Direct medical costs for patients with tuberous sclerosis complex and surgical resection of subependymal giant cell astrocytoma: a US national cohort study

Figures & data

Figure 1. Study design, duration, and selection criteria.

Figure 2. Sample selection scheme.

Table 1. Percentages of patients with a claim for SEGA-related conditions in three different time periods.

Clinical condition	Last pre-surgery period	First post-surgery period	Cross-period difference^a		Second post-surgery period	Cross-period difference^b		p-value of fixed surgery effect^d
			%	p Value^c		%	p Value^c
Seizure	63.8%	89.4%	25.5%	0.002	87.2%	23.4%	0.010	<0.05
Hydrocephalus	34.0%	59.6%	25.5%	0.003	55.3%	21.3%	0.002	<0.05
Vision Disorders	34.0%	36.2%	2.1%	0.415	38.3%	4.3%	0.235	0.318
Blindness	2.1%	2.1%	0.0%	ND	2.1%	0.0%	ND	ND
Coma	10.6%	14.9%	4.3%	0.291	14.9%	4.3%	0.320	0.305
Deafness	10.6%	10.6%	0.0%	ND	10.6%	0.0%	ND	ND
Speech Loss	8.5%	8.5%	0.0%	ND	8.5%	0.0%	ND	ND
Headache	53.2%	70.2%	17.0%	0.008	72.3%	19.1%	0.006	<0.05
Stroke or Hemiparesis	27.7%	36.2%	8.5%	0.038	34.0%	6.4%	0.041	<0.05
Vision Loss	2.1%	2.1%	0.0%	ND	2.1%	0.0%	ND	ND
Cognitive Difficulties	14.9%	23.4%	8.5%	0.097	21.3%	6.4%	0.159	0.101
Muscle Weakness	0.0%	2.1%	2.1%	0.000	2.1%	2.1%	0.075	<0.05
Papilloedema	8.5%	8.5%	0.0%	ND	10.6%	2.1%	0.379	0.328
Balance Disorders	4.3%	6.4%	2.1%	0.074	6.4%	2.1%	0.075	0.060
Loss of Sensation	4.3%	4.3%	0.0%	ND	4.3%	0.0%	ND	ND
Nausea & Vomiting	29.8%	38.3%	8.5%	0.391	36.2%	6.4%	0.390	0.287
Depression	6.4%	6.4%	0.0%	ND	6.4%	0.0%	ND	ND
Anxiety	8.5%	12.8%	4.3%	0.331	12.8%	4.3%	0.320	0.187
Attention Deficit Disorder	8.5%	14.9%	6.4%	0.410	14.9%	6.4%	0.477	0.299
Autism	14.9%	23.4%	8.5%	0.024	23.4%	8.5%	0.025	<0.05
Sleep Disorders	6.4%	6.4%	0.0%	ND	8.5%	2.1%	0.549	0.718

^aThis cross-period difference was between the period from the 2nd through 6th month after the surgery and the period of the last 6 months before the surgery.

^bThis cross-period difference was between the period from the 7th through 12th month after the surgery and the period of the last 6 months before the surgery.

^cThis is p Value based on paired sample dependent t-test for repeated pre–post measures with a bootstrapping technique.

^dThis is p-value based on repeated measures analysis of variance for fixed surgery effect with a bootstrapping technique over the three periods.

Figure 3. Cross-period comparison of direct medical costs by half and full years. All cross-period differences were statistically significant based on repeated measures analysis with bootstrapping.

Figure 4. Cross-period comparison of direct medical costs by study period. All cross-period variations were statistically significant based on repeated measures analysis with bootstrapping. Also, the last pre-surgery period was 6 months before the surgery, the first post-surgery period was from the 2nd through 6th post-surgery month, and the second post-surgery period was from the 7th through 12th post-surgery month.

Table 2. Direct medical costs by types and study periods.

Cost types and study period	Cost estimates (n = 47)^a
	Mean	STD
Total inpatient, outpatient, and medication costs
Pre-surgery year	$8543.1	$11,187.6
First half year = First pre-surgery period (1st through 6th month)	$1766.0	$4286.2
Second half year = Last pre-surgery period (7th through 12th month)	$6777.2	$8912.3
Post-surgery year	$85,397.0	$56,258.9
First half year (1st through 6th month)	$74,155.4	$49,790.1
Surgery month	$58,515.9	$39,164.5
First post-surgery period (2nd through 6th month)	$15,639.5	$35,485.6
Second half year = Second post-surgery period (7th through 12th month)	$11,241.6	$19,298.6
Inpatient costs
Pre-surgery year	$3770.3	$7903.5
First half year = First pre-surgery period (1st through 6th month)	$249.9	$1220.4
Second half year = Last pre-surgery period (7th through 12th month)	$3520.3	$7715.3
Post-surgery year	$71,562.1	$50,506.9
First half year (1st through 6th month)	$64,973.6	$46,476.5
Surgery month	$55,485.6	$38,541.3
First post-surgery period (2nd through 6th month)	$9488.0	$33,764.8
Second half year = Second post-surgery [eriod (7th through 12th month)	$6588.5	$17,748.7
Outpatient costs
Pre-surgery year	$3472.9	$5246.7
First half year = First pre-surgery period (1st through 6th month)	$963.3	$2507.5
Second half year = Last pre-surgery period (7th through 12th month)	$2509.6	$3205.1
Post-surgery year	$11,497.2	$9971.3
First half year (1st through 6th month)	$7843.5	$7801.5
Surgery month	$2729.1	$2906.4
First post-surgery period (2nd through 6th month)	$5114.4	$6918.4
Second half year = Second post-surgery period (7th through 12th month)	$3653.6	$3898.3
Inpatient and outpatient costs
Pre-surgery year	$7243.2	$9834.9
First half year = First pre-surgery period (1st through 6th month)	$1213.3	$3523.1
Second half year = Last pre-surgery period (7th through 12th month)	$6029.9	$8263.1
Post-surgery year	$83,059.2	$55,045.1
First half year (1st through 6th month)	$72,817.1	$48,798.7
Surgery month	$58,214.7	$39,112.8
First post-surgery period (2nd through 6th month)	$14,602.5	$34,797.9
Second half year = Second post-surgery period (7th through 12th month)	$10,242.1	$19,470.2
Medication costs
Pre-surgery year	$1300.0	$2818.1
First half year = First pre-surgery period (1st through 6th month)	$552.7	$1480.7
Second half year = Last pre-surgery period (7th through 12th month)	$747.3	$1549.6
Post-surgery year	$2337.7	$4028.2
First half year (1st through 6th month)	$1338.3	$2268.0
Surgery month	$301.2	$425.0
First post-surgery period (2nd through 6th month)	$1037.0	$1978.0
Second half year = Second post-surgery period (7th through 12th month)	$999.5	$1821.5

^aCross-period differences and annual cost differences before and after the surgery were all statistically significant at p < 0.05 using repeated measures analysis and bootstrapping techniques.

Appendix Diagnosis codes for identifying SEGA-related conditions.

SEGA-related condition	ICD9-CM (4th or 5th digit may be omitted)
Seizure	3459, 7803
Hydrocephalus	3313, 3314, 7410, 7423
Vision Disorders	360, 361, 362, 363, 364, 365, 367, 368, 369, 370, 371, 372, 373, 374, 375, 376, 377, 378, 379, 921, 918, 930, 940, 870, 871, v720
Blindness	369
Coma	78001, 78002, 78003
Deafness	38843, 389
Speech Loss	4381, 31531, 3079, 7843, 78441, 7845
Headache	339, 784
Stroke or Hemiparesis	342, 431, 432, 4330, 43311, 43321, 43331, 43381, 43401, 43411, 43491, 4382, 4385, V171, V1254, 99702
Vision Loss	3699
Cognitive Difficulties	317, 318, 319, 33183
Muscle Weakness	72887
Papilloedema	377
Balance Disorders	7804
Loss of Sensation	7820
Nausea & Vomiting	7870
Depression	2962, 2963, 2980, 311, V790
Anxiety	30000, 30002, 29384, 313
Attention Deficit Disorder	3140
Autism	299
Sleep Disorders	3074, 327, 7805