A longitudinal analysis of costs associated with change in disease activity in systemic lupus erythematosus

Figures & data

Table 1. Patient characteristics.

	n = 178
Age (years; mean ± SD)	50.6 ± 15.0
Male, n (%)	16 (9.0%)
Race, n (%)
White	170 (95.5%)
Black	3 (1.7%)
Asian	2 (1.1%)
Hispanic	1 (0.6%)
Other	2 (1.1%)
Body mass index^a (mean ± SD)	28.6 ± 7.1
Smoker, n (%)	27 (15.2%)
CCI^a (mean ± SD)	1.9 ± 1.5
Use of SLE therapies^b,c
Corticosteroids	59 (33.1%)
Hydroxychloroquine	59 (33.1%)
NSAIDs	29 (16.3%)
Immunosuppressives	13 (7.3%)
Mycophenolate Mofetil	3 (1.7%)

^aMeasured during the entire eligibility period prior to the index date.

^bMeasured during 90 days prior to the first SLEDAI score.

^cCalculated using drug claims data only.

Table 2. Description of SLEDAI scores.

	Mean ± SD	n	%
Number of encounters per patient	7.54 ± 8.41
Number of days between first and last SLEDAI score^a	1035 ± 779
First SLEDAI score	2.29 ± 3.10
Difference between a patient’s highest and lowest SLEDAI score^a	4.35 ± 4.09
Number of patients with average SLEDAI score
Avg SLEDAI score = 0		45	25.3%
Avg SLEDAI score > 0		133	74.7%
Avg SLEDAI score ≥ 6		17	9.6%
Number of patients with at least one SLEDAI score
>0		133	74.7%
≥6		69	38.8%
SLEDAI scores (n = 1343)
All SLEDAI scores	2.15 ± 3.04
Change since previous SLEDAI score^a	−0.06 ± 3.00
Number of days since previous SLEDAI score^a	128 ± 149

^aAmong the 144 patients with ≥2 SLEDAI score calculation.

Table 3. Annualized HRU.

	Median	Mean	SD
Total HRU	24.0	34.2	37.0
Inpatient days	0.4	1.9	4.1
Outpatient visits	19.2	24.8	24.1
ER admissions	0.0	0.3	0.9
Other visits	1.5	7.1	22.3

Table 4. Annualized healthcare costs.

		Total costs			Medical costs			Drug costs
	n	Median	Mean	SD	Median	Mean	SD	Median	Mean	SD
Mean SLEDAI score = 0	45	$7512	$14,419	$25,478	$6115	$13,047	$25,055	$773	$1372	$1503
0 < Mean SLEDAI score ≤ 2	65	$9529	$22,401	$32,079	$8211	$19,994	$30,958	$1140	$2407	$3174
2 < Mean SLEDAI score ≤ 4	34	$10,655	$22,080	$40,565	$7862	$19,721	$39,028	$1644	$2359	$2793
4 < Mean SLEDAI score	34	$13,756	$14,636	$12,963	$7616	$10,854	$12,710	$2942	$3782	$3489
Overall	178	$9655	$18,839	$29,776	$7416	$16,440	$28,850	$1526	$2399	$2927

Table 5. Monthly HRU: Regression coefficients and average expected number of medical encounters for each SLEDAI score.

SLEDAI score	Medical encounters^a	Inpatient Days^b	ER Admissions^c	Outpatient visits^d
0	3.15	0.10	0.01	2.53
1	3.24	0.10	0.01	2.58
2	3.33	0.11	0.02	2.62
3	3.41	0.12	0.02	2.67
4	3.51	0.13	0.02	2.72
5	3.60	0.13	0.02	2.77
6	3.70	0.14	0.02	2.82
7	3.80	0.15	0.02	2.87
8	3.90	0.16	0.03	2.92
9	4.00	0.18	0.03	2.97
10	4.11	0.19	0.03	3.02
11	4.22	0.20	0.04	3.08
12	4.33	0.22	0.04	3.13
13	4.45	0.23	0.04	3.19
14	4.57	0.25	0.05	3.24
15	4.69	0.27	0.05	3.30
16	4.82	0.28	0.06	3.36
17	4.95	0.30	0.07	3.42
18	5.08	0.33	0.07	3.48

^aRegression coefficient = 0.026; p = 0.002.

^bRegression coefficient = 0.068; p < 0.001.

^cRegression coefficient = 0.100; p ≤ 0.001.

^dRegression coefficient = 0.018; p = 0.028.

Table 6. Monthly healthcare costs^a: Regression coefficients and average expected costs for each SLEDAI score.

SLEDAI score	Total costs^b	Medical costs^c	Drug costs^d
0	$1006	$780	$86
1	$1044	$817	$91
2	$1084	$855	$96
3	$1126	$896	$101
4	$1169	$938	$106
5	$1213	$982	$112
6	$1260	$1029	$118
7	$1308	$1077	$124
8	$1358	$1128	$131
9	$1410	$1182	$138
10	$1464	$1237	$146
11	$1520	$1296	$153
12	$1578	$1357	$162
13	$1639	$1421	$170
14	$1702	$1488	$180
15	$1767	$1558	$189
16	$1834	$1632	$199
17	$1905	$1709	$210
18	$1978	$1790	$222

^aCosts were measured from a payer’s perspective and reported in 2011 USD.

^bRegression coefficient = 0.038; p = 0.005.

^cRegression coefficient = 0.046; p = 0.005.

^dRegression coefficient = 0.052; p < 0.001.