Table 1 Summary of input parameters applied in the base-case model
VariablesValueLow CIHigh CIDistributionRef
Probability of NSR at 1 year
Odds ratio0.09680.05200.1641Posterior
Annual probability of recurrent AF after year 1
Stroke risk for AF (%)
Hazard ratio relative to NSR*1.601.112.30Log normal14
Stroke risk reduction with OACs (RR)
Warfarin relative to placebo0.330.240.45Log normal13
Warfarin relative to aspirin0.590.400.86Log normal13
OAC use (%)
Mortality risk from stroke (RR)
In year 17.406.508.50Betapert16
In subsequent years2.302.002.70Betapert16
Adverse toxicity from AADs (%)
General toxicity (year 1)12.5010.0015.00Betapert22
General toxicity (⩾ 2 years)
Withdrawal due to toxicity (year 1)10.006.2512.50Betapert22
Withdrawal due to toxicity (⩾ 2 years)
Pulmonary complication given withdrawal15.191.0030.00Betapert22
Irreversible pulmonary complication25.000.0030.00Betapert22
Mortality from irreversible pulmonary event20.005.0025.00Betapert22
Adverse bleeding from OACs (%)
Major bleed on warfarin2.401.708.10Betapert26
Minor bleed on warfarin15.8015.0016.60Betapert26
Bleeding risk reduction on aspirin (RR)
Major bleed0.580.350.97Log normal13
Minor bleed0.450.320.64Log normal13
Bleeding risk reduction on no OACs (RR)
Major bleed0.450.250.82Log normal13
Minor bleed0.460.360.59Log normal13
RFCA procedural complications (%)
Operative death0.050.000.09Beta9
Cardiac tamponade1.220.991.45Beta9
PV stenosis0.740.540.94Beta9
Mean number of procedures per patient1.3041.2931.315Normal9
Utilities associated with health statesSE
Decrement for NSR given RFCA0.00003027
Decrement for NSR given AADs0.01990.0100Gamma27
Decrement for AF given RFCA0.00340.0017Gamma28
Decrement for AF given AADs0.09250.0361Gamma28
Disabled stroke0.380.0460Beta19
Non-disabled stroke0.740.0260Beta19
Combined stoke (30.9% disabled)0.6319
Decrement for pulmonary toxicity0.03290.0030Gamma21
Decrement for non-pulmonary toxicity or bleeding event (days of perfect health lost)10Betapert22
Unit costs (£)
RFCA accumulated cost†9810Fixed
Complication from cardiac tamponade815Fixed18
Complication from PV stenosis3217Fixed18
Outpatient initiation of amiodarone154Fixed18
Amiodarone (200 mg daily, per annum)32Fixed29
AF health state (per annum)646Fixed2
NSR health state (per annum)646Fixed2
Stroke (year 1)9431Fixed19
Stroke (⩾ 2 years, per annum)2488Fixed19
Warfarin (5 mg daily, per annum)19Fixed29
Aspirin (75 mg daily, per annum)20Fixed29
Toxic event1497Fixed30
Reversible toxicity (per day)0.43Fixed29
Irreversible toxicity (50 mg daily)158Fixed29
Major bleeding event1573Fixed26
Minor bleeding event87Fixed26
  • AAD, anti-arrhythmic drug; AF, atrial fibrillation; CHADS2, congestive heart failure, hypertension, age 75, diabetes mellitus, and prior stroke; CI, confidence interval or credible interval; NSR, normal sinus rhythm; OAC, oral anticoagulants; PV, pulmonary vein; RFCA, radiofrequency catheter ablation; RR, relative risk; SE, standard error.

  • *Used to determine the stroke risk for NSR. The hazard ratio is applied to the CHADS2 stroke risk scores for AF.

  • †RFCA procedural cost consists of total consumable (£5687), ward (£182 based on 2 days), and lab (£1979 based on 200 minutes) costs plus VAT and administration costs (Fitzpatrick A, personal communication, 2007).