Process: CESH used a series of electronic databases to find studies related to renal artery stenosis, renal hypertension (high blood pressure due to kidney disease), and renal vascular disease (diseases of the kidney blood vessels). It also looked at abstracts and posters from academic conferences, and asked for citations from an expert panel and drug manufacturers to find the most up-to-date research. It then screened the materials, including only studies where researchers followed patients for at least 6 months.
In the end, CESH found:
15 studies comparing medication alone versus PTRAS with medication.
48 studies that looked at only one type of intervention: medication alone or PTRAS with medication, without a comparison between the two.
20 case reports of individual patient experiences
CESH also reviewed 20 case reports of patients with extreme symptoms of renal artery stenosis.
Of the 15 comparative studies, 8 were non-randomized controlled studies and 7 were randomized controlled trials (the gold standard of research).
Researchers included studies that only looked at one type of intervention because they were also interested in the long term outcomes and adverse events associated with each type of treatment.
In this case, it wasn’t possible to use meta-analysis to combine data from the various studies because the study designs and the types of participants in each study weren’t similar enough. Instead, researchers looked at each study individually and described how their results compared to each other.