Meta-regression of the association between follow-up duration and risk ratio of death in trials of zidovudine monotherapy

The relationship between study design, results, and reporting of randomized clinical trials of HIV infection. Decrease in the magnitude of the treatment effect with increasing mean duration of follow-up in studies of zidovudine monotherapy. Studies are represented by dots the size of which is proportional to the inverse of the variance of the observed logarithm of the risk ratio. The depicted regression line is weighted by the inverse of the variance.