Background
Methods
The model
Clinical model parameters
Expected values of probabilities | Parameter | Expected value (standard error) | Source | |
---|---|---|---|---|
after THR | after TKR | |||
Prophylaxis with enoxaparin | ||||
Major bleeding | par_1 | 0.002 (0.0006) | 0.005 (0.0015) | |
VTE event | par_2 | 0.035 (0.0047) | 0.187 (0.0132) | |
Pre-discharge VTE1
| par_3 | 0.240 (0.0181) | 0.530 (0.0221) | [18] |
DVT | par_4 | 0.964 (0.0252) | 0.976 (0.0120) | |
Distal DVT | par_5 | 0.415 (0.0677) | 0.875 (0.0007) | |
Symptomatic DVT | par_6 | 0.167 (0.0507) | 0.122 (0.0256) | |
Asymptomatic DVT becomes symptomatic | par_7 | 0.200 (0.1789) | 0.048 (0.0466) | [20] |
Non-fatal PE | par_8 | 0.500 (0.3536) | 0.875 (0.1654)² | |
Prophylaxis with rivaroxaban | ||||
Major bleeding | par_1 | 0.002 (0.0006) | 0.005 (0.0015) | |
VTE event | par_9 | 0.010 (0.0025) | 0.096 (0.0103) | |
Pre-discharge VTE1
| par_3 | 0.240 (0.0181) | 0.530 (0.0221) | [18] |
DVT | par_10 | 0.750 (0.1083) | 0.994 (0.0089)² | |
Distal DVT | par_11 | 0.917 (0.0798) | 0.886 (0.0358) | |
Symptomatic DVT | par_12 | 0.250 (0.1250) | 0.099 (0.0331) | |
Asymptomatic DVT becomes symptomatic | par_7 | 0.200 (0.1789) | 0.048 (0.0466) | [20] |
Non-fatal PE | par_13 | 0.875 (0.1654)² | 0.500 (0.5000)² |
Resource consumption and costs
Prophylaxis strategies
Days of prophylaxis duration | Non-DRG included costs (€) for prophylaxis | Source | ||
---|---|---|---|---|
Enoxaparin sodium3
| Rivaroxaban | |||
In hospital (total duration) | Costs for hospitals | |||
MB with or without VTE1 - after THR- after TKR | 5.0 (5)5.0 (5) | 0.000.00 | 13.0013.00 | |
Pre-discharge VTE without MB² - after THR- after TKR | 7.0 (7)7.0 (7) | 0.000.00 | 18.2018.20 | |
Post-discharge VTE or no VTE and no MB - after THR- after TKR | 12.4 (32)12.7 (13) | 0.000.00 | 32.2433.02 | |
After discharge (total duration) | Costs for SHI | |||
Post-discharge VTE or no VTE and no MB - after THR- after TKR | 19.6 (32)0.3 (13) | 106.621.63 | 134.852.06 |
Diagnostics and treatment for pre-discharge VTE events
Additional length of stay for pre-discharge VTE events
Resource consumption | DVT after THR (units) | DVT after TKR (units) | nf PE after THR(units) | nf PE after TKR(units) | Unit prices (€) | Source | |
---|---|---|---|---|---|---|---|
In hospital | Diagnostics | ||||||
Blood gas analysis | 0.0 | 0.0 | 1.0 | 1.0 | 4.95 | ||
D-dimer | 1.0 | 1.0 | 1.0 | 1.0 | 9.90 | ||
Doppler ultrasound | 1.0 | 1.0 | 0.0 | 0.0 | 9.90 | ||
Chest X-ray | 0.0 | 0.0 | 1.0 | 1.0 | 7.70 | ||
ECG | 0.0 | 0.0 | 1.0 | 1.0 | 8.36 | ||
CT | 0.0 | 0.0 | 1.0 | 1.0 | 154.00 | ||
Echocardiography | 0.0 | 0.0 | 1.0 | 1.0 | 27.50 | ||
Treatment | |||||||
Enoxaparin sodium | 12.0 | 12.0 | 12.0 | 12.0 | 9.98 | ||
Subcutaneous injection | 12.0 | 12.0 | 12.0 | 12.0 | 2.20 | ||
Blood sample (TZ) | 1.0 | 1.0 | 1.0 | 1.0 | 5.50 | ||
Phenprocoumon (days) | 10.3 | 10.0 | 11.0 | 12.7 | 0.17 | ||
Anticoagulant monitoring1
| 2.0 | 2.0 | 2.0 | 2.0 | 8.80 | ||
Compression therapy | 1.0 | 1.0 | 1.0 | 1.0 | 5.23 | ||
Additional LOS2 (€) | 1,086.27 | 919.15 | 1,716.45 | 1,973.73 | |||
Total costs for hospital (€) | 1,282.27 | 1,115.14 | 2,105.22 | 2,362.79 | |||
In hospital | Extra DRG reimbursement³ | 0 | 0 | 0 | 191.46 | ||
Outpatient | Treatment | ||||||
Outpatient visit4
| 1.0 | 1.0 | 1.0 | 1.0 | 53.16 | ||
Phenprocoumon (days) | 79.7 | 80.0 | 79.0 | 77.3 | 0.17 | ||
INR measurement | 10.0 | 10.0 | 10.0 | 10.0 | 1.68 | ||
Compression stockings | 2.0 | 2.0 | 2.0 | 2.0 | 36.90 | ||
Total costs for health insurance (€) | 157.35 | 157.40 | 157.23 | 348.40 |
Diagnostics and treatment for post-discharge VTE events
Resources | DVT² (units) | Non-fatal PE² (units) | Fatal PE³(units) | Unit prices(€) | Source | |
---|---|---|---|---|---|---|
In hospital | Diagnosis, treatment and hospitalization (€) | 1,838.33 | 3,543.48 | 1,256.43 | [16] | |
Outpatient | Treatment | |||||
Outpatient visit1
| 1.0 | 1.0 | 0.0 | 53.16 | ||
Phenprocoumon (days) | 83.4 | 79.7 | 0.0 | 0.17 | ||
INR measurement | 10.0 | 10.0 | 0.0 | 1.68 | ||
Compression stockings | 2.0 | 2.0 | 0.0 | 36.90 | ||
Total costs for health insurance (€) | 1,995.89 | 3,700.43 | 1,256.43 |
Cost-effectiveness analysis and probabilistic sensitivity analysis
Costs of resources | Parameter | Expected costs (€) (standard error) | |||
---|---|---|---|---|---|
After THR | After TKR | ||||
Hospital perspective | SHI perspective | Hospital perspective | SHI perspective | ||
Prophylaxis costs with enoxaparin in the case of | |||||
Post-discharge VTE or no VTE and no MB | par_14 | 0 | 106.42 (10.64) | 0 | 1.63 (0.16) |
Prophylaxis costs with rivaroxaban in the case of | |||||
MB with or without VTE | par_15 | 13.00 (1.30) | 0 | 13.00 (1.30) | 0 |
Pre-discharge VTE without MB | par_16 | 18.20 (1.82) | 0 | 18.20 (1.82) | 0 |
Post-discharge VTE or no VTE and no MB | par_17 | 32.24 (3.22) | 134.85 (13.49) | 33.02 (3.30) | 2.06 (0.21) |
Total costs of pre-discharge VTE | |||||
DVT | par_18 | 1,282.27 (128.33) | 157.35 (17.74) | 1,115.14 (111.51) | 157.40 (15.74) |
Non-fatal PE | par_19 | 2,105.22 (210.52) | 157.23 (15.73) | 2,362.79 (236.28) | 348.40 (34.84) |
Total costs of post-discharge VTE | |||||
DVT | par_20 | 0 | 1,995.89 (199.59) | 0 | 1,995.89 (199.59) |
Non-fatal PE | par_21 | 0 | 3,700.43 (370.04) | 0 | 3,700.43 (370.04) |
Fatal PE | par_22 | 0 | 1,256.43 (125.64) | 0 | 1,256.43 (125.64) |
Results
Type of surgery | Costs (€) | Incremental costs (€) | VTE events per person | Incremental effect (events avoided) | ICER (€ per event avoided) |
---|---|---|---|---|---|
THR | |||||
Rivaroxaban | 33.8 (3.3) | 31.8 (3.4) | 0.005 (0.002) | 0.007 (0.005) | 1,564 |
Enoxaparin | 2.05 (0.7) | 0.012 (0.005) | |||
TKR | |||||
Rivaroxaban | 38.8 (3.9) | 20.6 (5.6) | 0.014 (0.005) | 0.020 (0.007) | 1,014 |
Enoxaparin | 18.1 (4.3) | 0.035 (0.009) |
Type of surgery | Costs (€) | Incremental costs (€) | VTE events per person | Incremental effect(events avoided) | ICER(€ per event avoided) |
---|---|---|---|---|---|
THR | |||||
Rivaroxaban | 146.5 (14.2) | 17.8 (19.6) | 0.005 (0.002) | 0.007 (0.005) | 875 |
Enoxaparin | 128.7 (14.9) | 0.012 (0.005) | |||
TKR | |||||
Rivaroxaban | 20.7 (9.0) | −27.3 (10.7) | 0.014 (0.005) | 0.020 (0.007) | dominant |
Enoxaparin | 48.0 (16.9) | 0.035 (0.009) |
The cost-effectiveness acceptability curves
The ANCOVA analysis and deterministic sensitivity analysis
Total hip replacement | Total knee replacement | |||||||
---|---|---|---|---|---|---|---|---|
Incremental events
|
Incremental costs (hospital)
|
Incremental costs (SHI)
|
ICER (SHI)
|
Incremental events
|
Incremental costs (hospital)
|
Incremental costs (SHI)
|
ICER (SHI)
| |
Base case | 0.0070 | 31.8 | 18.0 | 2,569.3 | 0.0203 | 20.7 | −27.2 | dominance |
Probability that a VTE event is a DVT during prophylaxis with enoxaparin (Parameter 4) | ||||||||
0.90 0.95 0.99 | 0.00850.00730.0064 | 31.431.732.0 | 15.017.419.3 | 1,762.72,364.33,006.6 | 0.03220.02440.0181 | 6.215.723.4 | −49.9−35.0−23.0 | dominancedominance dominance |
Probability that a DVT is symptomatic during prophylaxis with enoxaparin (Parameter 6) | ||||||||
0.090.170.26 | 0.00490.00710.0095 | 32.631.830.9 | 21.017.914.5 | 4,244.12,523.91,521.3 | 0.01470.02860.0443 | 24.215.55.8 | −21.8−35.3−50.4 | dominance dominance dominance |
Probability that an asymptomatic DVT becomes symptomatic (Parameter 7) | ||||||||
0.010.150.60 | 0.00270.00590.0160 | 31.831.831.8 | 26.320.20.7 | 9,570.33,428.341.9 | 0.01750.02790.0613 | 20.720.720.7 | −21.4−42.893.2 | dominance dominance 1520.0 |
Probability that a DVT is symptomatic during prophylaxis with rivaroxaban (Parameter 12) | ||||||||
0.060.160.50 | 0.00820.00760.0055 | 31.431.632.4 | 16.517.320.0 | 2,026.22,291.63,626.0 | 0.11230.10320.0723 | 18.524.143.0 | −30.6−21.88.2 | dominance dominance 113.3 |
Prophylaxis costs with enoxaparin in the case of post-discharge VTE or no VTE and no ME (Parameter 14) | ||||||||
20% lower20% higher | 0.00700.0070 | 31.8 31.8 | 39.2−3.2 | 5,592.5dominance | 0.0203 0.0203 | 20.7 20.7 | −26.9−27.5 | dominance dominance |
Prophylaxis costs with rivaroxaban in the case of post-discharge VTE or no VTE and no ME (Parameter 17) | ||||||||
20% lower20% higher | 0.00700.0070 | 25.438.3 | −8.944.9 | dominance6,402.5 | 0.02030.0203 | 14.227.2 | −27.6−26.8 | dominance dominance |