Glomerular disease: why is there a dearth of high quality clinical trials?

There is a paucity of high quality clinical trials in glomerular disease, particularly in non-diabetic kidney disease. The aims of this review include quantifying the extent of this problem and exploring reasons for the scarcity of such trials in primary glomerular disease, with an emphasis on immunoglobulin A nephropathy, minimal change disease, focal segmental glomerulosclerosis, and membranous nephropathy in comparison with the more common diseases of diabetic nephropathy and lupus nephritis. Reasons for the dearth of high quality clinical trials in primary glomerular disease include (1) low prevalence of disease; (2) variability in clinical presentation; (3) variability in treatment response; (4) lack of consensus in definitions; (5) difficulty in recruiting patients; (6) high costs of randomized controlled trials; and (7) lack of collaborative efforts. To facilitate greater numbers of high quality clinical trials in glomerular disease, practice guidelines should establish common classification systems of disease and common clinical end points, industry and non-industry sponsored research should find common ground and work together toward advancing science, and national registries should be created to encourage collaborations across institutions and across nations.