Summary

Objective: To understand how Hong Kong primary care doctors use antibiotics for respiratory disease.

Design: Diagnosis and drug data obtained from logbooks submitted by candidates for the FHKCFP examinations and participants in the Diploma in Family Medicine course.

Subjects: 40 candidates and 104 diploma students who participated in 1999 and 2000, producing 9,321 consultations and 11,500 problems or diagnoses.

Main outcome measures: Diagnoses made and antibiotics prescribed.

Results: The diagnoses are similar to previous morbidity studies in Hong Kong. Upper Respiratory Tract Infection was the most common diagnosis, comprising 30% of private practice and 21% of public practice. Standard front line antibiotics (Amoxycillin, Amoxycillin/Clavulanate, Bacampicillin, Cefalexin/Cefedroxil and Erythromycin) comprised about 72% of respiratory prescribing, but 10.7% were old, and possibly inappropriate antibiotics, while about 16.6% were new broad spectrum drugs which may increase development of resistant organisms.

Conclusion: Doctors can use these results to reflect on their prescribing, to reduce inappropriate antibiotic use, and when they do prescribe, choose drugs that are less likely to cause development of resistance.

Keywords: Prescribing, antibiotics, primary care, Hong Kong, respiratory infections

摘要

目的：暸解目前香港基層醫生如何使用抗生素治療呼吸道疾病。

設計：資料來源為香港家庭醫學院院試考生及家庭醫學文憑課程學生所提供的日誌。

對象：包括1999至2000年度的40名院試考生和104名文憑學生。資料合共提供9321次診症及11500個診斷。

測量內容：診斷結果及抗生素的使用。結果：診斷結果與以往香港疾病相似。上呼吸道感染 為最常見的疾病，佔私人醫療30%及公共醫療21%。用以治療呼吸道疾病的抗生素，72%屬標準常用的抗生素，但有10.7%為過時且可能已不適用的抗生素， 另外16.6%為新型抗生素可能引起更多抗藥性。

結論：醫生可以此項調查作為參考，以減少使用不適 合的抗生素，以及選擇較少引起抗藥性的抗生素。

主要詞彙： 處方，抗生素，基層醫療，香港，呼吸道感染

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Introduction

Drug resistant bacteria are becoming prevalent in Hong Kong, and Hong Kong doctors are accused of unnecessarily prescribing antibiotics at higher rates than in other countries. Hong Kong is a modern city, whose medical profession works with the latest technology. Once drugs are licensed, there are few controls, and pharmaceutical companies market directly to doctors.

Doctors learn basic antibiotic use during their undergraduate education, then more during their postgraduate hospital education phase. However, many doctors currently in practice only did an internship, while others spent up to several years in hospital work. Even if they obtained extra training, drug use in hospitals is very different from that in the community. Therefore much primary care antibiotic use must be learned through continuing education. As in most other countries, continuing education is often sponsored by drug companies, and in a competitive market, it is not surprising that this continuing education for doctors is mostly focused on topics in which drug companies have a current interest. This focuses on new drugs, but seldom discusses how to use old drugs, for which there is no longer much profit margin.

These considerations may affect the use of drugs in practice. We wished to know what antibiotics doctors in general practice use for common infections in every day practice.

Methods

We obtained data linking diagnosis and prescribing from two sources: logbooks provided by examinees of the Hong Kong College of Family Physicians (HKCFP), and an audit program conducted as part of a postgraduate Diploma in Family Medicine.

For the examination of the HKCFP, candidates are required to provide a logbook containing 100 consecutive consultations, with diagnoses and drugs prescribed. Permission to analyse these (under conditions of confidentiality) was obtained from the Board of Examination of the HKCFP and individual consent from the candidates.

Our department runs a postgraduate Diploma in Family Medicine, which requires one half day a week of class time over the course of a year. Students come from a wide range of general practices in Hong Kong, including Department of Health general outpatient services and Hospital Authority clinics, private hospitals, Accident & Emergency Departments, solo and group private practices. As part of that course, for a session on rational drug use, students completed a logbook of 50 consecutive cases in which they record the age, sex, diagnosis(es), and drugs prescribed. They also completed a short questionnaire including their demographic and practice characteristics.

Diagnoses in the logbooks were coded with ICPC2,¹ and the drugs were coded by the WHO ATC classification.² All coding and entry was done twice: the diagnosis by medical students, the drugs by pharmacy students. The doubly coded sets were compared using a computer program. Discrepancies were resolved by a research nurse, and checked by the principal author (JAD) if necessary. The final data set was analysed using standard computer programs. For this analysis, all systemic antibiotics were analysed, excluding antivirals and antifungals. (Codes J01 AA to J01 XX)

Results

There were 144 doctors and 9321 consultations in this data set. Table 1 shows characteristics of doctors, and numbers of patients from each series. Doctors listed one problem for 7,314 consultations, two for 1,590, three for 269, four for 47 and none for eleven, making a total of 11,500 problems or diagnoses. Table 2 shows the problems or diagnoses listed, in descending order of frequency. The private doctors were more likely to see acute infections, and less likely to see chronic disease, but the order of frequency is comparable.

Antibiotics were prescribed in 2104 consultations. The 1298 antibiotics prescribed by these doctors for respiratory diagnoses are listed in Table 3, divided into standard front line drugs, old drugs, and new.

Both the most recent and some of the oldest antibiotics were used. Because respiratory diagnoses were the most common causes of prescribing, the rate of use for these diagnoses is shown in Figures 1 and 2, in the first, divided by age, and the second by private and public sector. Overall, antibiotics were prescribed for only 27.5% of these infections and there are clear differences between diagnoses. There is little age difference in prescribing rates, and private doctors tend to prescribe more than those in public, except that Bronchitis and Tonsillitis stand out with much higher prescribing rates than other diagnoses in both sectors. No penicillin was prescribed for tonsillitis/pharyngitis or throat symptoms.

Table 1: Characteristics of doctors in the data set and their number of reported patient consultations
a.	Diploma of Family Medicine, CUHK, 1999-2000, 2000-2001
	Gr aduate from:		Private			Public			Total
	Hong Kong		54		(2708)	12		(604)	66		(3312)
	Mainland China		17		(850)	4		(202)	21		(1052)
	Western Countries		16		(816)	1		(50)	17		(866)
	Total		87		(4374)	17		(856)	104		(5230)
b.	Conjoint HKCFP/RACGP Fellowship Examination 1999, 2000
	Graduate from:		Private			Public			Total
	Hong Kong		11		(1100)	15		(1501)	27	*	(2701)
	Mainland China		1		(100)	0		(0)	1		(100)
	Western Countries		2		(200)	6		(600)	10	**	(1000)
	Total		14		(1400)	21		(2101)	40	#	(4001)

	Missing data
	*	1 doctor who graduated from Hong Kong with missing sector
	**	2 doctors who graduated from Western Countries with missing sector
	#	2 doctors from public sector with missing place of graduation

Table 2: First 20 diagnoses listed by doctors in private and public sectors, in descending order of frequency#
Diagnoses		Private			Public			All
		N	%		N	%		N	%
Upper respiratory infection, acute		2118	30.3		874	21.1		3092	26.9
Hypertension, uncomplicated		157	2.3		417	10.0		585	5.1
Cough		334	4.8		51	1.2		386	3.4
Gastroenteritis, presumed infection		294	4.2		79	1.9		385	3.3
Dermatitis, contact/allergic		121	1.7		142	3.4		272	2.4
Acute bronchitis/bronchiolitis		191	2.7		33	0.8		232	2
Diabetes, non-insulin dependent		59	0.8		152	3.7		218	1.9
Sneezing/nasal congestion		185	2.7		8	0.2		193	1.7
Throat symptom/complaint		151	2.2		22	0.5		173	1.5
Fever		126	1.8		21	0.5		147	1.3
Tonsillitis acute		117	1.7		22	0.5		139	1.2
Medical examination		44	0.6		59	1.4		130	1.1
Asthma		84	1.2		37	0.9		126	1.1
Abdominal pain/cramps, general		90	1.3		28	0.7		118	1
Cystitis/urinary infection, other		85	1.2		29	0.7		118	1
Allergic rhinitis		50	0.7		59	1.4		114	1
Dermatophytosis		43	0.6		63	1.5		114	1
Headache		87	1.2		25	0.6		112	1
Stomach function disorder		87	1.2		17	0.4		108	0.9
Lipid disorder		35	0.5		66	1.6		104	0.9
Others		2530	36.3		1948	47.0		4634	40.3
Total		6988	100		4152	100		11500	100
5 doctors (360 consultations) with missing sector and place of graduation
# Significant difference between private and public sector for all categories except asthma

Table 3: Antibiotics prescribed by doctors for URTI and all other respiratory diagnoses Columns show numbers of patients given each drug and % of antibiotics prescribed for this diagnosis group
a.	Standard
		Antibiotics			URTI			All other respiratory diagnoses
		Amoxycillin			274	38.6		176	29.9
		Amoxycillin/clavulanate			62	8.7		108	18.3
		Bacampicillin			8	1.1		6	1.0
		Sultamicillin			14	2.0		8	1.4
		Cefalexin/cefadroxil			122	17.2		74	12.5
		Phenoxymethyl penicillin			4	0.6		4	0.7
		Erythromycin			43	6.1		32	5.4
		Total			527	74.3		408	69.2
		% of antibiotics used for all diagnoses				17.0			25.0
b.	Old type	Antibiotics			URTI			All other respiratory diagnoses
		Tetracycline/doxycycline			10	1.4		8	1.4
		Ampicillin			25	3.5		2	0.3
		Cloxacillin			3	0.4		2	0.3
		Ampicillin/cloxacillin			22	3.0		15	2.6
		Trimethoprim			3	0.4		1	0.2
		Sulfamethoxazole and trimethoprim			11	1.6		11	1.9
		Clindamycin/lincomycin			14	2.0		5	0.8
		Metronidazole			2	0.3		4	0.7
		Gentamicin			0	0		1	0.2
		Total			90	12.6		49	8.4
		% of antibiotics used for all diagnoses				3.0			3.0
c.	New types
		Antibiotics			URTI			All other respiratory diagnoses
		-	2nd generation cephalosporins
				Cefuroxime/cefaclor/cefradine	53	7.5		55	9.3
		-	3rd generation cephalosporins
			Ceftriaxone/cefetamet/ceftibuten		4	0.5		3	0.6
		-	New macrolides
				Roxi-, Clari-, Azithro-, Spiramycin	11	1.5		34	5.8
		-	Fluoroquinolones
				Ofloxacin	10	1.4		4	0.7
				Ciprofloxacin	6	0.8		23	3.9
				Norfloxacin	3	0.4		5	0.8
				Others	1	0.1		3	0.4
		Total			88	12.2		127	21.5
		% of antibiotics used for all diagnoses				2.8			7.8
d.	Unclear/Not fully specified antibiotic				4			5
		Total Antibiotics			709			589
		Total Diagnoses			3092			1631
		% of diagnosis prescribed antibiotics			22.9			36.1

Both the most recent and some of the oldest antibiotics were used. Because respiratory diagnoses were the most common causes of prescribing, the rate of use for these diagnoses is shown in Figures 1 and 2, in the first, divided by age, and the second by private and public sector. Overall, antibiotics were prescribed for only 27.5% of these infections and there are clear differences between diagnoses. There is little age difference in prescribing rates, and private doctors tend to prescribe more than those in public, except that Bronchitis and Tonsillitis stand out with much higher prescribing rates than other diagnoses in both sectors. No penicillin was prescribed for tonsillitis/pharyngitis or throat symptoms.

Figure 1: Antibiotic prescribing rate for respiratory diagnoses, by age of patients

Figure 2: Antibiotic prescribing rate for respiratory diagnoses by private and public sector doctors

Discussion

These groups of doctors are interested in improving themselves, paying substantial fees, and taking their own time to attend and study for a postgraduate course, or attempt postgraduate examinations. They come from a wide range of backgrounds, representing major groups of doctors in primary care in Hong Kong, with the exception of those who work as primary care specialists. The number and type of problems seen is similar to previous morbidity studies in Hong Kong.³ More than one diagnosis was recorded for 1906 (20.6%) of consultations. This may reflect short consultations, or recording behaviour: observers might code more "problems" than those doing the consultations.

Most of the antibiotics were prescribed for respiratory infections, which comprised the largest group of consultations. This justifies the current campaign focussing on appropriate use of antibiotics in this field. Overall, these doctors prescribed antibiotics only for a small proportion of such patients, and at a lower rate than found in reports from elsewhere.^4,5 These results are consistent with opinion surveys of Hong Kong Doctors.⁶ However, since many more of our patients have respiratory infections, it may be that the threshold for patients attending doctors in Hong Kong is lower, with less attempt at self-care before seeking medically sanctioned treatments. If so, a low rate of antibiotic prescribing may still provide more overall antibiotic use than a high prescribing rate in communities where the threshold for attending doctors is higher, and therefore only sicker patients are seen.

The ICPC coding allows both conventional disease diagnoses, and symptom descriptions, which is often most appropriate in primary care, when criteria for a formal diagnosis are not present. These decisions are necessarily subjective, and will vary between doctors: the "cough" of one may be labelled as "bronchitis" or asthma by another. Nevertheless the words chosen indicate their thoughts about the pathology, and decision-making about treatment.

The figures show little difference in prescribing rates for children and adults, except for chronic obstructive airway disease (COAD), which is not diagnosed among children. Not surprisingly, the highest rates of prescribing are for "tonsillitis" and "bronchitis", for which doctors have learned that antibiotics are important, though recent evidence now shows their minimal value in developed countries.^7,8 There is also substantial prescribing for conditions that are labelled as upper respiratory infections, or even runny nose and asthma, where authorities have recommended against antibiotics for a long time.

Overall there is less prescribing of antibiotics by the doctors from the public sector. The difference may occur because of working under a different system, which provides less pressure for prescribing to retain the favour of the patients, or with a different population, with different range of pathology. Alternatively, doctors in the public sector may include a large number of trainees who have been educated more about recent thinking on minimal antibiotic use. This requires further detailed analysis to elucidate.

This data is biased, coming from doctors who are concerned about education and quality and including some who have formal vocational training in Family Medicine. It is possible that some may have presented their practice selectively to appear better than they are. If so, the problems demonstrated may be worse in the reality of such primary care medical practice. Since few specialists were trained for the primary care that they perform, there is no reason to believe their prescribing is any different in this aspect of their work.

In recent years the medical literature has increasingly questioned the value of antibiotics for respiratory infections in ambulatory care, especially for less severe infections. The Cochrane reviews summarise that literature, and those on bronchitis and tonsillitis show minimal clinical effect.^{7, 8} There is an argument that streptococcal tonsillitis or pharyngitis must be treated to prevent rheumatic fever, but with improved social conditions in Hong Kong, the risk for this disease is extremely low⁹: probably lower than the risk of side effects from Penicillin which is still the drug of choice for streptococcal pharyngitis,⁷ but was not prescribed for this diagnosis. Other choices have higher side effect rates than penicillin.

These doctors used many "new drugs", which shows that they have learned about such drugs soon after they come onto the market. In discussions, doctors argue that they must use these drugs because of recent publicity about drug-resistant bacteria, especially Streptococcus pneumoniae. However, some of these doctors are also using old drugs to which bacteria are likely to be resistant. Broad spectrum drugs such as tetracyclines, extended spectrum macrolides, oral cephalosporins, extended spectrum fluoroquinolones and even amoxycillin/clavulanic acid induce resistance quickly. It appears that such use is one factor creating and maintaining high rates of resistance. And there is increasing evidence that this occurs not just at an ecological level, but personal: those who take more antibiotics are more likely to carry resistant organisms.¹⁰

Some drugs are potentially dangerous, and no longer used in most developed countries, except in specific situations. These include chloramphenicol, lincomycin and clindamycin, and injections of gentamicin. Better alternatives are available for others. For example, because it is poorly absorbed, oral ampicillin is likely to cause diarrhoea and select for resistant bacteria or overgrowth of candida in the gut flora. It should no longer be used, since the absorption of amoxycillin, sultamicillin or bacampicillin is higher. The combination of cloxacillin and ampicillin is irrational at best, though it has been frequently used in hospitals and may represent a learned habit that is difficult to break.

Conclusion

It is difficult for private doctors to change behaviour because of the perception that Chinese patients value the doctor's treatment more than advice and like other countries put pressure on doctors to prescribe.⁵ This is true for some, but many do not wish for antibiotics unless needed.¹¹ A small proportion of antibiotic prescribing is appropriate for the fraction of patients whose illness could be complicated by bacteria or atypical infection. However, the need is likely to be less than the levels observed. Patients may still need symptom relief, and appropriate symptomatic treatment will still help.

It appears that continuing education programs and drug advertising in Hong Kong encourage taking on new information and new treatments possibly to an excessive extent, but do not effectively teach which old behaviours should be retained or abandoned. This problem is aggravated by the structure of medical practice in Hong Kong. Studies elsewhere have shown that doctors who are isolated from the mainstream are more likely to develop idiosyncratic style, yet this is the norm for medical practice in Hong Kong. Once doctors leave the hospital system, few are able to continue working regularly with other colleagues. The daily discussion and sharing that often occurs in a group situation helps doctors to assess whether their knowledge is up to date, and whether their approach is getting off track, yet this is simply unavailable to most. Thus our system makes maintaining high quality care difficult. Individual doctors concerned about quality can undertake audits and try to change. Health care reformers, and those involved in continuing education must consider how to improve this situation.

Acknowledgement

We thank the doctors for their courage in presenting their work for audit and scrutiny.

Funding for coding was provided by grants from the student employment program of Chinese University of Hong Kong, and New Asia College. Ms Heidi Tse organized and analysed the data.

Key messages

1. Overall antibiotic prescribing for upper respiratory infections was 22.9%.
2. Antibiotics were prescribed at low rates for many conditions where their use has been discouraged.
3. Antibiotics were prescribed at high rates for tonsillitis and bronchitis, despite recent evidence showing little value.
4. Old types of antibiotics were used in a small proportion. No penicillin was prescribed for pharyngitis.
5. New broad spectrum antibiotics were used inappropriately for a proportion of cases.
6. Primary care doctors can reduce their antibiotic prescribing further and use fewer broad spectrum antibiotics.

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References