Table 2.
Summary of base-case model inputs and their sources.
| Input | Data | Source |
|---|---|---|
| COHORT SETTINGS | ||
| Start age (years) | eTHR: 68.7 (SD = 11.32) eTKR: 69.3 (SD = 9.58) |
National Joint Registry Annual Report 2016 (Board NE, 2017) |
| Male | eTHR: 40% eTKR: 44% |
National Joint Registry Annual Report 2016 (Board NE, 2017) |
| BMI (kg/m2) | eTHR: 28.7 eTKR: 30.9 |
National Joint Registry Annual Report 2016 (Board NE, 2017) |
| BASELINE RISKS–e THR | ||
| DVT (symptomatic and asymptomatic) | 5.54% | Calculated based on (Jameson et al., 2011) and (Quinlan, 2007) |
| Symptomatic DVT | 0.94% | (Jameson et al., 2011) |
| Proportion of symptomatic DVTs that are proximal | 83.3% | (Revankar et al., 2013) based on data from ADVANCE trials |
| Asymptomatic DVT | 4.6% | Calculated based on (Jameson et al., 2011) and (Quinlan, 2007) |
| Proportion of asymptomatic DVTs that are proximal | 26.2% | (Revankar et al., 2013) based on data from ADVANCE trials |
| Non-fatal PE | 0.68% | (Jameson et al., 2011) |
| Mortality from PE | 17% (1/6) | Randomized controlled trials in our systematic review |
| Major bleeding at the surgical site | 2.29% | Single-arm meta-analysis of the LMWH (standard dose, standard duration) randomized controlled trials in our systematic review |
| GI and cerebrospinal bleeding | 0.72% | (Jameson et al., 2011) |
| Other major bleeding | 0.2% | Single-arm meta-analysis of the LMWH (standard dose, standard duration) randomized controlled trials in our systematic review |
| Clinically-relevant non-major bleeding (CRNMB) | 2.95% | Single-arm meta-analysis of the LMWH (standard dose, standard duration) randomized controlled trials in our systematic review |
| Wound haematoma as percentage of CRNMB | 22.73% (5/22) | Calculated from the LMWH randomized controlled trials in our systematic review |
| Heparin-induced thrombocytopenia (HIT) | 0.17% | Single-arm meta-analysis of the LMWH (standard dose, standard duration) randomized controlled trials in our systematic review |
| BASELINE RISK - eTKR | ||
| DVT (symptomatic and asymptomatic) | 14% | Calculated based on (Jameson et al., 2012) and (Quinlan, 2007) |
| Symptomatic DVT | 0.63% | (Jameson et al., 2012) |
| Proportion of symptomatic DVTs that are proximal | 20% | (Revankar et al., 2013) based on data from ADVANCE trials |
| Asymptomatic DVT | 13.37% | Calculated based on (Jameson et al., 2012) and (Quinlan, 2007) |
| Proportion of asymptomatic DVTs that are proximal | 8.8% | (Revankar et al., 2013) based on data from ADVANCE trials |
| Non-fatal PE | 0.45% | (Jameson et al., 2012) |
| Mortality from PE | 17% | assumed equal to eTHR as there were no events in the single trial of LMWH (standard dose, standard duration)+ AES |
| Major bleeding at the surgical site | 0.64% | Single-arm meta-analysis of the LMWH (standard dose, standard duration) randomized controlled trials in our systematic review |
| GI and cerebrospinal bleeding | 0.39% | (Jameson et al., 2012) |
| Other major bleeding | 0.2% | Single-arm meta-analysis of the LMWH (standard dose, standard duration) randomized controlled trials in our systematic review |
| CRNMB | 4.15% | Single-arm meta-analysis of the LMWH (standard dose, standard duration) randomized controlled trials in our systematic review |
| Wound haematoma as percentage of CRNMB | 18.97% (11/58) | Calculated from the LMWH randomized controlled trials in our systematic review |
| HIT | 0.92% | Single-arm meta-analysis of the LMWH (standard dose, standard duration) randomized controlled trials in our systematic review |
| OTHER PARAMETERS | ||
| Proportion requiring return to theater after surgical site major bleeding | 100% | Standard definition of major bleeding and expert opinion |
| Proportion requiring intervention after GI bleeding | 13% | CG92 (National Clinical Guideline Centre, 2010) |
| Surgical site infection due to haematoma | 25.77% (25/97) | Wang 2014 (Wang et al., 2014) |
| Probability of revision/return to theater due to infection | 44% (11/25) | Wang 2014 (Wang et al., 2014) |
| LONG TERM EVENTS | ||
| 2-year incidence of PTS after: | ||
| Symptomatic proximal DVT | 40% | (Kahn et al., 2016) and committee Expert opinion |
| Symptomatic distal DVT | 10% | (Heit et al., 2001; Botteman et al., 2002) and committee opinion |
| Asymptomatic proximal DVT | 15% | (Wille-Jørgensen et al., 2005) |
| Asymptomatic distal DVT | 3.75% | (Heit et al., 2001; Botteman et al., 2002) |
| Non-fatal PE | 15% | Committee expert opinion |
| Proportion of PTS that is severe | 23% | [(Wolowacz et al., 2009); average from 8 incidence studies] |
| 2-year incidence of CTEPH after non-fatal PE | 3.2% (95% CI: 1.5%−3.1%) | [(Ende-Verhaar et al., 2017); systematic review of incidence studies] |
| CTEPH mortality | 20% | CG92 (National Clinical Guideline Centre, 2010) |
| COSTS (£) | ||
| Symptomatic proximal DVT | eTHR: £457 eTKR: £457 |
NG89 (Venous thromboembolism in over 16s: reducing the risk of hospital-acquired deep vein thrombosis or pulmonary embolism), Appendix P (National Institute for Health and Care Excellence, 2018) |
| Symptomatic distal DVT | eTHR: £295 eTKR: £295 |
NG89 (Venous thromboembolism in over 16s: reducing the risk of hospital-acquired deep vein thrombosis or pulmonary embolism), Appendix P (National Institute for Health and Care Excellence, 2018) |
| Non-fatal PE | eTHR: £991 eTKR: £992 |
NG89 (Venous thromboembolism in over 16s: reducing the risk of hospital-acquired deep vein thrombosis or pulmonary embolism), Appendix P (National Institute for Health and Care Excellence, 2018) |
| Return to theater for surgical site bleeding | eTHR: £6,278 eTKR: £6,177 |
NHS Schedule for Reference Costs 2015–2016 [(Department of Health, 2016); unit cost for primary eTHR] NHS Schedule for Reference Costs 2015–2016 [(Department of Health, 2016); unit cost for primary eTKR] |
| GI bleeding with intervention | £2,409 | NHS Schedule for Reference Costs 2015–2016 (Department of Health, 2016) |
| GI bleeding without intervention | £855 | NHS Schedule for Reference Costs 2015–2016 (Department of Health, 2016) |
| Haemorrhagic stroke | ||
| Acute event-admission | £4,354 | Weighted Cost of non-elective long stay admission for stroke with CC score 0-3 to 16+. HRG codes AA35A to AA35F.NHS Schedule for Reference Costs 2015–2016 (Department of Health, 2016) |
| Acute event- other costs for the first 90 days | £3,255 | Three month costs calculated based Weighted average cost of the cost of stroke dependent state and independent state in year 1 from CG144 [VTE management and thrombophilia testing] less the cost of the acute stroke admission (National Clinical Guideline Centre, 2012a) Costs inflated to 2015–2016. |
| Year 1–dependent state | £29,776 | CG144 [VTE management and thrombophilia testing; (National Clinical Guideline Centre, 2012a)] Costs inflated to 2015–2016 |
| Year 1–independent state | £4,971 | CG144 [VTE management and thrombophilia testing; (National Clinical Guideline Centre, 2012a)] Costs inflated to 2015–2016 |
| Year 2+ – dependent state | £15,108 | CG144 [VTE management and thrombophilia testing; (National Clinical Guideline Centre, 2012a)] Costs inflated to 2015–2016 |
| Year 2+ – independent state | £1,172 | CG144 [VTE management and thrombophilia testing; (National Clinical Guideline Centre, 2012a)] Costs inflated to 2015–2016 |
| CRNMB (post-discharge) | £242 | Committee expert opinion (2 outpatient visits) |
| Surgical site infection- medically treated | £3,696 | NHS Schedule for Reference Costs 2015–2016 |
| Revision surgery for infected joint | eTHR: £19,514 eTKR: £19,203 | Kallala 2015 and NHS Schedule for Reference Costs 2015–2016 |
| HIT | £463 | NHS Schedule for Reference Costs 2015–2016 (Department of Health, 2016) |
| Amputation after HIT: | ||
| acute event | £10,300 | CG 147 [Lower Limb Peripheral Arterial Disease; (National Clinical Guideline Centre, 2012b)] adjusted for inflation to 2015–2016 values |
| Year 1 | £31,259 | CG 147 [Lower Limb Peripheral Arterial Disease–(National Clinical Guideline Centre, 2012b)] adjusted for inflation to 2015–2016 values |
| Year 2+ | £25,987 | CG 147 [Lower Limb Peripheral Arterial Disease; (National Clinical Guideline Centre, 2012b)] adjusted for inflation to 2015–2016 values |
| PTS | ||
| Mild/Moderate -Year 1 | £841 | Caprini 2003 (Caprini et al., 2003) converted to 2000 GBP OECD PPP conversion and inflated to 2015–2016 values |
| Mild/Moderate -Year 2+ | £342 | Caprini 2003 converted to 2000 GBP OECD PPP; (Organisation for Economic Co-operation Development (OECD), 2012) conversion factor and inflated to 2015–2016 values |
| Severe -Year 1 | £3,824 | Caprini 2003 converted to 2000 GBP OECD PPP conversion; (Organisation for Economic Co-operation Development (OECD), 2012) and inflated to 2015–2016 values |
| Severe -Year 2+ | £1,680 | Caprini 2003 converted to 2000 GBP OECD PPP conversion; (Organisation for Economic Co-operation Development (OECD), 2012) and inflated to 2015–2016 values |
| CTEPH | ||
| Operable-Y1 | £28,671 | NG89 (Venous thromboembolism in over 16s: reducing the risk of hospital-acquired deep vein thrombosis or pulmonary embolism), Appendix P (National Institute for Health and Care Excellence, 2018) |
| Recurrent/Resistant- Year 1 | £29,470 | NG89 (Venous thromboembolism in over 16s: reducing the risk of hospital-acquired deep vein thrombosis or pulmonary embolism), Appendix P (National Institute for Health and Care Excellence, 2018) |
| Inoperable-Year 1 | £9,677 | NG89 (Venous thromboembolism in over 16s: reducing the risk of hospital-acquired deep vein thrombosis or pulmonary embolism), Appendix P (National Institute for Health and Care Excellence, 2018) |
| Recurrent/resistant- Year 2 | £21,845 | NG89 (Venous thromboembolism in over 16s: reducing the risk of hospital-acquired deep vein thrombosis or pulmonary embolism), Appendix P (National Institute for Health and Care Excellence, 2018) |
| Chronic-Year 2+ | £13,967 | NG89 (Venous thromboembolism in over 16s: reducing the risk of hospital-acquired deep vein thrombosis or pulmonary embolism), Appendix P (National Institute for Health and Care Excellence, 2018) |
| Treated CTEPH | £147 | NG89 (Venous thromboembolism in over 16s: reducing the risk of hospital-acquired deep vein thrombosis or pulmonary embolism), Appendix P (National Institute for Health and Care Excellence, 2018) |
BMI, body mass index; CRNMB, clinically-relevant non-major bleeding; CTEPH, chronic thromboembolic pulmonary hypertension; DVT, deep vein thrombosis; eTHR, elective total hip replacement; eTKR, elective total knee replacement; GI, gastrointestinal; HIT, Heparin-induced thrombocytopenia; LMWH, low molecular weight heparin; PE, pulmonary embolism; PTS, post-thrombotic syndrome.