Asthma mistaken for chronic obstructive pulmonary disease

Asthma mistaken for chronic obstructive pulmonary disease

CORRESPONDENCE Most studies that detect risk factors in the perinatal period seem to belong to “cul-de-sac epidemiology”.3 Despite the publication of...

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CORRESPONDENCE

Most studies that detect risk factors in the perinatal period seem to belong to “cul-de-sac epidemiology”.3 Despite the publication of such research in authoritative medical or scientific journals, the findings are shunned by the medical community and the media. Such epidemiological studies are not replicated and are rarely quoted after publication. Cul-de-sac epidemiology is one of the reasons for the Primal Health Research Data Bank.4 This bank contains hundreds of references and abstracts of studies that explore correlations between what happens during the primal period (fetal life, perinatal period, and year after birth) and what will happen later on in life in terms of health and behaviour. Michel Odent Primal Health Research Centre, London NW3 2JR, UK (e-mail: [email protected]) 1 2

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Fairburn CG, Harrison PJ. Eating disorders. Lancet 2003; 361: 407–16. Cnattingius S, Hultman CM, Dahl M, Sparen P. Very preterm birth, birth trauma, and the risk of anorexia nervosa among girls. Arch Gen Psychiatry 1999; 56: 634–38. Odent M. Between circular and cul-de-sac epidemiology. Lancet 2000; 355: 1371. Birthworks Primal Health Research Data Bank. http://www.birthworks.org/ primalhealth (accessed March 6, 2003).

Sir—Christopher Fairburn and Paul Harrison1 do not mention diabetes mellitus among the risk factors for eating disorders. A multicentre casecontrol study2 showed that the prevalence of eating disorders was about twice as high among adolescent girls with type 1 diabetes as among agematched controls. Since deliberate insulin underdosing or omission is a common weight-loss strategy in diabetic women with eating disorders,3 and thus contributes to an increased risk of microvascular complications,4 the presence of a disordered eating behaviour should be carefully investigated in adolescent women with type 1 diabetes.5

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Authors’ reply Sir—In constructing our list of risk factors for eating disorders, we considered both perinatal factors and type 1 diabetes mellitus as potential candidates. Certain specific adverse perinatal events emerged as risk factors for anorexia nervosa in a welldesigned population-based study.1 We did not include this finding in our list since we decided to restrict it to associations that have been replicated. We were also concerned that the association might apply only to a particularly severe subgroup of cases, since the study was restricted to hospital inpatients. There have been several studies of type 1 diabetes mellitus as a possible risk factor for eating disorders. These studies have varied substantially in quality and their findings have been inconsistent. Of the four studies that used the optimum method for assessing eating disorders,2–5 just one found that there was an increase in risk.5 We therefore view the association as not proven. This is not to imply that the cooccurrence of diabetes mellitus and an eating disorder is not medically serious. *Christopher G Fairburn, Paul J Harrison Oxford University Department of Psychiatry, Warneford Hospital, Oxford OX3 7JX, UK (e-mail: [email protected])

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Francesca Pezzetta, *Luca Mascitelli Pronto Soccorso/Area d’Emergenza Ospedale San Michele, Gemona del Friuli, Italy (FP); and *Casa di Cura “Città di Udine”, 33100 Udine, Italy (LM) (e-mail: [email protected]) 1 2

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Fairburn CG, Harrison PJ. Eating disorders. Lancet 2003; 361: 407–16. Jones JM, Lawson ML, Daneman D, Olmsted MP, Rodin G. Eating disorders in adolescent females with and without type 1 diabetes: cross sectional study. BMJ 2000; 320: 1563–66. Rodin GM, Daneman D. Eating disorders and IDDM: a problematic association. Diabetes Care 1992; 15: 1402–12.

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Rydall AC, Rodin GM, Olmsted MP, Devenyi RG, Daneman D. Disordered eating behavior and microvascular complications in young women with insulin-dependent diabetes mellitus. N Engl J Med 1997; 336: 1849–54. Becker AE, Grinspoon SK, Klibanski A, Herzog DB. Eating disorders. N Engl J Med 1999; 340: 1092–98.

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Cnattingius S, Hultman CM, Dahl M, Sparen P. Very preterm birth, birth trauma, and the risk of anorexia nervosa among girls. Arch Gen Psychiatry 1999; 56: 634–38. Fairburn CG, Peveler RC, Davies B, Mann JI, Mayou RA. Eating disorders in young adults with insulin-dependent diabetes mellitus: a controlled study. BMJ 1991; 303: 17–20. Peveler RC, Fairburn CG, Boller I, Dunger D. Eating disorders in adolescents with insulin-dependent diabetes mellitus: a controlled study. Diabetes Care 1992; 15: 1356–60. Striegel-Moore RH, Nicholson TJ, Tamborlane WV. Prevalence of eating disorder symptoms in preadolescent and adolescent girls with IDDM. Diabetes Care 1992; 15: 1361–68. Jones JM, Lawson ML, Daneman D, Olmsted MP, Rodin G. Eating disorders in adolescent females with and without type 1 diabetes: cross sectional study. BMJ 2000; 320: 1563–66.

Asthma mistaken for chronic obstructive pulmonary disease Sir—A diagnosis of chronic obstructive pulmonary disease (COPD) is often made inappropriately when symptoms of asthma are mistakenly thought to be characteristic of COPD. In a preliminary survey of 52 junior physicians in the UK, I found much variation in use of the term COPD.1 I subsequently completed a survey of 300 junior physicians in a central hospital in Kathmandu, Nepal. I asked them to write down what diseases they would include for a diagnosis of COPD. Respondents had graduated from different countries, including Nepal, India, Bangladesh, Pakistan, China, and Russia. 112 (37·4%) respondents included chronic bronchitis and emphysema in a diagnosis of COPD. 106 (35·3%) of the physicians included chronic bronchitis, emphysema, and chronic asthma as characteristic of COPD. These diseases together with bronchiectasis and fibrosis were included in a diagnosis of COPD by 82 (27·3%) respondents. Thus, more than 60% of respondents included asthma as part of a diagnosis of COPD. Patients with asthma who are mistakenly diagnosed with COPD could be denied inhaled steroids. The underuse of inhaled steroids in asthmatic patients and overuse in patients with a diagnosis of COPD are well known. Jatulis and colleagues’ analysis2 of 6-month pharmacy claims for 5173 asthmatic patients in the USA showed that, on average, only 41·3% received inhaled steroids. Another study in the USA by Enright and co-workers3 showed that only 30% of patients aged 65 years or older who had definite asthma were taking inhaled steroids. Similarly, Sin and Tu’s Canadian study4 showed that 40% of patients with asthma aged 65 years or older who had had a recent acute exacerbation of asthma did not receive inhaled steroid therapy within 90 days of discharge from hospital. By contrast, Van Andel and colleagues5 found that of 3720 patients with fairly stable COPD with moderate to severe airway obstruction, up to 41·4% were using inhaled steroids. Overall, these reports show that there is some confusion among physicians about the term COPD, which simply indicates obstructive chronic bronchitis and emphysema. Use of the term COPD by physicians and prevalence of asthma among presumed COPD patients warrant further investigation. Madhur D Bhattarai Bir Hospital, Post Box 3245, Kathmandu, Nepal (e-mail: [email protected])

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For personal use. Only reproduce with permission from The Lancet Publishing Group.

CORRESPONDENCE

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Bhattarai MD. Why not call chronic obstructive pulmonary disease (COPD) simply obstructive bronchitis and emphysema (OCBE)? Proc R Coll Phys (Edinb) 2000; 30: 265. Jatulis DE, Meng Y, Elashoff RM. Preventive pharmacologic therapy among asthmatics: five years after publication of guidelines. Ann Allergy Asthma Immunol 1998; 81: 82–88. Enright PL, McClelland RL, Newman AB, Gottlieb DJ, Lebowitz MD, and for the Cardiovascular Health Study Research Group. Underdiagnosis and undertreatment of asthma in the elderly. Chest 1999; 116: 603–13. Sin DD, Tu JV. Underuse of inhaled steroid therapy in elderly patients with asthma. Chest 2001; 119: 720–25. Van Andel AE, Reisner C, Manjoge SS, Witek TJ. Analysis of inhaled corticosteroids and oral theophylline use among patients with stable COPD from 1987 to 1995. Chest 1999; 115: 703–07.

Hormonal contraception and cervical cancer Sir—The results of Jennifer Smith and colleagues’ meta-analysis (April 5, p 1159)1 reinforce reports of a positive correlation between duration of use of hormonal contraceptives and cervical neoplasia. However, despite the controls and limitations carefully detailed therein, the overview as presented does not exclude nonhormonal covariables as the proximate cause of this association. The human papillomavirus (HPV)dependent pathogenesis of cervical neoplasia implicates unprotected sexual exposure as a necessary contributing factor. At least 80% of unmarried women who use hormonal contraception choose not to use additional barrier prophylaxis.2 Hence, hormonal contraceptive use—rather than hormonal effects per se—might be associated with a higher aggregate temporal exposure of the cervix to HPV-infected male epithelia or secretions. Consistent with this suggestion, data from cohort studies have indicated a higher rate of incident HPV infection in individuals who use oral contraceptives.3 Moreover, since the induction of cervical cancer bears a strong quantitative relation to viral load,4 Smith and colleagues’ unexplained finding of a greater relative risk in cohort rather than in case-control studies is consistent with an inadvertent failure to select exposure-equivalent controls for the latter, notwithstanding the surrogate PCR-based and serological HPVpositive endpoints included for this purpose. The finding that condom use shortens the duration of HPV persistence in infected men5 further supports the plausibility of differential exposure as a confounder.

Little is known about the carcinogenic contribution of simultaneous or sequential infection with multiple HPVs, reinfection with similar HPVs, or coinfection with nonHPV organisms such as herpes simplex virus, but multi-hit viral interactions of this kind seem at least as likely as hormones to increase the risk of cervical cancer. Conversely, as with the above-mentioned HPV-positive subset analysis, the assumption that casecontrol data on reported condom use or numbers of sexual partners adequately control for quantitative variations in unprotected sex associated with use of hormonal contraception should not be accepted without question. The possibility that hormones can directly promote progression of cervical cancer remains an important one, and could well prove to be the case. However, until an effective vaccine becomes available, doctors should not hesitate to emphasise that only the correct and invariant use of barrier prophylaxis can reliably minimise the morbidity of HPVdependent neoplasia. Richard J Epstein Division of Haematology and Medical Oncology, Department of Medicine, Queen Mary Hospital, University of Hong Kong, Hong Kong (e-mail: [email protected]) 1

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Smith JS, Green J, de Gonzalez AB, et al. Cervical cancer and use of hormonal contraceptives: a systematic review. Lancet 2003; 361: 1159–67. Gregson J, Kirkman R. Double Dutch: looking at the usage of combined pill plus condom in girls. Eur J Contracept Reprod Health Care 1999; 4: 45–48. Xi LF, Carter JJ, Galloway DA, et al. Acquisition and natural history of human papillomavirus type 16 variant infection among a cohort of female university students. Cancer Epidemiol Biomarkers Prev 2002; 32: 658–65. Munoz N, Bosch FX. HPV and cervical neoplasia: review of case-control and cohort studies. IARC Sci Publ 1992; 119: 251–61. Hippelainen M, Hippelainen M, Saarikowski S, Syrjanen S. Clinical course and prognostic factors of human papillomavirus infections in men. Sex Transm Dis 1994; 21: 272–79.

Reporting on the eye and other surgical organ systems Sir—In their interesting survey on the causes of bias or over-representation of organ systems in case reports, Alasdair Coles and colleagues (April 5, p 1230)1 write that “Analysed as a whole, Case reports may reflect specialties that are generally regarded

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as especially interesting or difficult.” Although we agree that neurology holds this charm, and that this factor might indeed have a part to play in the specialty reaching the top of the pile, we strongly disagree with the obvious implication that the same reason holds true all the way down the list of ranked specialties. This potentially misleading implication arises because Coles and colleagues have not noted that the breakdown of the organs they list by specialty is in fact a fairly clearcut division along medical and surgical lines—into general medical specialties at the top and surgical specialties at the bottom, along with psychiatry. Only nephrology is in the bottom half of the table, where the listed surgical specialties of ophthalmology, ear nose throat (ENT), and obstetrics and gynaecology are found. In fact, we estimate that non-medical specialties account for, at most, only 10% of reports in their study. This finding is not surprising, since these reports are formally aimed at general physicians.1 General physicians will, by and large, have rotated during their training through those medical specialties that are listed, but few through those surgical ones that dominate the bottom of the table. They also initiate active management in these medical disciplines in their routine clinical practice. Thus, we suggest that these practical, rather than intellectual reasons, account for the fact that the reporting of cases breaks down according to organ and specialty, and not, as suggested by the authors, since the ones near the top are difficult, interesting, or more intellectually challenging disciplines than those near the bottom. Indeed, which is the more challenging to a general physician— reading about a very specialised area like ophthalmology or ENT, to which he or she is unlikely to have had postgraduate exposure, or reading about reports in specialties such as cardiology or neurology, which are organ systems general physicians actively manage on a day-to-day basis? Our own specialty of ophthalmology is surely at the very bottom of the table of named specialties for this reason. This result is despite the fact that this surgical organ is also the window on the internal milieu of the body—a wonderful clue to medical conditions and scientific processes—and thus of great interest to general physicians. Indeed, Coles and colleagues have analysed the topic as a whole, and likewise we also believe that these reasons for over-

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For personal use. Only reproduce with permission from The Lancet Publishing Group.