Table 1.
Model Parameters (Probabilities, Utilities, Costs)
| Parameter | Baseline Value | Range | References |
|---|---|---|---|
| Probabilities | |||
| Prevalence of Appendicitis in Base Case | 0.30 | 0.24–0.37 | (5, 14–19) |
| MRI | |||
| Sensitivity | 0.80 | 0.44–0.97 | (13, 16–19) |
| Specificity | 0.99 | 0.94–1.00 | (13, 16–19) |
| CT | |||
| Sensitivity | 0.86 | 0.64–0.97 | (5, 13–15) |
| Specificity | 0.97 | 0.86–1.00 | (5, 13–15) |
| Maternal Outcomes | |||
| SSI (non-perforated/perforated) | 0.025/0.10 | 0.00–0.15 | (10, 22) |
| Perioperative mortality | 0.001 | 0.00–0.01 | (2, 20, 21) |
| Fetal Outcomes | |||
| Prematurity, baseline | 0.12 | N/A | (55) |
| Prematurity, following surgery | 0.167 | 0.12–0.25 | (25–39) |
| Fetal loss, baseline | 0.01 | 0.003–0.05 | (24) |
| Fetal loss, following surgery | 0.11 | 0.06–0.19 | (25–39) |
| Childhood Cancer | |||
| Baseline (incidence/100,000) | 8.9 | 5.0–23.2 | (56) |
| After CT (relative risk) | 1.4 | 1.4–100 | (40) |
| Death During Induction Therapy | 0.03 | 0–0.05 | (57, 58) |
| Relapse (10 yr. incidence) | 0.20 | 0.18–0.23 | (57) |
| Death During Relapse | 0.70 | 0.50–1.00 | (59) |
| Lifetime Mortality | Life Table | Age Specific | (41) |
| Utilities* | |||
| Mother | |||
| Acute appendicitis | 0.73 | 0.50–1.00 | (43, 47, 48) |
| Well | Table | Age Adjusted | (49) |
| Child | |||
| Premature | 0.70 | 0.25–1.00 | (44, 45) |
| Cancer (Leukemia) | 0.80 | 0.10–0.90 | (46, 48) |
| Premature/Cancer | 0.56 | 0.18–0.92 | |
| Well | Table | Age Adjusted | (49) |
| Costs (2010 $) | |||
| Procedural | |||
| Appendectomy, Non-perforated | $11,130 | $7,932– $18,474 | (50, 51) |
| Appendectomy, Perforated | $18,474 | $11,130 – $26,103 | (50, 51) |
| CT | $694 | $480 – $941 | (50, 51) |
| MRI | $1,274 | $940 – $10,441 | (50, 51) |
| Fetal Loss | $24,882 | $0–$248,819 | ** |
| Surgical Site Infection | $3,132 | $0 – $31,323 | (60) |
| Lifetime | Table | Age Adjusted | (52) |
| Prematurity | $64,867 | $0 – $532,491 | (53) |
| Childhood Cancer | |||
| First Year of Treatment | $74,287 | $74,287 – $148,573 | (54)** |
| Second Year of Treatment | $9,375 | $9,375 – $18,750 | (54)** |
| Third Year of Treatment | $9,375 | $9,375 – $18,750 | (54)** |
| Cancer Death | $177,317 | $177,317 – $354,635 | (54)** |
| Non-Cancer Death | $24,882 | $24,882 – $49,764 | (54)** |
*
The utility decrement associated with appendicitis lasted one month; the utility decrement for prematurity was continued for the life of the child to simulate the potential for life-long disability; the utility decrement for childhood cancer was continued until either cancer-related death or cancer cure.
**
Expert opinion and/or unpublished data was used in determination of the base case parameterization. A cost for fetal loss was included to simulate a period of fetal distress, the need for removal of the products of conception, or the possibility of longer hospitalization.
***
References listed in Appendix