Wednesday, April 18, 2007
From the chronic pain world....
Annals of Internal Medicine just published a metaanalysis of randomized, controlled trials for chondroitin for osteoarthritis pain (22 trials, over 4000 patients, median dose of chondroitin 1000mg daily, median duration of treatment 25 weeks). Basically they found (surprise!) a lot of heterogeneity between the trials but when they looked at the better quality trials (the larger trials which had intention to treat analysis & good allocation concealment) therapy with chondroitin didn't seem to have much effect. They looked at their data in many ways, and it seems that chondroitin probably has a mild effect compared to placebo, but insofar as this effect diminishes with larger, better designed trials it seems highly probably that this effect is minimal and not anything one would advocate for their patients. Doesn't diminish traditional analgesic use, etc. It's a good example of how small trials can be misleading, particularly for agents that are of marginal benefit.
Anyway, none of this is very interesting. The metaanalysis is worth reading for other reasons: maybe it's been a while since I read a metaanalysis in Annals but this one was actually a treat to read. The authors describe in language, understandable to non-statisticians (something absent from many a metaanalysis), all the different analyses they did, why, why and how they did exploratory analyses, what they mean for interpreting this large body of heterogeneous data, what the research implications of all of this is, and came up with realistic clinical recommendations based on their findings (much more helpful than the annoying conclusion to many a Cochrane review 'there are insufficient data to support the use of X for Y'). I may not have learned much about chondroitin but did about metaanalyses.
The NEJM has a review on the management of adult fecal incontinence. It spends most of its time on fecal incontinence due to neurologic conditions (strokes, spinal cord injuries) and pelvic muscle weakness but also addresses overflow diarrhea in constipated patients and fecal incontinence from things like radiation proctitis. It's a problem which is thankfully rare in my practice, but devastating for the patient when it occurs; as well as something about which I've had very little training (other than overflow diarrhea).