One fourth of observational studies gave different results than randomized trials, and between-study heterogeneity was more common in observational studies in the field of digestive surgery.

Background: To compare single-with two-layer intestinal anastomosis after intestinal resection: a meta-analysis of randomized controlled trials.

Antiplatelet agents resulted in reduced proteinuria and protected renal function in patients with IgA nephropathy. However, studies of high-quality design were rare, and most studies assessed surrogate outcomes. More properly designed studies are needed to reach a definitive assessment of this matter.

A dialysate calcium concentration of 2.5 meq/l was not shown to have positive effects on HRQOL.