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Three Part Question

Can the number of [Emergency Room visits] and the [phase of the lunar cycle] be linked [ showing more visits during the full moon]?

Clinical Scenario

Your last evening shift in the emergency department was particularly busy. The charge nurse remarked, "There must be a full moon out tonight." You wonder if there is truly any link between ED census and the lunar phases, or is this belief simply a myth.

Search Strategy

Medline 1966-07/07 using the OVID interface, Cochrane Library (2007), PubMed clinical queries.
[(exp moon OR lunar.mp) AND (exp emergencies OR emergency.mp OR emergency medicine OR exp emergency medical services OR exp emergency service, hospital)]. LIMIT to human AND English

Search Outcome

35 papers were found, of which 29 papers were irrelevant to the study question or of insufficient quality for inclusion.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Thompson DA. Adams SL 1996 March United States	All patients seen in the emergency room of a community hospital over 4 years	This study was a retrospective analysis of effect of the lunar cycle on the number of ED visits and hospital admissions	Number of Patients seen in ER on each day of the lunar cycle	There was no statistical increase during the full moon	The study does not break the patients up by complaint and demographics
			Percentage of Patients arriving by ambulance on each day of the lunar cycle	There was no statistical increase during the full moon
			Percentage of total patients that wereadmited during each day of the lunar cycle	There was no statistical increase during the full moon
			Percentage of total patients that wereadmited to a monitored unit during each day of the lunar cycle	There was no statistical increase during the full moon
Wolbank S. Prause G. Smolle-Juettner F. Smolle J. Heidinger D. Quehenberger F. Spernbauer P 2003 July Austria	Patients with life threatening condition that were evaluated by the staff of 4 emergency vehicles in an urban community	This is a retrospective study looking at the relationship of number of emergency cases and the phase of the moon, distance of moon from earth, and in regards to the sign of the Zodiak	The influence of the Lunar cycle to the number of emergency cases	No corelation between the number of emegency cases and the phase of the moon	The tables are difficult to follow. They are not very clear on who was evaluating these patients and determining who was sick and who was not. Half of the patients evaluated where determined not to be sick enough to be included in the study
			The influence of the distance the moon is from the earth on the number of emergency cases	There is no significant relationship between the distance the moon is from the earth and the number of emergency cases
			Does the sign of the zodiak influence the number and type of emergency cases	There was no relationship between the sign of the Zodiak and the number of type of emergency cases
Zargar M. Khaji A. Kaviani A. Karbakhsh M. Yunesian M. Abdollahi M 2004 May. India	5800 trauma patients, 3543 excluded due to lack of data seen at three large medical centers in Tehran	A retrospective study evaluating the effect of the lunar cycle on the number of trauma admissions to the ER, the GCS score, and the severity of injuries	The relationship of the Full moon on the number of Trauma admissions to the ER	There was not relationship between the number of ER trauma admissions and the full moon	The definition of the severity of the trauma is lacking. This study is only looking at trauma pts
			The relationship of the patient's GCS score and the Full moon	There was not a significant lower average GCS score on the full moon
			The relationship between the severity of the injury and the Full moon	The severity of injury was not increased during the full moon

Comment(s)

Numerous articles have been published examining the relationship between the moon and human behavior. The findings of these studies have been contradictory and confusing. Some of these studies did not control for confounding variables such as month or day of the week. Another potential problem in the evaluation of the lunar effect is inadequate sample size. A large sample size in necessary to be able to detect weak trends. Trauma or psychiatric cases that arrive on full moon days may be more memorable to staff members whose expectations were piqued. This serves as positive reinforcement for their belief in lunar effects.

Clinical Bottom Line

The presence of a full moon appears to have no effect on ED patient volume, ambulance runs, admissions to the hospital, or admissions to a monitored unit. The expression, "There must be a full moon out tonight," will likely remain in emergency medicine folklore. However, the belief that the ED is busier during the full moon cannot be substantiated.

References

1. Thompson DA. Adams SL Full moon and ED Patient Volumes: Unearthing a Myth American Journal of Emergency Medicine March 1996:161-4
2. Wolbank S. Prause G. Smolle-Juettner F. Smolle J. Heidinger D. Quehenberger F. Spernbauer P The Influence of Lunar Phenomena on the Incidence of Emergency Cases. Resuscitation Issue 58 (2003):97-102,
3. Zargar M. Khaji A. Kaviani A. Karbakhsh M. Yunesian M. Abdollahi M The full moon and admission to emergency rooms Indian Journal of Medical Sciences Vol58(5):191-5, 2004 May.