Table 1.
Characteristics of included studies
| Authors | Sample size, No. | Age, y | Men, % | Follow‐up, mo | Design | Contents of FDC | Definition of Adherence or Persistence | Difference in Persistence | Difference in Adherence (MPR or PDC) | Newcastle‐Ottawa Rating |
|---|---|---|---|---|---|---|---|---|---|---|
| Dezii, 200018 | 2268 | – | – | 12 | Retrospective cohort | Lisinopril/hydrochlorothiazide | Patients were regarded as persistent if they renewed their prescription within three times the number of days supplied by the previous prescription | 68.7% vs 57.8%, P < .05 | – | 6 of 9 |
| Dezii, 200018 | 1674 | – | – | 12 | Retrospective cohort | Enalapril/hydrochlorothiazide | Patients were regarded as persistent if they renewed their prescription within three times the number of days supplied by the previous prescription | 70.0% vs 57.5%, P < .05 | – | 6 of 9 |
| Taylor, 200319 | 5732 | 53 | 50 | 12 | Retrospective cohort | Amlodipine besylate/benazepril HCl | Adherence was measured by the MPR during the study period | ‐ | 80.8% vs 73.8%, P < .001 | 8 of 9 |
| Brixner, 200820 | 2189 | – | 47.1 | 12 | Retrospective cohort | Valsartan and hydrochlorothiazide |
Adherence was measured by calculating the MPRs for all patients with at least two prescription fills for dual therapy. MPR was defined as the total days supplied divided by the difference in days between the first fill and the last day of the last days supplied Patients were classified as persistent if they remained on dual therapy and did not discontinue therapy at 365 days. |
54% vs 19%, P < .001 | 62.1% vs 53.0%, P < .001 | 7 of 9 |
| Dickson, 200821 | 5704 | 76.0 ± 7.2 | 17.4 | 12 | Retrospective cohort | Amlodipine besylate/benazepril HCl | Compliance defined as the MPR, which was the total days’ supply of drug (excluding last prescription fill) divided by the length of follow‐up | – | 63.4% vs 49.0%, P < .0001 | 6 of 9 |
| Hess, 200822 | 14449 | 62.5 | 43.1 | 12 | Retrospective cohort | ARB/hydrochlorothiazide, ACEI/hydrochlorothiazide, ACEI/CCB |
Compliance, defined as MPR, was measured over 12 mo Persistence was measured as the percentage of patients who did not experience a lapse in therapy of more than 30 d since their last prescription refill |
58.3% vs 14.9%, P < .001 Regression‐adjusted differences: 42.5% (40.6%–44.5%), P < .001 |
76.9% vs 54.4%, P < .001 Regression‐adjusted differences: 22.1% (19.9%–24.1%), P < .001 |
7 of 9 |
| Hsu, 201523 | 7348 | 55.2 | 55.6 | 24 | Prospective cohort | ARB and thiazide diuretics |
Adherence was measured as the MPR, calculated as the number of days’ supply of medication dispensed during a specified follow‐up period divided by the number of days from the first dispensing to the end of the follow‐up period Persistence was measured as continuously refilling the prescription for either an FDC or free combination during the follow‐up period |
26.1% vs 19.5%, P < .001 | 42.06% vs 32.45%, P < .001 | 8 of 9 |
| Tung, 201524 | 16505 | 60.4 | 52.0 | 15.2 | Retrospective cohort | ARB/CCB | Adherence was measured as PDC | – | 80.35 ± 21.90% vs 72.57 ± 25.95%, P < .001 | 6 of 9 |
| Levi, 201625 | 6612 | 67.1 | 48.2 | 6 | Retrospective cohort | Olmesartan/amlodipine | Adherence was estimated by calculating the PDC | – | 55.1% vs 15.9%, P < .001 | 8 of 9 |
ACEI, angiotensin‐converting enzyme inhibitor; ARB, angiotensin receptor blocker; CCB, calcium channel blocker; FDC, fixed‐dose combination; HCl, hydrochloric acid; MPR, medication possession ratio; PDC, proportion of days covered.