (60%–80%) | [96] | |
| Colonized patient room contaminated | 19% | Triangular (14%–35%) | [96–98] | |
| Active CDI patient room contaminated | 47% | Triangular (36%–60%) | [96–101] | |
| Non–C. difficile patient room contaminated | 7% | Triangular (5%–15%) | [97, 100, 101] | |
Abbreviations: CDI, Clostridium difficile infection; C.difficile, Clostridium difficile; EO, expert opinion; SD, standard deviation.
aReferences for input parameter sources are included in the Supplementary Materials.