Study designs of evaluations included in the review
No inclusion criteria were specified for the study design. The review included randomised controlled trials (RCTs) and retrospective database analyses.
Specific interventions included in the review
Studies that compared fixed-dose combination medications with free-drug combination medications were eligible for inclusion. Studies in the review compared fixed-dose combinations of medications with the same medications given separately. They included treatments for tuberculosis (TB) (isoniazide and rifampicin with or without pyrazinamide), human immunodeficiency virus (HIV) (lamivudine with zidovudine), hypertension (amlodipine with benazepril; lisinopril or enalapril with hydrochlorothiazide; angiotensin-receptor blockers with diuretic) and diabetes (glyburide with metformin).
Participants included in the review
No inclusion criteria were specified for the participants. The studies included men and women aged from 40 to 68 years with hypertension, diabetes, TB or HIV.
Outcomes assessed in the review
Studies that reported compliance with medication regimens were eligible. Compliance was defined in the review as adherence or persistence. The included studies used a range of measures of compliance, such as pill counting, questionnaires, medication possession ratios (calculated from prescription fill dates), urine testing, and persistence (continuing to take drug, fill prescriptions) or not lost to follow-up. The review also reported efficacy outcomes; these comprised sputum conversion rates and radiological improvement in patients with TB, and treatment failure in patients with HIV (viral load). The patients were followed up for a mean of 13.1 months (standard deviation 8.6 months; range: 4 months to 2 years).
How were decisions on the relevance of primary studies made?
The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.