Introduction
Methods
Data Source
Study Design
Patient Selection
Study Measures
Statistical Analysis
Results
Demographics and Clinical Characteristics
Unmatched sample | PS-matched sample | ||||
---|---|---|---|---|---|
CIU/CSU cohort | Control cohort | Standardized differenced | Control cohort | Standardized differenced | |
N = 548 | N = 24,157 | N = 548 | |||
Matching factors | |||||
Agea, mean ± SD [median] (Q1–Q3, IQR) | 4.47 ± 3.28 [4.00] (2–7, 6) | 5.50 ± 3.45 [5.00] (2–8, 6) | 30.6% | 4.38 ± 3.22 [3.00] (2–7, 5) | 2.7% |
Male, n (%) | 281 (51.3) | 12,380 (51.2) | 0.1% | 275 (50.2) | 2.2% |
Race, n (%) | |||||
White | 288 (52.6) | 12,716 (52.6) | 0.2% | 289 (52.7) | 0.4% |
Black | 87 (15.9) | 5132 (21.2) | 13.8% | 93 (17.0) | 3.0% |
Hispanic | 22 (4.0) | 1085 (4.5) | 2.4% | 16 (2.9) | 6.0% |
Other | 50 (9.1) | 1851 (7.7) | 5.3% | 53 (9.7) | 1.9% |
Unknown | 101 (18.4) | 3373 (14.0) | 12.1% | 97 (17.7) | 1.9% |
Statea, n (%) | |||||
Missouri | 227 (41.4) | 10,528 (43.6) | 4.4% | 226 (41.2) | 0.4% |
Iowa | 212 (38.7) | 7897 (32.7) | 12.5% | 206 (37.6) | 2.3% |
Mississippi | 66 (12.0) | 3442 (14.2) | 6.5% | 76 (13.9) | 5.4% |
Kansas | 43 (7.8) | 2290 (9.5) | 5.8% | 40 (7.3) | 2.1% |
Eligibility for additional insurance coverageb, n (%) | |||||
HMO plan | 218 (39.8) | 9342 (38.7) | 2.3% | 214 (39.1) | 1.5% |
Year of index date, n (%) | |||||
2014 | 240 (43.8) | 9579 (39.7) | 8.4% | 241 (44.0) | 0.4% |
2015 | 308 (56.2) | 14,578 (60.3) | 8.4% | 307 (56.0) | 0.4% |
Quan-Charlson comorbidity indexb, mean ± SD [median] (Q1–Q3, IQR) | 0.16 ± 0.38 [0] (0–0, 0) | 0.07 ± 0.29 [0] (0–0, 0) | 25.1% | 0.15 ± 0.37 [0] (0–0, 0) | 2.0% |
Non-matching factors: | |||||
CIU/CSU-related comorbiditiesb, n (%) | |||||
Atopic conditions | 219 (40.0) | 3573 (14.8) | 58.8% | 124 (22.6) | 38.1% |
Eczema/dermatitis | 118 (21.5) | 1630 (6.7) | 43.4% | 51 (9.3) | 34.4% |
Allergic rhinitis | 69 (12.6) | 1289 (5.3) | 25.6% | 35 (6.4) | 21.3% |
Asthma | 62 (11.3) | 1151 (4.8) | 24.3% | 57 (10.4) | 2.9% |
Atopic dermatitis | 58 (10.6) | 808 (3.3) | 28.7% | 28 (5.1) | 20.5% |
Food and other allergies | 38 (6.9) | 131 (0.5) | 34.2% | 5 (0.9) | 31.4% |
Other conditions | |||||
Conjunctivitis | 27 (4.9) | 609 (2.5) | 12.7% | 24 (4.4) | 2.6% |
Anxiety | 9 (1.6) | 177 (0.7) | 8.4% | 2 (0.4) | 12.8% |
Anaphylaxis | 4 (0.7) | 4 (0.0) | 11.7% | 0 (0.0) | 12.1% |
Depression | 1 (0.2) | 35 (0.1) | 0.9% | 0 (0.0) | 6.0% |
Baseline HRU (PPPY), mean ± SD [median] (Q1–Q3, IQR) | |||||
Inpatient visits | 0.14 ± 0.63 [0] (0–0, 0) | 0.07 ± 0.51 [0] (0–0, 0) | 11.8% | 0.10 ± 0.52 [0] (0–0, 0) | 7.6% |
Inpatient days | 0.66 ± 6.67 [0] (0–0, 0) | 0.54 ± 7.18 [0] (0–0, 0) | 1.7% | 0.50 ± 4.49 [0] (0–0, 0) | 2.8% |
Length of inpatient stay among patients with ≥ IP visit | 3.62 ± 4.39 [2] (2–3, 1) | 5.61 ± 6.73 [3] (2–5, 3) | 35.1% | 4.21 ± 3.79 [3] (2–5, 3) | 14.4% |
ED visits | 1.72 ± 2.89 [0] (0–2, 2) | 0.67 ± 1.61 [0] (0–0, 0) | 44.9% | 0.97 ± 2.16 [0] (0–2, 2) | 29.2% |
Outpatient visits | 23.27 ± 17.45 [20] (16–26, 10) | 15.60 ± 13.82 [14] (10–20, 10) | 48.7% | 16.43 ± 10.57 [16] (12–20, 8) | 47.4% |
Urgent care facility visits | 0.22 ± 1.10 [0] (0–0, 0) | 0.08 ± 0.58 [0] (0–0, 0) | 15.8% | 0.07 ± 0.74 [0] (0–0, 0) | 16.3% |
Home care | 0.60 ± 3.16 [0] (0–0, 0) | 0.42 ± 3.82 [0] (0–0, 0) | 5.1% | 0.57 ± 3.73 [0] (0–0, 0) | 1.0% |
Office visit | 12.20 ± 12.08 [10] (4–16, 12) | 6.18 ± 9.06 [4] (2–8, 6) | 56.5% | 7.01 ± 7.19 [4] (2–10, 8) | 52.2% |
Ambulatory surgery center visits | 0.01 ± 0.15 [0] (0–0, 0) | 0.01 ± 0.12 [0] (0–0, 0) | 3.1% | 0.02 ± 0.19 [0] (0–0, 0) | 4.3% |
Other outpatient visits | 10.24 ± 10.69 [12] (8–12, 4) | 8.92 ± 8.69 [10] (0–12, 12) | 13.5% | 8.77 ± 5.94 [10] (3–12, 9) | 17.0% |
Baseline healthcare costs (US$2016, PPPY), mean ± SD [median] (Q1–Q3, IQR) | |||||
Total healthcare costs | 4381 ± 8186 [2432] (1150–4480, 3330) | 2964 ± 7801 [1410] (328–3159, 2830) | 17.7% | 3681 ± 8794 [1628] (483–3860, 3377) | 8.2% |
Prescription drug costs | 648 ± 2396 [118] (0–527, 527) | 393 ± 2782 [0] (0–163, 163) | 9.8% | 777 ± 5942 [37] (0–282, 282) | 2.8% |
Medical costs | 3733 ± 7569 [1978] (953–3709, 2757) | 2571 ± 6939 [1242] (273–2713, 2441) | 16.0% | 2904 ± 5758 [1444] (403–3172, 2769) | 12.3% |
Inpatient costs | 317 ± 2128 [0] (0–0, 0) | 261 ± 4372 [0] (0–0, 0) | 1.6% | 476 ± 4339 [0] (0–0, 0) | 4.7% |
ED costs | 157 ± 407 [0] (0–92, 92) | 54 ± 214 [0] (0–0, 0) | 31.8% | 88 ± 268 [0] (0–0, 0) | 20.2% |
Outpatient costs | 3259 ± 7072 [1869] (912–3442, 2530) | 2256 ± 4930 [1173] (251–2535, 2284) | 16.5% | 2340 ± 3341 [1363] (381–2971, 2591) | 16.6% |
Urgent care facility costs | 10 ± 90 [0] (0–0, 0) | 3 ± 62 [0] (0–0, 0) | 9.1% | 2 ± 20 [0] (0–0, 0) | 13.0% |
Home care costs | 123 ± 1046 [0] (0–0, 0) | 103 ± 2651 [0] (0–0, 0) | 1.0% | 53 ± 301 [0] (0–0, 0) | 9.1% |
Office visit costs | 1234 ± 1976 [577] (0–1514, 1514) | 677 ± 2266 [27] (0–656, 656) | 26.2% | 784 ± 1796 [155] (0–911, 911) | 23.9% |
Ambulatory surgery center costs | 23 ± 334 [0] (0–0, 0) | 7 ± 194 [0] (0–0, 0) | 5.6% | 14 ± 179 [0] (0–0, 0) | 3.1% |
Other outpatient costs | 1869 ± 6574 [503] (9–1833, 1824) | 1465 ± 3340 [432] (0–1729, 1729) | 7.7% | 1487 ± 2966 [435] (6–1877, 1871) | 7.5% |
Observation periodc, mean ± SD [median] (Q1–Q3, IQR) | 419 ± 148 [397] (292–540, 248) | 397 ± 138 [383] (281–499, 218) | 15.7% | 406 ± 137 [389] (292–510, 218) | 9.5% |
Treatment Patterns in CIU/CSU Cohort
Baseline perioda | Observation period | |||
---|---|---|---|---|
CIU/CSU patients | At 6 months of follow-up | At 12 months of follow-up | At 18 months of follow-up | |
N = 548 | N = 548 | N = 329 | N = 135 | |
Number of CIU/CSU claims, mean ± SD [median] (Q1–Q3, IQR) | 1.04 ± 2.10 [0.00] (0–1, 1) | 2.76 ± 3.27 [2.00] (1–4, 3) | 4.40 ± 5.62 [2.00] (1–6, 5) | 5.93 ± 8.28 [3.00] (1–8, 7) |
Individual CIU/CSU treatment use, n (%) | ||||
Non-sedating H1-antihistamines | 115 (21.0) | 284 (51.8) | 192 (58.4) | 70 (51.9) |
Cetirizine | 85 (15.5) | 243 (44.3) | 166 (50.5) | 62 (45.9) |
Loratidine | 34 (6.2) | 65 (11.9) | 45 (13.7) | 17 (12.6) |
Other H1-antihistamines | 49 (8.9) | 129 (23.5) | 93 (28.3) | 47 (34.8) |
Oral corticosteroids | 51 (9.3) | 133 (24.3) | 101 (30.7) | 48 (35.6) |
Leukotriene receptor antagonists | 42 (7.7) | 86 (15.7) | 63 (19.1) | 32 (23.7) |
Montelukast | 42 (7.7) | 86 (15.7) | 63 (19.1) | 32 (23.7) |
H2-antihistamines | 33 (6.0) | 74 (13.5) | 46 (14.0) | 23 (17.0) |
Anxiolytics | 21 (3.8) | 79 (14.4) | 53 (16.1) | 26 (19.3) |
Antidepressants | 8 (1.5) | 10 (1.8) | 6 (1.8) | 4 (3.0) |
CIU/CSU treatment switchb, n (%) | – | 65 (15.7) | 40 (14.8) | 20 (18.0) |
CIU/CSU treatment in combinationc, n (%) | ||||
Non-sedating H1-antihistamines + oral corticosteroid | – | 25 (4.6) | 21 (6.4) | 7 (5.2) |
Non-sedating H1-antihistamines + montelukast | – | 53 (9.7) | 46 (14.0) | 23 (17.0) |
Non-sedating H1-antihistamines + oral corticosteroid + montelukast | – | 12 (2.2) | 9 (2.7) | 4 (3.0) |
Oral corticosteroids + montelukast | – | 6 (1.1) | 4 (1.2) | 3 (2.2) |
Pill burdend, mean ± SD [median] (Q1–Q3, IQR) | – | 2.98 ± 3.50 [2.01] (1–4, 3) | 2.55 ± 2.50 [2.01] (1–3, 2) | 2.63 ± 2.96 [1.73] (1–3, 3) |
Physician specialtye, n (%) | ||||
Pediatric | 120 (21.9) | 138 (25.2) | 100 (30.4) | 45 (33.3) |
Allergy and immunology | 5 (0.9) | 74 (13.5) | 49 (14.9) | 18 (13.3) |
Dermatology | 9 (1.6) | 13 (2.4) | 12 (3.6) | 6 (4.4) |
Family or general practice | 153 (27.9) | 189 (34.5) | 132 (40.1) | 63 (46.7) |
Radiology | 56 (10.2) | 47 (8.6) | 45 (13.7) | 24 (17.8) |
Acute caref | 22 (4.0) | 25 (4.6) | 18 (5.5) | 9 (6.7) |
Laboratory | 10 (1.8) | 22 (4.0) | 19 (5.8) | 12 (8.9) |
Emergency medicine | 11 (2.0) | 14 (2.6) | 8 (2.4) | 4 (3.0) |
Otherg | 354 (64.6) | 375 (68.4) | 257 (78.1) | 108 (80.0) |
Unknown | 277 (50.5) | 283 (51.6) | 175 (53.2) | 81 (60.0) |
HRU and Costs
CIU/CSU | Control | CIU/CSU vs. control | ||
---|---|---|---|---|
n = 548 | n = 548 | IRRb (95% CI) | P valueb | |
Observation perioda (days), mean ± SD [median] | 419 ± 148 [397] | 406 ± 137 [389] | ||
All-cause healthcare resource utilization (PPPY), mean ± SD [median] | ||||
Inpatient visits | 0.15 ± 0.61 [0] | 0.09 ± 0.62 [0] | 2.05 (1.07, 3.92) | 0.031* |
Inpatient days | 1.66 ± 15.63 [0] | 0.90 ± 11.89 [0] | 2.32 (0.64, 8.44) | 0.200 |
Emergency department visits | 1.67 ± 2.11 [1] | 0.76 ± 1.51 [0] | 2.20 (1.77, 2.72) | < 0.001* |
Outpatient visits | 24.39 ± 17.06 [21] | 14.60 ± 9.26 [14] | 1.64 (1.52, 1.78) | < 0.001* |
Urgent care facility visits | 0.23 ± 1.02 [0] | 0.10 ± 0.63 [0] | 1.99 (1.00, 3.95) | 0.050 |
Home care visits | 0.77 ± 4.02 [0] | 0.43 ± 3.29 [0] | 1.67 (0.80, 3.47) | 0.173 |
Office visits | 12.87 ± 11.76 [9] | 5.35 ± 5.38 [4] | 2.36 (2.11, 2.63) | < 0.001* |
Ambulatory surgery center visits | 0.02 ± 0.12 [0] | 0.00 ± 0.05 [0] | 2.91 (0.79, 10.73) | 0.110 |
Other outpatient visits | 10.50 ± 10.37 [11] | 8.71 ± 5.12 [11] | 1.21 (1.09, 1.34) | < 0.001* |
CIU/CSU-relatedc healthcare resource utilization (PPPY), mean ± SD [median] | NA | |||
Inpatient visits | 0.04 ± 0.23 [0] | |||
Inpatient days | 0.62 ± 7.22 [0] | |||
Emergency department visits | 0.50 ± 0.82 [0] | |||
Outpatient visits | 2.52 ± 1.61 [2] | |||
Urgent care facility visits | 0.08 ± 0.35 [0] | |||
Home care visits | 0.01 ± 0.13 [0] | |||
Office visits | 2.42 ± 1.62 [2] | |||
Ambulatory surgery center visits | 0.00 ± 0.00 [0] | |||
Other outpatient visits | 0.02 ± 0.14 [0] |
CIU/CSU | Control | CIU/CSU vs. control | ||
---|---|---|---|---|
n = 548 | n = 548 | Mean cost differenceb (95% CI) | P valueb | |
Observation perioda (days), mean ± SD [median] | 419 ± 148 [397] | 406 ± 137 [389] | ||
All-cause pharmacy and medical costs (US$ 2016, PPPY), mean ± SD [median] | 4149 ± 7509 [2455] | 2295 ± 5702 [1572] | 1853 (1116, 2641) | < 0.001* |
All-cause prescription drug costs | 894 ± 2014 [319] | 606 ± 4601 [37] | 288 (− 183, 650) | 0.196 |
All-cause medical costs | 3255 ± 6983 [1919] | 1690 ± 2967 [1386] | 1565 (1025, 2283) | < 0.001* |
Inpatient costs | 394 ± 2923 [0] | 190 ± 2441 [0] | 204 (− 126, 510) | 0.216 |
Emergency department costs | 138 ± 270 [0] | 63 ± 177 [0] | 75 (53, 99) | < 0.001* |
Outpatient costs | 2723 ± 6040 [1777] | 1436 ± 1541 [1262] | 1286 (870, 1915) | < 0.001* |
Urgent care facility costs | 5 ± 31 [0] | 1 ± 12 [0] | 4 (1, 7) | 0.004 |
Home care costs | 105 ± 656 [0] | 32 ± 263 [0] | 73 (19, 145) | 0.004 |
Office visit costs | 1412 ± 2269 [722] | 561 ± 957 [160] | 851 (652, 1061) | < 0.001* |
Ambulatory surgery center costs | 21 ± 182 [0] | 5 ± 102 [0] | 16 (− 1, 34) | 0.068 |
Other outpatient costs | 1178 ± 5009 [263] | 837 ± 1160 [196] | 342 (7, 871) | 0.032 |
CIU/CSU-relatedc pharmacy and medical costs (US$ 2016, PPPY), mean ± SD [median] | 410 ± 776 [242] | NA | ||
CIU/CSU-related prescription drug costs | 108 ± 267 [34] | |||
CIU/CSU-related medical costs | 302 ± 703 [165] | |||
Inpatient costs | 45 ± 502 [0] | |||
Emergency department costs | 31 ± 77 [0] | |||
Outpatient costs | 225 ± 448 [128] | |||
Urgent care facility costs | 1 ± 12 [0] | |||
Home care costs | 2 ± 16 [0] | |||
Office visit costs | 221 ± 448 [126] | |||
Ambulatory surgery center costs | 0 ± 0 [0] | |||
Other outpatient costs | 1 ± 8 [0] |