Low incidence of paradoxical reductions in HDL-C levels in dyslipidemic patients treated with fenofibrate alone or in combination with ezetimibe or ezetimibe/simvastatin

BACKGROUND

Fibrates have been reported to cause paradoxical decreases in HDL-C in certain patients.

DESIGN AND METHODS

This post-hoc analysis explored the frequency/magnitude of HDL-C reductions in a pooled database of mixed dyslipidemic patients (LDL-C:3.4-5.7 mmol/L;TG:1.7-5.7 mmol/L) receiving placebo (PBO), fenofibrate (FENO), ezetimibe plus FENO (EZE+FENO), or EZE/simvastatin plus FENO (EZE/SIMVA+FENO) for 12 weeks.

RESULTS

PBO-treated patients had the highest incidence of HDL-C reductions from baseline (45%) compared with patients taking FENO (14%), EZE+FENO (9%), or EZE/SIMVA+FENO (9%). Reductions <30% reflected natural variability since the largest reduction in HDL-C approached 30% in the PBO group. Only 3 patients exhibited HDL-C reductions ≥30% (i.e., 2 patients in the FENO group and 1 in the EZE+FENO group). There were no differences in demographic/biochemical characteristics between patients with and without HDL-C reductions.

CONCLUSIONS

The incidence of paradoxical HDL-C reductions was low in mixed dyslipidemic patients receiving FENO alone or combined with EZE or EZE/SIMVA.

Paradoxical decrease in HDL-cholesterol and apolipoprotein A1 with simvastatin and atorvastatin in a patient with type 2 diabetes

Statins are agents widely used to lower LDL-cholesterol (LDL-C) in primary and secondary prevention of coronary heart disease. The five statins available in the UK (simvastatin, pravastatin, fluvastatin, atorvastatin and rosuvastatin) differ in many of their pharmacologic properties. In addition to lowering LDL-C, statins also increase HDL-cholesterol (HDL-C) moderately. There have been rare reports of significant HDL-C decreases in patients commenced on fibrates and when thiazolidinediones are added to fibrates. This is known as a 'paradoxical HDL-C decrease' as both groups of agents usually increase HDL-C. This phenomenon has never been clearly documented following statin therapy. We now describe a patient with type 2 diabetes who showed this paradoxical fall in HDL-C (baseline HDL-C: 1.8 mmol/L; on simvastatin 40 mg HDL-C 0.6 mmol/L; on atorvastatin 20 mg HDL-C 0.9 mmol/L) with a similar decrease in apolipoprotein A1. No similar decrease was observed with pravastatin and rosuvastatin therapy. This phenomenon appeared to be associated with statin treatment and not a statin/fibrate combination. Our patient clearly demonstrated a paradoxical HDL-C fall with simvastatin and atorvastatin, but not pravastatin or rosuvastatin. Simvastatin and atorvastatin share many pharmacokinetic properties such as lipophilicity while pravastatin and rosuvastatin are relatively hydrophilic and are not metabolized by cytochrome P450 3A4. However, these characteristics do not explain the dramatic reductions in HDL-C observed.

Paradoxical decrease in high-density lipoprotein cholesterol with fenofibrate: a quite rare phenomenon indeed

Some recent clinical reports have suggested that paradoxical decreases in high-density lipoprotein cholesterol (HDL-C) levels after fenofibrate treatment may be quite common. These appear to occur mainly in patients with combined fibrate/statin therapy and possibly in those with low baseline HDL-C. Reports on HDL-C reductions after fenofibrate are possibly supported by the disappointing results in terms of HDL-C responses from the recent FIELD study. A survey on 581 patients treated for 1 year or longer was carried out in our Clinical Center. This indicated that paradoxical HDL-C reductions are a relatively uncommon phenomenon. Not more than 15.3% of the present series showed an HDL-C reduction, mostly of a modest degree. Further, reductions of HDL-C appear to occur mainly in individuals with significant HDL-C elevations (>50 mg/dL), almost never in patients with low HDL-C. Otherwise, there seems to be no impact of a previous diagnosis of diabetes or hypertension on the HDL-C changes. From a very recent pharmacogenomic study on the apo A1/C3/A4/A5 gene cluster, genetic influences appear only to reduce the positive impact of fenofibrate on HDL-C, but do not indicate any risk of occurrence of HDL-C reductions. Also based on our very long experience with this drug, it appears that fenofibrate raises HDL-C levels in the vast majority of treated patients, with a particularly dramatic effect in individuals with low HDL-C and hypertriglyceridemia.