Combining evidence from observational and experimental studies in a systematic review: example from a health technology assessment study on laser ablation for varicose veins

Article type
Authors
Albäck A, Saarinen J, Malmivaara A, Kuukasjärvi P
Abstract
Background: Surgery for varicose veins is one of the most common surgical procedures. Many new techniques for this treatment are now available, one of the most important ones is endovenous laser ablation of superficial truncal veins.
Objective: To evaluate the efficacy and safety of endovenous laser ablation for superficial truncal veins.
Methods: Search strategies, selection process, quality assessment, data extraction and a qualitative analysis were performed according to the established principles for a systematic review. Both prospective observational studies and randomized trials were included.
Results: Seven prospective uncontrolled studies including at least 100 legs and with a follow-up of at least 12 months as well as four randomized controlled trials were encountered. In the short term the efficacy of endovenous laser treatment seem to be comparable to that of open surgery, but there seem to be less postoperative morbidity and shorter sick leaves. The frequency of severe adverse effects is reported to be low. Long-term data is still lacking and many technical aspects of the procedure are under investigation.
Discussion: The uncontrolled studies did provide valid information on the closure of the treated vein, as well as on adverse effects, and thus these studies did expand the data from randomized trials. However, more data from thoroughly designed controlled trials are needed before the best treatment of superficial truncal venous incompetence can be settled.