Sore throat management in general practice

Transcription

1 Family Practice Oxford University Press 1996 VoL13, No 3 Printed in Great Britain Sore throat management in general practice Paul Little and Ian Williamson Little P and Williamson I. Sore throat management in general practice. Family Practice 1996; 13: This paper discusses primary care management of sore throat in the context of recent national 'consensus' guidelines from the Drugs and Therapeutics Bulletin. The guidelines advise taking a throat swab, using typical clinical features where swabs are not available, and suggest that antibiotics shorten the duration of symptoms and prevent complications. Systematic reviews and individual studies indicate that the evidence for prescribing antibiotics for most presentations of sore throat in general practice is marginal, and the benefits are probably outweighed by the likely costs of antibiotics. Using clinical scorecards or symptom clusters to identify individuals who would benefit from treatment is insensitive with low predictive value, although inexpensive. Using throat swabs as a gold standard for diagnosis is inappropriate since they are neither very specific nor sensitive, and will greatly increase costs of management. The relative lack of evidence for the efficacy of antibiotics and for the use of throat swabs from primary care research, and also an unbalanced perspective of dangers and complications related predominantly to a secondary care setting, underlines the problem of achieving valid consensus guidelines. Guidelines not firmly based on evidence appropriate to the intended setting are more likely to be received sceptically and hinder getting research into practice. Keywords. Sore throat, clinical guidelines, tonsilitis, pharyngitis, throat swab. Introduction Although sore throat is one of the commonest conditions managed in primary care, 1 management is still controversial, and guidelines which suggest changing management are likely to have significant implications for both patients and the National Health Service." The principle of 'getting evidence into practice' 4 and the use of guidelines is also particularly topical: guidelines should be based on good evidence, be feasible and be appropriate for the setting in which they will be used. 3 What national guidelines are available for the management of sore throat in primary care? The respected and widely read Drugs and therapeutics bulletin (DTB), which develops consensus guidelines through an expert panel system, recently reviewed the diagnosis and treatment of sore throat. 6 All UK general practitioners (GPs) receive the DTB and thus it is a very influential source of advice and guidance for primary care. Their guidelines advised (i) taking a throat swab since "the precision in diagnosis is greatly increased"; (ii) where throat swabs are not possible, targeting treatment according to "typical clinical features", especially in children; (iii) that antibiotics shorten the duration of symptoms and prevent complications. Received 28 December 1995; Accepted 28 January Primary Medical Care, Aldermoor Health Centre, Aldermoor Close, Southampton SO 16 5ST, UK. What is the evidence in each of these areas? This deserves critical discussion not only because they are important scientific and clinical issues for a very common clinical problem, but also in the context of guidelines and applying evidence in practice. This paper first discusses the burden of disease in primary care. Then we will deal with the evidence for the efficacy of antibiotics, of the use of throat swabs and of targeting treatment to particular groups according to clinical signs. Burden of disease for primary care Estimates of attendance rates (per capita per annum) for sore throat vary: for pharyngitis and tonsillitis in single practices, 17 * 0.2 for sore throats in a region, 9 and for the possibly atypical practices in the national morbidity survey 10 approximately 0.1 (assuming 1 in 4 'respiratory' attendances are for sore throat 8 and allowing for re-attendance 1112 ). Using the latter conservative figure along with UK populations estimates, 13 and assuming that a consultation costs 10, M then the cost of the GP consultations for sore throat is approximately 60 million per annum even if no drugs are prescribed let alone other costs (see below). The health service burden is increasing a 14% increase for respiratory attendances since the last 317

2 318 Family Practice an international journal morbidity survey 10 despite no obvious change in the pathological basis for sore throat during the last 30 years. 13 Extra cost implications of throat swabbing The cost of swabbing all acute sore throats routinely in general practice would be approximately 40 million annually, assuming 4 per swab* and probably at least 3 for the extra time (2-3 min organizing the swab, feeding back results to patients, pulling notes, documenting results, writing notes, writing scripts, etc.). Do antibiotics prevent complications? Rheumatic fever (RF) and glomerulonephritis (GN) The studies on the prevention of RF were carried out using penicillin injections on post-war barracked military personnel, where attack rates were high (0.3-5 %). 16 This may not be generalizable to the use of oral antibiotics in a modern community setting with lower attack rates, and where only 50% of children complete a 10-day course. 17 Individuals who have had oral antibiotics in general practice may be as likely to develop RF or GN as those not taking antibiotics The incidence of RF probably declined well before the advent of antibiotics. 20 In the USA, but not the UK or Europe, the incidence temporarily increased in the 1980s 21 and the steady decline since 1984 is difficult to attribute to antibiotics since most subjects do not present to health professionals. 11J2 The average UK GP during a lifetime of practice has an approximately one in five chance of seeing a case of either poststreptococcal GN or RF following a sore throat The principal problem of prescribing to prevent RF and GN is that subjects may not have a significant sore throat, and those with sore throats mostly do not attend their GP Even if oral antibiotics in the community were of proven benefit, either GP surgeries would need to be overwhelmed with patients or antibiotics would need to be freely available in the community to effectively prevent such complications. This would result in greater likelihood of penicillin resistance and greater use of more expensive drugs.^^ Septicaemia The DTB underlined this complication, and quoted a case review where the mortality from streptococcal bacteraemia was 50%." Although there have been more case reports of serious streptococcal infections in Europe and the USA in the past 5 years, this may not reflect a true increase. Furthermore, the majotity are associated with an initial soft tissue focus (e.g. skin, muscle, fascia) or deeper focus (e.g. empyema, osteomyelitis) rather than pharyngitis, 13 ' 30 and with strains not typical of pharyngeal types. 13J0 This is also borne out in the above UK case series: 27 in only one of the cases was the throat described as the possible initial source, and the patient would not have been a candidate for a trial of no antibiotics in any case (the initial provisional diagnosis was meningitis). Thus it is misleading to imply that streptococcal septicaemia could be prevented by antibiotics prescription to patients attending GPs with the normal range of presentation of sore throat. Suppurative complications There is some evidence for a small protective effect of antibiotics on the likelihood of developing either otitis media or sinusitis. 16 However, these studies are old and took place when the complications were more common, involved small numbers of complications in any case and were mainly on institutionalized servicemen, so it is again very difficult to extrapolate the results to modern general practice. The two studies addressing the issue in general practice had wide confidence intervals for the odds ratio for developing complications (greatly overlapping 1 for the prevention of otitis media). There have been few studies addressing the issue of the prevention of quinsy using oral antibiotics: a postwar study in a military setting used intramuscular penicillin. 16 Quinsy did apparently decline significantly after the war, 33 but how much of this is due to improved socio-economic conditions and how much due to antibiotics is not clear. John Fry, in a review of complications of sore throat in 30 years of practice (3000 cases of tonsillitis and presumably an equivalent number of pharyngitis), documented three cases of serious cervical adenitis and 20 cases of quinsy 34 all of which settled with parenteral antibiotics (hence were possibly peri-tonsillar cellulitis and not 'true' quinsy) and no other complications; his prescribing for sore throats is 25% (i.e. a low prescriber). A search of computerized notes ( ) of 8000 current patients in our practice serving a deprived area of Southampton revealed 14 diagnoses of 'quinsy' or 'early quinsy': only three attended with a prior sore throat; two of these had oral antibiotics which did not prevent quinsy developing. All cases settled with parenteral penicillin (hence were possibly peri-tonsillar cellulitis). Thus quinsy or peritonsillar cellulitis is rare and most cases do not present to the GP with prior sore throat. Hence there is considerable doubt from current evidence that oral antibiotics will effectively prevent complications of sore throat, which are rare in any case. Do antibiotics reduce symptom burden? The evidence for symptomatic relief in sore throat is also marginal. Of the five placebo controlled trials done in general practice, there may be a small improvement in the number of patients well after 3 days

3 FIGURE 1 Percentage of patients without sore throat following presentation to a general practitioner; patients randomized either to penicillin (n = 256) or placebo (n = 272) Reproduced by kind permission of the authors and the practitioner from Whitfield and Hughes, comparing penicillin to control, 16 the figures vary from 12 % (the largest trial) to 38 %. However the largest trial (n = 528) so far 33 showed this benefit only for a small subgroup, and furthermore demonstrated that illness was not shortened at all irrespective of initial presentation with fever, purulent tonsils or lymphadenitis (see Figure 1). Another major problem in prescribing antibiotics to ease symptoms is the evidence from placebo controlled trials (in Group A Beta Haemolytic Streptococcus (GABHS)-swab-positive patients) that the recurrence rate is significantly higher in subjects treated with penicillin immediately compared to treatment delayed for hours (37% and 16% respectively relapsed within 4 months). This may be due to preventing immunity to streptococcus developing. 12 The effect of delaying antibiotics on symptom resolution is similar to not giving antibiotics at all since most of the symptom reduction is in the first few days of presentation. 12 Thus in disease that has a time course of approximately 7-10 days either in treated or in untreated individuals, 16 and identifying patients with GABHSpositive throat swabs, patients treated early with antibiotics will be symptomatically better off by 12% for the 3-5 days following taking antibiotics, 12 but 20% more patients will be exposed to the whole range (i.e. 100%) of symptoms due to relapse that they would not have been exposed to if they were not given antibiotics, i.e. probably cancelling any net benefit. Thus antibiotics probably do not reduce the symptom 'burden'. Could a subgroup be targeted to improve outcome, and would this affect prescribing? Could particular subgroups be identified? Unfortunately, symptom clusters do not seem to be a good indicator of streptococcal infection or antibiotic response. 33 The Sore throat management 319 'typical' features of sudden pain, fever, exudate and tender adenopathy 'especially' in children* are only present in approximately 15% of cases of streptococcal pharyngitis. 3 * In US emergency centres, the Breese symptom score although specific (94%) was only modestly predictive (positive predictive value 59%) and not sensitive (26%) compared to throat swabs. 37 This leads on to the guidelines using the throat swab as a diagnostic 'gold standard'. 6 The sensitivity and specificity of the throat swab are low 26-30% and 73-80% respectively when compared to a rise in the anti-streptolysin O titre (ASOT) titre The ASOT titre is likely to be more important than throat swab in predicting outcome in view of the 100% association between definite cases of RF and either high initial level of ASOT or a rise in ASOT. 24 The low predictive value of throat swabs relates to the high symptomless carrier rates 6-^0 % 24 - SM1 especially in children. 6^ The DTB conclusion that streptococcal "infection" is "more common" in children may just reflect higher carriage rates. The high carrier rate would explain why ASOT rises, in only 20-50% of individuals with sore throat and GABHS-positive swab, and may contribute to the apparent 'failure' rate of approximately 20% with penicillin therapy." Although ASOT titres are liable to be a much better indication of immunologically significant infection rather than the throat swab (which cannot distinguish carriage of streptococci from infection), the delay, cost and inconvenience of serial ASOT titres rule out routine clinical use. Even if throat swabs were taken there is the difficulty of using the results in changing treatment decisions: even with a rapid antigen test, where the results were available comparatively quickly (within hours, unlike the hours for the throat swab), the results made a difference to prescribing decisions in only 13 % of cases. 44 Costs of prescribing The marginal benefit of prescribing must be weighed against the possible costs. Routine prescribing encourages dependence and re-attendance: 11 40% re-attend during the following 6 months if not prescribed an antibiotic for sore throat versus 60% if an antibiotic is prescribed, thus taking up surgery time with a largely self-limiting condition and resulting in considerable opportunity cost for both the GP and the patient. The effect of consistent advice over a long time is likely to further reduce re-attendance. Taking the 20% figure as a conservative estimate of the reduction in attendance, this would save an estimated 12 million annually. There is no evidence about the further medicalization or anxiety-inducing effects of using throat swabs and a 2-3 day delay in 'diagnosis', but this is likely to increase the medicalizing effect (by creating the

4 320 Family Practice an international journal perception that it is important to do a throat swab with a sore throat to allow proper management and hence that it is important to attend the GP to have a swab taken). Like all screening it may exacerbate anxiety unless handled carefully. 45 In the context of greater attendance for respiratory and trivial problems, we need to be sure that policies will not encourage this process further by unnecessarily medicalizing self-limiting conditions. In addition to the re-attendance costs for patient and surgery, there are other costs: side-effects of antibiotic use such as the 3.8% allergy rate, 4 * between 10 and 60% of children experiencing diarrhoea on treatment, 474 * oral and genital Candida albicans particularly if broad spectrum antibiotics are used, and unwanted pregnancy following reduced efficacy of oral contraceptives. Considering dangerous side-effects, following penicillin treatment the estimated incidence of anaphylaxis is between 1.5 and 4 cases per with two patient deaths per ^ If every case of acute pharyngitis and acute exudative tonsillitis were treated with penicillin, i.e. approximately cases per GP per year, then in the average working lifetime (35 years) a GP would expect to have an approximately one in three to one in fourteen chance of seeing death by anaphylaxis from treating sore throat, i.e. of the same order of magnitude as seeing a case of nephritis or RF following a sore throat, neither of which have a high fatality rate. Behaviour and prescribing Discussing prescribing as if patients were just symptom and disease clusters is highly artificial. Psychosocial factors for both the doctor and the patient are important determinants of prescribing, and good practice requires their acknowledgement and exploration before prescribing. GPs probably perceive more pressure to prescribe than exists, given that 41 % of patients entering consultations expect a prescription but 67 % leave with one. 31 Patients probably find explanation, symptomatic treatment, and no antibiotics an acceptable option even in painful upper respiratory conditions as evidenced by the uncontrolled report of the acceptability of no antibiotic treatment in otitis media, 52 and a controlled trial of no antibiotic prescription with advice in sore throat. 11 Summary We argue that the evidence for prescribing antibiotics for sore throat is marginal. Complications are rare, and on current evidence may not be preventable by prescribing for sore throat in primary care. The benefits are probably outweighed by the likely costs of antibiotics: the complications, including death (rare); diarrhoea and allergy (common); relapse (common); medical dependence and associated health service costs (common); and possible unknown psychological costs. The exception would be the rare individuals who are septicaemic or with quinsy where the risks of not treating are likely to be much greater. Using clinical scorecards or symptom clusters to identify individuals who would benefit from treatment is insensitive with low predictive value, although inexpensive. Using throat swabs as a gold standard for diagnosis is inappropriate since, although they are reasonably specific, they are insensitive and not very predictive and will greatly increase costs of management. GPs should share with patients the evidence about the modest efficacy, likely complications and relapse rate with antibiotics for most presentations of sore throat, and negotiate to improve the symptomatic management of sore throat without relying routinely on antibiotics. The relative lack of evidence for the efficacy of antibiotics and for the use of throat swabs from primary care research, and also an unbalanced perspective of dangers and complications related predominantly to a secondary care setting, underlines the problem of achieving valid consensus guidelines. Guidelines which are not adequately based on evidence in the setting in which they will be used, and do not sufficiently take account of the practical implications of implementation, are likely to be received sceptically and adhered to poorly and will hinder getting research into practice. 4-5 References 1 Hodgkin K. Towards earlier diagnosis in primary care. Edinburgh: Churchill Livingstone, Little PS, Williamson I. Controversies in management Are antibiotics appropriate for sore throats? Costs outweigh the benefits. BrUedJ 1994; 309: Schwartzman P. Controversies in management. Are antibiotics appropriate for sore throats? Careful prescribing is beneficial. BrUedJ 1994; 309: Dunning M, McQuay H, Milne R. Getting a Grip. Health Serv J 1994; Appendix H: University of Leeds, University of York, Royal College of Physicians. Implementing Clinical Practice Guidelines. Effective Health Care Bull 1994; 8: Diagnosis and treatment of streptococcal sore throat. Drugs Ther BuU 1995; 33: Fry J. Medicine in three societies. Lancaster: Medical and Technical Publishing Co. Ltd, Howie J. A new look at respiratory illness in general practice. J RCoUGen Pract 1973; 23: Howie J, Richardson I, Gill G, Dumo D. Respiratory illness and antibiotic use in general practice. / R Coll Gen Pract 1971; 21: HMSO, OPCS. Morbidity statistics from general practice: Fourth national study London: HMSO, 1994.

5 Sore throat management Herz MJ. Antibiotics and adult sore throat an unnecessary ceremony. Fam Pract 1988; 5: Pichichero ME, Disney F, Talpey W ex al. Adverse and beneficial effects of immediate treatment of Group A b-haemolytic streptococcal pharyngitis. Fed Infect Dis J 1987; 6: Central Statistical Office. Annual abstract of statistics. London: HMSO, Daly E, Vessey MP, Barlow D, Gray A, McPherson K, Roche M. Hormone replacement therapy in a risk benefit perspective. In Berg G, Hammar M (eds). The modem management of die menopause. London: Parthenon, Shulman ST, Gerber MA, Tanz RR, Markowitz MD. Streptococcal pharyngitis: the case for penicillin-therapy. Fed Infect Dis J 1994; 13: Del Mar C. Managing sore throat: a literature review n. Do antibiotics confer benefit? MedJAust 1992; 156: Chamey E, Bynum R, Eldridge D et al. How well do patients take oral penicillin? Pediatrics 1967; 40: Howie J, Foggo B. Antibiotics, sore throat and rheumatic fever. J R Coll Gen Pract 1985; 35: Taylor JL, Howie J. Antibiotics, sore throat and acute nephritis. J R Coll Gen Pract 1983; 33: White P. Changes in the prevalence of various types of heart disease in New England. JAMA 1953; 33: HMSO. Hospital inpatient enquiry London: HMSO, Tauber KA, Rowley AM, Shulman ST. A seven year ( ) U.S. nationwide hospital survey of acute rheumatic fever (Abstract). Am Heart Assoc Sci Sessions 1992; 86: I-36I. 23 Banks M, Beresford S, Morrell D, Waller J, Watkins C. Factors influencing the demand for primary care in women aged years: a preliminary report. Int J Epidemiol 1975; 4: Valkenburg HA, Haverkorn MJ, Goslings WRO. Streptococcal pharyngitis in the general population. II. The attack rate of not treated with penicillin. J Infect Dis 1971; 124: Baquero F, Martinez-Beltran J, Loza E. A review of antibiotic resistance patterns of Streptococcus pneumoniae in Europe. J Antimicrob Chemother 1991; 28 (suppl C): Tanz RR, Hofer C. A survey of U.S. pediatrician strategies for managing Group A streptococcal pharyngitis. XII Lanoefield Symposium, St Petersburg, Russia, Francis J, Warren RE. Streptococcus pyogenes bacteraemia in Cambridge: a review of 67 episodes. Q J Med 1988; 68: Stevens DL, Tanner MH, Winship J. Severe Group A streptococcal infections associated with toxic shock like syndrome and scarlet fever toxin. N Eng J Med 1989; 321: Shulman ST. Invasive and toxin-related diseases caused by group A streptococci. Ped Infect Dis J 1991; 10: Johnson DR, Stevens DL, Kaplan EL. Epidemilogical analysis of Group A streptococcal serotypes associated with severe systemic infections, rheumatic fever OT uncomplicated pharyngitis. / Infect Dis 1992; 166: Chappie PAL, Franklin LM, Paulett JD. Treatment of acute sore throat in general practice. Therapeutic trial with observations on symptoms and bacteriology. Br Med J 1956; 1: Taylor B, Abbott GD, Kerr M, Fergusson DM. Amoxycillin and co-trimoxazole in presumed viral infections of childhood: placebo controlled trial. Br Med J 1977; 2: Peter G, Smith A. Streptococcal infections of the skin and pharynx. N Eng J Med 1977; 297: , Fry J. Acute throat infections. Update 1979; 18: Whitfield MJ, Hughes AO. Penicillin in sore throat. Practitioner 1981; 2: Kiselica D. Group A beta haemolytic streptococcal pharyngitis: current clinical concepts. Am Fam Phys 1994; 49: Reed BD, Huck W, French T. Diagnosis of Group A b- haemolytic strep using clinical scoring criteria, directigen group A streptococcal test and culture. JAMA 1990; 150: Del Mar C. Managing sore throat: a literature review I. Making the diagnosis. Med J Austr 1992; 156: Caplan C. A case against the use of the throat culture in the management of streptococcal pharyngitis. J Fam Pract 1979; 8: Chun LT, Reddy V. Occurrence and prevention of rheumatic fever among ethnic groups of Hawaii. Am J Dis Child 1984; 138: 476-^ Feery BJ, Forsell P, Gulasekharam J. Streptococcal sore throat in general practice. MedJAust 1976; 1: Kaplan EL, Franklin HT, Dudding BA, Wannmaker LW. Diagnosis of streptococcal pharyngitis: differentiation of active infection from the carrier state in the symptomatic child. J Infect Dis 1971; 123: Siegel AC, Johnson EE. Controlled studies of streptococcal pharyngitis in a pediatric population II. Behaviour of type specific immune response. N Eng J Med 1961; 265: Burke P, Bain J, Lowes A, Athersuch R. Rational decisions and managing sore throat. Br Med J 1988; 296: Marteau T. Reducing the psychological costs. BrMedJ 1991; 301: Madden TA. Adverse penicillin reactions in the records of a general practice. / R Coll Gen Pract 1977; 27: Bolme P, Eriksson M. Influence of diarrhoea on the oral absorption of penicillin V and ampicillin in children. ScandJ Infect Dis 1975; 7: Hoigne R, Zoppi M, Sonntag R. Penicillins. In MNG Dukes (ed.). Meyler's Side Effects of Drugs. Elsevier, 1992: Howie J. Clinical judgement and antibiotic use in general prac- %tice. BrMedJ 1976; 2: Howie J, Bigg AR. Family trends in psychotropic and antibiotic prescribing in general practice. BrMedJ 1980; 1: Cartwright A, Anderson R. General practice revisited: a second study of general practice. London: Tavistock, Pitts J. Shared decision making in the informed treatment of acute otitis media. Practitioner 1987; 231: