Summary measures of number needed to treat: how much clinical guidance do they provide in neuropathic pain?
BACKGROUND
Several systematic reviews of randomized controlled trials (RCTs) of drugs to treat neuropathic pain have reported summary estimates of efficacy - specifically, the number needed to treat (NNT).


OBJECTIVE
To examine whether summary NNTs for drugs to treat neuropathic pain provide useful guidance for clinical decision making.


METHODS
We examined the methods used to pool data across RCTs in systematic reviews - in particular, the extent of heterogeneity of agents (and dosages), neuropathic pain syndromes, and outcome measures.


RESULTS
Published summary estimates of NNTs of drugs to treat neuropathic pain embody substantial heterogeneity, in that they reflect a pooling of data across agents with different mechanisms of action, across patients with different neuropathic pain syndromes, and/or across different outcome measures.


CONCLUSIONS
Summary NNT estimates may have limited clinical relevance, due to problems of heterogeneity. The most that can be extracted from systematic reviews published to date is the identity of drugs that have demonstrated efficacy for specific types of neuropathic pain, and the strength of such evidence.
Edelsberg
John
J
Policy Analysis Inc., Four Davis Court, Brookline, MA 02445, USA.
Oster
Gerry
G
D000700:Analgesics / Q000627:therapeutic use; D000818:Animals; D017408:Guidelines as Topic; D006801:Humans; D010146:Pain / Q000188:drug therapy / Q000209:etiology*; D059408:Pain Management; D010523:Peripheral Nervous System Diseases / Q000150:complications* / Q000628:therapy*; D016032:Randomized Controlled Trials as Topic
D000700:Analgesics