Definitions for the levels of evidence (I–IV) can be found at the end of the "Major Recommendations" field.
Guidelines
Non-dihydropyridine calcium channel blockers (CCBs) offer a small protective effect on proteinuria in diabetic nephropathy, beyond their antihypertensive action. (Level II Evidence - Type 2 diabetes, small volume). There is no evidence that CCBs influence decline of glomerular filtration rate (GFR) in diabetic nephropathy, beyond their antihypertensive effect. One RCT in hypertensive normoalbuminuric Type 2 diabetic patients shows no benefit of verapamil over placebo in progression to microalbuminuria.
Suggestions for Clinical Care
(Suggestions are based on Level III and IV sources)
- There is insufficient evidence to recommend routine use of dihydropyridine calcium channel blockers (CCBs) in diabetic nephropathy, unless required for antihypertensive action.
- There is a small additional benefit on proteinuria from addition of nondihydropyridine CCBs to angiotensin-converting enzyme inhibitors (ACEIs). (Level III evidence – Type 2 diabetes, small volume)
- CCBs are recommended as second-line treatment in diabetic nephropathy, and are frequently required for optimal blood pressure (BP) control. There is a small benefit of non-dihydropyridines over dihydropyridines for protection against progression of proteinuria.
Definitions:
Levels of Evidence
Level I: Evidence obtained from a systematic review of all relevant randomized controlled trials (RCTs)
Level II: Evidence obtained from at least one properly designed RCT
Level III: Evidence obtained from well-designed pseudo-randomized controlled trials (alternate allocation or some other method); comparative studies with concurrent controls and allocation not randomized, cohort studies, case-control studies, interrupted time series with a control group; comparative studies with historical control, two or more single arm studies, interrupted time series without a parallel control group
Level IV: Evidence obtained from case series, either post-test or pretest/post-test
