Medical costs and healthcare resource use in patients with lupus nephritis and neuropsychiatric lupus in an insured population

Figures & data

Figure 1.  Selection of subjects with SLE (2003–2008).

Table 1.  Demographic characteristics of lupus nephritis subjects and matched controls (2003–2008).

	Lupus nephritis (n = 907)		Controls (n = 2721)		p-value^a
	n	%	n	%
Index year
2003	163	17.97	492	18.08	–
2004	123	13.56	372	13.67	–
2005	119	13.12	358	13.16	–
2006	175	19.29	536	19.70	–
2007	144	15.88	429	15.77	–
2008	183	20.18	534	19.63	–
Age
18–44	457	50.39	1371	50.39	–
45–64	398	43.88	1194	43.88	–
65+	52	5.73	156	5.73	–
Gender
Male	110	12.13	330	12.13	–
Female	797	87.87	2391	87.87	–
Region
Northeast	83	9.15	249	9.15	–
Midwest	275	30.32	825	30.32	–
South	429	47.30	1287	47.30	–
West	120	13.23	360	13.23	–
Pre-index comorbidities
Cataract	45	4.96	90	3.31	0.016
Cardiovascular disease^b	90	9.92	123	4.52	<0.001
Osteoporosis	89	9.81	67	2.46	<0.001
Avascular necrosis	14	1.54	2	0.07	<0.001
Osteoarthritis	115	12.68	156	5.73	<0.001
Diabetes	29	3.20	184	6.76	<0.001
Hypertension	319	35.17	508	18.67	<0.001
Depression	110	12.13	268	9.85	0.057
Malignancy	17	1.87	91	3.34	0.023
Cerebrovascular events (stroke/history of stroke)	5	0.55	18	0.66	0.725
	Mean	SD	Mean	SD
Pre-index length of time on insurance (days)	1042.11	648.98	985.47	541.74	–

^aStatistical testing was not executed for variables used for hard-matching. Matching was performed using the Quan-Charlson comorbidity score, not using individual comorbidities.

^bAngina pectoris, unstable angina, coronary artery bypass surgery, myocardial infarction, cardiomyopathy, valvular disease, pericarditis, percutaneous coronary artery procedure, peripheral vascular disease.

Figure 2.  Average annual component costs of lupus nephritis subjects and matched controls (2003–2008).

Table 2.  Annual (post-index) healthcare resource use of lupus nephritis subjects and matched controls (2003–2008).

	Lupus nephritis (n = 907)		Controls (n = 2721)		p-value
	n	%	n	%
Post-index resource utilization
Ambulatory visits	904	99.67	2571	94.49	<0.001
Visit to primary care physician	806	88.86	2273	83.54	<0.001
Visit to Nephrologist	320	35.28	6	0.22	<0.001
Visit to Neurologist	122	13.45	100	3.68	<0.001
Visit to Rheumatologist	620	68.36	32	1.18	<0.001
Visit to Dermatologist	206	22.71	422	15.51	<0.001
Emergency department visits	431	47.52	503	18.49	<0.001
Inpatient hospital stays	438	48.29	246	9.04	<0.001
Diagnostic services (lab and radiology)	897	98.90	2353	86.48	<0.001
Durable medical equipment^a	153	16.87	213	7.83	<0.001
Post-index medications
Systemic corticosteroids^b	615	67.81	428	15.73	<0.001
Methotrexate	80	8.82	5	0.18	<0.001
Azathioprine	99	10.92	1	0.04	<0.001
Cyclophosphamide	29	3.20	2	0.07	<0.001
Mycophenolate mofetil	189	20.84	0	0.00	<0.001
Anti-malarials^c	449	49.50	7	0.26	<0.001
Rituximab	10	1.10	1	0.04	0.001
	Mean^d	SD	Mean^d	SD
Post-index resource utilization
Count of ambulatory visits	30.45	23.21	10.23	11.55	<0.001
Visit to PCP	6.40	6.82	3.34	3.49	<0.001
Visit to Nephrologist	1.79	3.99	0.00	0.08	<0.001
Visit to Neurologist	0.34	1.12	0.08	0.51	<0.001
Visit to Rheumatologist	3.43	3.94	0.03	0.32	<0.001
Visit to Dermatologist	0.51	1.28	0.29	0.90	<0.001
Count of emergency department visits	1.48	3.35	0.53	2.30	<0.001
Count of inpatient hospital stays	0.84	1.24	0.10	0.38	<0.001
Total length of inpatient stay (days)	6.42	14.96	0.55	3.22	<0.001
Post-index medication dispensings
Systemic corticosteroids^b	3.73	4.62	0.31	1.00	<0.001
Methotrexate	0.49	1.97	0.02	0.41	<0.001
Azathioprine	0.61	2.14	0.00	0.08	<0.001
Cyclophosphamide	0.16	1.16	0.00	0.11	<0.001
Mycophenolate mofetil	1.19	2.88	0.00	0.00	<0.001
Anti-malarials^c	2.97	3.95	0.01	0.35	<0.001
Rituximab	0.03	0.32	0.00	0.13	0.009

^aMedical equipment included spirometer, exercise equipment, enteral nutrition infusion pump, parenteral nutrition infusion pump, automatic external defibrillator, orthotic procedures and devices, prosthetic procedures and implants, and enuresis alarm, including medical equipment delivery, set-up, and/or dispensing service component of another HCPCS code.

^bSystemic corticosteroids included betamethasone, corticotropin, dexamethasone, methylprednisolone, prednisolone, prednisone, or triamcinolone.

^cChloroquine HCl, chloroquine phosphate, hydroxychloroquine sulfate, quinacrine HCl.

^dMean values are per patient per year.

Table 3.  Demographic characteristics of NPSLE subjects and matched controls (2003–2008).

	NPSLE (n = 1062)		Controls (n = 3186)		p-value^a
	n	%	n	%
Index year
2003	158	14.88	474	14.88	–
2004	163	15.35	495	15.54	–
2005	162	15.25	483	15.16	–
2006	193	18.17	583	18.30	–
2007	164	15.44	494	15.51	–
2008	222	20.90	657	20.62	–
Age
18–44	484	45.57	1452	45.57	–
45–64	518	48.78	1554	48.78	–
65+	60	5.65	180	5.65	–
Gender
Male	73	6.87	219	6.87	–
Female	989	93.13	2967	93.13	–
Region
Northeast	93	8.76	279	8.76	–
Midwest	277	26.08	831	26.08	–
South	526	49.53	1578	49.53	–
West	166	15.63	498	15.63	–
Pre-index comorbidities
Cataract	67	6.31	110	3.45	<0.001
Cardiovascular disease^b	109	10.26	126	3.95	<0.001
Osteoporosis	102	9.60	83	2.61	<0.001
Avascular necrosis	7	0.66	1	0.03	0.004
Osteoarthritis	181	17.04	177	5.56	<0.001
Diabetes	27	2.54	197	6.18	<0.001
Hypertension	279	26.27	610	19.15	<0.001
Depression	457	43.03	319	10.01	<0.001
Malignancy	16	1.51	93	2.92	0.010
Cerebrovascular events (stroke/history of stroke)	24	2.26	16	0.50	<0.001
	Mean	SD	Mean	SD
Pre-index length of time on insurance (days)	1069.34	657.48	999.51	557.01	–

^aStatistical testing was not executed for variables used for hard-matching. Matching was performed using the Quan-Charlson comorbidity score, not using individual comorbidities.

^bAngina pectoris, unstable angina, coronary artery bypass surgery, myocardial infarction, cardiomyopathy, valvular disease, pericarditis, percutaneous coronary artery procedure, peripheral vascular disease.

Figure 3.  Average annual component costs of NPSLE subjects and matched controls (2003–2008).

Table 4.  Annual (post-index) healthcare resource use of NPSLE subjects and matched controls (2003–2008).

	NPSLE (n = 1062)		Controls (n = 3186)		p-value
	n	%	n	%
Post-index resource utilization
Ambulatory visits	1060	99.81	3020	94.79	<0.001
Visit to primary care physician	989	93.13	2667	83.71	<0.001
Visit to Nephrologist	62	5.84	11	0.35	<0.001
Visit to Neurologist	349	32.86	123	3.86	<0.001
Visit to Rheumatologist	736	69.30	47	1.48	<0.001
Visit to Dermatologist	240	22.60	483	15.16	<0.001
Emergency department visits	608	57.25	569	17.86	<0.001
Inpatient hospital stays	470	44.26	251	7.88	<0.001
Diagnostic services (lab and radiology)	1056	99.44	2775	87.10	<0.001
Durable medical equipment^a	220	20.72	209	6.56	<0.001
Post-index medications
Systemic corticosteroids^b	631	59.42	499	15.66	<0.001
Methotrexate	100	9.42	13	0.41	<0.001
Azathioprine	79	7.44	2	0.06	<0.001
Cyclophosphamide	14	1.32	3	0.09	<0.001
Mycophenolate mofetil	74	6.97	1	0.03	<0.001
Anti-malarials^c	564	53.11	13	0.41	<0.001
Rituximab	4	0.38	1	0.03	0.026
Post-index resource utilization	Mean^d	SD	Mean^d	SD
Count of ambulatory visits	33.25	21.82	9.88	10.83	<0.001
Visit to PCP	7.06	7.01	3.22	3.17	<0.001
Visit to Nephrologist	0.23	1.34	0.01	0.21	<0.001
Visit to Neurologist	1.00	1.99	0.08	0.55	<0.001
Visit to Rheumatologist	3.31	3.90	0.04	0.48	<0.001
Visit to Dermatologist	0.50	1.29	0.30	1.11	<0.001
Count of emergency department visits	2.30	4.68	0.48	2.12	<0.001
Count of inpatient hospital stays	0.75	1.18	0.09	0.34	<0.001
Total length of inpatient stay (days)	5.88	14.65	0.49	3.43	<0.001
Post-index medication dispensings
Systemic corticosteroids^b	2.77	4.01	0.26	0.80	<0.001
Methotrexate	0.57	2.43	0.03	0.52	<0.001
Azathioprine	0.38	1.67	0.00	0.17	<0.001
Cyclophosphamide	0.06	0.71	0.00	0.12	0.005
Mycophenolate mofetil	0.37	1.61	0.00	0.04	<0.001
Anti-malarials^c	3.23	4.02	0.02	0.41	<0.001
Rituximab	0.01	0.19	0.00	0.02	0.065

^aMedical equipment included spirometer, exercise equipment, enteral nutrition infusion pump, parenteral nutrition infusion pump, automatic external defibrillator, orthotic procedures and devices, prosthetic procedures and implants, and enuresis alarm, including medical equipment delivery, set-up, and/or dispensing service component of another HCPCS code.

^bSystemic corticosteroids included betamethasone, corticotropin, dexamethasone, methylprednisolone, prednisolone, prednisone, or triamcinolone.

^cChloroquine HCl, chloroquine phosphate, hydroxychloroquine sulfate, quinacrine HCl.

^dMean values are per patient per year.