St James's University Hospital, Leeds
Leeds General Infirmary
Academic Unit of Child and Adolescent Mental Health, Leeds, UK
Correspondence: Dr Nicola J. Dummett, Child and Family Unit, St James's University Hospital, Beckett Street, Leeds LS9 7TF, UK
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ABSTRACT |
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Aims To test the hypothesis that such presentations are followed by higher long-term utilisation rates of secondary health care even excluding further abdominal symptoms, and particularly for self-harm, than presentations with acute appendicitis.
Method New hospital attendance rates, liaison psychiatry attendances and self-harm attendances of patients with normal appendices at emergency appendicectomy were compared with those of appendicitis patients.
Results Attendance rates of all kinds were significantly higher for normal appendix patients than for appendicitis patients, with equal strengths of finding for males and females.
Conclusions People with normal appendices at emergency appendicectomy show higher long-term rates of hospital attendance. This has implications for how these patients are best managed by health care systems.
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INTRODUCTION |
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METHOD |
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Sample
The sample size was determined by examining the records of a random sample
of 20 patients who had attended a West Leeds hospital at least once since 1984
and noting the number of recorded hospital attendances for each patient. These
data (mean 1.4 attendances over 16 years, s.d.=0.84) indicated that at 5%
significance level and 80% power, 253 normal appendix cases and 253 inflamed
appendix comparisons would be needed to detect a difference in means of 0.2
(15%).
To provide at least 15 years' post-operative observation, histology records were scrutinised for consecutive appendix specimens removed in West Leeds hospitals from 1984 onwards. The pathologist (N.J.M.) excluded patients with indeterminate tissue findings, and assigned 336 patients whose appendices had no pathologic change to a normal appendix group and 333 patients whose appendices were acutely inflamed to an inflamed appendix comparison group. Equal numbers of cases from each group were taken for each year of sampling to reduce differential cohort effects. Case notes were untraceable for 168 patients (82 from the normal appendix group and 86 from the inflamed appendix group). Case notes for each of the remaining patients were obtained, and N.J.M. excluded a further 25 patients (20 normal appendix and 5 inflamed appendix) where other causative tissue changes (for example, a ruptured ovarian cyst) had been evident at laparotomy or where appendicectomy had not followed a clinical suspicion of acute appendicitis. The second researcher (N.J.D.), masked to appendix histological status (normal or inflamed) of each patient, then scrutinised the notes for every hospital contact at any of the West Leeds hospitals over the patient's lifetime to quantify attendance data up to the year 2000. Finally, 20 patients over 65 years of age at the time of the study were excluded.
Measures
The general measure of attendance chosen for this study was lifetime new
hospital attendance rate expressed as attendances per notional 100 years. This
was, for each patient, calculated from the sum of new out-patient appointments
actually attended, case note records of attendances at accident and emergency
departments (attendances resulting in admission and therefore entries in the
hospital case notes), and unplanned in-patient and out-patient attendances
over the patient's lifetime (i.e. from birth to the study date), divided by
the patient's age at the study date. This measure therefore included
attendances both before and after appendicectomy, but excluded routine
follow-up visits and planned admissions. New attendance rates were chosen
because, first, the focus of interest in this study was the point of entry
into the hospital system, which is more related to patient (and referrer)
variables than within-hospital activity, which is more strongly determined by
hospital medical staff. Second, the preliminary audit showed total (new and
follow-up visit) attendance data to be so widely distributed about the mean
that sample sizes of thousands of cases would be necessary to show group
differences with any degree of certainty. In comparison, lifetime new hospital
attendance data were far more closely distributed about the mean. The audit
also showed that thousands of patients would be required to make comparisons
between actual hospital in-patient episodes because these were much rarer
events.
Records of clinical contacts over each patient's lifetime were scrutinised and the nature of the presenting complaint on each occasion was recorded. Presentations as a result of deliberate self-harm and attendances at hospital liaison psychiatry services were noted. Occasions on which patients had presented with anterior abdominal pain that was not clearly attributable to another organ system (for example, a clear history of menorrhagia or confirmed urinary tract infection) were also specifically recorded. This enabled calculation of non-abdominal attendance rates by excluding presentations that might have been due to residual undetected abdominal disease and therefore possibly overrepresented in the normal appendix group.
Statistical analyses
Attendance rates were found to be skewed, with a large proportion of each
group having an attendance rate of zero (no other hospital contact than the
index appendicectomy admission). Non-parametric tests were therefore applied
to differences in attendance rates between subject and comparison groups using
the Statistical Package for the Social Sciences
(SPSS, 2001). Variables such
as attendances with self-harm or liaison psychiatry attendances, where values
were commonly zero, were converted to binary variables indicating presence or
absence but with no magnitude of the variable for each case. Relative risk
calculations using 2 x 2 tables and the formula of Altmann (1991: p.
267) and logistic regression were then performed to compare groups. The sample
was further subdivided by gender and age at appendicectomy to yield a
childhood appendicectomy group (ages up to and including 18 years) and an
adult appendicectomy group (ages 19 years and above), and attendance rates
were then compared for normal appendix and inflamed appendix patients within
these subgroups. The effects on hospital attendance of age, of appendix
histology, of age at appendicectomy and of gender were further investigated by
regression analysis of total lifetime new hospital attendance.
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RESULTS |
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All attendance rates of all kinds studied were higher for patients in the normal appendix group than for the inflamed appendix patients for the entire sample and for every subgroup studied (Tables 3, 4 and 5). These findings held at the 5% level of significance for the entire sample and held consistently for both male and female subgroups and for childhood and adult appendicectomy subgroups, but with varying degrees of strength with inevitable losses of statistical precision being due to the smaller sizes of these subgroups (Tables 4 and 5).
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Lifetime new hospital attendances and non-abdominal
attendances
For the entire sample, the median lifetime new attendance rate of the
normal appendix patients (6.5 attendances per notional 100 years) was 1.9
times that of the inflamed appendix patients (3.4 attendances per notional 100
years) (Table 3). This finding
held even when presentations with abdominal symptoms were excluded: for the
entire sample, median lifetime new non-abdominal attendance rate
of the normal appendix patients (5.4 attendances per notional 100 years) was
1.9 times that of the inflamed appendix patients (2.9 attendances per notional
100 years) (Table 3). These
findings remained significant both for all males and for all females in the
whole sample, when analysed separately
(Table 4).
Deliberate self-harm and psychiatric attendances
For the entire sample, the percentage of normal appendix patients attending
hospital with deliberate self-harm (7.9%) was 3.6 times that for inflamed
appendix patients (2.2%), a significantly raised relative risk
(Table 5). For the entire
sample, the percentage of normal appendix patients with psychiatric
attendances (10.5%) was 2.6 times that for inflamed appendix patients (4.0%),
also a significantly raised relative risk
(Table 5).
Calculations using logistic regression produced similar results, although with consistently higher values both for the estimates of relative risk and for the upper confidence limits for both deliberate self-harm and liaison psychiatry attendances. Table 5 gives the more conservatice results.
Gender effects
Subgroup analyses by gender and age at appendicectomy (Tables
4 and
5) showed no significant
overall effect of female gender. Regression analysis to look at the effects of
gender, age, appendix histology (normal or inflamed) and age at appendicectomy
on total hospital attendance showed that only appendix histology had
significant influence on the total number of new hospital attendances
(Table 6).
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DISCUSSION |
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Increased lifetime hospital attendance
In this study, people who underwent emergency removal of a normal appendix
tended to account for nearly twice as many new hospital encounters over their
lifetime as did those with acute appendicitis, even when further presentations
with possible undiagnosed abdominal disease are excluded. This result is
therefore not just the result of persistent undiagnosed abdominal disease in
the normal appendix group. The fact that attendance rates were
not binomially distributed in this group
(Table 3) suggests that the
results are not just owing to the behaviour of a frequently attending
minority. These findings confirm earlier reports of non-significant trends in
smaller studies, and suggest that increased hospital attendance is an enduring
behavioural trait, probably related to increased contributions from
psychosocial factors, as suggested in earlier studies.
Self-harm and liaison psychiatry attendance
The hospital attendance discrepancy between the normal and inflamed
appendix groups shows a nearly four-fold ratio for self-harm and attending
liaison psychiatry. These results also confirm earlier findings of
non-significant trends in smaller studies.
Gender and age effects
Unlike previous studies, this study finds no significant overall effect of
female gender. Gender differences between normal and inflamed appendix groups
do not appear to have contributed to the results in an important way. Gender
effects may, of course, be strongly culturally determined and have reduced
since earlier studies. The regression analysis of total hospital attendance
also suggests that gender, age, and age at appendicectomy differences between
the normal and inflamed appendix groups have not contributed significantly.
The study exclusion criteria do not appear to have influenced gender or age
distributions between comparison groups, since gender and age distributions
for included and excluded cases from each comparison group are broadly the
same.
Limitations of the study
A weakness of this study is that it was not prospective, but outcome events
all preceded data collection, which was carried out masked to appendix
histology. Second, it is undoubtedly the case that significant migration would
have occurred over the course of these case histories and many patients would
have been lost to follow-up. There is no reason to believe, however, that
migration would have affected the comparison groups differentially to produce
a systematic bias. A further weakness is that attendance figures have not
included all accident and emergency attendances because only those resulting
in hospital admission were recorded in the in-patient medical record. However,
there are no grounds to suspect that this incompleteness of data has biased
the comparisons made. Additionally, we made no attempt to trace hospital
contacts at the other large Leeds hospital because we judged that disregarding
such attendances would also not introduce systematic bias into the study.
Clinical implications
Children and adults found to have a normal appendix at emergency
appendicectomy have a significantly higher number of lifetime hospital
attendance for all presentations, and not simply further abdominal
presentations, than people found to have acute appendicitis. They are also at
significantly higher risk of the adverse outcomes of self-harm and psychiatric
disturbance. Emergency removal of a normal appendix is a frequent treatment
event; identifying and helping patients to tackle underlying psychosocial
problems that have been repeatedly shown to increase health care-seeking
behaviour should yield clinical and financial benefits. This has implications
for clinicians and managers. It is of note that very few case records in this
study reported (either in the case notes themselves or in the accompanying
nursing notes) the giving of advice or assistance for even extreme
psychosocial stressors. Certainly, a large number of comments recorded in the
medical notes implied continuing adherence to an exclusively medical model for
illness presentation and management, for example: I am convinced there
is no surgical cause for these symptoms, but I have no choice but to
operate; I have reassured this patient four times today and
still there is no improvement; and threatened to take an
overdose if not seen by a surgeon orthopaedic surgeon to see urgently
please.
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Clinical Implications and Limitations |
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LIMITATIONS
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ACKNOWLEDGMENTS |
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REFERENCES |
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Received for publication February 13, 2002. Revision received June 26, 2002. Accepted for publication June 27, 2002.
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