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. 2011 Apr 28;4:37–47. doi: 10.2147/JAA.S17709

Table 1.

Baseline characteristics of the initiation and step-up populations

Initiation population (N = 56,347)
Step-up population (N = 9169)
pMDI (N = 39,746) BAI (N = 9809) DPI (N = 6792) P-value pMDI (N = 6245) BAI (N = 1388) DPI (N = 1536) P-value
Male sex 17,294 (43.5) 4062 (41.4) 3013 (44.4) <0.001 2735 (43.8) 571 (41.1) 735 (47.9) 0.001
Age at index date (y) 28 (12–42) 30 (13–45) 22 (11–42) <0.001 27 (10–45) 21 (12–44) 20 (11–42) 0.150
BMI [no. (%) with data] (kg/m2) [n = 28,166 (70.9)] [n = 7235 (73.8)] [n = 4509 (66.4)] <0.001 [n = 4627 (74.1)] [n = 1011 (72.8)] [n = 1094 (71.2)] 0.099
24.9 (21.3–29.3) 25.0 (21.5–29.4) 24.7 (20.9–29.0) 24.9 (20.7–29.7) 24.7 (20.4–29.4) 24.1 (20.4–28.9)
Charlson comorbidity index
  0 37,143 (93.5) 9116 (92.9) 6309 (92.9) 0.162 5750 (92.1) 1289 (92.9) 1427 (92.9) 0.873
  1 1534 (3.9) 397 (4.0) 276 (4.1) 116 (1.9) 21 (1.5) 24 (1.6)
  ≥2 1069 (2.7) 296 (3.0) 207 (3.0) 379 (6.1) 78 (5.6) 85 (5.5)
Socioeconomic status 17.9 (9.9–31.4) 17.4 (8.9–32.1) 17.9 (8.6–35.3) 0.218 19.8 (10.5–33.9) 20.7 (10.2–32.7) 20.1 (8.7–35.3) 0.878
Smoking status [no. (%) with data] [n = 18,950 (47.7)] [n = 4575 (46.6)] [n = 2706 (39.8)] 0.031 [n = 3074 (49.2)] [n = 679 (48.9)] [n = 646 (42.1)] 0.024
  Current smoker 6917 (36.5) 1668 (36.5) 908 (33.6) 985 (32.0) 213 (31.4) 244 (37.8)
  Ex-smoker 3452 (18.2) 836 (18.3) 491 (18.1) 530 (17.2) 103 (15.2) 105 (16.3)
  Non-smoker 8581 (45.3) 2071 (45.3) 1307 (48.3) 1559 (50.7) 363 (53.5) 297 (46.0)
Recorded comorbidity
  Rhinitis 6254 (15.7) 1765 (18.0) 1191 (17.5) <0.001 1344 (21.5) 308 (22.2) 357 (23.2) 0.331
  GERD 2545 (6.4) 796 (8.1) 474 (7.0) <0.001 508 (8.1) 125 (9.0) 115 (7.5) 0.323
  Cardiac disease 1227 (3.1) 302 (3.1) 185 (2.7) 0.266 216 (3.5) 48 (3.5) 56 (3.6) 0.936
1+ prescriptions, prior 12 mo
  Beta blockers 1121 (2.8) 343 (3.5) 184 (2.7) 0.001 134 (2.1) 24 (1.7) 20 (1.3) 0.082
  NSAIDs 5974 (15.0) 1576 (16.1) 905 (13.3) <0.001 1031 (16.5) 223 (16.1) 219 (14.3) 0.099
  Acetaminophen 6338 (15.9) 1523 (15.5) 1011 (14.9) 0.069 1339 (21.4) 257 (18.5) 275 (17.9) 0.001

Notes: Values shown are n (%) or median (interquartile range). P-values for comparison among the three cohorts calculated with χ2 test for categorical data, Kruskal–Wallis test for continuous data.

Abbreviations: BAI, breath-actuated inhaler; BMI, body mass index; DPI, dry powder inhaler; GERD, gastroesophageal reflux disease; pMDI, pressurized metered-dose inhaler; NSAIDs, nonsteroidal anti-inflammatory agents.