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. 2025 Aug 21;15(8):e097863. doi: 10.1136/bmjopen-2024-097863

Table 3. Univariate and multivariate logistic regression analysis of predictors of polypharmacy.

Drug class Cumulative polypharmacy
(6-month window)
Consecutive polypharmacy
(6-month window)
Crude OR (95% CI) Adjusted OR (95% CI) Crude OR (95% CI) Adjusted OR (95% CI)
Sex
 Male (reference) 1 1 1 1
 Female 1.390
(1.381 to 1.399)
1.391
(1.382 to 1.401)
1.563
(1.545 to 1.580)
1.484
(1.467 to 1.501)
Age group
 65–69 (reference) 1 1 1 1
 70–74 1.107
(1.097 to 1.117)
1.185
(1.174 to 1.197)
1.256
(1.238 to 1.275)
1.290
(1.270 to 1.309)
 75–79 1.134
(1.123 to 1.145)
1.232
(1.22 to 1.245)
1.317
(1.297 to 1.337)
1.317
(1.297 to 1.338)
 80–84 1.022
(1.012 to 1.033)
1.118
(1.106 to 1.130)
1.177
(1.157 to 1.197)
1.158
(1.138 to 1.179)
 ≥85 0.744
(0.736 to 0.752)
0.749
(0.741 to 0.758)
0.798
(0.781 to 0.815)
0.744
(0.728 to 0.761)
Fund
 Civil Servants (reference) 1 1 1 1
 Rural 0.296
(0.294 to 0.299)
0.244
(0.242 to 0.246)
0.183
(0.179 to 0.187)
0.156
(0.153 to 0.160)
 Iranian and Universal Health Insurance 0.702
(0.695 to 0.709)
0.731
(0.724 to 0.739)
0.557
(0.547 to 0.566)
0.601
(0.590 to 0.611)
 Other Social Strata 1.415
(1.394 to 1.436)
1.277
(1.258 to 1.297)
2.727
(2.691 to 2.764)
2.448
(2.415 to 2.482)
 Foreign Citizens 0.254
(0.236 to 0.274)
0.231
(0.214 to 0.249)
--- ---
Main anatomical groups (ATC-1)
 A (non-users as reference) 11.308
(11.221 to 11.396)
9.320
(9.246 to 9.395)
46.471
(43.778 to 49.329)
29.711
(27.985 to 31.544)
 B (non-users as reference) 10.475
(10.382 to 10.569)
9.590
(9.502 to 9.679)
11.745
(11.528 to 11.965)
9.272
(9.098 to 9.448)
 C (non-users as reference) 12.322
(12.227 to 12.418)
10.502
(10.419 to 10.587)
32.427
(31.118 to 33.792)
22.597
(21.681 to 23.553)
 D (non-users as reference) 2.825
(2.576 to 3.097)
2.192
(1.995 to 2.409)
2.620
(2.432 to 2.823)
2.054
(1.9 to 2.221)
 G (non-users as reference) 4.841
(4.778 to 4.905)
4.191
(4.135 to 4.248)
3.646
(3.605 to 3.687)
2.901
(2.867 to 2.936)
 H (non-users as reference) 7.257
(7.2 to 7.314)
6.111
(6.061 to 6.161)
4.972
(4.9 to 5.044)
3.514
(3.462 to 3.566)
 J (non-users as reference) 6.964
(6.914 to 7.015)
5.787
(5.743 to 5.831)
8.422
(8.239 to 8.608)
5.705
(5.579 to 5.834)
 L (non-users as reference) 4.652
(4.523 to 4.785)
4.603
(4.473 to 4.737)
3.005
(2.948 to 3.063)
3.022
(2.961 to 3.084)
 M (non-users as reference) 6.779
(6.727 to 6.831)
5.468
(5.424 to 5.512)
6.625
(6.519 to 6.732)
4.460
(4.387 to 4.534)
 N (non-users as reference) 9.903
(9.829 to 9.978)
8.033
(7.971 to 8.096)
17.764
(17.215 to 18.33)
11.463
(11.106 to 11.832)
 P (non-users as reference) 5.963
(5.88 to 6.048)
4.772
(4.705 to 4.841)
3.777
(3.735 to 3.819)
2.846
(2.813 to 2.88)
 R (non-users as reference) 9.175
(9.098 to 9.252)
7.406
(7.343 to 7.470)
7.829
(7.7 to 7.961)
5.214
(5.125 to 5.304)
 S (non-users as reference) 2.564
(2.544 to 2.585)
2.235
(2.216 to 2.253)
3.258
(3.222 to 3.295)
2.572
(2.542 to 2.601)

Adjustment variables: age group, sex, fund and province.

A, alimentary tract and metabolism; ATC, Anatomical Therapeutic Chemical classification; B, blood and blood-forming organs; C, cardiovascular system; D, dermatologicals; G, genitourinary system and sex hormones; H, systemic hormonal preparations excluding sex hormones and insulins; J, anti-infectives for systemic use; L, antineoplastic and immunomodulating agents; M, musculoskeletal system; N, nervous system; P, antiparasitic products, insecticides and repellents; R, respiratory system; S, sensory organs.