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. 2011 Jan 26;11:17. doi: 10.1186/1472-6963-11-17

Table 2.

Determinants of generics use (logistic regression)

Model A Cantons and patients variables Model B Model A + substitution groups dummies Model C Model A + substitution groups variables
Coeff. [95%CI] Coeff. [95%CI] Coeff. [95%CI]
CANTON:
 Aargau (reference)
 Vaud -0.253 [-0.31,-0.20] -0.247 [-0.31,-0.19] -0.248 [-0.31,-0.19]
 Ticino -1.391 [-1.46,-1.32] -1.459 [-1.53,-1.39] -1.463 [-1.53,-1.39]
PATIENTS' VARIABLES Female 0.023 [0.00,0.05] 0.031 [0.01,0.06] 0.017 [-0.01,0.04]
Age:
 0-19 0.340 [0.24,0.44] 0.238 [0.12,0.36] 0.207 [0.09,0.32]
 20-39 0.291 [0.22,0.36] 0.101 [0.02,0.18] 0.127 [0.05,0.21]
 40-59 0.237 [0.18,0.30] 0.158 [0.09,0.22] 0.164 [0.10,0.23]
 60-79 (reference)
 80+ -0.135 [-0.21,-0.06] -0.018 [-0.10,0.06] -0.041 [-0.12,0.04]
Age 0-19 in Vaud 0.199 [0.12,0.28] -0.004 [-0.10,0.09] 0.086 [-0.00,0.18]
Age 20-39 in Vaud 0.026 [-0.05,0.10] 0.055 [-0.02,0.14] 0.051 [-0.03,0.13]
Age 40-59 in Vaud -0.058 [-0.12,0.01] -0.051 [-0.12,0.02] -0.046 [-0.11,0.02]
Age 80+ in Vaud 0.185 [0.10,0.27] 0.194 [0.10,0.29] 0.211 [0.12,0.30]
Age 0-19 in Ticino -0.437 [-0.58,-0.30] -0.548 [-0.70,-0.40] -0.484 [-0.63,-0.34]
Age 20-39 in Ticino -0.160 [-0.26,-0.06] -0.176 [-0.28,-0.07] -0.168 [-0.27,-0.07]
Age 40-59 in Ticino -0.208 [-0.29,-0.13] -0.192 [-0.28,-0.11] -0.189 [-0.27,-0.10]
Age 80+ in Ticino 0.095 [-0.01,0.20] 0.075 [-0.03,0.18] 0.098 [-0.01,0.20]
Optional health insurance deductible 0.065 [0.04,0.09] 0.039 [0.01,0.07] 0.043 [0.02,0.07]
Out-of-pocket participation 0.233 [0.18,0.28] 0.146 [0.09,0.20] 0.178 [0.12,0.23]
Out-of-pocket participation at age 0-19 0.084 [-0.02,0.19] 0.069 [-0.04,0.18] 0.043 [-0.07,0.15]
Out-of-pocket participation at age 20-39 0.205 [0.13,0.28] 0.165 [0.08,0.25] 0.139 [0.06,0.22]
Out-of-pocket participation at age 40-59 0.052 [-0.01,0.11] -0.020 [-0.09,0.05] -0.025 [-0.09,0.04]
Out-of-pocket participation at age 80+ -0.161 [-0.24,-0.09] -0.150 [-0.23,-0.07] -0.136 [-0.22,-0.05]
Out-of-pocket participation in Vaud -0.062 [-0.12,-0.01] -0.066 [-0.12,-0.01] -0.067 [-0.12,-0.01]
Out-of-pocket participation in Ticino -0.107 [-0.18,-0.04] -0.097 [-0.17,-0.02] -0.116 [-0.19,-0.04]
Treatment complexity:
 1-5 drugs 0.112 [0.08,0.14] 0.096 [0.06,0.13] 0.082 [0.05,0.11]
 6-10 drugs (reference)
 11-15 drugs -0.063 [-0.09,-0.03] -0.055 [-0.09,-0.02] -0.055 [-0.09,-0.02]
 16-20 drugs -0.089 [-0.13,-0.05] -0.101 [-0.14,-0.06] -0.102 [-0.14,-0.06]
 21+ drugs -0.186 [-0.23,-0.14] -0.175 [-0.22,-0.13] -0.174 [-0.22,-0.13]
PHYSICIANS' VARIABLES Specialist prescriber -0.245 [-0.27,-0.22] -0.203 [-0.23,-0.17] -0.194 [-0.22,-0.16]
Hospital prescriber in Aargau -0.871 [-0.93,-0.81] -1.125 [-1.19,-1.06] -1.101 [-1.17,-1.04]
Hospital prescriber in Vaud -0.344 [-0.40,-0.29] -0.559 [-0.62,-0.50] -0.571 [-0.63,-0.51]
Hospital prescriber in Ticino -0.737 [-0.84,-0.63] -0.778 [-0.89,-0.67] -0.756 [-0.86,-0.65]
SUBSTITUTION GROUPS' VARIABLES Number of generics:
 1-2 (reference)
 3-4 0.506 [0.46,0.55]
 5-6 0.745 [0.70,0.79]
 7+ 0.522 [0.46,0.58]
Number of treated patients:
 1-1000 (reference)
 1001-2000 0.109 [0.07,0.15]
 2001-3000 0.412 [0.35,0.47]
 3001+ 0.013 [-0.03,0.06]
Price of brand medication:
 1st quintile 0.181 [0.13,0.23]
 2nd quintile -0.006 [-0.07,0.05]
 3rd quintile (reference)
 4th quintile 0.072 [0.03,0.12]
 5th quintile -0.064 [-0.12,-0.01]
Relative price difference:
 1st quintile -0.303 [-0.35,-0.25]
 2nd quintile -0.167 [-0.21,-0.12]
 3rd quintile (reference)
 4th quintile 0.026 [-0.02,0.07]
 5th quintile 0.219 [0.16,0.28]
Administration mode: Oral (reference)
 Topic -0.644 [-0.71,-0.57]
 Inhalation, nasal & ophthalmic -1.329 [-2.05,-0.61]
 Parenteral, rectal & vaginal -0.676 [-0.76,-0.59]
Original with special galenic form -0.476 [-0.55,-0.41]
At least one drug sold under license -0.309 [-0.36,-0.26]
Multiple package sizes -0.233 [-0.27,-0.19]
Constant -0.554 [-0.60,-0.50] 0.717 [0.64,0.80] -0.289 [-0.38,-0.20]
Substitution groups dummies No Yes No
3 char. ATC codes dummies No No Yes

Pseudo-R-squared 0.089 0.229 0.194
AIC 196,349 166,597 173,677
BIC 196,671 169,867 174,542
Area under ROC curve 0.699 0.811 0.791
Hosmer-Lemeshow chi2 4.295 101.676 139.595
Prob > chi2 0.830 0.000 0.000
Observations 173,212 173,212 173,212