Table 2. Frequencies and costs of ambulatory medical care utilization in patients with systemic lupus erythematosus and controls over an eight-year period preceding the index date.

Years preceding index date	Annual frequencies of ambulatory medical care utilization		P	Annual costs of ambulatory medical care utilization		P
	Patients with SLE	Controls		Patients with SLE	Controls
	n = 337	n = 1,348		n = 337	n = 1,348
8	8.31±13.23	4.04±9.63	<0.001	232±697	98±454	<0.001
	(1, 0–13)	(0, 0–3)		(18, 0–251)	(0, 0–47)
7	9.74±12.80	4.95±10.76	<0.001	289±1450	107±288	<0.001
	(5, 0–15)	(0, 0–6)		(82, 0–293)	(0, 0–94)
6	12.15±13.64	6.05±11.79	<0.001	398±1488	135±407	<0.001
	(8, 1–18)	(0, 0–9)		(142, 13–407)	(0, 0–145)
5	14.41±13.18	7.30±12.74	<0.001	520±2000	186±848	<0.001
	(11, 5–20)	(1, 0–10)		(218, 73–453)	(12, 0–204)
4	16.03±13.61	7.86±12.45	<0.001	632±2404	208±903	<0.001
	(13, 6–23)	(2, 0–12)		(243, 93–542)	(16, 0–225)
3	16.81±13.27	8.10±12.83	<0.001	750±2420	216±893	<0.001
	(14, 6–23)	(2, 0–12)		(265, 110–632)	(20, 0–220)
2	17.47±15.18	7.84±12.72	<0.001	760±2460	218±949	<0.001
	(13, 6–25)	(1, 0–12)		(291, 109–751)	(27, 0–230)
1	25.23±15.24	8.07±13.05	<0.001	1134±2503	216±897	<0.001
	(22, 15–32)	(2, 0–12)		(680, 419–1186)	(27, 0–230)

Values are mean ± standard deviation and (median, 25^th–75^th percentile).

Costs were converted to US dollars based on annual exchange rates and adjusted to 2010 figures based on Taiwan's consumer price index.

SLE, systemic lupus erythematosus.