Table 4.
Multivariate logistic regression analysis of factors associated with polypharmacy
| No. of patients (%) | Univariate analysis | Multivariate analysis | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| No Polypharmacy | Polypharmacy | Unadjusted odds ratio | 95% C.I. | p value | Adjusted odds ratio | 95% C.I. | p value | |||
| Lower | Upper | Lower | Upper | |||||||
| Age | ||||||||||
| 18–64 | 284 (75.9%) | 90 (24.1%) | Reference | |||||||
| ≥65 | 121 (44%) | 154 (56%) | 4.016 | 2.870 | 5.620 | <.001 | 2.373 | 1.435 | 3.923 | .001 |
| Gender | ||||||||||
| Male | 180 (67.2%) | 88 (32.8%) | Reference | |||||||
| Female | 225 (59.1%) | 156 (40.9%) | 1.418 | 1.023 | 1.966 | .036 | .992 | .624 | 1.576 | .972 |
| Ethnicity | ||||||||||
| Indo-trinidadian | 146 (58.9%) | 102 (41.1%) | Reference | |||||||
| Afro-trinidadian | 181 (65.1%) | 97 (34.9%) | .767 | .539 | 1.092 | .141 | ||||
| Mixed | 74 (63.2%) | 43 (36.8%) | .832 | .529 | 1.308 | .425 | ||||
| Other | 4 (66.7%) | 2 (33.3%) | .716 | .129 | 3.981 | .702 | ||||
| Education | ||||||||||
| None | 6 (25%) | 18 (75%) | Reference | |||||||
| Primary | 118 (54.1%) | 100 (45.9%) | .282 | .108 | .739 | .010 | .297 | .075 | 1.174 | .083 |
| Secondary | 217 (69.6%) | 95 (30.4%) | .146 | .056 | .379 | <.001 | .314 | .081 | 1.221 | .095 |
| Vocational | 11 (55%) | 9 (45%) | .273 | .076 | .978 | .046 | 1.196 | .209 | 6.834 | .840 |
| University | 51 (71.8%) | 20 (28.2%) | .131 | .045 | .377 | .000 | .255 | .057 | 1.145 | .075 |
| Not recorded | 2 (50%) | 2 (50%) | .333 | .038 | 2.910 | .320 | 2.535 | .106 | 60.427 | .565 |
| Medical formulation | ||||||||||
| OTC | 107 (45%) | 131 (55%) | 3.229 | 2.310 | 4.513 | <.001 | 5.243 | 3.212 | 8.559 | <.001 |
| Herbal | 25 (48.1%) | 27 (51.9%) | 1.891 | 1.071 | 3.341 | .028 | 3.608 | 1.649 | 7.896 | .001 |
| Combination | 63 (43.8%) | 81 (56.3%) | 2.698 | 1.848 | 3.938 | <.001 | 7.590 | 4.317 | 13.347 | <.001 |
| Chronic illness | ||||||||||
| DM | 55 (32.9%) | 112 (67.1%) | 5.399 | 3.693 | 7.894 | <.001 | 4.499 | 2.589 | 7.817 | <.001 |
| HTN | 68 (30%) | 159 (70%) | 9.270 | 6.400 | 13.427 | <.001 | 7.227 | 4.316 | 12.101 | <.001 |
| IHD | 10 (14.7%) | 58 (85.3%) | 12.317 | 6.157 | 24.640 | <.001 | 7.774 | 3.294 | 18.348 | <.001 |
| Psych | 7 (20.6%) | 27 (79.4%) | 7.074 | 3.031 | 16.512 | <.001 | 4.341 | 1.428 | 13.201 | .010 |
| Asthma | 32 (56.1%) | 25 (43.9%) | 1.331 | .768 | 2.304 | .308 | ||||
Each ‘medical formulation’ and ‘chronic illness’ was treated as an independent covariate in the equation; for each of these variables, patients without the variable were used as the reference
OTC over the counter, DM diabetes mellitus, HTN hypertension, IHD ischaemic heart disease