‘Cure’ as the gold standard for likelihood ratio assessment: theoretical considerations

Abstract

A gold standard is necessary to assess the validity of homeopathic symptoms. The gold standard is ‘cure’, but this is difficult to define, and depends on consensus. The likelihood ratio (LR) method will give valid results only if the gold standard is reliable. False positives (patients incorrectly classified as cured) weaken results of LR investigation. Weakening the standard to enlarge the research population will seriously bias the results. The same gold standard should be used in LR assessment of all symptoms.

Keywords

likelihood ratio - Bayesian analysis - gold standard - cure - consensus

• References

• 1 Stolper CF, Rutten ALB, Lugten RF, Barthels RJ. Improving homeopathic prescribing by applying epidemiological techniques: the role of likelihood ratio. Homeopathy 2002; 91: 230–238.
• 2 Riber C, Tonnesen H, Aru A, Bjerregaard B. Observer variation in the assessment of the histopathologic diagnosis of acute appendicitis. Scand J Gastroenterol 1999; 34: 46–49.
• 3 Ozge A, Bugdayci R, Sasmaz T, et al. The sensitivity and specificity of the case definition criteria in diagnosis of headache: a school-based epidemiological study of 5562 children in Mersin. Cephalalgia 2003; 23: 138–145.
• 4 Castaneda R, Lechuga D, Ramos RI, Magos C, Orozco M, Martinez H. Endemic goiter in pregnant women: utility of the simplified classification of thyroid size by palpation and urinary iodine as screening tests. Br J Obstet Gynaecol 2002; 109: 1366–1372.
• 5 Herren KR, Mackway-Jones K, Richards CR, Seneviratne CJ, France MW, Cotter L. Is it possible to exclude a diagnosis of myocardial damage within six hours of admission to an emergency department? Diagnostic cohort study. BMJ 2001; 323: 372.
• 6 Buntinx F, Truyen J, Embrechts P, Moreel G, Peeters R. Chest pain: an evaluation of the initial diagnosis made by 25 Flemish general practitioners. Fam Pract 1991; 8: 121–124.
• 7 Bouter LM, Dongen MCJM van Bedreigingen van de interne validiteit. Epidemiologisch onderzoek; opzet en interpretatie. Houten/Diegem: Bohn Stafleu Van Loghum, 1995, pp 186–221.
• 8 Kent JT. Prognosis after observing the action of the remedy. Lectures on Homeopathic Philosophy, XXXV, Wellingborough, Northamptonshire: Thorsons Publishers Ltd., 1900, pp 224–234.
• 9 Swayne J. The response to the prescription. Homeopathic Method. New York: Churchill Livingstone, 1998, pp 169–185.
• 10 European Committee for Homeopathy. Data Collection in Homeopathic Practice: A Proposal for an International Standard, 1999.
• 11 ADHOM: Academic Departments of the Glasgow Homeopathic Hospital. The Development of the GHHOS, the IDCCIM Action Research & the PC-HICOM Project. Interim Report, February 2003.
• 12 Stolper CF, Kipp RP, Lugten RFG. A proposed consensus on evaluating a case: results of the VHAN conference. Homeopath Links 1998; 11: 51–53.
• 13 Rutten ALB, Stolper CF, Lugten RF, Barthels RJ. Assessing likelihood ratio of clinical symptoms: handling vagueness. Homeopathy 2003; 92: 182–186.
• 14 Payer L. Medicine & culture. Varieties of Treatment in the United States, England, West Germany and France, New York: Holt and Company, 1998.
• 15 Committee on Clinical Practice Guidelines IoM. Guidelines for Clinical Practice: From Development to Use. Washington DC: National Academic Press, 1992.
• 16 Weller SC, Mann NC. Assessing rater performance without a “gold standard” using consensus theory. Med Decision Making 1997; 17: 71–79.
• 17 Rutten ALB, Stolper CF, Lugten RF, Barthels RJ. Is assessment of likelihood ratio of homeopathic symptoms possible? A pilot study. Homeopathy 2003; 92: 213–216.
• 18 Rutten ALB, Stolper CF, Lugten RF, Barthels RJ. Repertory and likelihood ratio: time for structural changes. Homeopathy 2004, accepted for publication.