(a).
| Probability parameters (1-year cycle)a | Base-case value | Range (95% CI) | Probability distributionb | Sources |
|---|---|---|---|---|
| Remission in AZA group | ||||
| Probability of lupus-related death during remission | Age-dependentg | n/a | n/a | Bernatsky et al. 2006 [27]; Arias 2011 [28]; Cochrane 2012 [13] |
| Probability of ESRD during remission | 0.0061 | 0.0012–0.0317 | Beta (35.9, 11,927.1) | Cochrane 2012 [13] |
| Probability of relapse during remission | 0.0716 | 0.0463–0.1140 | Beta (5106.9, 135,192.3) | Cochrane 2012 [13] |
| Remission in MMF group | ||||
| Probability of lupus-related death during remission | Age-dependentf | n/a | n/a | Bernatsky et al. 2006 [27]; Arias 2011 [28]; Cochrane 2012 [13] |
| Probability of ESRD during remission | 0.0025 | 0.0005–0.0125 | Beta (16.6, 6771.3) | Cochrane 2012 [13] |
| Probability of relapse during remission | 0.0367 | 0.0244–0.0564 | Beta (16.0, 419.5) | Cochrane 2012 [13] |
| Relapse in MMF group | ||||
| Probability of lupus-related death during relapse | Age-dependente | n/a | n/a | Bernatsky et al. 2006 [27]; Arias 2011 [28] |
| Probability of ESRD during relapse | 0.1183 | 0.0455–0.2910 | Beta (491.1, 3670.9) | Cochrane 2012 [13] |
| Probability of complete and partial remissions | 0.8319 | 0.6613–0.9313 | Beta (45.7, 9.2) | Cochrane 2012 [13] |
| Relapse in AZA group | ||||
| Probability of lupus-related death during relapse | Age-dependente | n/a | n/a | Bernatsky et al. 2006 [27]; Arias 2011 [28] |
| Probability of ESRD during relapse | 0.1183c | 0.0455–0.2910 | Beta (491.1, 3670.9) | Cochrane 2012 [13] |
| Probability of complete and partial remissions | 0.8319c | 0.6613–0.9313 | Beta (45.7, 9.2) | Cochrane 2012 [13] |
| ESRD due to lupus nephritis | ||||
| Probability of death due to lupus nephritis ESRD | Age-dependentd | n/a | n/a | USRDS 2012 [20]; Sule et al. 2011 [29] |
AZA: azathioprine; MMF: mycophenolate mofetil; CYC: cyclophosphamide; ESRD: end stage renal disease; CI: confidence interval.
aProbabilities from the data sources were reported over various follow-up durations. Probabilities were converted to rates and then to 6-month probabilities [15]. First, the probabilities were converted to yearly rates (event per patient per year) using the equation r = − (1/t)ln(1 − P), where r = rate; t = time in years; P = probability of an event occurring during time t.
These annual rates were then converted to 6-month probabilities using the equation P = 1 − e −rt, where r = one-year rate; t = time in years; P = probability of an event occurring during time t.
bBeta distributions are characterized by (α, β).
cProbability based on MMF for relapse in either AZA- or MMF-based regimen.
dThe age-specific annual mortality rate for the general dialysis population in 2011 [20] is multiplied by hazard ratio (HR) 1.7. In a USRDS study, Sule et al. found that adult patients with ESRD secondary to SLE were at increased risk of death compared with other adult patients (HR 1.7; 95% CI 1.2–2.7) [29]. Conversion between rates and probabilities as noted above.
eIn the relapse state for both MMF and AZA strategies, the rate of lupus-related death is derived from age-specific annual mortality rate in the general population [28] multiplied by a standardized mortality ratio (SMR) 7.9. In a cohort of 9,547 SLE patients, Bernatsky et al. estimated an SMR 7.9 in those with nephritis [27]. Conversion between rates and probabilities as noted above.
fValues in (e) divided by 9.3, given that the relative risk of lupus-related death during relapse versus remission on MMF treatment is 9.3 [13].
gValues in (f) × 0.58, given that the relative risk of lupus-related death during remission on AZA versus MMF is 0.58 [13].