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Negatives can be positive
- John H. Lange (2 August 2003)
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Negative Feedback - Statins
- Arnold J Jenkins (5 September 2003)
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John H. Lange, Environmental and Occupational Consultant Envirosafe Training and Consultants, P.O. Box 114022, Pittsburgh, PA 15239
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Abbasi (1) suggests that many editors do not want to publish negative results. This is true. Most consider more glory and delight in reporting the positive results and letting a lack of findings (negative results) pass by. However, negative findings may be the most important and in some cases be the positive. For example, most epidemiologists report only on the positive findings, yet the lack or absence of disease or event may be of the greatest importance, which is the negative. For example, the hygiene hypothesis in children (2) suggest a lower “rate of respiratory” disease in those growing up in certain environments. This also true for the occupational hygiene hypothesis which reports (3,4) lower than expected rates of lung cancer in those exposed to endotoxin (organic) containing dust. It is suggested that there are numerous other benefits of the negative, like occupational exposure at low doses resulting in this example a reduction of disease, but are envisioned by only a few. Let us not forget the importance of negative findings in general. They permit others’ not to experience the same negative again and allow us to look beyond for gains from the negative. In every dark lining there is a silver cloud. References 1. Abbasi K. the positive in negative. BMJ 2003; 327: (August 2). 2. Liu AH, Murphy JR. Hygiene hypothesis: fact or fiction? J Allergy Clin Immunol 2003; 111: 471-8. 3. Lange JH, Rylander R, Fedeli U, Mastrangelo G. Extension of the "hygiene hypothesis" to the association of occupational endotoxin exposure with lower lung cancer risk. J Allergy Clin Immunol 2003; 112: 219-220 4. Enterline PE, Keleti G, Sykora JL, Lange JH. Endotoxin, cotton dust and cancer. Lancet. 1985; 2: 934-935. Competing interests: None declared |
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Arnold J Jenkins, Principal in General Practice Colne Road Surgery, Colne Road, Burnley BB10 1LG
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EDITOR – I applaud your Editor’s choice ‘The positive in negatives”(1), the benefits of publishing negative findings should be obvious. As a general practitioner I wonder how many £millions the NHS could save if the Medical Research Council, the British Heart Foundation and the Lancet shared your view. An example is in the prescribing of statins, as they are a major cost in my practice, as I am sure they are to many practitioners. Even in general practice I recognised the Scandinavian Simvastatin Survival Study(2) as a seminal paper in the benefits of statins, and as we used to be taught to evaluate evidence (as opposed to stick to protocols), I read it. I was surprised to learn that more women died in the treated group than in the control group. On discussion with cardiological colleagues I was assured that as the numbers were small it was a statistical anomaly, resolvable by larger studies. Imagine my delight when I heard of the large MRC/BHF Heart Protection Study(3) showing clear benefits in the use of statins for women. On reading this study I was therefore disappointed to find the total mortality data for women – missing! I now understand that the total mortality benefit for women was not statistically significant and therefore was not published(4). I do not understand why the censors of this paper do not realise two things. One, any meta analyses based on this study are likely to be skewed. Two, in such long term studies total mortality, not improvement in the condition, should be the ‘gold standard’ for evaluation (eg euthanasia provides 100% cure of headache, but should be ruled out on the mortality data). I have yet to find a paper showing a statistically significant reduction in female mortality, for statin treated groups. It would therefore appear that any benefit, if found, will be minimal. Yet we are almost compelled by protocols such as the National Service Framework for Coronary Heart Disease (Chapter Two, Page Five) and local prescribing incentives to prescribe for this sub-group. Also the ‘Supporting Documentation to the New General Medical Services Contract’ (NHS Confederation / BMA – 2003) indicates that such statin prescribing may become a ‘Quality indicator’! (Quality and outcomes framework – CHD 8.1). I wonder whether the money could be better spent or we should abandon the little evidence based medicine we currently have? Arnold J. Jenkins Competing interests - none (1) Abbassi K. Editor’s Choice ‘The Positive in Negatives’ BMJ 2003; 327: prologue (Aug 2nd) (2) Scandinavian Simvastatin Survival Study Group. Randomised trial of cholesterol lowering in 4,444 patients with coronary heart disease: the Scandinavian simvastatin survival study (4S). Lancet 1994; 344: 1383-1389 (3) Heart Protection Study Collaborative Group. MRC/BHF heart protection study of cholesterol lowering in 20,536 high-risk individuals: a randomised placebo-controlled trial. Lancet 2002; 360: 7-22. (4) Personal E-mail from ‘hps@ctsu.ox.ac.uk’ (ref (3)) - 12 Sep 2002 Competing interests: None declared |
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