NIVO Score Accurately Predicts Mortality, Noninvasive Ventilation Failure in Patients With AECOPD

The Noninvasive Ventilation Outcomes (NIVO) score is a reliable tool in predicting in-intensive care unit (ICU) mortality, 1-year mortality, and NIV failure among patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD), according to a study published in Annals of Intensive Care.¹

AECOPD are common and recognized as the main contributor to mortality in those with COPD.² The researchers noted that implementing prognostic scoring systems has emerged as a “valuable resource” for health care professionals in making informed decisions and tailoring interventions to each patient's needs.³

For example, the Dyspnea, Eosinopenia, Consolidation, Acidemia, and atrial Fibrillation (DECAF) score predicts mortality in patients hospitalized for AECOPD, regardless of the acidemia presence.¹ Its overall performance is good but diminishes in patients who require mechanical ventilation.⁴

The NIVO score was recently developed to predict mortality in patients with AECOPD who require mechanical ventilation, whether NIV or invasive mechanical ventilation (IMV)¹; it was built using a large multicenter population in the UK.

The score relies on 6 variables assessed at hospital admission: arterial blood pH, presence of chest radiograph consolidation, level of consciousness as per the Glasgow coma scale, presence of atrial fibrillation, extended Medical Research Council dyspnea scale (eMRCD), and time to acidemia. The researchers noted that it accurately predicts mortality risk for those hospitalized with AECOPD requiring mechanical ventilation.

Conversely, it has only been evaluated for short-term mortality. Consequently, they conducted a study to assess the performance of the NIVO score in predicting 1-year mortality among this population. They also evaluated the NIVO score’s ability to predict NIV failure, emphasizing the importance of the early identification of NIV failure risk.

The Noninvasive Ventilation Outcomes (NIVO) score is a reliable predictor of intensive care unit (ICU) mortality, one-year mortality, and NIV failure in patients with acute exacerbations of COPD (AECOPD). | Image Credit: sudok1 - stock.adobe.com

They analyzed patients hospitalized for an AECOPD in the ICU at the European Hospital of George Pompidou in Paris, France, between January 1, 2018, and December 31, 2022. Eligible patients included those with AECOPD aged 40 years or older who were hospitalized for at least 1 night and required mechanical ventilation, either NIV or IMV. The researchers only accounted for patients once, regardless of multiple admissions.

Data were individually extracted from the medical records of eligible patients. Also, the NIVO score was calculated before mechanical ventilation initiation. It categorized patients into 4 risk levels: low risk (0-2), medium risk (3-4), high risk (5-6), and very high risk (7-9).

In terms of outcomes, they assessed mortality at the end of the ICU stay (in-ICU mortality) and 1 year after ICU admission among all patients and a subgroup of those alive at 30 days of admission. Additionally, NIV failure was defined as intubation or death without intubation.

The researchers identified 190 eligible patients with AECOPD requiring mechanical ventilation. The mean (SD) age of these patients was 73 (12) years, and most (57%; n = 108) were males. Of the included patients, 44 (23%) died in the ICU and 78 (41%) died within 1 year of admission. Therefore, the median (IQR) length of ICU stay was 6 (4-11) days, time to in-ICU death was 7 (3-19) days, and follow-up was 545 (48-1250) days.

Also, the researchers found that all prognostic scores (NIVO, DECAF, and Sequential Organ Failure Assessment [SOFA] scores) were higher in non-survivors than survivors. More specifically, the NIVO score more accurately predicted both in-ICU (area under the curve [AUC], 0.79) and 1-year mortality (AUC, 0.68) than the DECAF or SOFA scores.

Additionally, high and very high NIVO scores were associated with higher in-ICU (HR, 2.6; 95% CI, 1.1-6.2) and 1-year mortality (HR, 4.4; 95% CI, 1.8-10.9) than low or moderate scores. When the researchers excluded the 43 patients who died within 30 days of ICU admission, higher NIVO scores at admission were still associated with higher 1-year mortality.

Lastly, of the 184 patients who received NIV, 62 (34%) had NIV failure, with a median failure delay of 12 (IQR, 2-24) hours. The researchers found that NIV failure resulted in IMV in 38 patients (61%) and ICU death in 41 patients (66%). It was also associated with high in-ICU and 1-year mortality.

The researchers concluded that the NIVO score more accurately predicted NIV failure than either in-ICU or 1-year mortality (AUC, 0.85). They noted that patients with high (HR, 11.8; 95% CI, 1.6-86.4) or very high (HR, 41.6; 95% CI, 5.6-307.9) NIVO scores had a significantly higher risk of NIV failure. More specifically, a NIVO score of 5 or greater was associated with a 56% probability of NIV failure.

They acknowledged their limitations, one being that the study was conducted at a single site in France, which may limit the generalizability of their findings. Also, their relatively small sample size may have influenced the results and should be considered when interpreting their findings. However, the researchers expressed confidence in their findings.

“The NIVO score is a reliable tool for predicting in-ICU mortality even in health care systems outside the UK,” the authors concluded. “Furthermore, our study suggests that the use of the NIVO score may be extended to predict 1-year mortality but also NIVO failure with a good accuracy in the AECOPD population.”

References

1. Alzaabi O, Guerot E, Planquette B, Diehl JL, Soumagne T. Predicting outcomes in patients with exacerbation of COPD requiring mechanical ventilation. Ann Intensive Care. 2024;14(1):159. doi:10.1186/s13613-024-01394-z
2. Halpin DM, Decramer M, Celli B, Kesten S, Liu D, Tashkin DP. Exacerbation frequency and course of COPD. Int J Chron Obstruct Pulmon Dis. 2012;7:653-661. doi:10.2147/COPD.S34186
3. Keegan MT, Soares M. What every intensivist should know about prognostic scoring systems and risk-adjusted mortality. Rev Bras Ter Intensiva. 2016 Sep;28(3):264-269. doi: 10.5935/0103-507X.20160052
4. Steer J, Gibson J, Bourke SC. The DECAF Score: predicting hospital mortality in exacerbations of chronic obstructive pulmonary disease. Thorax. 2012;67(11):970-976. doi:10.1136/thoraxjnl-2012-202103