I’m not a statistician by any means, but I will say an example from High Yield Biostatistics by Dr. Glaser really caught my attention. This stuff is pretty confusing, so I’m going to simplify his numbers a bit further.

There was a study called WOSCOPS that treated obese men with statins. WOSCOPS was a huge study, involving 6,000 men for 5 years. 3,000 of them were given the statin, and 3,000 were given placebo.

Over the course of the study, about 75 men in the placebo group died from heart attacks, while only 50 died in the statin group. We calculate the mortality rates for each group as 50/3000 = 1.6%, and 75/3000 = 2.5%.

Calculating the relative risk reduction is easy:
1 - (risk in the population of interest / risk in the population as a whole)
1 - (1.6%/2.5%) = 33%
Therefore, the WOSCOPS study reported an incredible 33% reduction in cardiovascular mortality from statins. Amazing! Cardiologists everywhere rushed to put their patients on statins, right?

Not so fast.

The absolute risk reduction is calculated by subtracting the 2 percentages. 2.5% - 1.6% = 0.6%. We then calculate the number needed to treat as 1/ARR. This comes out to 166… which means we would have to give 166 men statins for 5 years to prevent one of them dying from a heart attack. This reflects the fact that the heart attacks happened at a relatively low frequency in the study.

Multiply 166 people x $100 a month (the cost of the statin) x 60 months in the study… and you get roughly $1,000,000.

It costs $1,000,000 to buy enough statins to save one life over a five year period. This is why healthcare costs so damn much.

Sorry for the absence†, I’ve been a bit more stressed out than usual. A few quick things:

General Antibiotics for the USMLE Step I

Bacteria
(Almost) Any Gram +: Penicillin
Respiratory Problems: Erythromycin
Big 3 Meningitis(es): 3G Ceph
Diarrhea: Fluoroquinolones
Zoonoses: Tet/Doxycycline
G.E.T. & anaerobes: Metronidazole
Random stuff: TMP/SMX

Parasites
___Worms: Mebendazole / Pyrantel Pamoate (round, hook, whip, pin)
Tapeworm: Albendazole (for cyst form only)
Flukes: Praziquantel
Filiariae: Diethylcarbamazine

A few notes:
Penicillin for community acquired pneumococcus (gram+), 3G Ceph if nosocomial.
TMP/SMX is a random catch-all, including Nocardia (Gram+ but acts like a fungus).
Doxycycline can be used in renal patients, unlike Tetracycline.
1G Cephalosporins are often used pre-op in a surgery suite.
Ampicillin is most often used as prophylaxis before dental work in RHD.
Diethylcarbamazine works for Onchocerca too, but it itches like the dickens. Preferred Tx is ivermectin.

HLA Subtype mnemonics††

Goodpas2ures (DR2)
H3mochromatosis (A3)
Di4b3tes (DR3, DR4)
Ha5himoto’s (DR5)
Steroid Responsive Nephrotic S7ndrome (DR7)
Gr8ves (B8)

Random side note: Type I diabetes is twice as likely to develop in infants who were not breastfed.

† treat with ethosuximide.
†† by the way, I apologize profusely to those of you readers who AREN’T taking the boards in a week. I’m sure this stuff is pretty obnoxious. It’ll get more fun REAL soon, I promise. I start wards in June.

Interesting Fact #1

People suffering from Celiac Sprue used to be barred from the Catholic priesthood. Don’t believe me? A priest taking communion is an integral part of Catholic mass - not only for their own salvation but for that of the congregation.

Unfortunately, since the communion wafer must be made from wheat (according to Roman Catholic doctrine), and there is no leeway for use of rice wafers, the Congregation barred people suffering from Celiac sprue from the priesthood, as they could not complete the sacrament. Luckily, through the miracles† of modern science, a new ultra-low-gluten wafer is available and the ban on Celiac Priests is lifted.

Interesting Fact #2

Ever wondered where the name Maalox came from? The most common antacids are made from Magnesium, Aluminum, or Calcium. Maalox is a combination of Magnesium Hydroxide and Aluminum HydrOxide. MaAlOx.

For all you USMLE studiers out there, this combination allows for regular bowel habits by combining the diarrhea-producing Magnesium antacids with the constipating Aluminum ones.

†irony?

A few fracture types:

Greenstick Fracture: Similar in appearance to a green twig that has broken only halfway through and then splayed out. More common in kids.
Chalkstick Fracture: Looks like a piece of chalk snapped clean in half. More common in Paget’s Disease of the bone.

Sorry it’s short… I’m exhausted!

We were studying SBS today at our local pizza place, and the waitress figured that we needed a break from studying. After making sure that we wouldn’t be offended, she told us the following joke:

What’s the difference between Jesus and a pictures of Jesus?
Only takes one nail to hang a picture.

Most interesting thing I learned all day.