Table 2.

Cochrane meta‐analysis methods

Inclusion criteria

All randomized, placebo‐controlled trials of adjunctive tolcapone or entacapone therapy

Trials enrolled patients having a clinical diagnosis of Parkinson's disease with long‐term motor complications such as dyskinesia and/or end‐of‐dose deterioration

Trial and data identification methods

Computerized searches of MEDLINE, EMBASE, the Cochrane Controlled Trials Register

Hand searches of relevant neurology journals and the reference lists of located trials

Contacting manufacturers of entacapone (Orion) and tolcapone (Valeant)

Outcomes of interest

ON time and OFF time

Changes in United Parkinson's Disease Rating Scale scores

Reduction in levodopa dose

Frequency of adverse events

All‐cause withdrawals and withdrawal due to lack of efficacy

Data extraction

Independently, each author used a standardized form to record outcomes of interest from each trial

Forms were checked for agreement/accuracy

For continuous variables, the weighted mean difference across all the trials with each drug was calculated, and 95% confidence intervals were determined

A similar method was used for dichotomous variables (withdrawal, adverse events; Peto odds ratio)

From Higgins JPT, et al. (Cochrane Handbook, 2005).