Introduction

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A small proportion of patients attending outpatient clinics in secondary care attend frequently and are responsible for a high proportion of healthcare costs. ^{1 2} Early studies showed that many such patients consult for physical symptoms which, after extensive investigation, remain medically unexplained.³ These symptoms occur commonly in all medical settings, yet they remain poorly understood and are often persistent and disabling.⁴ There have been few studies of frequent attenders in secondary care. Previous work has been limited to single specialties and teaching hospitals⁵ or has focused on inpatient admissions.⁶

We examined the outpatient consultations of frequent attenders in all the general hospitals across one regional health authority and included both medical and surgical specialties. We estimated the prevalence of medically unexplained symptoms in those patients who most frequently attend outpatient services.

	Methods

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South Thames (West) NHS region has recorded outpatient hospital activity in computerised form since 1991. To identify frequent attenders we defined a population in which potential subjects were all patients in the region aged 18-65 years who had a new appointment to secondary medical or surgical care in 1993 (index appointments). We excluded specialties for specific conditions, such as obstetrics (but not gynaecology), oncology, and psychiatry.

We followed patients with index appointments over a three year period to assess their overall service use within the region by counting all outpatient appointments. The population was stratified by two age groups (18-45 years and 46-65 years). Frequent attenders were then defined as the top 5% of outpatient users in each age group.

We randomly selected 200 patients from the total in each age group (24 489 aged 18-45 years; 36 743 aged 46-65 years) for inclusion in the study. The study was approved by the local research ethics committee.

A consultation episode was defined as all appointments after referral and was completed after discharge, death, or referral elsewhere. We recorded details of the reason(s) for referral and identified investigations and treatment received at each appointment. Finally, we noted the diagnosis (if given) for each consultation episode and determined whether the episode was medically unexplained, mixed (evidence of both physical and psychological disorder), or factitious. Criteria for a medically unexplained episode were that the patient presented with physical symptoms, the patient received investigations for these symptoms, and the investigations and clinical examination revealed no abnormality or only abnormalities that were thought to be trivial or incidental. ^{7 8}

	Results

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Of the 12 NHS trusts we contacted in the region, only one refused examination of its medical records. A total of 361 (90%) sets of case notes were traced and obtained for examination: 189 (95%) for patients aged 18-45 years and 172 (86%) for patients aged 46-65. In total 971 consultation episodes were recorded. The median number of referrals (consultation episodes) over the three year period was 2 (range 1-8) and the overall median number of appointments was 18 (range 13-45).

Table 1 shows the demographic characteristics of the frequent attenders. Of the 361 patients, 97 (27%) had one or more medically unexplained episodes. Of the 971 consultation episodes, 164 (17%) were "definitely" medically unexplained, 44 (5%) were "probably" medically unexplained, 30 (3%) were mixed episodes, and 1 (0.1%) was recorded as a factitious disorder.

Table 2 shows the referral complaints divided into 30 categories and the number of consultation episodes stratified by age and the percentage that were medically unexplained. Medically unexplained symptoms occurred commonly in all of the specialties investigated with the exception of dermatology. Gastroenterology and neurology had a particularly high rate, with at least 50% of referrals remaining medically unexplained. More details are given on the BMJ's website.

	Discussion

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In this study of medically unexplained symptoms we found that such symptoms are common in patients who frequently attend several secondary care specialties. Most previous studies on this issue have focused on primary care settings. By looking at secondary medical care, we have used a population that has been extensively investigated, thus affording a greater degree of confidence in the patients' diagnoses. By including different hospitals and a range of specialties we were able to capture a comprehensive record of healthcare usage, which is important as these symptoms often involve more than one bodily system and patients may be attending different clinics. The principal methodological limitation was the retrospective use of medical records for data collection. However, the most important information for the purpose of this studydetails of investigations and final diagnosisare generally well documented in hospital case notes. A further limitation is that although the reliability of this method in recognising medically unexplained symptoms has been shown,⁷ there has been no evaluation of its validity.

Complaints that often remain medically unexplained in primary care and in new patients attending clinicsabdominal pain, headache, and low back painare also likely to remain medically unexplained in frequent attenders. While some patients with unexplained symptoms are discharged from secondary care after their assessment, many continue to attend, are often referred on to another specialty, and become frequent attenders in secondary care.

Medically unexplained symptoms are associated with high rates of disability.^9-11 Patients report poorer levels of physical and social functioning than those who receive a medical diagnosis and spend between 1.3 and 4.9 days in bed each month compared with patients with major medical problems, who average one day or less. ^{9 12} The management of patients with unexplained symptoms is perceived as unsatisfactory from the perspective of both the patient and the physician.¹³ Also, patients may undergo extensive investigation and medical treatment, which may not only be inappropriate but also hazardous.¹⁴ Iatrogenic factors such as inappropriate information, overinvestigation, and overtreatment are common in the management of these patients. ^{15 16} Avoidance of these factors forms the mainstay of most advice on management.¹⁷ We have shown that medically unexplained symptoms account for a considerable proportion of presentations in frequent attenders in secondary care and conclude that these patients should be considered a focus for attention.

	Acknowledgments

We thank all of the NHS trusts who agreed to participate in this study and in particular the medical records staff who assisted in retrieval of case notes. We also thank Dr R Hooper for providing statistical advice and helpful comments on the paper.

Contributors: All authors were involved in the planning and design of the study. SR collated and analysed the data and was the principal writer of the paper. SW helped in interpretation of the data and writing of the paper. TC took part in the study design. MH participated in the analysis and interpretation of data and writing of the paper. SR, TC, and MH are guarantors.

	Footnotes

Editorial by Turner

Funding: NHS Executive National Research and Development Programme.

Competing interests: None declared.

The full version of this paper appears on the BMJ's website

	References

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1.	Zook CJ, Moore FD. High-cost users of medical care. N Engl J Med 1980; 302: 996-1002[Medline].
2.	Garfinkel SA, Riley GF, Iannacchinoe VG. High-cost users of medical care. Health Care Financing Review 1988; 9: 41-52[Medline].
3.	Wamoscher Z. The returning patient: a survey of patients with high attendance rate. J Coll Gen Pract 1966; 11: 166-173.
4.	Kroenke K, Mangelsdorff AD. Common symptoms in ambulatory care: incidence, evaluation, therapy, and outcome. Am J Med 1989; 86: 262-266[Medline].
5.	Bass C, Bond A, Gill D, Sharpe M. Frequent attenders without organic disease in a gastroenterology clinic. Gen Hosp Psychiatry 1999; 21: 30-38[Medline].
6.	Fink P. The use of hospitalizations by persistent somatizing patients. Psychol Med 1992; 22: 173-180[Medline].
7.	Reid S, Crayford T, Richards S, Nimnuan C, Hotopf M. Recognition of medically unexplained symptomsdo doctors agree? J Psychosom Res 1999; 47: 483-485[Medline].
8.	Hotopf M, Mayou R, Wadsworth M, Wessely S. Childhood risk factors for adults with medically unexplained symptoms: results from a national birth cohort study. Am J Psychiatry 1999; 156: 1796-1800[Abstract/Full Text].
9.	Smith Jr GR, Monson RA, Ray DC. Patients with multiple unexplained symptoms: their characteristics, functional health and health care utilization. Arch Intern Med 1986; 146: 69-72[Medline].
10.	Katon W, Lin E, von Korff M, Russo J, Lipscomb P, Bush T. Somatization: a spectrum of severity. Am J Psychiatry 1991; 148: 34-40[Abstract].
11.	Escobar JI, Burman MA, Karno M, Forsythe A, Golding JM. Somatization in the community. Arch Gen Psychiatry 1987; 44: 713-718[Medline].
12.	Wells KB, Stewart A, Hays RD, Burman A, Rogers W, Daniels M, et al. The functioning and well-being of depressed patients: results from the medical outcomes study. JAMA 1989; 262: 914-919[Medline].
13.	Lin EHB, Katon W, von Korff M, Bush T, Lipscomb P, Russo J, et al. Frustrating patients: physician and patient perspectives among distressed high users of medical services. J Gen Intern Med 1991; 6: 241-246[Medline].
14.	Fink P. Surgery and medical treatment in persistent somatizing patients. J Psychosom Res 1992; 36: 439-447[Medline].
15.	Kouyanou K, Pither C, Wessely S. Iatrogenic factors and chronic pain. Psychosom Med 1997; 59: 597-604[Medline].
16.	Kouyanou K, Pither CE, Rabe-Hesketh S, Wessely S. A comparative study of iatrogenesis, medication abuse, and psychiatric morbidity in chronic pain patients with and without medically unexplained symptoms. Pain 1998; 76: 417-426[Medline].
17.	Wilkie A, Wessely S. Patients with medically unexplained symptoms. Br J Hosp Med 1994; 51: 421-427[Medline].

(Accepted 21 December 2000)