(b).

Cost parameters (over 6-month period)	Mean costs ($)	Range ($)	Probability distributiong	Sources/Comments
AZA 150 mg/day × 6 monthsa	769.86	343.98–2626.26	Gamma (59.1, 0.08)	Red Book 2013 [12]
MMF 2000 mg/day × 6 monthsb	4833.92	1135.68–5773.04	Gamma (23.4, 0.005)	Red Book 2013 [12]
MMF 3000 mg/day × 6 monthsb	7250.88	1703.52–8659.56	Gamma (52.6, 0.007)	Red Book 2013 [12]
Monthly infusion of CYC 0.75 gm/m2  × 6 months to treat LN relapsed	6233.52c	4675.14–7791.90	Gamma (42.1, 0.006)	Red Book 2013 [12], CMS 2013 [16]; range assumed to be ±25% mean
Direct costs × 6 months (nonpharmaceuticals)e
Remission	1684.17	1263.13–2105.21	Gamma (31.5, 0.019)	Clarke et al. 2008 [17]; Clarke et al. 2004 [18]; range assumed to be ±25% mean
Relapse	3243.43	2432.57–4054.29	Gamma (29.2, 0.009)	Clarke et al. 2008 [17]; Clarke et al. 2004 [18]; range assumed to be ±25% mean
Indirect costs × 6 monthsf
Remission	8033.19	6024.89–10041.49	Gamma (16.1, 0.002)	Clarke et al. 2008 [17]; Panopalis et al. 2007 [19]; range assumed to be ±25% mean
Relapse	8564.07	6423.05–10705.09	Gamma (18.3, 0.002)	Clarke et al. 2008 [17]; Panopalis et al. 2007 [19]; range assumed to be ±25% mean
ESRD/dialysis: mean cost per person × 6 months	43,304	n/a	Gamma (75.0, 0.002)	USRDS 2012 [20]
Major infection (inpatient cost for septicemia, ICD9 code 038.9)	17,183	16,849–17,517	Gamma (32.8, 0.002)	Healthcare Cost and Utilization Project [21]

AZA: azathioprine; MMF: mycophenolate mofetil; CYC: cyclophosphamide (intravenous); ESRD: end stage renal disease; USRDS: United States Renal Data System; LN: lupus nephritis.

^aBased on unit cost of AZA 50 mg tablet = $1.41 (range 0.63–4.81) [12].

^bBased on unit cost of MMF 500 mg tablet = $6.64 (range 1.56–7.93) [12].

^cBased on monthly cost of intravenous CYC 0.75 gm/m²  = $1038.92 [12, 16].

^dSee Supplemental Table 6: costs of individual components of intravenous cyclophosphamide infusion.

^eComponents of direct costs included care provided by specialists, nonspecialists, nonphysician healthcare professionals, laboratory studies, imaging studies, emergency room visits, outpatient surgery, and hospitalizations [18].

^fIndirect costs included time lost from labor and nonlabor (i.e., household work) market activity as well as time that a caregiver spent helping the patient receiving healthcare services and the time the caregiver spent doing housework [19].

^gGamma distributions are characterized by (α, λ); α = μ ²/s ², λ = μ/s ², where μ = mean; s ² = variance.