The P Value And Its Significance
When diversifying an investment portfolio, one needs to consider investing in the healthcare industries. Pharmaceutical companies that have strong pipelines of investigation drugs have strong growth speculations. In addition to examining its pipelines, one also needs to be able to evaluate the results of its clinical trials. When a news program reports the results of a clinical trial for a new drug to be "statistically significant," what does it mean? And how did they come up with that conclusion? One of the most important values to look for when interpreting the results of a study is the P value. Elenbaas et al defines P value as "the probability that a type I error has been committed, and that the null hypothesis has been falsely rejected." Let's briefly talk about the null hypothesis, type I error, and type II error. Lets say a new drug A is being compared to a currently available drug B. The first assumption that investigators will make is that the new drug A is equivalent or is equal in efficacy to the currently available drug B. This assumption is called the null hypothesis (H0). A contradicting assumption to the null hypothesis is the alternative hypothesis (H1). H1 says that the new drug A is more effective than the currently available drug B. In fact, the alternative hypothesis (H1) is what the investigators want to prove because the pharmaceutical companies developing the new drugs fund most of its clinical trials. Type I error occurs when H0 is rejected when it is really true. In other words, investigators believe that the new drug A is more effective than the currently available drug B (rejecting H0), when drug A is equal in efficacy to drug B, or worst, not as effective as drug B. Type II error occurs when H1 is actually true (drug A is more effective than drug B), but the investigators failed to reject H0 (did not reject the hypothesis that drug A is equal in efficacy as drug B). With the technical terminologies defined, lets go back to the P value. To reiterate, P value is "the probability that a type I error has been committed, and that the null hypothesis has been falsely rejected." (Elenbass et al). The P value is said to be "statistically significant" when it is < 0.05. For example, a clinical trial comparing the effectiveness between drug A and drug B, found that drug A worked better at lowering the blood pressure than drug B, and the P value was calculated to be 0.04. This means that there is a 4% chance that a type I error is being committed (investigators falsely believe that drug A is more effective than drug B, when they are equal in efficacy). 0.05 is the largest acceptable P value in clinical literature. When investigators claim that drug A is more effective than drug B, they were correct 95% of the time, with only less than 5% chance error. There are many other important statistical values, but they are beyond the scope of this article. Now, whenever a reporter on television reports the results of a clinical trial for a new drug to be "statistically significant," one can perform their own verification by obtaining a copy of that study and look for the P value. References: 1. Elenbaas RM, Elenbass JK, and Cuddy PG, et al. Evaluating the medical literature part II: statistical analysis. Annals of Emergency Medicine. October 1983;12(10):35-45. 2. Anderson HG, Kendrach MG, and Trice S, et al. Understanding statistical and clinical significance: hypothesis testing. Journal of pharmacy practice. June 1998;11(3):181-195. http://www.onlinefreedomwork.com
Related News
|
 |
|
|
RELATED ARTICLES
The Ease of Using a Motorized Wheelchair to Improve Mobility
No person likes to feel housebound and dependent on others. While people who have been injured or suffering from a debilitating disease may not have full functionality of their motor skills, it is still possible for them to be semi-independent and mobile with motorized wheelchairs and other home medical equipment. It can't be over emphasized how critical that sense of independence can be. Quality, dependable Motorized Wheelchairs and other home medical equipment are the means of transportation that many people choose as their way to get around.
How To Medically Treat Nail Fungus
Warning: This article is for information only and can not be used to supplement your doctor's advice. You should contact your doctor for nail fungus treatment.
After Viagra, Its Now a Premature Orgasm Pill for Women
Pfizer's exciting drug history traces back to the most popular Viagra drug, which treats erectile dysfunction in men. Now, they are gearing up to hit the bull's eye with a new premature orgasm pill for women.
How Distressing is Social Phobia?
I remember a friend in college who would blush, sweat, and tremble when required by a teacher to speak in class. A few weeks before the presentation, he'd be anxious, agitated, and couldn't sleep. Because I was still a student then, I didn't have any clue what he was going through. But I knew that something was terribly wrong.
Low Blood Pressure ? Why is Your Blood Pressure Low?
Why is your blood pressure low?
Food for Thought
Depression is a disorder marked by sadness, low energy, impaired concentration, and feelings of dejection. Some people believe that depression is normal. Hectic daily activities and the conflict between family and career cause constant stress. Yet depression and anxiety as a response to stress are not normal. They can be signs of illness, which may worsen and result in physical symptoms or an inability to function.
Lipitor Lawyer: Statin Drugs Cause Muscle Damage in 98%
Doctors have been encouraged to prescribe the cholesterol-lowering drugs called statins quite liberally. Patients who suffer heart attacks often have elevated levels of cholesterol, so statins like Lipitor are prescribed to lower the cholesterol. There have been no conclusive studies to prove the full effectiveness of these drugs, however, and some doctors worry that reducing cholesterol simply takes away the warning signs of heart disease. The drug companies also claim that statin drugs have a low, nearly nonexistent incidence of side effects. These claims are based on trials of the drug on a carefully screened group of people, hardly a representative selection of the general public. Considering the rigorous selection process for drug trials, it is hardly a surprise that 51% of prescription drugs found to have serious adverse side effects not detected prior to FDA approval.
Antibiotics and Bowel Flora
The word Antibiotic is constructed from Greek words anti, which means "against" and bios, meaning "life", is a phrase used to describe an antibacterial substance made from micro-organisms, all though nowadays most are made synthetically. Antibiotics inhibit the growth or destroy other micro-organisms; penicillin, cephalosporin, amino-glycosides, streptomycin and tetracycline are all examples of common antibiotics. Penicillin is the largest group of antibiotics to be used in modern clinical medicine. Misuse and overuse of antibiotics has caused a lot of bacteria to become immune to them. This is why nowadays many hospitals are having problems in combating strains of bacteria such as methicillin-resistant staphylococcus aureus, other wise known as MRSA.
Is the Mexican Pharmacy safe to buy drugs online?
Are you frustrated with the high prices of prescription drugs? Take a look at a Mexican Pharmacy. Not only can you save a lot of money but you can also be sure that you are getting quality medicines and online customer service that provides you all the necessary information on drugs. Whether you are looking for prescription medication or herbal products Mexican Pharmacy is your souce for your purchasing medicines.These are all claims that are associated with Mexican pharmacies catering today. But there are some risks involve in it too, which cannot be totally ignored. Awareness is one sure step towards better informed consumer for health care products.
Army Report Validates Prediction of Vaccine-Induced Epidemic
"The more we do to you, the less you seem to believe we are doing it." - Joseph Mengele
Another Cold Sore! Why Me?
An estimated 85 million Americans have acquired the herpes
simplex (cold sore) virus. And the majority had received the
virus before the age of 3.
Lamictal Rash Lawyer
Lamictal, or lamotrigine, is an anti-seizure medication that has been prescribed to treat epileptic seizures for about 10 years. In addition to its mood stabilizing effects, Lamictal has antidepressant effects as well that have been prescribed for bipolar or manic depressive patients. Some researchers have suggested that Lamictal be the first-prescribed medication for bipolar patients suffering from more depressed versions of the disorder. Often antidepressants prescribed for bipolar disorder will trigger manic phases, increasing the rate of unhealthy mood swings, but Lamictal does not appear to have this same effect.
Chronic Head, Facial, Or Neck Pain That Won?t Go Away - Could It Be TMJ?
I stumbled across TMJ when I needed treat a literal pain in the neck that would not go away. It seemed that the pain in my neck came from my jaws. "TMJ" refers to disorders of the jaw muscles and of the temporomandibular joint, the hinge at the side of the head that joins the lower jaw, mandible, to the temporal bone of the skull. TMJ expert John Taddey, D.D.S. states that one the most common symptoms of TMJ is a dull, aching pain around the ears which can radiate to the neck, shoulders, and back of the head. These symptoms may be coupled with tenderness of the jaw muscles and a headache.
Stevens Johnson Syndrome Lawyer Says: Get Help
SJS is an allergic reaction to certain medications that can result in death. It has been linked to pain killers, antibiotics, barbiturates, anti-convulsants, non-steroid anti-inflammatory drugs, arthritis medications, and sulfa antibiotics such as Bextra, Arava, Aventis, Remicade, Allopurinol, Phenytoin, Carbamazepine, Ibuprofen, Daypro, children's Motrin, Advil, Lamectal and Topamax. Stevens Johnson Syndrome reactions include inflammation of mucosal membranes (mouth, throat, eyes, genital tract, intestinal tract), skin burning, lesions, blisters and bleeding which can lead to infections, burning and soughing off of sheets of cells in the lungs, permanent blindness, dry eyes, photophobia, chronic obstructive pulmonary disease, asthma, permanent loss of nail beds, scarring of the mucosal membranes, arthritis, and chronic fatigue syndrome.
Drug Them and Send Them Out
It was around 1986, when my son Lewis was diagnosed of having ADHD. I like using the term "accused" of having ADHD. I really disagree with anyone who goes this route to get the child to learn. Most of the time it's the teachers of our children that does the diagnosing. Is this sane? Should we trust their opinion.
5 Risks to Avoid When Purchasing Discount Medicines Online
With the increasing price of prescription medications, many consumers are finding it more difficult to afford the price of prescriptions. Due to this, a large number of such consumers are looking for alternate ways to find affordable medications. One of theses avenues is purchasing medicines online. While there is no doubt that it is possible to save a good bit of money by purchasing medicines online, consumers should be aware of all the facts; including risks, before proceeding.
Redux Lawyer Discusses Fen-Phen Fad
In the early nineties, Redux was the original miracle diet pill. A predecessor to fenphen, Redux was just the "fen", fenfluramine in the form dexfenfluramine. The drug increased the production of seratonin, which gave the brain feelings of satiety, or fullness. Overweight people felt a great responsibility lifted from their shoulders. In Redux, the drug industry promised a thin, healthy body without painful exercise or unpleasant diet restrictions! Within three months, doctors were writing 85,000 prescriptions for Redux every week.
Bextra and Vioxx Withdrawal Spurs Price Increase Among Rivals
The market for painkillers is huge. People don't like pain and inflammation, and last year Americans spent nearly $4 billion on just two of them ? Vioxx and Bextra. Those two drugs, part of a family of non-steroidal anti-inflammatory drugs known as COX-2 inhibitors, were withdrawn from the market recently amid concerns that they can cause heart attacks and strokes. The loss of these two drugs to the marketplace is huge, as they were the two largest sellers in a fairly narrow field. COX-2 inhibitors differ from traditional non-steroidal anti-inflammatory drugs in that they inhibit production of the COX-2 enzyme that causes inflammation but do not interfere with COX-1, the enzyme that protects the stomach lining. Patients who use these drugs are thought to suffer less from internal discomfort and bleeding than those who took traditional anti-inflammatories, such as naproxen and ibuprofen.
The Pharmaceutical Drug Cartel and the FDA
According to the Los Angeles Times, the California Association of Physicians and Surgeons, and even the Center for Diseases Control's own admission, well over 100,000 people in this country die each year from "properly" administered prescription drugs. This is absolutely shocking!
Patient Communication: Picking Up Where Medicine Leaves Off
We've all seen patients who were far beyond the reach of medical treatment suddenly defy the odds and recover. We've also seen patients who were well on the road to recovery, take a turn for the worse for seemingly no reason at all. No matter what the technology or how terrific we are at our jobs, sometimes medicine just isn't enough.
|
