Sampling bias and Laparoscopic Cholecystectomy

Keyhole surgery to remove the gallbladder is called laproscopic cholecystectomy.

Whilst waiting for my gallbladder to be removed, I did the usual online research I would do for any medical procedure. Checking at reputable sites like the NHS, NIH, and found some very practical advice at the Royal College of Surgeons. YouTube also had some good background on what a gallbladder is posted by tomiwa007 interspersed with some more graphic videos of the procedure itself (best avoided unless you want to be a surgeon), and a load of junk videos including self proclaimed “natural” cure providers.

One aspect of the research which was a little disconcerting was the comments I found online by other people who’d had the procedure. They were overwhelmingly negative. The NHS site above is a fairly typical example. One or two people saying “I wish I’d had it done years ago” and dozens saying “I got terrible diarrhea”, or who got other complications of surgery, or who had long lasting pain following the procedure.

Now it is inevitable for any such procedure that those who had issues subsequently are much more likely to visit such sites (for help and advice), and thus much more likely to comment. However for gallbladder removal thereĀ  seemed a rather extreme trend to the negative.

This prompted me to ask the people I knew personally who’d had their gall bladders removed what the experience was like, all four of whom told me they were happy with the results of the procedure, one told me in no uncertain terms to get it done ASAP.

Now both groups have sampling problems. The online comments self select for bad outcomes. My friends are self selected for good outcomes (at least regarding mortality, none have died in such surgery, but obviously I couldn’t befriend ones who might have). My friends also have a bias towards people who share my lifestyle, and in one case my thyroid condition (which may be a good thing).

However the results of changing my sampling method are that a roughly 10 to 1 result against the procedure becomes a 4 to 0 result in favour.

Currently at day 10 without a gallbladder and so far everything is fine, and whilst the sites where they went in were a little sore, nothing as painful as biliary colic. Going into work 4 days after surgery was too early, but by day 5 I was fine with a busy day.

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