Retrospective analysis of drug utilization, health care resource use, and costs associated with IFN therapy for adjuvant treatment of malignant melanoma

Figures & data

Figure 1 Attrition of sample size, by reason.

Table 1 Demographic and clinical characteristics

Measure	Non-metastatic, post-surgery melanoma cohort				P-value
	Patients with IFN therapy following index surgery (N=179)		Patients without IFN therapy following index surgery (N=1,820)		IFN treatment vs non-IFN
	N	Column %	N	Column %
Total patients	179	100	1,820	100
Age at first melanoma-related surgery					<0.0001
18–54 years	104	58.1	714	39.2
55–64 years	56	31.3	546	30.0
64–74 years	14	7.8	265	14.6
75–84 years	5	2.8	233	12.8
≥85 years	0	0.0	62	3.4
Mean	53		58		<0.0001
SD	10.7		14.8
Median	53		59
Minimum	21		19
Maximum	78		96
Sex
Male	102	57.0	1,070	58.8
Female	77	43.0	750	41.2
Geographic region					0.0116
Northeast	26	14.5	299	16.4
North Central	50	27.9	434	23.8
South	77	43.0	667	36.6
West	22	12.3	402	22.1
Unknown	4	2.2	18	1.0
Physician specialty at index
Dermatology	0	0.0	5	0.3
Oncology	2	1.1	40	2.2
Other	35	19.6	331	18.2
Primary care	15	8.4	185	10.2
Surgeon	116	64.8	1,163	63.9
Unknown	11	6.1	96	5.3
Comorbidities of interesta
Diabetes mellitus	25	14.0	284	15.6
Hyperlipidemia	59	33.0	625	34.3
Essential hypertension	71	39.7	779	42.8
Congestive heart failure	4	2.2	81	4.5
Cerebrovascular disease	3	1.7	107	5.9	0.0150
Chronic pulmonary disease	17	9.5	191	10.5
Dementia	0	0.0	5	0.3
Osteoporosis	5	2.8	54	3.0
Charlson comorbidity indexb
0	150	83.8	1,414	77.7
1	16	8.9	216	11.9
2	9	5.0	118	6.5
3	2	1.1	48	2.6
4+	2	1.1	24	1.3

Notes:

a Measured during 365 days prior to index surgery;

b for patients who used chemotherapy after index surgery, their follow-up period is censored at the first chemotherapy.

Abbreviations: SD, standard deviation; vs, versus.

Table 2 Treatment patterns of IFN therapy

Measure	Non-metastatic, post-surgery melanoma cohort
	Patients with IFN therapy following index surgery (N=179)
	N	Column %
Total patients	179	100
Total patients completing induction phasea	100	55.9
Total patients starting maintenance phaseb	110	61.5
Patients who completed ≥80% of maintenance dose	19	10.6
Patients who completed <50% of maintenance dosec	60	33.5
Patients who discontinued maintenance phase because end of enrollmentc,d	9	5.0
Patients who completed <50% of maintenance dose (discontinuation)	51	28.5
Patients who completed maintenance phase	0	0.0
Total duration of IFN therapy
1 day (only dose of IFN)	8	4.5
2–29 days	50	27.9
30–90 days	38	21.2
91–180 days	17	9.5
181–365 days	57	31.8
>365 days	9	5.0
Duration of IFN therapy (days)
Mean: 143
SD: 135.7
Median: 73
Minimum: 1
Maximum: 568
Total IFN doses
Mean: 57
SD: 50.4
Median: 36
Minimum: 1
Maximum: 168

Notes:

a Induction phase is defined as first 42 days from the start of IFN therapy (20 doses in the induction phase is considered complete);

b maintenance phase is defined as the period from the 43rd to 365th day from the start of IFN therapy (144 doses in the maintenance phase is considered complete; fewer than 72 doses [50% of 144] is considered a discontinuation);

c National Drug Code is counted according to the days of supply: 28 days of supply =12 doses (j codes counted as single dose);

d if final prescription (date + days of supply) is within 60 days of final enrollment date, it is not considered a discontinuation.

Abbreviation: SD, standard deviation.

Table 3 Per-patient per-year health care utilization and costsa

Measure	Non-metastatic, post-surgery melanoma cohort										Ratio IFN treatment/non-IFN treatment b	P-value for mean cost
	Patients with IFN therapy following index surgery (N=179)					Patients without IFN following index surgery (N=1,820)
Resource	N	Mean	SD	IQR	Median	N	Mean	SD	IQR	Median
Index surgery
Anesthesia	172	$1,014	$640	$458	$869	1,733	$679	$444	$379	$613	1.49	<0.0001
Surgery	179	$2,030	$1,079	$777	$1,740	1,818	$1,419	$742	$677	$1,249	1.43	<0.0001
Pathology	174	$370	$198	$155	$330	1,740	$400	$239	$180	$362	0.93
Hospital care	36	$454	$274	$372	$372	$229	$433	$311	$309	$329	1.05
Follow-up surgery/surgeries
Anesthesia	80	$762	$409	$360	$663	672	$636	$376	$362	$592	1.20	0.0054
Surgery	7	$1,688	$1,051	$1,552	$1,380	77	$2,032	$2,751	$1,457	$1,195	0.83
Pathology	130	$376	$107	$88	$359	1,219	$321	$98	$99	$310	1.17	<0.0001
Hospital care	56	$490	$252	$243	$430	418	$549	$268	$300	$497	0.89
Melanoma-related medical services
Outpatient services	178	$32,414	$2,498	$3,490	$32,200	1,791	$10,556	$1,128	$1,504	$10,444	3.07	<0.0001
Office visits	177	$1,995	$709	$697	$1,824	1,771	$1,048	$409	$358	$972	1.90	<0.0001
Outpatient laboratory	165	$277	$136	$167	$248	1,163	$79	$42	$47	$72	3.50	<0.0001
Impatient services	80	$10,868	$4,716	$5,369	$10,798	448	$11,358	$6,241	$8,554	$10,626	0.96
Radiation therapy	33	$7,627	$5,006	$4,406	$5,948	148	$8,360	$5,836	$6,836	$6,681	0.91
Total cost
Melanoma-related medical	178	$38,730	$4,254	$2,679	$39,140	1,797	$13,995	$2,676	$5,411	$15,276	2.77	<0.0001
Non-melanoma-related medical	179	$22,415	$12,668	$10,204	$19,026	1,811	$18,442	$13,438	$7,753	$15,416	1.22	<0.0001
Overall total cost	179	$60,755	$3,972	$7,283	$58,968	1,818	$31,641	$2,471	$6,182	$31,214	1.92	<0.0001

Notes:

a Adjusted for age index date (group), insurance type at index date, region, sex, specialty at index date, year of diagnosis, year of index, listed comorbidities, and listed chemotherapy;

b ratio IFN treatment/non-IFN treatment was based on mean values. Costs reported in 2012 USD.

Abbreviations: SD, standard deviation; IQR, interquartile range.

Table S1 Identification codes for data analysis

CPT4 codes for surgical intervention*
38562	Removal, pelvic lymph nodes
38564	Removal, abdomen lymph nodes
38571/38572	Laparoscopy, lymphadenectomy
38700/38720/38724	Removal of lymph nodes, neck
38740/38745	Remove armpit lymph nodes
38746	Remove thoracic lymph nodes
38747	Remove abdominal lymph nodes
38760/38765	Remove groin lymph nodes
38770	Remove pelvis lymph nodes
38780	Remove abdomen lymph nodes
CPT4 codes for HCRU associated with surgery*
00100–01999	All anesthetic codes
88302/88304/88305/88307/88309	Tissue examination by pathologist
80500/80502	Laboratory pathology consultation
88399	Surgical pathology procedure
89240	Pathology laboratory procedure
99218/99219/99220	Observation care
99221/99222/99223	Initial hospital care
99234/99235/99236	Observation/hospitalization same date
99238/99239	Hospital discharge day
99251/99252/99253/99254/99255	Inpatient consultation
CPT4 codes for HCRU associated with IFN therapy*
96413	Chemotherapy administration, IV infusion
99201/99202/99203/99204/99205	Office/outpatient visit, new
99211/99212/99213/99214/99215	Office/outpatient visit
CPT4 codes for blood laboratory work associated with IFN therapy*
85025	Complete CBC with auto differential WBC
80438/80439/80440	TRH stimulation panel
J codes (chemotherapy) associated with a melanoma diagnosis#
J9214	Injection, IFN-α-2b
J9130	Dacarbazine, 100 mg
J9140	Dacarbazine, 200 mg
J8700	Temozolomide, oral, 5 mg
J9060	Cisplatin, powder or solution, per 10 mg
J9062	Cisplatin, 50 mg
J9045	Injection, carboplatin, 50 mg
J9265	Injection, paclitaxel, 30 mg
J9050	Injection, carmustine, 100 mg
J9360	Injection, vinblastine sulfate, 1 mg
J9228	Injection, ipilimumab, 1 mg

Notes:

* American Medical Association, 2009;

# Centers for Medicare and Medicaid Services, 2009.

Abbreviations: CBC, complete blood count; IV, intravenous; TRH, thyrotropin-releasing hormone; WBC, white blood cell; HCRU, health care resource use.

Table S2 Improbable sites of lymph node metastasis from selected primary cancers

Primary cancer	Improbable sites of lymph node metastasis
140–149	196.3, 196.5
150–159	196.0, 196.3, 196.5
160–165	196.3, 196.5
170–171	None
174–175	196.0, 196.5
176	None
179–183	196.0, 196.3, 196.5
184	196.0, 196.3
185–186	196.0, 196.3, 196.5
187	196.0, 196.3
188–189	196.0, 196.3, 196.5
190	196.3, 196.5
191–192	196.0, 196.3, 196.5
193	196.3, 196.5
194	196.0, 196.3, 196.5
209.0–209.3	196.0, 196.3, 196.5

Note: Codes for multiple lymph node sites and unspecified sites (ICD-9-CM 196.8, 196.9) will be considered equally probable for melanoma and other primary cancers and thus are not included in the table.

Abbreviation: ICD-9, International Statistical Classification of Diseases, Ninth Revision.