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I read with interest the article by Skinner, Carter and Haxton
assessing whether case management of frequent attenders to an urban
emergency department reduces frequency of subsequent attendances.1 The
case for multidisciplinary management of frequent attenders is well-made
and the reported practice of case review and implementation of care plans
However, a possible c...
However, a possible considerable limitation to this study is not
fully elucidated in the authors’ discussion. While mention is made that
the reduction seen in attendances by frequent attenders following case
review “may be due to the natural ebb and flow in the presentations of
these patients”1, comment is not made on the potential substantial effects
of the differing seasons in which the study was conducted (October 2006 to
March 2007 control, compared to April 2007 to September 2007 post-
Watters et al have previously observed that the number of patient
attendances to the Emergency Department at the Royal Infirmary Edinburgh
is subject to monthly variation.2 Chi-squared analysis of the total
numbers of patients presenting each month presented by Watters et al
confirms variation in numbers of patients by month (chi2 = 105.24, p
<0.001) even when the varying numbers of days in each month is taken
into account (chi2 = 57.03, p <0.001).
Further to this variation in total attendances is the seasonal
variation in presentations of different clinical conditions. The most
common documented diagnoses in this group of frequent attenders was stated
to include “alcohol-related problems (46%), mental health problems (37%)
and chronic complaints such as abdominal or chest pain (40%)”. Other
diagnoses included COPD / asthma and drug abuse. However, the
presentations of many of these conditions have been shown to be subject to
seasonal variation. Arkfen et al’s study of frequent visitors to
psychiatric emergency services found that admission was more frequent in
inclement weather 3; Halpern et al observed a seasonal variation in
emergency department “psychiatric visits” with results supporting the
“existence of a Christmas effect”, they also noted that substance abusers
were more likely to attend the emergency department during the weeks
surrounding Christmas 4.
It is also known that patients with ischaemic heart disease are more
likely to become severely symptomatic during colder temperatures, and
“cold stress” contributes to a higher mortality rate from this condition
during the winter 5. Winter predominance seasonal variation in
presentation rates for abdominal pain is also suspected, and has been
demonstrated in children 6. Ballester et al observed “clear temporal
patterns of COPD emergency” with more emergencies in winter 7.
With more than half of the frequent attenders’ documented diagnoses
subject to seasonal variation with increased presentations during winter
months, it would appear that there is an as yet unaddressed confounding
bias in the observed decreased number of subsequent attendances in the
(summer) months following case management intervention. I eagerly await
the mentioned follow-up study, and will be interested to ascertain whether
the results seen so far are indeed sustainable over time.
Competing interests: None
1. Skinner J, Carter L, Haxton C. Case management
of patients who frequently present to a Scottish emergency department.
Emerg Med J 2009; 26: 103-105.
2. Watters DA, Brooks S, Elton RA, et al. Sports
injuries in an accident and emergency department. Emerg Med J 1984; 1: 105
3. Arfken C, Zeman LL, Yeager L, et al. Frequent
visitors to psychiatric emergency services: staff attitudes and temporal
patterns. J Behav Health Serv Res 2002; 29(4): 490-496.
4. Halpern SD, Doraiswamy PM, Tupler LA, et al.
Emergency department patterns in psychiatric visits during the holiday
season. Ann Emerg Med 1994; 24(5): 939-943.
5. Houdas Y, Deklunder G, Lecroart JL. Cold
exposure and ischemic heart disease. Int J Sports Med 1992; 13 Suppl1:
6. Saps M, Blank C, Khan S, et al. Seasonal
variation in the presentation of abdominal pain. J Pediatr Gastroenterol
Nutr 2008; 46(3): 279-84.
7. Ballester F, Pérez-Hoyos S, Rivera ML, et al.
[The patterns of use and factors associated with the patient admission of
hospital emergencies for asthma and chronic obstructive pulmonary
disease]. Arch Bronconeumol 1999; 35(1): 20-26.