Table 1.
Input Variables
| Input Variable* | Base-Case Estimate | Range for Sensitivity Analysis | Range in Published Studies | References |
|---|---|---|---|---|
| Recurrent thromboembolism within 3 mo | ||||
| Unfractionated heparin, % | 6.00 | 4–8 | 2.9–9.6 | (1,4,8–12,25,26) |
| LMWH, % | 4.40 | 3.2–6.1 | 0–6.9 | (4,8–12,25) |
| Relative risk LMWH/UH | 0.73 | 0.54–1.3 | (25,27) | |
| Pulmonary embolism during heparin treatment | ||||
| Unfractionated heparin, % | 0.60 | 0.5–1 | 0.4–1.9 | (11,12,28 |
| LMWH, % | 0.60 | 0.4–1.2 | — | Estimated |
| Relative risk LMWH/UH | 1.0 | 0.8–1.2 | — | Estimated |
| Heparin-related complications | ||||
| Major bleed† | ||||
| Unfractionated heparin, % | 4.00 | 3–8 | 0–15 | (1,3,4,8–12,15,29) |
| LMWH, % | 1.60 | 0.6–7.2 | 0–15 | (8–12,15) |
| Relative risk LMWH/UH | 0.40 | 0.2–0.9 | (8,27) | |
| Heparin-induced thrombocytopenia | ||||
| Unfractionated heparin, % | 1 | 0–2 | 1–3 | (1,4,15) |
| LMWH, % | 0 | 0–2 | < 1 | (1,10,15,30) |
| Relative risk LMWH/UH | 0 | 0–1 | — | Estimated |
| Mortality, % | ||||
| Pulmonary embolism | 5 | 1–20 | 1.5–21 | (1,28,31–36) |
| Heparin-induced thrombocytopenia | 5 | 0–50 | < 50 | (37–40) |
| Bleed | 0.10 | 0–5 | — | (15) |
| After recurrent thromboembolism | 8.80 | 5–14 | — | (28) |
| Duration of therapy, d | 6 | 5–10 | 5.5–6.5 | (11–13) |
| Duration of LMWH therapy in the hospital, d | 2.50 | 1–10 | — | (11) |
| Day of occurrence of heparin-induced complication | 4 | 3–7 | — | Estimated |
| Relative risk of recurrent thrombosis after a complication | 1.50 | 1–10 | < 37 | Estimated,30) |
| Eligibility for outpatient treatment, LMWH strategy, % | 40 | 0–70 | 35–70 | (11–13) |
| Patients never hospitalized, LMWH strategy, % | 30 | 0–50 | 36–48 | (11,12) |
| Cost of treatment,† | ||||
| Deep venous thrombosis | ||||
| Unfractionated heparin | 2,863 | 1,500–5,000 | 1,573–7,736 | (17,41–48) |
| LMWH, 6 d in the hospital | 3,144 | 2,500–5,000 | 1,030–3,102 | (17,41,42,49) |
| LMWH, 6 d at home | 1,540 | 1,000–2,000 | — | See Appendix |
| Pulmonary embolism | 6,760 | 5,000–15,000 | 6,072–12,004 | (43,46–48,50) |
| Major bleed | 3,660 | 2,000–10,000 | 1,812–11,214 | (17,43,46–48) |
| Heparin-induced thrombocytopenia | 3,520 | 2,000–10,000 | — | See Appendix |
*
LMWH indicates low molecular-weight heparin; UH, intravenous unfractionated heparin.
†
Associated with a decrease in hemoglobin of ≥2g/dL, retroperitoneal, intracranial, prosthetic joint, or if it resulted in transfusion of ≥2 U of blood.
‡
All costs are expressed in 1996 U.S. dollars. See Appendix for detailed explanation of derivation of costs and range for sensitivity analysis. Data from literature were converted to 1996 U.S. dollars by applying the exchange rate for foreign currency (Federal Reserve Bank of St. Louis: http://www.stls.frb.org/fred/data/exchange.html) and using the Consumer Price Index for medical care (Bureau of Labor Statistics: http://stats.bls.gov/blshome.html).