Surgical procedures and their cost estimates among women with newly diagnosed endometriosis: a US database study

Figures & data

Table 1.  Demographics and comorbidities at baseline, by study cohort.

	Study cohorts
	Endometriosis cohort	Population control cohort	p-value*
	(n = 15,891)	(n = 63,564)
Age (%)			0.99
18–24	5.2	5.2
25–29	9.8	9.8
30–34	19.4	19.4
35–39	28.0	28.0
40–45	37.7	37.7
Age, mean (SD)	36.4 (6.32)	36.4 (6.47)	0.37
Region (%)			0.99
Northeast	6.7	6.7
North Central	23.5	23.5
South	52.9	52.9
West	15.9	15.9
Unknown	1.0	1.0
Type of insurance plan enrolled, %			<0.01
Missing	2.5	4.7
Comprehensive	7.7	5.2
Exclusive provider organization	0.7	0.9
Health maintenance organization	19.8	19.4
Point of service	12.0	11.4
Preferred provider organization	53.2	54.0
Point of service with capitation	4.0	3.2
Consumer driven health plan	0.1	1.2
Endometriosis-related comorbidities, %
Abdominal pain	22.0	1.9	<0.01
Infertility	5.5	0.2	<0.01
Migraine	4.7	0.6	<0.01
Depression	6.5	1.1	<0.01
Interstitial cystitis	0.7	0.02	<0.01
Irritable bowel syndrome	1.9	0.2	<0.01
Chronic fatigue	0.3	0.1	<0.01
Charlson Comorbidity Index, mean (SD)	0.14 (0.53)	0.03 (0.25)	<0.01
Percent			<0.01
0	88.2	97.7
1	6.8	1.3
2	3.9	0.8
>2	1.2	0.2

*χ² test was used for the comparison of age categories, region of residence, type of insurance plan enrolled, and the presence of comorbidities, Student’s t-test was used for the comparison of age, and Wilcoxon rank-sum test was used for the comparison of Charlson Comorbidity Index.

SD, standard deviation.

Table 2.  Proportion of patients with endometriosis-related surgical procedures in 1-year post-index period.

	Endometriosis cohort (n = 15891)			Population control cohort (n = 63564)
	All	On index date	After index date	All	On index date	After index date
Any of the selected surgery, %*	65.5	49.0	19.5	1.5	0.0	1.5
Any hysterectomy, %	28.8	22.0	7.0	0.6	0.0	0.6
Abdominal hysterectomy, %	22.1	16.4	5.8	0.4	0.0	0.4
Vaginal hysterectomy, %	6.8	5.7	1.3	0.2	0.0	0.2
Any diagnostic or therapeutic laparoscopy, %	35.6	25.1	11.9	0.7	0.0	0.7
Diagnostic laparoscopy, %	6.2	3.9	2.4	0.1	0.0	0.1
Therapeutic laparoscopy, %	31.6	22.5	10.2	0.6	0.0	0.6
Laparotomy, %	1.0	0.6	0.5	0.0	0.0	0.0
Oophorectomy, %	2.7	1.8	0.9	0.1	0.0	0.1

Note: Proportion of patients receiving surgeries on and after index date may add up to more than the proportion of patients receiving surgeries during the 1-year post-index period because patients may have received repeated surgeries during the year.

χ² tests were used to detect the difference between endometriosis and population control cohorts. All proportions were significantly different between cohorts.

Table 3.  Surgery rates by age group during 1-year post-index period (include index date) among endometriosis patients.

	Age group (years)			p-value
	18–24	25–34	35–45
	(n = 820)	(n = 4,637)	(n = 10,434)
Any of the selected surgery, %	49.3	59.6	69.4	<0.01
Any hysterectomy, %	1.1	15.6	36.9	<0.01
Abdominal hysterectomy, %	1.0	11.5	28.5	<0.01
Vaginal hysterectomy, %	0.1	4.1	8.6	<0.01
Any diagnostic or therapeutic laparoscopy, %	47.0	43.2	31.3	<0.01
Diagnostic laparoscopy, %	13.3	8.7	4.5	<0.01
Therapeutic laparoscopy, %	37.9	37.9	28.3	<0.01
Laparotomy, %	0.5	0.9	1.2	0.03
Oophorectomy, %	1.2	2.1	3.0	<0.01
Number of surgeries during 1 year post
Mean (SD)	0.6 (0.7)	0.7 (0.7)	0.8 (0.6)
Percent
0	50.7	40.4	30.6	<0.01
1	41.7	49.2	60.3
2	6.8	9.3	8.0
3+	0.7	1.2	1.1

Cochran–Armitage trend tests were used to detect trend of surgery rates across age subgroups, and Cochrane Mantel–Haenszel tests were used to detect the significant difference of number of surgeries across the age sub-groups. A p-value <0.05 was considered statistically significant.

Table 4.  Sensitivity analysis: surgery rates by period and age group.

(a) Rate of surgery	Surgery rate in during and 1 year following diagnosis
	All (n = 8,830)	On index date		After index date
Any of the selected surgery, %	77.1	58.8		22.0
Any hysterectomy, %	46.6	36.7		10.1
Abdominal hysterectomy, %	37.1	28.3		9.0
Vaginal hysterectomy, %	9.7	8.5		1.2
Any diagnostic or therapeutic laparoscopy, %	30.3	20.1		11.5
Diagnostic laparoscopy, %	4.9	2.8		2.2
Therapeutic laparoscopy, %	26.9	18.0		10.0
Laparotomy, %	1.6	0.9		0.7
Oophorectomy, %	4.2	2.9		1.3
(b) Rate of surgery by age group (years)	Surgery rate by age at first endometriosis diagnosis					p-value
	18–24 (n = 298)		25–34 (n = 2,188)		35–45 (n = 6,344)
Any of the selected surgery, %	55.7		68.4		81.2	<0.01
Any hysterectomy, %	3.0		29.8		54.5	<0.01
Abdominal hysterectomy, %	2.7		22.9		43.6	<0.01
Vaginal hysterectomy, %	0.3		6.9		11.1	<0.01
Any diagnostic or therapeutic laparoscopy, %	50.3		38.5		26.5	<0.01
Diagnostic laparoscopy, %	14.4		7.8		3.4	<0.01
Therapeutic laparoscopy, %	42.0		33.7		23.9	<0.01
Laparotomy, %	1.0		1.4		1.7	0.16
Oophorectomy, %	2.4		4.0		4.3	0.17
Number of surgeries during 1 year post, mean (SD)	0.7 (0.7)		0.8 (0.7)		0.9 (0.6)
0	44.3		31.6		18.8	<0.01
1	43.3		56.8		72.6
2	10.7		9.8		7.4
3+	1.7		1.7		1.2

Cochran–Armitage trend tests were used to detect trend of surgery rates across age subgroups, and Cochrane Mantel–Haenszel tests were used to detect the significant difference of number of surgeries across the age sub-groups. A p-value <0.05 was considered statistically significant.

Table 5.  Characteristics and cost of surgery.

	Abdominal hysterectomy		Vaginal hysterectomy		Diagnostic laparoscopy		Therapeutic laparoscopy		Laparotomy (n = 25)		Oophorectomy (n = 127)
	(n = 1,010)		(n = 217)		(n = 283)		(n = 2738)
Settings
Inpatient settings, n (%)	1,010	(100)	153	(70.5)	–	–	432	(15.8)	18	(72.0)	105	(82.7)
Outpatient settings, n (%)	–	–	64	(29.5)	283	(96.9)	2,306	(84.2)	7	(28.0)	22	(17.3)
Characteristics of hospital admissions with selected surgery
Length of stay in days, mean (SD)	2.59	(2.31)	1.53	(0.61)	–	–	1.68	(1.40)	2.33	(1.33)	2.81	(1.64)
Discharge status
Home self care, n (%)	1,000	(99)	152	(99)	–	–	430	(100)	18	(100)	105	(100)
Other, n (%)	10	(1)	1	(1)	–	–	2	(0)	0	(0)	0	(0)
Characteristics of surgery performed in outpatient settings
Place of service
Outpatient hospitals, n (%)	–	–	58	(90.6)	247	(87.3)	1,959	(85.0)	6	(85.7)	21	(95.5)
Physician’s office, n (%)	–	–	2	(3.1)	4	(1.4)	45	(2.0)	0	(0.0)	0	(0.0)
Ambulatory surgical centers, n (%)	–	–	1	(1.6)	29	(10.3)	259	(11.2)	1	(14.3)	0	(0.0)
Other, n (%)	–	–	3	(4.7)	3	(1.1)	43	(1.9)	0	(0.0)	1	(4.6)
Total cost of surgical procedures, mean (SD)	$11,397	($8,749)	$8,568	($4,678)	$4,289	($3,313)	$6,856	($5,801)	$7,806	($5,236)	$10,084	($7,443)

All costs were adjusted to 2009 US dollars.

SD, standard deviation.

Table

Conditions	ICD-9-CM code10
Abdominal pain	789.0
Infertility	628.xx
Migraine	346.x
Depression	296.2x, 296.3x, 300.4, 309.1, 311.xx
Interstitial cystitis	595.1
Irritable bowel syndrome	564.1x
Chronic fatigue syndrome	780.71

ICD-9-CM Index to Diseases Addenda (FY09). Effective October 1, 2008. http://www.cdc.gov/nchs/icd/icd9cm_addenda_guidelines.htm#addenda Last accessed on 7/15/2010

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