Table 2.
Outcomes of studies included in the analysis
| Author/year | Adherence measure | Outcome measure | Results | Adjustment | ||||
|---|---|---|---|---|---|---|---|---|
| Sex | Age | Other† | ||||||
| Simplification of drug regimen | ||||||||
| Rea et al. (2021) | Proportion of days covered | RR (95% CI) | Association between PDC > 75% and single-pill combination of statin and ezetimibe vs. two-pill or separate administration: 2.12 (1.89–2.38) | X | X | X | ||
| Treatment discontinuation | RR (95% CI) | Association between single-pill vs. two-pill administration of a statin and ezetimibe and treatment discontinuation: 0.68 (0.63–0.74) | ||||||
| Patient education and information | ||||||||
| Eussen et al. (2010) | Incidence of discontinuation | HR (95% CI) | > 65 years old: 0.903 (0.569–1.433) | |||||
| Qvist et al. (2020) | Proportion of days covered | % (95% CI) | 6 months |
Continuous: Intervention: 78.3%, Control: 71.4%, (p = 0.04) |
||||
|
PDC ≥ 80%: Intervention: 63.2 (56.8–69.2) Control: 53.4 (46.5–60.2) | ||||||||
| 12 months |
Continuous: Intervention: 75.1%, Control: 69.1%, (p = 0.12) |
|||||||
|
PDC ≥ 80%: Intervention: 70.1 (63.9–75.7) Control: 63.2 (56.4–69.6) | ||||||||
| 60 months |
Continuous: Intervention: 69.2%, Control: 65.7%, (p = 0.34) |
|||||||
|
PDC ≥ 80%: Intervention: 57.6 (51.1–63.8) Control: 53.9 (47.0-60.7) | ||||||||
| PD (95% CI) | 6 months | Crude: 9.8 (0.5–19.0), p = 0.04 | X | |||||
| Adjusted: 10.1 (0.9–19.4), p = 0.03 | ||||||||
| 12 months | Crude: 6.9 (-2.0-15.8), p = 0.13 | |||||||
| Adjusted: 7.1 (-1.7-16.0), p = 0.11 | ||||||||
| 60 months | Crude: 3.7 (-5.7-13.0), p = 0.44 | |||||||
| Adjusted: 4.0 (-5.3-13.3), p = 0.4 | ||||||||
| Intensified patient care | ||||||||
| Casula et al. (2015) | Medication possession ratio | Difference (%) | 65–79 years old: +6.3 (NR) post-intervention vs. pre-intervention | |||||
| ≥ 80 years old: +8.3 (NR) post-intervention vs. pre-intervention | ||||||||
| Faridi et al. (2016) | Proportion of days covered | OR (95% CI) of PDC ≥ 80% | 90 days | ≤ 1 week: Reference | X | X | X | |
| 1-2 weeks: 0.95 (0.86‐1.04), p = 0.25 | ||||||||
| 2-6 weeks: 0.98 (0.89‐1.070), p = 0.61 | ||||||||
| > 6 weeks: 0.78 (0.70-0.87), p < 0.001 | ||||||||
| 1 year | ≤ 1 week: Reference | |||||||
| 1-2 weeks: 0.93 (0.83‐1.05), p = 0.25 | ||||||||
| 2-6 weeks: 0.96 (0.86‐1.07), p = 0.43 | ||||||||
| > 6 weeks: 0.78 (0.68-0.89), p < 0.001 | ||||||||
| Guerard et al. (2018) | Proportion of days covered | IRR | 65–80 years old: 1.013 (not significant) | X | X | X | ||
| Kooy et al. (2013) | Proportion of days covered | OR (95% CI) of PDC ≥ 80% | Card + Counseling | Crude: 1.22 (0.72–2.06), p = 0.45 | X | |||
| Adjusted: 1.18 (0.69–2.01), p = 0.55 | ||||||||
| Card only | Crude: 1.33 (0.76–2.32), p = 0.55 | |||||||
| Adjusted: 1.49 (0.83–2.69), p = 0.18 | ||||||||
| Card only, Secondary prevention in women | Adjusted: 8.26 (2.20–31.0), p = 0.002 | |||||||
| Administrative improvements | ||||||||
| Ivers et al. (2013) | Proportion of days covered | N (%) of PDC > 80% | < 31 days | 8962 (76.1%) | X | X | X | |
| 31–60 days | 887 (87.0%) | |||||||
| > 60 days | 3019 (90.5%) | |||||||
| OR (95% CI) of PDC > 80% | < 31 days | 1 (Reference) | ||||||
| 31–60 days | 2.0 (1.7–2.4) | |||||||
| > 60 days | 3.0 (2.6–3.4) | |||||||
| Lester et al. (2016) | Proportion of days covered | OR (95% CI) of PDC > 80% | 1.51 (1.26–1.82) | X* | X | X | ||
| Schmittdiel et al. (2015) | Proportion of days covered | RR of PDC ≥ 80% | Mean days supply of drugs in therapeutic category | < 31: Reference | X | X | X | |
| 31–60: 1.11, p < 0.001 | ||||||||
| 61–90: 1.47, p < 0.001 | ||||||||
| > 90: 1.61, p < 0.001 | ||||||||
| Mail order pharmacy | 0%: Reference | |||||||
| 1-50%: 1.01, p > 0.05 | ||||||||
| 51-100%: 1.07, p < 0.001 | ||||||||
| Generic drug copayment for 30-day supply | > 10$: Reference | |||||||
| $0-$10: 1.02, p < 0.01 | ||||||||
| Annual individual out-of-pocket maximum | >$2000: Reference | |||||||
| $0-$2000: 1.02, p < 0.001 | ||||||||
| Large-scale pharmacy-led automated telephone intervention | ||||||||
| Derose et al. (2013) | Proportion of dispensation | OR (95% CI) | > 70 years old: 2.32 (1.70–3.18) | X | X | X | ||
| Vollmer et al. (2014) | Proportion of days covered | PD (95% CI) | IVR + vs. UC | 0.035 (0.012–0.058), p = 0.003 | X | X | X | |
| IVR vs. UC | 0.029 (0.006–0.051), p = 0.013 | |||||||
| IVR + vs. IVR | 0.006 (-0.017-0.029), p = 0.606 | |||||||
RR = Risk Ratio, CI = Confidence interval, PDC = Proportion of days covered, HR = Hazard Ratio, PD = Proportion difference, NR = Not reported, OR = Odds Ratio, IRR = Incidence rate ratio, IVR + = Interactive voice recognition with a personalized reminder letter, UC = Usual care, IVR = Interactive voice recognition
*: This manuscript adjusted for gender and not sex
†: Additional covariates were adjusted for within these manuscripts; Examples include high blood pressure, diabetes and total number of medications taken by the patient