Table 1.
Characteristics of included studies in meta-analysis of adherence to drug therapy and mortality
| Study | Study type | Treatment groups (No of participants) | Adherence measures | Threshold for good adherence | Observation period |
|---|---|---|---|---|---|
| Post-myocardial infarction management: | |||||
| Coronary Drug Project Research Group 1980w1 | Randomised controlled trial | Placebo (2695), clofibrate (1065) | Pill count, clinician's impression | ≥80% | ≥5 years |
| Wei et al 2002w5 | Cohort | Statins (427) | Pharmacy refill | ≥80% | Average 2.4 years |
| Cotter et al 2004w6 | Cohort | Acetylsalicylic acid (64) | Thromboxane blood level | Less than healthy volunteer | 1 year |
| β blocker heart attack trial (men) 1990w2 | Randomised controlled trial | Placebo (1094), propranolol (1081) | Pill count | >75% | 1 year |
| β blocker heart attack trial (women) 1993w3 | Randomised controlled trial | Placebo (240), propranolol (265) | Pill count | ≥75% | Median 26 months |
| Wei et al 2004w7 | Cohort | β blockers (386) | Pharmacy refill | ≥80% | Median 3.7 years |
| Canadian amiodarone myocardial infarction arrhythmia trial 1999w8 | Randomised controlled trial | Placebo (538), amiodarone (573) | Pill count | ≥66% | 2 years |
| Cardiac arrhythmia suppression trial 1996w4 | Randomised controlled trial | Placebo (579), encainide or flecainide (574) | Pill count | >80% | Average 10 months |
| HIV infection: | |||||
| San Andres Rebollo et al 2004w9 | Cohort | Antiretroviral therapy (950) | Self report | Continued use | 8 years |
| Cohn et al 2002w10 | Cohort | Antiretroviral therapy (626) | Self report | No missed doses in previous 48 hours | 56 weeks |
| Garcia de Olalla et al 2002w11 | Cohort | Antiretroviral therapy (1219) | Self report and pharmacy refill | ≥90% | 3 years |
| Grimwade et al 2005w12 | Cohort | Cotrimoxazole prophylaxis (1288) | Self report and frequency of clinic visits | Continued use, collection of new tablet supply, and ongoing attendance at clinic | 6 months |
| Hogg et al 2002w13 | Cohort | Antiretroviral therapy (1282) | Pharmacy refill | ≥75% | 1 year |
| Paterson et al 2000w14 | Cohort | Protease inhibitors (81) | Medication event monitoring system | ≥95% | Median 6 months |
| Wood et al 2003w15 | Cohort | Antiretroviral therapy (1422) | Pharmacy refill | ≥75% | 4 years |
| Primary prevention of cardiovascular disease: | |||||
| Physicians' health study 1994w16 | Randomised controlled trial | Placebo (10 989), acetylsalicylic acid (11 004) | Self report | ≥95% | Average 60.2 months |
| West of Scotland prevention study 1997w17 | Randomised controlled trial | Placebo (3293), pravastatin (3302) | Pill count | ≥75% | Mean 4.9 years |
| Other disease states: | |||||
| University Group Diabetes Project 1970w22 1971w18 (type 2 diabetes) | Randomised controlled trial | Placebo (205), tolbutamide (204) | Clinician's impression | ≥75% | ≥75% followed for ≥5 years |
| Howell et al 2004w19 (hypercholesterolaemia) | Cohort | Statins (869) | Pharmacy refill | ≥80% | 11 years |
| Miura et al 2001w20 (heart failure) | Cohort | Digoxin (431) | Blood levels of drug | Therapeutic range | 72 months |
| Dobbels et al 2004w21 (heart transplant) | Cohort | Immunosuppressive regimen(101) | Medication event monitoring system (for cyclosporin use) | No variation in dose compliance and no drug holidays | 5 years |