# The Effect of Pain on the Relationship Between Triage Acuity and Emergency Department Hospitalization Rate and Length of Stay

## TL;DR

This study shows that pain intensity affects how well triage levels predict hospitalization in emergency departments, leading to overtriage in patients with mild or moderate pain.

## Contribution

The study is the first to demonstrate that pain intensity modifies the relationship between triage acuity and hospitalization outcomes in U.S. emergency departments.

## Key findings

- Triage level 1 was associated with the highest hospitalization rate, but mild and moderate pain groups showed lower-than-expected odds of hospitalization.
- Pain intensity negatively impacts triage accuracy for hospitalization predictions, suggesting overtriage in mild and moderate pain groups.
- Emergency department length of stay patterns remained consistent across all pain intensity groups.

## Abstract

Little is known about the effect of pain on the relationship between triage and patient outcomes in United States emergency departments (ED). In this study we aimed to describe pain-associated ED visits and to explore how pain modifies the ability of ED triage to predict patient outcomes (hospitalization and ED length of stay [EDLOS)].

We obtained data from the National Hospital Ambulatory Medical Care Survey (NHAMCS), 2010–2021. Adult ED visits without missing data on pain score or triage level were included. We assessed pain scores at triage using a numeric rating scale (NRS) of 0–10. We further categorized the NRS scores into no (0), mild (1–3), moderate (4–6), and severe (7–10) pain. The five-level Emergency Severity Index was used for ED triage. The primary outcomes were hospital admission during the ED visit and EDLOS. For the analyses we used descriptive statistics and multivariable regression accounting for NHAMCS’s complex survey design.

Over the 12-year study period, there were 132,308 adult ED visits (representing 773,000,000 ED visits nationwide). Approximately 50% were triaged to level 3, followed by 30% to level 4. Approximately 45% reported severe pain, 21% moderate pain, 9% mild pain, and 25% no pain. Triage level 1 was associated with the highest rate of hospitalization (35%), with a gradual decrease in hospitalization rate from levels 2 to 4. Triage level 2 was associated with the longest mean EDLOS (5.6 hours), with a gradual decrease in EDLOS from levels 3 to 5. When stratified by pain intensity, the pattern of hospitalization altered in the mild and moderate pain groups. In these two pain-intensity groups, triage level 1 was associated with lower-than-expected odds of hospitalization, a 31% reduction suggested by the interaction term (adjusted odds ratio 0.69; 95% confidence interval .51–.92, P = .01). By contrast, the pattern of EDLOS persisted across all pain-intensity groups.

Mild and moderate levels of pain intensity appear to negatively impact the ability of triage to predict hospitalization, resulting in overtriage among patients in these two pain-intensity groups. Pain intensity in the ED should be carefully evaluated to avoid overtriage and ensure the appropriate allocation of resources.