INTRINSIC score could aid clinicians with triage

A novel risk prediction score identified intracerebral hemorrhage (ICH) patients at low risk for needing intensive care unit (ICU) services, a retrospective study showed.

Systolic blood pressure (SBP), Glasgow Coma Scale score, intraventricular hemorrhage, and ICH volume were independent predictors of critical care and made up the INTRINSIC score, reported Roland Faigle, MD, PhD, of Johns Hopkins University in Baltimore, and co-authors in Neurology.

While the score needs prospective validation, it can “aid clinicians with triaging of ICH patients by reliably predicting the risk of critical care interventions,” the researchers said. “Similarly, our score identifies ICH patients at low risk for critical care interventions, and patients with a score <2 may be considered for management in a stroke unit without critical care capabilities.”

Despite growing interest in criteria for ICU admission and its effect on medical and economic outcomes, “there are no established parameters that allow for risk stratification of risk of critical care needs in ICH patients, and there is no universally agreed-upon algorithm which identifies ICH patients who may forgo ICU admission,” Faigle and colleagues observed.

The researchers included 451 ICH patients between 2010-2018 at Johns Hopkins who were randomized to a development or a validation cohort in their analysis. All were initially admitted to the ICU and followed for use of specific services, including conditions requiring titration of IV antihypertensives or vasopressors, use of rate-modifying IV medications or procedures, and others.

The primary outcome was the need for a critical care intervention at any point during the hospitalization. Overall use of defined ICU services was 80.3%. Independent predictors of ICU needs were determined in logistic regression based on strength of observed associations to develop the score, which ranged from 0-9 with higher scores increasing the likelihood of need for ICU services.

The final score model included:

  • SBP 160-190 mm Hg, 1 point; SBP >190 mm Hg, 3 points.
  • Glasgow Coma Scale score 8-13, 1 point; score <8, 3 points.
  • Presence of blood in the ventricles (intraventricular hemorrhage) 1 point.
  • ICH volume 16-40 cm3, 1 point; >40 cm3, 2 points.

In the internal validation cohort, each 1-point increase in the score was associated with a 3-fold increase in odds for a critical care intervention with OR 3.00 (95% CI 2.13-4.22). For patients with a score of ≥1, odds of ICU needs were OR 37.36 (95% CI 10.26-136.04) compared with those with a score of 0.

In an external validation cohort from University Hospitals Cleveland Medical Center in Ohio, each 1-point increase in the score was associated with about a 2-fold increase in odds for a critical care intervention (OR 1.96, 95% CI 1.70-2.26) and odds of ICU needs in patients with a score ≥1 were about 6 times higher than in patients with a score of 0 (OR 6.22, 95% CI 2.49-15.55).

The area under the curve (AUC) for the internal validation cohort was 0.880 (95% CI 0.833-0.928), and for the external validation cohort 0.823 (95% CI 0.782-0.863).

“High specificity may be particularly desirable when contemplating potential patient transfer (or no transfer) to tertiary centers,” the researchers wrote. “We therefore propose a cut-point that predicts absence of critical care needs with high specificity (low false-positives), such as a score <2, which predicted the absence of critical care with 88.5% specificity in the external validation cohort.”

“With increasing resource constraints, such as the height of the Covid-19 pandemic when open ICU beds are a rarity, a higher score cut-point such as <3 could be considered,” they added.

In an accompanying editorial, Matthew Maas, MD, MS, of Northwestern University in Chicago, noted that in the past year, the “overwhelming demand for critical care services has highlighted the need to allocate services rationally and efficiently, but triage guidelines are broad and decisions are often subjective.”

“Like other prognostic scores, the INTRINSIC Score is best used alongside other clinical considerations since there will always be factors that are relevant on an individual level but aren’t common enough to emerge as statistical predictors in a model,” he suggested. “Integrating decision support tools into the electronic healthcare system can improve the appropriateness of clinical decisions.”

In the study, the cohort median age was 62 and 54% were male. The most common ICU interventions were IV medication infusions for uncontrolled hypertension (67.0%), mechanical ventilation (47.5%), hyperosmolar therapy for management of cerebral edema (47.5%), and external ventricular drain placement (22.8%). Most patients (53.4%) underwent more than a single intervention.

Timing was important: 89.2% of patients requiring critical care developed the need while still in the ED (89.2%). Most patients (69.5%) who were free of critical care needs by the end of their ED stay remained free of critical care needs for the duration of inpatient admission.

“Prior research has shown that the majority of major neurologic deterioration events that influence outcomes happen within the first 12 hours [of] symptom onset,” Maas pointed out. “Patients arriving with delay due to late presentation or interhospital transfer with no observable critical care needs may have already declared themselves appropriate for an intermediate care unit. The INTRINSIC Score may also find application in selectively shortening ICU observation intervals for lower risk patients who do not need critical care interventions within the first 12 hours.”

Limitations of the study include its retrospective nature. Findings are based on a single institution’s patients and an external validation cohort and may not apply to others.

  1. A novel risk prediction score identified intracerebral hemorrhage (ICH) patients at low risk for needing intensive care unit (ICU) services, a retrospective study showed.

  2. Despite growing interest in criteria for ICU admission and its effect on medical and economic outcomes, there are no established parameters that allow for stratification of risk of critical care needs in ICH patients, the researchers pointed out.

Paul Smyth, MD, Contributing Writer, BreakingMED™

Faigle is supported by a career development grant from the National Institute of Neurological Disorders and Stroke and The Morningstar Foundation. He reported no disclosures.

Maas reported no disclosures.

Cat ID: 38

Topic ID: 82,38,254,728,791,730,8,38,192,925