Path analysis modeling indicates free transport increases ambulance use for minor indications

Ting, Joseph Yuk Sang and Chang, Allan M. Z. (2006) Path analysis modeling indicates free transport increases ambulance use for minor indications. Prehospital Emergency Care, 10 4: 476-481. doi:10.1080/10903120600885209

Author Ting, Joseph Yuk Sang
Chang, Allan M. Z.
Title Path analysis modeling indicates free transport increases ambulance use for minor indications
Journal name Prehospital Emergency Care   Check publisher's open access policy
ISSN 1090-3127
Publication date 2006-10-01
Sub-type Article (original research)
DOI 10.1080/10903120600885209
Volume 10
Issue 4
Start page 476
End page 481
Total pages 6
Place of publication London, United Kingdom
Publisher Informa Healthcare
Language eng
Subject 320000 Medical and Health Sciences
Formatted abstract
Clinically unnecessary ambulance transport is increasing, diverting limited resources from patients needing ambulance transport. It was anecdotally observed that inappropriate ambulance use increased after abolition of a direct patient cost for ambulance transport.


In July 2003, direct patient fees were abolished in favor of a universally applied ambulance levy, potentially leading to increased ambulance use by patients with low illness acuity and admission rates.

The influence of age, illness acuity, and need for admission on ambulance use was assessed for 55,397 emergency department attendances in 2002 and 2004. Ambulance users were compared with nonusers in both years and attendances for 2002 compared with 2004 using chi-square test for two groups. Logistic regression provided a multivariate model leading to ambulance use. Path analysis modeling to assess interrelationships between factors associated with ambulance use was developed.

Ambulance users in both years were older, had more acute illness, and had greater need for admission compared with nonusers. The odds ratio (OR) of arrival by ambulance in 2004 compared with 2002 was 1.14 (95% confidence interval, [CI], 1.12 to 1.17). In 2002, ambulance users were older (OR, 1.42; 95% CI, 1.40 to 1.43), were more likely to need admission (OR, 2.28; 95% CI, 2.16 to 2.4) and had higher illness acuity (OR, 2.02; 95% CI, 1.94 to 2.09). There was a negative correlation between 2004 and illness acuity.


Ambulance use increased in 2004 after patient transport fees were abolished. Increased use was associated with decreased age, clinical acuity, and admission need. Abolishing direct patient cost stimulates ambulance use, potentially including inappropriate transport. Path analysis to assess the effect of changed funding on ambulance use could be used to the influence of other locally relevant factors contributing to ambulance use.
Keyword Ambulance use
Path analysis
Free patient transport
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
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Created: Mon, 06 Nov 2006, 10:00:00 EST by Joseph Y. Ting on behalf of School of Medicine