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Centre for Evidence-
Based Medicine

Example NNTs - Respiratory

Condition or Disorder Intervention vs. Control Outcome Follow-up Duration Event Rates % NNT (95% CI)
CER EER
Acute asthma1 Budesonide vs. placebo Relapse 21 days 25 13 9 (5 to 179)
Chronic obstructive pulmonary disease (COPD)2 Glucocorticoids vs. placebo First treatment failure (death, need for intubation and mechanical ventilation, readmission for COPD, or intensification of drug therapy) 1 and 3 months 1 month: 33 1 month: 23 10 (5 to infinity)
3 months: 48 3 months: 37 9 (4 to infinity)
Children with asthma3 Structured discharge packages vs. usual discharge packages at the time of discharge Readmission to hospital 6 months 38 15 5 (3 to 12)
Smoking cessation; using a nicotine inhaler4 Nicotine inhalers vs. placebo Self reported abstinence from smoking (verified by laboratory measurements) 1 year 18 29 10 (5 to 483)
Smoking cessation rates5 Intensive intervention (which includes a 30 minute behavioral counseling session given by nurses, a videotape from the American Heart Association and an audiotape of relaxation exercises vs. usual care (which includes printed material and a list of partially subsidized outpatient cessation programs) Confirmed smoking cessation 12 months 20 27 16 (9 to 25)
asthma; effectiveness in treating inner city patients6 Educational program vs. conventional asthma care and routine follow-up Attendance at follow up appointments, subsequent ED visits and hospitalization 6 months 27 59 3 (2 to 11)
Asthma7 Asthma clinic vs. standard treatment group Owning a peak flow meter 6 months 56 73 6 (3 to 31)
Waking at night because of asthma 20 7.0 8 (4 to 29)
Acute-on-chronic obstructive pulmonary disease8 Standard treatment plus pressure supported ventilation through a face or nasal mask vs. standard treatment alone Need for intubation After discharge 27 15 9 (5 to 69)
Death 20 10 10 (6 to 98)
Acute respiratory distress syndrome9 Lower tidal volumes vs. traditional tidal volumes (control) Death 180 days 40 31 12 (7 to 41)
Pulmonary infiltrates10 Ciprofloxacin vs. control (physician-directed antibiotics) Mortality 30 days 31 13 Not significant
Resistance or superinfection 38 14 5 (3 to 22)

References

  1. JAMA. 9 Jun 1999; 281: 2119-26
  2. N Engl J Med. 24 Jun 1999; 340:1941-7
  3. Arch Dis Child. Feb 1999; 80: 110-4
  4. Arch Intern Med. 11/25 Aug 1997; 157: 1721-8
  5. Arch Intern Med. 24 Feb 1997; 157: 409-15
  6. Arch Intern Med. 9/23 Aug 1999; 159: 1710-6
  7. Med J Aust. Jul 19, 1999; 171: 68-71
  8. Lancet. Jun 3, 2000; 355: 1931-5
  9. N Engl J Med. May 4, 2000; 342: 1301-8
  10. Am J Respir Crit Care Med. Aug 2000; 162: 505-11