Univariate and multivariate associations between multiple predictor variables and self-reported low medication adherence as measured by the eight-item MMAS* in 9202 adults surveyed from the general population
| Risk factors | n (% total) | Univariate results | Multivariate results | ||
| OR (95% CI) | p Value | Adjusted OR (95% CI) | p Value | ||
| Age | |||||
| 65+ | 1688 (24.2) | 0.158 (0.128 to 0.194) | <0.0001 | 0.174 (0.138 to 0.221) | <0.0001 |
| 46–64 | 4118 (44.8) | 0.330 (0.274 to 0.397) | <0.0001 | 0.313 (0.245 to 0.386) | <0.0001 |
| 26–45 | 2843 (30.9) | 0.658 (0.544 to 0.795) | <0.0001 | 0.632 (0.513 to 0.780) | <0.0001 |
| 18–25 (ref) | 553 (6.0) | ||||
| Ethnicity | |||||
| Hispanic | 1088 (11.8) | 1.630 (1.438 to 1.854) | <0.0001 | 1.237 (1.060 to 1.444) | <0.0068 |
| Non-Hispanic (ref) | 8114 (88.2) | ||||
| Black/African-American | 928 (10.7) | 1.413 (1.232 to 1.619) | <0.0001 | 1.423 (1.227 to 1.651) | <0.0001 |
| White (ref) | 7771 (89.3) | ||||
| Gender | |||||
| Female | 4976 (54.1) | 1.174 (1.080 to 1.276) | 0.0002 | 1.136 (1.033 to 1.249) | 0.0088 |
| Male (ref) | 4226 (45.9) | ||||
| Income and insurance | |||||
| Low income | 2229 (24.2) | 1.378 (1.248 to 1.522) | 0.1164 | − | − |
| Poverty | 1346 (14.6) | 1.612 (1.431 to 1.817) | <0.0001 | − | − |
| Neither poverty or low income (ref) | 5627 (61.2) | ||||
| No health insurance | 501 (5.4) | 1.502 (1.254 to 1.799) | <0.0001 | − | − |
| Health insurance (ref) | 8701 (94.6) | ||||
| Barriers to access | |||||
| Has difficulty with healthcare costs | 3963 (43.1) | 1.760 (1.618 to 1.914) | <0.0001 | 1.239 (1.104 to 1.391) | 0.0003 |
| No difficulty (ref) | 5239 (56.9) | ||||
| Has difficulty with medication cost | 4289 (46.6) | 1.761 (1.620 to 1.915) | <0.0001 | 1.240 (1.103 to 1.394) | 0.0003 |
| No difficulty (ref) | 4913 (53.4) | ||||
| Has difficulty with transportation to medical care | 3835 (41.7) | 2.073 (1.904 to 2.256) | <0.0001 | 1.321 (1.176 to 1.483) | <0.0001 |
| No difficulty (ref) | 5367 (58.3) | ||||
| Needs support of others | 4338 (47.1) | 1.916 (1.762 to 2.084) | <0.0001 | − | − |
| Does not need support (ref) | 4864 (52.9) | ||||
| Health status | |||||
| Poor health | 489 (5.3) | 1.929 (1.449 to 2.568) | <0.0001 | − | − |
| Fair health | 2167 (23.6) | 1.688 (1.328 to 2.146) | <0.0001 | 1.594 (1.199 to 2.119) | 0.0069 |
| Good health | 3930 (42.7) | 1.359 (1.076 to 1.716) | 0.7323 | − | − |
| Very good health | 2279 (24.8) | 1.123 (0.883 to 1.428) | <0.0001 | − | − |
| Excellent health (ref) | 337 (3.7) | ||||
| Health limiting activity a little bit | 2718 (29.5) | 1.447 (1.314 to 1.592) | <0.0001 | 1.333 (1.185 to 1.498) | 0.0003 |
| Health limiting activity a lot | 1836 (20.0) | 1.421 (1.274 to 1.585) | 0.0016 | − | − |
| Health not limiting (ref) | 4648 (50.5) | ||||
| Number of comorbidities | x̅=2.7, SD=2.1 | 1.058 (1.037 to 1.080) | <0.0001 | − | − |
| Healthcare utilisation | |||||
| utilised more than 2 providers | 4254 (46.2) | 1.483 (1.364 to 1.611) | <0.0001 | 1.270 (1.141 to 1.413) | <0.0001 |
| ≤2 providers (ref) | 4948 (53.8) | ||||
| Utilised more than 2 locations for primary healthcare services | 2317 (25.2) | 1.434 (1.319 to 1.558) | <0.0001 | − | − |
| ≤2 locations (ref) | 6885 (74.8) | ||||
| Visits Primary Care Physician (PCP) C every few years | 217 (2.4) | 1.514 (1.121 to 2.044) | <0.0001 | 2.057 (1.445 to 2.927) | <0.0001 |
| Visits PCP once a year | 1670 (18.4) | 0.770 (0.656 to 0.904) | 0.0318 | − | − |
| Visits PCP every 6 months | 2770 (30.5) | 0.558 (0.480 to 0.648) | <0.0001 | 0.917 (0.769 to 1.094) | <0.0001 |
| Visits PCP every 2–5 months | 3481 (38.4) | 0.719 (0.623 to 0.831) | <0.0001 | 0.928 (0.788 to 1.092) | <0.0001 |
| Every month (ref) | 937 (10.3) | ||||
| Receive most care in hospital/urgent care | 579 (6.4) | 1.615 (1.364 to 1.912) | <0.0001 | − | − |
| Other locations (ref) | 8528 (93.6) | ||||
| Visited ED 1–2 times in last 12 months | 2509 (27.3) | 1.497 (1.363 to 1.644) | 0.3380 | − | − |
| Visited ED three or more times in last 12 months | 541 (5.9) | 2.519 (2.104 to 3.016) | <0.0001 | 1.339 (1.073 to 1.672) | 0.0107 |
| No visits (ref) | 6152 (66.9) | ||||
| Geography | |||||
| Live in large city | 1372 (14.9) | 1.048 (0.908 to 1.209) | 0.2946 | − | − |
| Live in suburb of a large city | 3203 (34.8) | 0.900 (0.800 to 1.014) | 0.0020 | − | − |
| Live in small city or town | 2879 (31.3) | 1.061 (0.941 to 1.196) | 0.0915 | − | − |
| Rural (ref) | 1748 (19.0) | ||||
| Live in Midwest | 2273 (24.7) | 1.035 (0.912 to 1.174) | 0.7050 | − | − |
| Live in South | 3546 (38.5) | 1.075 (0.957 to 1.208) | 0.4545 | − | − |
| Live in West | 1624 (17.7) | 1.090 (0.950 to 1.249) | 0.3661 | − | − |
| Northeast (ref) | 1759 (19.1) | ||||
ED, emergency department;
* MMAS, Morisky Medication Adherence Scale. Use of the MMAS is protected by US copyright laws. Permission for use is required. A licence agreement is available from Donald E Morisky, ScD,ScM, MSPH, Professor, 294 Lindura Court, Las Vegas, NV 89138-4632; dmorisky@gmail.com.