TABLE 3.
Mean 180-Day Costs in the SjS-ILD Cohort and the SjS-Only Cohort Among a Total of 4,890 Propensity Score–Matched Subjects
| SjS-ILD cases (n= 815) | SjS-only controls (n = 4,075) | Adjusted cost ratio (95% CI)a,b | Adjusted average marginal cost (95% CI)a,b,c | |||||
|---|---|---|---|---|---|---|---|---|
| Mean (SD), $ | % | Median (IQR), $ | Mean (SD), $ | % | Median (IQR), $ | |||
| Total cost | 23,192 (48,189) | 100.0 | 7,960 (18,668) | 8,648 (17,478) | 100.0 | 3,369 (7,107) | 1.95 (1.76-2.15)d | 8,814 (7,149-10,479)d |
| Cost per HCRU category | ||||||||
| Inpatient | 8,997 (36,824) | 38.8 | 0 (1,532) | 1,952 (11,769) | 22.6 | 0 (0) | N/A | N/A |
| ED visit | 232 (964) | 1.0 | 0 (0) | 140 (645) | 1.6 | 0 (0) | N/A | N/A |
| Pharmacy | 3,785 (8,212) | 16.3 | 1,273 (3,575) | 1,977 (4,472) | 22.9 | 540 (1,879) | N/A | N/A |
| Physician office visit | 1,036 (1,076) | 4.5 | 720 (1,031) | 799 (921) | 9.2 | 545 (752) | N/A | N/A |
| Other outpatiente | 9,142 (21,304) | 39.4 | 2,929 (7,453) | 3,781 (8,723) | 43.7 | 1,062 (3,177) | N/A | N/A |
Variables that are used as independent variables in the propensity score model include the following: age, sex, residence region, index year, and plan product type
aGLM with a γ distribution and a log link was fit. Costs represented strictly to nonzero cost to fit γ distribution (N=4,836; 811 cases and 4,025 controls)
bIndependent variables included in the GLM were comparison group (ie, SjS-ILD vs SjS-only), age, dummy variables for index year categories, dummy variables for CCI categories, baseline RA, baseline SLE, and baseline systemic sclerosis
cCI was estimated using the delta method.
dP < 0.01
eOther outpatient services refer to outpatient services other than physician office visits, including laboratory, pathology, radiology, outpatient surgical, and ancillary services.
ED = emergency department; GLM = generalized linear model; HCRU = health care resource utilization; ILD = interstitial lung disease; N/A = not applicable; RA = rheumatoid arthritis; SjS = Sjögren syndrome; SLE = systemic lupus erythematosus.