Fibrates and statins in the treatment of diabetic retinopathy.

Diabetic retinopathy (DR) is one of the leading risk factors and causes of blindness worldwide. Tight glucose and blood pressure control has been shown to significantly decrease the risk of development as well as the progression of retinopathy and represents the cornerstone of medical management of DR. The two most threatening complications of DR are diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR). Photocoagulation is standard treatment for both DME and PDR. However, some patients suffer permanent visual loss despite therapy. Treatment with fibrates first showed reduction in hard exudates, an effect subsequently shown with statins in short term studies, in particular two randomized studies in patients with macular edema. In the FIELD study which pre-specified microvascular outcomes, fenofibrate reduced laser treatment for DME or PDR by 31%:164 (3.4%) patients on fenofibrate vs. 238 (4.9%) on placebo (p<0.001). In the ophthalmology sub-study of FIELD, the composite exploratory endpoint of 2-step progression of ETDRS retinopathy grade, macular edema or laser treatment was significantly reduced by 34%: 53 (11.1%) patients on fenofibrate vs. 75 (16.1%) on placebo (p=0.022). Conversely, there was no reduction in laser treatment or reduced progression of retinopathy in two large scale studies of statins where cardiovascular events were significantly reduced. Neither class of lipid-lowering drugs consistently improved visual acuity. In the ACCORD-EYE study, the combination of fenofibrate and simvastatin reduced by 40% the rate of progression of diabetic retinopathy compared with simvastatin alone. Other studies are needed to establish the place of lipid lowering drugs in the treatment of macular edema and the prevention of vision loss.

Effect of fenofibrate on kidney function: a 6-week randomized crossover trial in healthy people.

BACKGROUND: Fenofibrate was associated with increases in serum creatinine concentrations. The effect of short-term fenofibrate treatment on kidney function was investigated in subjects with normal kidney function. STUDY DESIGN: Double-blind, crossover, placebo-controlled. SETTING AND PARTICIPANTS: 24 middle-aged subjects with normal kidney function (estimated creatinine clearance > or = 80 mL/min). INTERVENTION: Subjects were treated with fenofibrate (160-mg/d tablet) and placebo in two 6-week periods separated by a washout. OUTCOMES AND MEASUREMENTS: The primary outcome measure was glomerular filtration rate measured by means of inulin clearance, with a test of noninferiority to rule out a change in the 95% confidence interval (CI) greater than 20%. Secondary outcomes included effective renal plasma flow measured by means of para-aminohippurate (PAH) clearance, creatinine clearance, creatinine secretion (ratio of creatinine to inulin clearance), serum cystatin C and uric acid, and urinary excretion of creatinine. Glomerular and tubular damage was evaluated by using albumin and retinol-binding protein levels and N-acetyl-beta-d-glucosaminidase activity. RESULTS: Inulin clearance was unchanged after fenofibrate (change [Delta] between treatments on 6-week values, 0.8 mL/min; 95% CI, -10.5 to 12.2; P = 0.9), but PAH clearance decreased (Delta, -33; 95% CI, -66 to -1; P = 0.05). Changes in inulin and PAH clearances were not greater than 20%. Plasma creatinine level increased (Delta, 0.11 mg/dL; 95% CI, 0.05 to 0.18; P < 0.05), and creatinine clearance decreased (Delta, -9.5 mL/min; 95% CI, -14.4 to -4.7; P < 0.001). Creatinine secretion and urinary creatinine excretion were unchanged (Delta, -0.05; 95% CI, -0.11 to 0.02; P = 0.2; Delta, 0.37 g/24 h; 95% CI, -0.13 to 0.88; P = 0.1, respectively). Plasma cystatin C level increased (Delta, 0.18 mg/L; 95% CI, 0.03 to 0.34; P = 0.02) and serum uric acid level decreased (Delta, -0.7 mg/dL; 95% CI, -1.2 to -0.3; P = 0.1). Urinary albumin and retinol-binding protein levels were unchanged, but urinary N-acetyl-beta-d-glucosaminidase activity increased (Delta, 20.0 mumol/h/mmol creatinine; 95% CI, 9.3 to 30.7; P = 0.001). LIMITATIONS: Short treatment duration and inclusion of healthy subjects precludes conclusions about effects of longer term use in patients with kidney disease. Small changes in glomerular filtration rate may be difficult to detect by using clearance methods. Interference with the creatinine assay cannot be excluded. CONCLUSION: Short-term fenofibrate treatment did not alter glomerular filtration rate by more than 20% in subjects with normal kidney function, but a smaller decrease cannot be ruled out. Increased serum creatinine levels may be caused by decreased creatinine clearance. The explanation for decreased creatinine clearance and increased serum creatinine levels in this study is not clear.