Effect of Calcium Polycarbophil on Type II Diabetes Mellitus Control: a Randomized Double-blind Study

There have been several publications in the medical literature linking the use of various types of fiber and the beneficial effects on lipid panel, glycosylated hemoglobin A1c, weight, blood pressure, and cardiovascular events in patients with type 2 diabetes mellitus or those at risk for diabetes1-5. Most of these studies utilize fiber sources from dietary food intake or psyllium.

However, diet modification and psyllium intake are difficult for patients to comply on daily basis and many patients do not continue to follow through on these interventions.

Polycarbophil is a bulk forming agent which is used for similar indications as psyllium for the treatment of constipation and irritable bowel syndrome. Because polycarbophil comes in oral tablets and capsules, patients may adhere to regular intake better compared to psyllium. However, it is unknown whether polycarbophil has similar beneficial properties compared to psyllium and other fiber types. Taking polycarbophil prior to each meal may improve diabetes control by allowing patients to have smaller meals and decrease the absorption rate of carbohydrates in the intestine.

The goal of this study is to determine whether taking calcium polycarbophil (also known as over-the-counter FiberconTM) regularly will improve the diabetes control. The proposed study will be a randomized, controlled, and double-blinded trial involving adult patients with type 2 diabetes mellitus. A total of 50 patients will be randomized to receive either calcium polycarbophil or placebo from the Family Medicine Center at East Carolina University and followed over 6 months. The primary outcome of the trial will be glycosylated hemoglobin A1c. Secondary outcome measures will include weight, blood pressure, and cholesterol level. Additional secondary outcome measures are the number and dosages of medications for diabetes mellitus, hypertension, and hyperlipidemia.

The potential benefits of this study include improved control of diabetes mellitus, hypertension, and hyperlipidemia, reflected by the improved outcomes mentioned above. Because calcium polycarbophil (FiberconTM) is a commonly used over-the-counter fiber product for constipation, and the dosage used in this study is well within the typical use recommended by the manufacturers, the potential adverse effects of this product is thought to be identical to that described for FiberconTM. Patients will receive their usual medical care by their own primary physicians regardless of their participation in this study. After the randomization to the intervention or the control group, the study team will only monitor the outcome measures and will not alter the medical care that the patients receive.

Study title:

Effects of calcium polycarbophil on type II diabetes mellitus control: a randomized double-blinded study.

Patient population:

East Carolina University Family Medicine Center (ECU FMC) outpatient clinic patients Age above 18 Diagnosed with type II diabetes mellitus (DM) for at least 24 months. At least 4 office visits within the past 24 months for DM follow up at ECU FMC or Geriatrics Center.

Hgb A1c within the past six months of 8% to 10%.

Exclusion criteria:

Dementia diagnosis or other psychiatric diagnoses that preclude the patient from being able to consent for this study by him/herself.

Already taking fiber supplementation (polycarbophil, psyllium, methylcellulose) Severe problems with previous use of fiber supplementation (i.e. fecal impaction) Dysphagia or other swallowing disorders (unable to swallow pills or 8 oz of water) Pregnancy during the study period

Consent:

Will be obtained from the patients for the study and HIPAA.

Study design:

Randomize 50 patients to intervention or placebo:

Intervention: 25 patients to receive calcium polycarbophil 625mg po TID before each meal with 8 oz glass of water for 6 months.

Placebo control: 25 patients to receive placebo po TID before each meal with 8 oz glass of water for 6 months.

Total of 50 participants projected from the following power calculation:

Assuming a difference between groups in HbA1c of 0.5%, a standard deviation of 0.5, a power of 80% and an alpha of 0.05, an estimated 18 patients in each group (n = 36 pts) will be needed to detect a difference. Assuming a 25% dropout rate, the goal of 25 patients in each group (n=50 pts) will be needed.

Patients, primary physicians, and the researchers will be blinded to therapy versus placebo. Randomization will be performed by the ECU FM pharmacist who will open a sealed envelope which will indicate whether the patient will receive the interventional medication or placebo. The tablets will be dispensed by the pharmacist without informing the patient, physicians, or research team member as to which group the patient was randomized.

All patient will continue with their usual DM care. The patients must follow up at 3 months and 6 months.

A research team member will perform telephone follow up at 1 week, 1 month, and 3 months for adverse events and compliance.

The outcomes will be analyzed by intention to treat analysis and analysis using patients who are compliant with the trial protocol.

Primary outcome:

HgbA1c at the time of enrollment, 3 months, and 6 months.

Secondary outcome:

Data will be gathered at the time of enrollment, 3 months, and 6 months:

Weight Blood Pressure Number and dosage of medications for diabetes, hypertension, and hyperlipidemia Serum LDL, HDL, triglycerides, total cholesterol Patient compliance with the study medication Adverse events including GI discomfort, constipation, excessive flatulence, fecal impaction, diarrhea, nausea, vomiting, hypoglycemia, etc.

Potential adverse events:

Side effects of Polycarbophil (MicroMedex 2.0): Abdominal fullness, flatus, vomiting, stomach cramps. Systemic adverse effects are not expected since calcium polycarbophil is not absorbed