Table 3.
Summary of evidence for demographic predictors of adherence to MTX
| Predictor | Study | N | Outcome | Unadjusted ES (95% CI)/univariate analyses | p Value | Adjusted ES (95% CI) | p Value |
|---|---|---|---|---|---|---|---|
| Gender | |||||||
| Per cent of male | Contreras-Yanez et al24* | 93 | Adherent (CQ ≥9) vs non-adherent (CQ ≤8) | 8 (17%) vs 5 (11.9%) | 0.55 | NP | NP |
| Salt and Frazier29* | 108 | Adherent (MARS ≥39) vs non-adherent (MARS ≤38) | 23 (24%) vs 4 (32%) | 0.69 | NP | NP | |
| Male vs female | de Thurah et al26 | 941 | Non-adherence (CMG) | 12.0 (10.5 to 13.5) vs 12.5 (11.4 to 13.5) | NS | ||
| Being male | de Thurah et al27† | 85 | Non-adherence (CQR ≤25th centile) at BL | PR 0.7 (0.2 to 1.7) | NS | PR 0.8 (0.3 to 2.0) | NS |
| de Thurah et al27† | 65 | Non-adherence (CQR ≤25th centile) at 9 mo | PR 0.4 (0.1 to 1.3) | NS | PR 0.3 (0.1 to 1.3) | NS | |
| de Klerk et al22*,‡ | 127 | Per cent of adherence (MEMS) | β 13.5 (NP) | <0.05 | 0.38 (NP) | <0.05 | |
| Age | |||||||
| Age in years | Salt and Frazier29* | 108 | Adherent (MARS ≥39) vs non-adherent (MARS ≤38) | 52±14 vs 53±9 | 0.77 | OR 1.01 (0.94 to 1.08) | 0.8 |
| Contreras-Yanez et al24* | 93 | Adherent (CQ ≥9) vs non-adherent (CQ ≤8) | 42.7±14.1 vs 38.9±13.4 | 0.18 | NP | NP | |
| Waimann et al30 | 107 | Per cent of adherence (MEMS) | r −0.07 | >0.20 | NP | NP | |
| >67 vs <55 years old | de Thurah et al26 | 941 | Non-adherence (CMG) | 13.1 (11.6 to 14.6) vs 10.8 (9.3 to 12.3) | <0.01 | Not defined | Sig |
| >55 | de Thurah et al27† | 85 | Non-adherence (CQR ≤25th centile) at BL | 0.5 (0.2 to 1.1) | NS | PR 0.6 (0.2 to 1.6) | NS |
| >55 | de Thurah et al27† | 65 | Non-adherence (CQR ≤25th centile) at 9 mo | PR 0.9 (0.4 to 2.0) | NS | PR 0.7 (0.3 to 1.7) | NS |
| Ethnicity | |||||||
| White vs non-white | Salt and Frazier29* | 108 | Adherent (MARS ≥39) vs non-adherent (MARS ≤38) | 84 (86%) vs 5 (56%) | 0.04 | OR 10.1 (1.66 to 61.4) | 0.01 |
| Hispanic vs white vs African-American | Waimann et al30 | 107 | Per cent of adherence (MEMS) | 66±17 vs 64±20 vs 60±24 | NS | NP | NP |
| Being single/living alone | |||||||
| Single | Contreras-Yanez et al24* | 93 | Adherent (CQ ≥9) vs non-adherent (CQ ≤8) | 23 (49%) vs 25 (54%) | 0.68 | NP | NP |
| Salt and Frazier29* | 108 | Adherent (MARS ≥39) vs non-adherent (MARS ≤38) | 16 (16%) vs 2 (22%) | 0.74 | OR 1.44 (0.15 to 13.7) | 0.75 | |
| Widowed/separated vs married | Waimann et al30 | 107 | Per cent of adherence (MEMS) | 56±19 vs 72±16 | <0.01 | NP | NP |
| Widowed/separated vs single | Waimann et al30 | 107 | Per cent of adherence (MEMS) | 56±19 vs 69±18 | <0.01 | NP | NP |
| Living alone vs not living alone | Waimann et al30 | 107 | Per cent of adherence (MEMS) | 56±21 vs 66±19 | <0.05 | NP | NP |
| Education | |||||||
| < High school vs ≥ high school | Waimann et al30 | 107 | Per cent of adherence (MEMS) | 67±19 vs 62±20 | NS | NP | NP |
| Years of education | Contreras-Yanez et al24* | 93 | Adherent (CQ ≥9) vs non-adherent (CQ ≤8) | 10.1±4.2 vs 11.4±3.5 | 0.09 | NP | NP |
| Salt and Frazier29* | 108 | Non-adherence (MARS ≤38) | OR 1.09 (1.50 to 0.79) | 0.61 | NP | NP | |
| School >10 years | de Thurah et al27† | 85 | Non-adherence (CQR ≤25th centile) at BL | PR 1.7 (0.7 to 3.8) | NS | PR 1.5 (0.5 to 4.1) | NS |
| de Thurah et al27† | 65 | Non-adherence (CQR ≤25th centile) at 9 mo | PR 1.3 (0.6 to 3.1) | NS | PR 1.0 (0.3 to 2.8) | NS | |
| Residence (rural vs urban) | Salt and Frazier29* | 108 | Adherent (MARS ≥39) vs non-adherent (MARS ≤38) | 55 (51%) vs 48 (53%) | 0.18 | OR 7.52 (0.70 to 83.3) | 0.1 |
| Employment status | |||||||
| Employed vs unemployed | Contreras-Yanez et al24* | 93 | Adherent (CQ ≥9) vs non-adherent (CQ ≤8) | 16 (34%) vs 15 (33%) | 1 | NP | NP |
| Employed | Salt and Frazier29* | 108 | Adherent (MARS ≥39) vs non-adherent (MARS ≤38) | 27 (26%) vs 25 (26%) | 0.72 | OR 2.19 (21.3 to 0.21) | 0.52 |
| Employed vs unemployed | Waimann et al30 | 104 | Per cent of adherence (MEMS) | 64±15 vs 63±14 | NS | NP | NP |
| Income <$20 000/year vs ≥$20 000/year | Waimann et al30 | 90 | Per cent of adherence (MEMS) | 62±19 vs 69±20 | NS | NP | NP |
| Low socioeconomic status | Contreras-Yanez et al24* | 93 | Adherent (CQ ≥9) vs non-adherent (CQ ≤8) | 43 (92%) vs 40 (87%) | 0.52 | NP | NP |
| Uninsured vs private vs medicaid | Waimann et al30 | 103 | Per cent of adherence (MEMS) | 65±15 vs 66±13 vs 64±19 | NS | NP | NP |
| English vs Spanish language | Waimann et al30 | 107 | Per cent of adherence (MEMS) | 64±21 vs 65±19 | NS | NP | NP |
*Studies judged low quality.
†MTX adherence.
‡Includes RA, PMR and gout.
9 mo, 9 months; BL, baseline; CMG, continuous measure of medication gaps; CQ, Compliance Questionnaire; ES, effect size; MEMS, Medication Electronic Monitoring System; CQR, Compliance Questionnaire-Rheumatology; MARS, Medication Adherence Revised Scale; MTX, methotrexate; NP, information not presented; NS, non-significant; PR, prevalence ratio; r, Pearson correlation coefficient; RA, rheumatoid arthritis; Sig, significant; β, regression coefficient.