The association between the lunar cycle and patterns of patient presentation to the emergency department

Abstract

Aim: To determine any association between the lunar synodic or anomalistic months and the nature and volume of emergency department patient consultations and hospital admissions from the emergency department (ED). Design: A retrospective, descriptive study. Setting: All South African EDs of a private hospital group. Patients: All patients consulted from 01 January 2005 to 31 December 2010. Methods: Data was extracted from monthly records and statistically evaluated, controlling for calendric variables. Lunar variables were modelled with volumes of differing priority of hospital admissions and consultation categories including; trauma, medical, paediatric, work injuries, obstetrics and gynaecology, intentional self harm, sexual assault, dog bites and total ED consultations. Main Results: No significant differences were found in all anomalistic and most synodic models with the consultation categories. Small but significant increases were found with a small number of synodic models around full moon with some categories, P2 medical, total paediatric consultations and total admissions. Significant decreases in admissions, particulary total admissions, were found around perigee. The effect sizes of all significant lunar associations were smaller than those of the calendric variables. Conclusions: Most comparisons demonstrated no lunar association. Small but significant associations were demonstrated around full moon with some synodic models. A number of anomalistic admission models demonstrated small but significant decreases in admissions at perigee.