Background
Methods
Setting
Recent generic medicine policy implemented in Switzerland
Studied population
Outcome
Predictors of generic drug use
Statistical model
Results
Univariate analysis
Frequency | Substitution rate | Odds ratio | 95%CI | |
---|---|---|---|---|
OUTCOME VARIABLE Use of a generic drug (yes = 1, no = 0) | 0.313 | |||
CANTONS | ||||
Aargau (reference) | 0.372 | 0.433 | ||
Vaud | 0.329 | 0.350 | 0.706 | [0.689, 0.722] |
Ticino | 0.299 | 0.124 | 0.186 | [0.181, 0.192] |
PATIENTS' VARIABLES Female: | ||||
no (reference) | 0.378 | 0.317 | ||
yes | 0.622 | 0.311 | 0.972 | [0.952, 0.993] |
Age: | ||||
0-19 | 0.100 | 0.411 | 2.057 | [1.986, 2.131] |
20-39 | 0.158 | 0.410 | 2.050 | [1.989, 2.112] |
40-59 | 0.250 | 0.344 | 1.543 | [1.502, 1.585] |
60-79 (reference) | 0.356 | 0.254 | ||
80+ | 0.136 | 0.228 | 0.868 | [0.838, 0.900] |
Optional health insurance deductible: | ||||
no (reference) | 0.619 | 0.344 | ||
yes | 0.381 | 0.264 | 0.685 | [0.671,. 0.700] |
Out-of-pocket participation: | ||||
no (reference) | 0.396 | 0.241 | ||
yes | 0.604 | 0.361 | 1.777 | [1.740, 1.816] |
Treatment complexity: | ||||
1-5 drugs | 0.215 | 0.424 | 1.429 | [1.390, 1.469] |
6-10 drugs (reference) | 0.290 | 0.340 | ||
11-15 drugs | 0.223 | 0.280 | 0.757 | [0.735, 0.779] |
16-20 drugs | 0.139 | 0.246 | 0.634 | [0.613, 0.657] |
21+ drugs | 0.133 | 0.202 | 0.491 | [0.473, 0.509] |
PHYSICIANS' VARIABLES Specialist prescriber: | ||||
no (reference) | 0.777 | 0.314 | ||
yes | 0.223 | 0.310 | 0.978 | [0.955, 1.003] |
Hospital prescriber: | ||||
no (reference) | 0.880 | 0.325 | ||
yes | 0.120 | 0.225 | 0.603 | [0.583,.0.624] |
SUBSTITUTION GROUPS' VARIABLES Number of generics | ||||
1-2 (reference) | 0.333 | 0.153 | ||
3-4 | 0.260 | 0.374 | 3.322 | [3.225, 3.422] |
5-6 | 0.298 | 0.415 | 3.934 | [3.823, 4.049] |
7+ | 0.110 | 0.382 | 3.430 | [3.305, 3.559] |
Number of treated patients: | ||||
1-1000 (reference) | 0.361 | 0.263 | ||
1001-2000 | 0.259 | 0.322 | 1.334 | [1.299, 1.370] |
2001-3000 | 0.122 | 0.223 | 0.803 | [0.774, 0.834] |
3001+ | 0.257 | 0.418 | 2.017 | [1.965, 2.070] |
Price of brand medication: | ||||
1st quintile | 0.189 | 0.327 | 1.000 | [0.969, 1.031] |
2nd quintile | 0.165 | 0.251 | 0.689 | [0.666, 0.713] |
3rd quintile (reference) | 0.239 | 0.327 | ||
4th quintile | 0.187 | 0.328 | 1.002 | [0.972, 1.034] |
5th quintile | 0.220 | 0.321 | 0.972 | [0.943,.1.001] |
Relative price difference: | ||||
1st quintile | 0.188 | 0.200 | 0.599 | [0.578, 0.620] |
2nd quintile | 0.200 | 0.347 | 1.267 | [1.227, 1.308] |
3rd quintile (reference) | 0.206 | 0.295 | ||
4th quintile | 0.204 | 0.301 | 1.029 | [0.996, 1.062] |
5th quintile | 0.203 | 0.416 | 1.701 | [1.649, 1.754] |
Administration mode: | ||||
Oral (reference) | 0.839 | 0.328 | ||
Topic | 0.095 | 0.285 | 0.817 | [0.788, 0.847] |
Inhalation, nasal & ophthalmic | 0.032 | 0.046 | 0.099 | [0.087, 0.112] |
Parenteral, rectal & vaginal | 0.034 | 0.273 | 0.769 | [0.726, 0.815] |
Original with special galenic form: | ||||
no (reference) | 0.862 | 0.338 | ||
yes | 0.138 | 0.160 | 0.373 | [0.359, 0.386] |
At least one drug sold under license: | ||||
no (reference) | 0.818 | 0.316 | ||
yes | 0.182 | 0.300 | 0.929 | [0.904, 0.954] |
Multiple package sizes: | ||||
no (reference) | 0.575 | 0.294 | ||
yes | 0.425 | 0.339 | 1.232 | [1.207, 1.258] |
Observations | 173,212 |
Multivariate analysis
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 |
Marginal effect | 95%CI | |
---|---|---|
CANTON | ||
Aargau (reference) | ||
Vaud | -0.040 | [-0.045 -0.034] |
Ticino | -0.260 | [-0.265 -0.255] |
PATIENTS' VARIABLES Female | 0.003 | [-0.001 0.007] |
Age: | ||
0-19 | 0.031 | [0.022 0.040] |
20-39 | 0.035 | [0.028 0.041] |
40-59 | 0.016 | [0.011 0.022] |
60-79 (reference) | ||
80+ | -0.005 | [-0.013 0.002] |
Optional health insurance deductible | 0.007 | [0.003 0.012] |
Out-of-pocket participation | 0.023 | [0.018 0.028] |
Treatment complexity: | ||
1-5 drugs | 0.014 | [0.009 0.020] |
6-10 drugs (reference) | ||
11-15 drugs | -0.009 | [-0.015 -0.004] |
16-20 drugs | -0.017 | [-0.024 -0.010] |
21+ drugs | -0.029 | [-0.037 -0.021] |
PHYSICIANS' VARIABLES Specialist prescriber | -0.032 | [-0.037 -0.027] |
Hospital prescriber | -0.131 | [-0.137 -0.125] |
SUBSTITUTION GROUPS' VARIABLES Number of generics: | ||
1-2 (reference) | ||
3-4 | 0.083 | [0.075 0.090] |
5-6 | 0.125 | [0.118 0.133] |
7+ | 0.085 | [0.076 0.095] |
Number of treated patients: | ||
1-1000 (reference) | ||
1001-2000 | 0.018 | [0.012 0.025] |
2001-3000 | 0.071 | [0.060 0.082] |
3001+ | 0.002 | [-0.006 0.010] |
Price of brand medication: | ||
1st quintile | 0.031 | [0.023 0.039] |
2nd quintile | -0.001 | [-0.011 0.009] |
3rd quintile (reference) | ||
4th quintile | 0.012 | [0.004 0.020] |
5th quintile | -0.011 | [-0.019 -0.002] |
Relative price difference: | ||
1st quintile | -0.050 | [-0.058 -0.042] |
2nd quintile | -0.028 | [-0.036 -0.020] |
3rd quintile (reference) | ||
4th quintile | 0.004 | [-0.004 0.013] |
5th quintile | 0.038 | [0.028 0.048] |
Original with special galenic form | -0.077 | [-0.088 -0.066] |
At least one drug sold under license | -0.051 | [-0.058 -0.043] |
Multiple package sizes | -0.039 | [-0.045 -0.032] |