Bandolier 92 reported a meta-analysis of trials looking at a comparison of stents versus balloon angioplasty indicating stents to be better.
This issue of Bandolier has an example of type I evidence a report of a meta-analysis on quinine in nocturnal leg cramps.
A systematic overview (meta-analysis) of outcome measures in Helicobacter pylori gastritis trials and functional dyspepsia.
That would leave only two studies, not much grist for the mill of meta-analysis there.
T he methodological limitations of this research that is common to all systematic reviews and meta-analysis are also mentioned.