We are currently updating our website, and will have our new version online soon. Please check back later this fall.

Mailing List

Subscribe to the KT Canada mailing list

Login

Welcome

Signup

Once you have signed up, you will receive a confirmation email with your username and password. To activate your account, follow the instructions in the email.

 

Centre for Evidence-
Based Medicine

Example NNTs - Neurology

Condition or Disorder Intervention vs. Control Outcome Follow-up Duration Event Rates % NNT (95% CI)
CER EER
Alcohol-related seizures1 Lorazepam vs. placebo Occurrence of a second seizure 6 hours 24 3 5 (4 to 9)
Care for acute stroke victims2 Patients were allocated to a Stroke unit or to Ward care Proportion of patients living at home 5 years 18.2 34.5 6 (4 to 21)
Migraine headaches3 Riboflavin vs. placebo Frequency of headaches 3 months 19 54 3 (2 to 11)
Headache days 15 57 3 (2 to 6)
Acute stroke unit care4 Stroke unit vs. general ward care Quality of life measured by the Frenchay Activity index ≥ 30 points 5 years 40.6 5 (2 to 80)
Non-disabling stroke; carotid endarterectomy5 Carotid endarterectomy vs. medical care Ipsolateral stroke 5 years 18.7 13.1 18 (10 to 186)
Any stroke 26.4 19.8 15 (8 to 100)
Stroke or death 36.4 27.9 12 (7 to 44)
Disabling stroke or death 20.1 14.9 19 (10 to 783)
Multiple sclerosis attacks6 Methylpredni-solone vs. placebo ≥ 1 point improvement on Kurtzke Expanded Disability Status Scale 1 year 22 50 4 (2 to 105)
Secondary progressive multiple sclerosis7 Interferon-b1b vs. placebo Progression 33 months 49.7 39.1 9 (6 to 30)
Acute Stroke8 Intra-arterial recombinant prourokinase plus intravenous heparin vs. intravenous heparin alone Proportion of patients with a modified Rankin score ≤ 2 90 days 25 40 7 (3 to 268)
Episodic cluster headache9 Verapamil vs. placebo Non-response (= having ≤ 50% reduction in cluster headache attack frequency) 2 weeks 100 20 1 (1 to 2)
Multiple sclerosis (MS)10 Interferon β-1a vs. placebo Mean change in scores on the Liebowitz Social Anxiety Scale and the proportion of responders on the Clinical Global Impression Scale 12 weeks 32 66 4 (3 to 5)

References

  1. N Engl J Med 1999 Mar 25;340(12):915-9
  2. Stroke 1997 Oct;28(10):1861-6
  3. Neurology 1998 Feb;50(2):466-70
  4. Stroke 1998 May;29(5):895-9
  5. N Engl J Med 1998 Nov 12;339(20):1415-25
  6. Neurology 1998 Aug;51(2):529-34
  7. BMJ 1998 Jul 25;317(7153):235-40
  8. JAMA. Dec1, 1999; 282: 2003-11
  9. Neurology. Mar 2000; 54: 1382-5
  10. N Engl J Med. Sept 28, 2000; 343: 898-904