Arch Intern Med 12 Feb 2007

Is pot smoking good for the lungs? Why no, it isn’t, not least because in order to smoke cannabis you also inhale the smoke of burning tobacco and Rizla paper. Here is a systematic review of what is known about the short- and long-term effects of marijuana on the lung. In the short term, it’s actually a bronchodilator: in the long term, it makes you cough and wheeze.

I’m generally impressed with the patience displayed by patients who take warfarin: every morning my computer brings up a whole list of INR results which are in the target range. Perhaps the credit should go to our local anticoagulation nurse, because the American IN-RANGE study found that the majority of patients were forgetting lots of doses. And this does affect outcomes, as you’d expect – the next paper reports on the international SPORTIF III/IV trials and shows that INR control in patients taking warfarin for atrial fibrillation is directly associated with death, MI and stroke.

We know that urine is meant to be sterile, but what if it grows E coli in an asymptomatic woman? Had we better get rid of the bug to prevent long-term kidney damage? This long-term population study from the Netherlands (actually two studies, fully analysed forwards and backwards) is very reassuring: there is no evidence of a link between asymptomatic bacteriuria in women and long-term renal failure.

Whisper it softly, but we tend to bypass clinical prediction rules in general practice. For something like gastrointestinal bleeding, we tend to pass the patient straight on and let someone else do the worrying. That usually means endoscopy of course, but here is a paper which validates a risk score that identifies a group of low-risk patients whom it is safe not to endoscope immediately. The bad news is that they are only 10% of the group.

We have entered the age of biochemical cardiology, but we don’t quite know what to do about it. I have said my piece on BNP and “heart failure