Static and Dynamic Variables Associated with Inpatient Aggression: A Two-Year Retrospective Study: Variables statiques et dynamiques associées au comportement agressif des patients hospitalisés : étude rétrospective de deux ans

Abstract

Background

Aggressive behaviour is common in mental health inpatient units, and can cause physical and psychological harm, low work satisfaction among staff and be disruptive to the clinical care of patients. Identification of static and dynamic variables associated with inpatient aggression may help identify opportunities for intervention to reduce such incidents.

Method

We carried out a two-year retrospective study of consecutive admissions to the Centre for Addiction and Mental Health, the largest mental health facility in Canada. We created a multivariable model of risk factors associated with aggression, which included static and dynamic variables, as well as the Dynamic Appraisal of Situational Aggression (DASA), which was measured daily.

Results

We included 4419 consecutive admissions comprising 88,124 patient-days. We found that High and Medium DASA scores were strongly associated with subsequent aggression (HR = 9.64, 95% CI = 7.75–11.99, and HR = 3.51, 95% CI = 2.82–4.37, respectively) after controlling for other variables. Other variables associated with aggression included the Aggressive Behaviour Scale of the Resident Assessment Instrument—Mental Health (RAI-ABS), male gender, younger age, ethnicity, PRN (as needed medication) administration, unit type, involuntary admission, medication refusal and self-harm. However, these variables were more weakly associated with subsequent aggression as compared to the DASA score categories.

Conclusions

Higher DASA scores are strongly associated with aggression after controlling for a range of other patient variables. Frequent structured measurement of dynamic variables using the DASA may help identify patients most at risk of aggression and assist clinical staff in directing interventions to where they are most needed to reduce aggression on inpatient units.

Plain Language Summary Title

What Factors Are Linked to Aggression in Mental Health Hospitals? A Two-Year Study

Plain Language Summary

Aggression in mental health hospitals is a serious concern. It can lead to injuries for staff and patients, cause emotional stress, and interfere with patient care. Being able to predict when aggression might happen can help staff take steps to prevent it. This study looked at over 4,400 patient admissions to Canada’s largest mental health hospital over two years. We analyzed more than 88,000 days of patient care to understand what factors were linked to aggression. We used a tool called the Dynamic Appraisal of Situational Aggression (DASA), which staff complete daily to assess how likely a patient is to become aggressive. We also looked at other factors, such as age, gender, use of â€oeas needed†medication, whether a patient was admitted involuntarily, and if they had refused medication or engaged in self-harm. The results showed that high or medium DASA scores were strongly linked to aggressive incidents, even when considering other factors. While things like age, gender, and previous behavior were also related to aggression, they were not as strongly predictive as DASA scores. This suggests that tracking day-to-day changes in behavior using tools like the DASA can help staff identify which patients are most at risk of becoming aggressive. This allows them to take early action, such as adjusting care or support, to help reduce aggression and keep the ward safer for everyone.