SUPPLEMENTARY MATERIAL
Table S1. Description of provincial health administrative databases used in this study.
Database Type of information available Start date for data availability
Discharge Abstract Database (DAD)
Information on hospital admissions and patients discharged from free- standing rehabilitation and
psychiatric hospitals in Alberta
April 1, 1993
Alberta Ambulatory Care Reporting System
(AACRS) and National Ambulatory Care Reporting System (NACRS)
Information on ambulatory care including day surgery, outpatient and community-based clinics, and
emergency department.
April 1, 1997
Pharmaceutical Information Network (PIN)
Information on medication dispensed from a variety of sources including community and outpatient
pharmacies.
April 1, 2008
Practitioners Claims Information on processed health professionals’ claims used to pay medical doctors and other allied practitioners (such as optometrist, podiatrists, podiatric surgeons, and dentists) and to track shadow-billed
January 1, 1994
claims.
Laboratory Services Information on laboratory tests from community laboratory services.
01 April 2012
Diagnostic Imaging Information on in-hospital inpatient and outpatient imaging tests.
01 January 2011
Table S2. Frequency of type of laboratory tests performed during the first year after the first visit to the pediatric rheumatologist in children with a complete year of observation (n= 292).
# Test name Frequenc
y of
Proportio n among
Number of patient
Proportio n of
laborator y tests
total number
of tests performe
d
with at least one
test performe
d
patients
1 Complete Blood Count 2211 13% 258 88%
2 C-Reactive Protein 1094 7% 252 86%
3 Creatinine 1053 6% 245 84%
4 Alanine Aminotransferase 1035 6% 250 86%
5 Erythrocyte Sedimentation Rate
1014 6% 245 84%
6 Aspartate Aminotransferase 934 6% 238 82%
7 Urea 916 5% 224 77%
8 Albumin 900 5% 234 80%
9
Gamma Glutamyl- Transferase
515 3% 149 51%
10 Alkaline Phosphatase 476 3% 138 47%
11 Ferritin 359 2% 117 40%
12 Anti-Nuclear Antibody 335 2% 163 56%
13 Electrolytes 328 2% 116 40%
14 Urinalysis with Microscopic 306 2% 123 42%
15 Protein total 291 2% 91 31%
16 Lactate Dehydrogenase 252 2% 84 29%
17 Extractable Nuclear Antigen 251 1% 139 48%
18 Complement 213 1% 75 26%
19 Immunoglobulins (IgG, IgM) 195 1% 136 47%
20 Blood Scan with Morphology 167 1% 63 22%
21 Antistreptolysin O 165 1% 78 27%
22 Tissue Transglutaminase 160 1% 145 50%
23
Thyroid Stimulating Hormone
149 1% 105 36%
24 Rheumatoid Factor 132 1% 105 36%
25
Iron and Total Iron Binding Capacity
123 1% 68 23%
26 Anti-Cyclic Citrullinated 121 1% 110 38%
Peptide
27 Hepatitis B Surface Antigen 120 1% 60 21%
28 Lipid panel 117 1% 40 14%
29 Bilirubin Total 111 1% 58 20%
30 Fibrinogen 105 1% 14 5%
31 Carbon Dioxide 103 1% 50 17%
33 Anion Gap Blood 98 1% 49 17%
34 Creatine 90 1% 56 19%
35
Other tests (include all remaining tests with frequency < 1%)
2,354 14% 185 63%
Total 16,793 100% 281 96%
Table S3. Frequency of distinct types of imaging tests performed during the first year after the first visit to the pediatric rheumatologist in patients with a complete year of observation (n=
359).
Type of test
Frequency of imaging tests
Proportion among total
number of tests performed
Number of patients with at least 1 test performed
Proportion of patients
General Radiography 560 56% 198 55%
Magnetic Resonance Imaging
349 33%
164 46%
Ultrasound 72 7% 43 12%
Computed Tomography 28 2% 18 5%
Total 1,009 100% 269 75%
Table S4. Yearly mean cost of sDMARDs and bDMARDs stratified by JIA subtype for a period of four years after the first visit to the pediatric rheumatologist.
Time points Year 1 Year 2 Year 3 Year 4
Yearly mean costs for sDMARDs, (standard deviation), min-max
Oligoarticular JIA $78 (163), 0-999 $149 (239), 0-1,168 $146 (246), 0-1,390 $216 (491), 0-3,049
n 135 121 88 68
Polyarticular JIA $271 (248), 0-1,557 $283 (244), 0-1,638 $298 (302), 0-1,497 $245 (280), 0-1,327
n 132 115 84 59
ERA $177 (203), 0-864 $204 (291), 0-1,403 $265 (312), 0-1,166 $331 (372), 0-1,318
n 62 50 41 26
Undifferentiated JIA $222 (232), 0-636 $269 (286), 0-1,039 $154 (283), 0-943 $288 (403), 0-1,906
n 16 12 11 6
Psoriatic JIA $297 (285), 0-823 $383 (414), 0-1,061 $358 (366), 0-993 $267 (310), 0-795
n 13 9 7 6
Systemic JIA $393 (992), 0-3,030 $25 (72), 0-203 NR NR
n 9 8 <5 <5
Yearly mean costs for bDMARDs, (standard deviation), min-max
Oligoarticular JIA $314 (1,606), 0-14,453 $1,284 (4,128), 0-20,887 $1,523(4,601), 0-20,422 $2,185 (5,673), 0-26,656
n 135 121 88 68
Polyarticular JIA $1,941 (4,250), 0-23,021 $3,954 (6,215), 0-23,464 $4,915 (7,759), 0-40,594 $4,864(6,866), 0-20,422
n 132 115 84 59
ERA $1,637 (3,622), 0-14,449 $3,283 (6,052), 0-22,446 $4,439 (7,124), 0-21,993 $4,063 (7,866), 0-21,214
n 62 50 41 26
Undifferentiated JIA $1,104 (3,648), 0-14,449 $2,272 (5,666), 0-19,270 $3,500 (7,492), 0-20,877 $3.404 (8.337), 0-20,422
n 16 12 11 6
Psoriatic JIA $2,075 (5,071), 0-14,126 $2,033 (4,968), 0-15,157 $4,413 (6,180), 0-15,709 $11,158 (15,764), 0-39,959
n 13 9 7 6
Systemic JIA $7,603 (9,815), 0-23,331 $5,560 (7,110), 0-16,439 NR NR
n 9 8 <6 <6
JIA: Juvenile idiopathic arthritis; sDMARDs: synthetic disease-modifying anti-rheumatic drugs; bDMARDs: biologic disease-modifying anti- rheumatic drugs; ERA: enthesis-related arthritis NR: Not Reportable, n < 6.
Figure S1. Overall and JIA-associated cumulative mean costs over a period of 6 years stratified by cost categories.
Figure S2. Box plot showing distribution of cumulative mean stratified by subtype after bootstrap analysis.
* Not reportable, n < 6.
Figure S3. Cumulative mean costs over time for the distinct JIA subtypes stratified by cost categories for a period of 4 years.
* Not reportable, n < 6.
Figure S4. Cumulative mean costs over time for the cost categories stratified by three distinct JIA subtypes with the largest sample sizes (oligoarticular JIA, polyarticular JIA, and ERA) for a
period of 4 years.
