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Table of NNTs
Condition Treatment Duration of treatment Comparator Outcome Odds Ratio NNT (95% CI) Reference
Acute otitis media Antibiotics short course no antibiotics or tympano-centesis Absence of presenting signs and symptoms at 7-14 days 2.9 (1.8 - 4.1) 7 [7]
acute sprains etc topical NSAID (good) 50% pain relief 2+
AIDS indinavir (triple therapy with nucleosides) 38 weeks dual therapy (nucleosides plus placebo) first clinical event (AIDS or death) 19 (12 to 50) Bandolier 44
Angina bisoprolol 8 weeks each therapy nifedipine complete cessation asymptomatic transient ischaemic episodes 2.7 (2.1 to 3.9) Bandolier 40
Angina bisoprolol 4 to 6 weeks placebo prevention exercise induced angina 2.8 (1.9 to 5.0) Bandolier 40
Angina isosorbide dinitrate 4 to 6 weeks placebo prevention exercise induced angina 5.0 (2.8 to 21) Bandolier 40
Anticipated preterm delivery Corticosteroids before delivery no treatment Risk of fetal RDS 11 (8 to 16)* [12]
Arthritis glucosamine 3 to 8 weeks placebo improved symptoms 5 (3.5 to 8.9) Bandolier 46
Asthma (childhood) nurse-led management training programme 4 weeks usual care readmission 6.1 (3.8 to 15) [29]
Asthma (childhood) budesonide and formoterol one year budesonide alone free of severe exacerbation for one year 11 (6.6 to 34) Bandolier 48
back pain epidural steroid 75% relief at 60 days 6
Childhood depression Antidepressants not stated placebo Improved 1.1 (0.5 - 2.2) not effective [9]
diabetic neuropathy anticonvulsants 50% pain relief 2.5
Dementia gingko one year placebo ADAS-Cog 4 points better 7.9 (4.2 t0 67) Bandolier 48
Dog bites Antibiotics short course placebo Infection 0.6 (0.4 - 0.8) 16 (9 to 92)* [13]
Erectile dysfunction alprostadil (transurethral) over 3 month period placebo erection enabling intercourse 2.3 (2.1 to 2.6) Bandolier 43
Esophageal variceal bleeding Endoscopic ligation intervention sclerotherapy Prevention of one re-bleeding episode 4 [6]
Flu vaccination no flu 23 11-5
Fungal nail infection Terbinafine 12/24 weeks griseofulvin Cured at 48 weeks 4.5 (2.3 - 8.8) 2.7 (1.9 to 4.5)* [4]
Gastric ulcer with NSAID - prevention misoprostol 4 weeks placebo presence of gastric ulcer 13 Bandolier 39
H pylori triple therapy eradication 1.1 36-3
Head lice Permethrin 14 days placebo Cure 1.1 (1.0 to 1.2)* [1]
Herpes zoster Acyclovir 5-10 days placebo Prevention of post herpetic neuralgia at 6 months 0.7 (0.5 - 1.1) not effective [17]
Hip fracture prevention calcium and vitamin D 3 years placebo prevent one fracture 20 (13-57) [27]
Homelessness critical time intervention 18 months usual services only homeless in 18th month 6.9 (3.5 to 284) Bandolier 45
Hypertension in the elderly Drug treatments at least 1 year no treatment Overall prevention of cardiovascular event over 5 years 18 (14 to 25) [14]
Lipid lowering
primary prevention various 5 years no treatment prevent one myocardial infarction or cerebrovascular death 69 (54 to 99) [28]
secondary prevention various 5 years no treatment prevent one myocardial infarction or cerebrovascular death 16 (13 to 19) [28]
primary prevention statins mean 4 years plus placebo all bad things 35 (24 to 63) Bandolier 47
secondary prevention statins mean 2.9 years placebo all bad things 11 (10 -13) Bandolier 47
Major GI bleeding and NSAID use Misoprostol 6 months placebo Prevent any GI complication 0.6 (0.4 - 0.85) 166 (97 to 578)* [16]
MI ACE inhibitor [AIRE trial] death within 6 months 18 11-1
Migraine Subcutaneous sumatriptan single dose placebo Headache relieved at 2 hours 2.0 (1.8 to 2.2)* [3]
Migraine Oral sumatriptan single dose placebo Headache relieved at 2 hours 2.6 (2.3 to 3.2)* [3]
Moderate or severe postoperative pain Paracetamol 1000 mg single dose placebo At least 50% pain relief 3.6 (3.0 to 4.4) [5]
Myocardial infarction Aspirin plus streptokinase 1 h i.v. infusion of streptokinase, 1 month of oral aspirin no treatment Five-week vascular mortality, prevent one death 20* [15]
Myocardial infarction and diabetes insulin (intensive schedule) three years usual care one year mortality 14 (7.3 to 164) Bandolier 48
neuropathic pain antidepressants 50% pain relief 2.5
Oesophagitis omeprazole 8 weeks ranitidine endoscopic healing rate 3.3 Bandolier 36
Oesophagitis omeprazole 1 year ranitidine maintenance of endoscopic healed erosive gastritis 2.8 Bandolier 36
Peptic ulcer Triple therapy 6-10 weeks histamine antagonist H pylori eradication 44 (34 - 56) 1.1 (1.08 to 1.15) [2]
Peptic ulcer Triple therapy 6-10 weeks histamine antagonist Ulcers remaining cured at one year 9.4 (6.3 - 14.0) 1.8 (1.6 to 2.1) [2]
Peptic ulcer Triple therapy 6-10 weeks histamine antagonist Ulcer healing at 6-10 weeks compared with histamine antagonist 5.0 (3.3 - 7.7) 4.9 (4.0 to 6.4) [2]
Peripheral artery disease Naftidrofuryl 3 or 6 months placebo Pain free walking distance improved by 50% (1 year) 1.5 (1.2 - 2.0) 10.3 (6.3 to 29)* [8]
Peripheral artery disease Naftidrofuryl 3 or 6 months placebo Preventing critical cardiac events (1 year) compared with placebo 0.6 (0.4 - 0.96) 24 (13 to 266)* [8]
Positive GP consultation Positive GP consultation 2 weeks negative consultation get better in 2 weeks 4 (3 to 9) Bandolier 42
postop pain good oral analgesic (ibuprofen 400 mg) 50% pain relief 2
postop pain bad oral analgesic (codeine 60 mg) 50% pain relief 18
Postoperative vomiting Droperidol single dose placebo Prevention over 48 hours in children undergoing squint correction 2.5 (1.7 - 3.6) 4.4 (3.1 to 7.1) [10]
Prostate - benign hypertrophy finasteride 2 years placebo prevent one operation 39 (23 to 111) Bandolier 46
Stroke primary prevention
MRC 17,354 individuals 36-64 years diastolic 90-109 mmHg benzoflurazide propranolol 5.5 years placebo Prevent one stroke at one year 850 [18]
SHEP 4736 individuals 60 years or older systolic 160-219 mmHg and diastolic <90 mmHg clorthalidone atenolol 4.5 years placebo Prevent one stroke at one year 43 (27 to 95) [19]
STOP 1627 individuals 70-84 years systolic 180-230 mmHg and diastolic ≥90 mmHg or diastolic 105-120 mmHg atenolol hydrochlorothiazide plus amiloride metoprolol pindolol 4 years placebo Prevent one stroke at one year 34 (20 to 123) [20]
MRC 4396 individuals 65-74 years systolic 160-209 mmHg diastolic <115 mmHg diuretic beta-blocker 5.8 years placebo 70 (36 to 997) [21]
WOSCOPS 6595 men 45-64 years cholesterol over 6.5 mmol/L privastatin 4.9 years placebo 641 (135 to no benefit) [22]
Stroke secondary prevention
CATS 1072 patients 1 week to 4 months after stroke ticlopidine 2 years placebo 15 (9 to 41) [23]
SALT 1360 patients 50-79 years TIA or minor stroke in previous 3 months low dose aspirin 2.7 years placebo 38 (16 to 85) [24]
4S 4444 patients35 - 70 years angina or MI cholesterol 5.5-8.0 mmol/L simvastatin 5.4 years placebo 65 (38 to 224) [25]
ESPS2 6602 patients >18 years TIA or stroke in previous 3 months aspirin

dipyridamole

aspirin plus dipyridamole

 2 years placebo 37 (20 to 319)

42 (21 to >1000)

8 (13 to 29)

 [26]
trigeminal neuralgia anticonvulsants 50% pain relief 2.5
Ulcerative colitis transdermal nicotine 4-6 weeks placebo symptom improvement 3.7 (2.4 to 8.4) Bandolier 39
Venous thrombo-embolism Graduated compression stockings not stated legs without stockings Episodes of venous thromboembolism 0.3 (0.2 - 0.4) 9 (7 to 13)* [11]
* calculated from data in report
1 Vander Stichele RH, Dezeure EM, Bogaert MG. Systematic review of clinical efficacy of topical treatments for head lice. British Medical Journal 1995; 311:604-8.
2 Moore RA. Helicobacter pylori and peptic ulcer. A systematic review of effectiveness and an overview of the economic benefits of implementing that which is known to be effective (http://www.ebandolier.com/bandopubs/hpyl/hpall.html).
3 Tfelt-Hansen P. Sumatriptan for the treatment of migraine attacks-a review of controlled clinical studies. Cephalalgia 1993; 13:238-44.
4 Haneke E, Tausch I, Bräutigam M, Weidinger G, Welzel D. Short-duration treatment of fingernail dermatophytosis: A randomized, double-blind study with terbinafine and griseofulvin. Journal of the American Academy of Dermatology 1995; 32:72-77.
5 Moore A, Collins S, Carroll D, McQuay H. Paracetamol with and without codeine in acute pain: a quantitative systematic review. Pain 1997; 70:193-201.
6 Laine L, Cook D. Endoscopic ligation compared with sclerotherapy for treatment of esophageal variceal bleeding. A meta-analysis. Annals of Internal Medicine 1995; 123:280-7.
7 Rosenfeld RM, Vertrees JE, Carr J, Cipolle RJ, Uden DL, Giebink GS et al. Clinical efficacy of antimicrobial drugs for acute otitis media: metaanalysis of 5400 children from thirty-three randomized controlled trials. Journal of Pediatrics 1994; 124:355-67
8 Lehert P, Comte S, Gamand S, Brown TM. Naftidrofuryl in intermittent claudication: a retrospective analysis. Journal of Cardiovascular Pharmacology 1994; 23 (Suppl3):S48-S52.
9 Hazell P, O'Connell D, Heathcote D, Robertson J, Henry D. Efficacy of tricyclic drugs in treating child and adolescent depression: a meta-analysis. British Medical Journal 1995; 310:897-901.
10 Tramer M, Moore A, McQuay H. Prevention of vomiting after paediatric strabismus surgery: a systematic review using the numbers-needed-to-treat method. British Journal of Anaesthesia 1995; 75:556-61.
11 Wells PS, Lensing AWA, Hirsh J. Graduated compression stockings in the prevention of postoperative venous thromboembolism. Archives Internal Medicine 1994; 154:67-72.
12 Crowley PA. Antenatal corticosteroid therapy: a meta-analysis of the randomized trials, 1972 to 1994. American Journal of Obstetrics & Gynecology 1995; 173:322-35.
13 Cummings P. Antibiotics to prevent infection in patients with dog bite wounds: a meta-analysis of randomized trials. Annals of Emergency Medicine 1994; 23:535-40.
14 Mulrow CD, Cornell JA, Herrera CR, Kadri A, Farnett L, Aguilar C. Hypertension in the elderly. Journal of the American Medical Association 1994; 272:1932-8.
15 Randomised trial of intravenous streptokinase, oral aspirin, both, or neither among 17,187 cases of suspected acute myocardial infarction: ISIS-2. ISIS-2 (Second International Study of Infarct Survival) Collaborative Group. Lancet 1988; 2:349-60.
16 Silverstein FE, Graham DY, Senior JR, Davies HW, Struthers BJ, Bittman RM et al. Misoprostol reduces serious gastrointestinal complications in patients with rheumatoid arthritis receiving nonsteroidal anti-inflammatory drugs. American College of Physician
17 Lancaster T, Silagy C, Gray S. Primary care management of acute herpes zoster: systematic review of evidence from randomized controlled trials. British Journal of General Practice 1995; 45:39-45.
18 MRC trial of treatment of mild hypertension: principal results. British Medical Journal 1985 291: 97-104.
19 Prevention of stroke by antihypertensive drug treatment in older persons with isolated systolic hypertension. Journal of the American Medical Association 1991 265: 3255-64.
20 B Dahlöf et al. Morbidity and mortality in the Swedish trial in old patients with hypertension (STOP-hypertension). Lancet 1991 338:1281-5.
21 MRC trial of treatment of hypertension in older adults: principal results. British Medical Journal 1992 304:405-12.
22 J Shepherd et al. Prevention of coronary heart disease with privastatin in men with hypercholesterolaemia. New England Journal of Medicine 1995 333:1301-7.
23 M Gent et al. The Canadian American ticlopidine study (CATS) in thromboembolic stroke. Lancet 1989 i: 1215-20.
24 Swedish aspirin low-dose trial (SALT) of 75 mg aspirin as secondary prophylaxis after cerebrovascular ischaemic events. Lancet 1991 338:1345-9.
25 Randomised trial of cholesterol lowering in 4444 patients with coronary heart disease: the Scandinavian simvastatin survival study (4S). Lancet 1994 344: 1383-9.
26 HC Diener et al. European stroke prevention study 2. Dipyridamole and acetylsalicylic acid in the secondary prevention of stroke. Journal of Neurological Sciences 1996 143: 1-13.
27 MC Chapuy, ME Arlot, F Debouef etc. Vitamin D3 and calcium to prevent hip fractures in elderly women. New England Journal of Medicine 1992 327: 1637-42.
28 CM Rembold. Number-needed-to-treat analysis of the prevention of myocardial infarction and death by antidyslipidemic therapy. Journal of Family Practice 1996 42: 577-86.
29 P Madge, J McColl, J Paton. Impact of a nurse-led home management training programme in children admitted to hospital with acute asthma: a randomised controlled study. Thorax 1997 52: 223-8.



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