Effect of Combining Psyllium Fiber With Simvastatin in Lowering Cholesterol: A clinical study

The present study was carried out to investigate the efficacy and safety of Combining Psyllium Fiber With Simvastatin in Lowering Cholesterol
Objective: Soluble fiber supplements are recommended to reduce levels of low-density lipoprotein cholesterol (LDL-C). We evaluated the LDL-C€“lowering effect of psyllium husk added to low-dose simvastatin therapy.
Treatment Offered
The study group comprised men (n = 40) and women (n = 28) aged 18 to 80 years, who met the NCEP ATP III criteria for drug treatment of hyperlipidemia and dietary intervention. All patients gave informed consent, and the Robert Wood Johnson Medical School Institutional Review Board approved the study. Patients were excluded if they had a body mass index (calculated as weight in kilograms divided by the square of height in meters) greater than 32, triglyceride levels greater than 400 mg/dL (>4.5 mmol/L), elevated liver enzymes aspartate aminotransferase or alanine aminotransferase greater than 1.5 times the upper limit of normal, allergy to psyllium or known hypersensitivity to statins, or weight change within 5% of the baseline weight before randomization. Women with childbearing potential who were not using a birth control method and pregnant or lactating women were excluded. Patients taking medications that affect lipid levels, including corticosteroids, thiazides, β-blockers, estrogens, and progesterone, at doses that could not be stably maintained for the duration of the study were excluded. Patients using the calcium channel blocker verapamil hydrochloride and immunosuppressive drug therapy were excluded. Other exclusions were an active biliary disease, multiple lipid-lowering medications, myocardial infarction, coronary angioplasty, coronary artery bypass grafts, severe or unstable angina pectoris within 3 months before screening, uncontrolled hypertension, secondary causes of hyperlipidemia, type I or uncontrolled type II diabetes mellitus, unreliability as a study participant based on the investigator€™s prior knowledge of the subject, and any significant factor that compromised the patient€™s safety or compliance. Seventy-two patients were randomized to treatment, and 68 completed the study. One patient was excluded because of a protocol violation, and 3 patients withdrew consent.
Results
mographic and baseline clinical characteristics were similar among the treatment groups (Table 1). The mean age overall was 64 years (age range, 31-77 years). There were similar proportions of men and women in each treatment arm. The mean body mass index overall was 27.5 and was significantly higher in those patients randomized to 10 mg of simvastatin plus placebo. Almost 87% (59/68) of the patients had 2 or more coronary heart disease risk factors, and 62% (42/68) had coronary heart disease or clinical atherosclerotic disease. The mean baseline levels of lipids and lipoproteins for the total study cohort were as follows: LDL-C: 173 mg/dL (4.48 mmol/L) (range, 105-271 mg/dL [2.72-7.02 mmol/L]), total cholesterol: 251 mg/dL (6.50 mmol/L) (range, 160-352 mg/dL [4.14-9.12 mmol/L]), HDL-C: 46 mg/dL (1.19 mmol/L) (range, 30-83 mg/dL [0.78-2.15 mmol/L]), triglycerides: 157 mg/dL (range, 49-290 mg/dL), Apo B: 150 mg/dL (range, 80-237 mg/dL), and Apo A-I: 69 mg/dL (range, 20-167 mg/dL).
Patient Characteristics at Baseline by Treatment Group*
Figure 1 shows plots of the mean levels of LDL-C, by treatment group, during the study. The baseline values for computing changes in LDL-C, as well as the other lipid variables, were obtained by averaging the levels at weeks €“1 and 0. Most of the patients who enrolled had been taking some kind of statin therapy previously; only 3 had been taking Metamucil, all for constipation. The mean reductions in total cholesterol, LDL-C, and Apo B for the different treatment groups are shown in Table 2 and Figure 2.
Fig.1: Plots of mean levels of low-density lipoprotein cholesterol (LDL-C) per visit, by treatment group, during the study. To convert cholesterol to millimoles per liter, multiply by 0.0259.
At the end of 8 weeks of treatment, total cholesterol had dropped by 66 mg/dL (1.71 mmol/L]) (ˆ’26%) in the group receiving 10 mg of simvastatin plus psyllium, a decrease slightly more than that achieved by treatment with 20 mg of simvastatin, which produced a drop of 61 mg/dL (1.58 mmol/L) (ˆ’24%) from baseline (P = .33) (Table 2). The LDL-C levels dropped 63 mg/dL (1.63 mmol/L) (ˆ’36%) in the group receiving 10 mg of simvastatin plus psyllium, with the additive effect equaling that seen with 20 mg of simvastatin (P = .70). Reductions from baseline in Apo B were more pronounced with the combination therapy at 50 mg/dL (ˆ’32%), compared with 43 mg/dL (ˆ’29%) with 20 mg of simvastatin (P<.05). Triglyceride levels were not significantly changed from baseline values in any of the treatment groups (Table 2 and Figure 3). There was no significant change from baseline in HDL-C in the psyllium supplement group, although a blunting of the HDL-C increase with statin treatment was observed. Similar results were seen in the Apo A-I levels.
Absolute Change From Baseline in Serum Lipid and Lipoprotein Levels, by Week and Treatment Group*
Fig.2: Charts showing mean percentage changes from baseline at 4 and 8 weeks in total cholesterol, low-density lipoprotein cholesterol (LDL-C), and apolipoprotein B.
Conclusion
In summary, although combination therapies are common in the practice of medicine, physicians have been cautious when it comes to the treatment of dyslipidemia because of the increased likelihood of the patient developing undesirable adverse effects or liver dysfunction. Psyllium supplementation should be considered as a safe and well-tolerated dietary alternative to escalating the dose of statin to enhance LDL-C lowering.
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