Score to identify the severity of adult patients with influenza A (H1N1) 2009 virus infection at hospital admission

Abstract

The objective of this paper was to develop a prognostic index for severe complications among hospitalized patients with influenza A (H1N1) 2009 virus infection. We conducted a prospective observational cohort study of 618 inpatients with 2009 H1N1 virus infection admitted to 36 Spanish hospitals between July 2009 and February 2010. Risk factors evaluated included host-related factors and clinical data at admission. We developed a composite index of severe in-hospital complications (SIHC), which included: mortality, mechanical ventilation, septic shock, acute respiratory distress syndrome, and requirement for resuscitation maneuvers. Six factors were independently associated with SIHC: age >45 years, male sex, number of comorbidities, pneumonia, dyspnea, and confusion. From the β parameter obtained in the multivariate model, a weight was assigned to each factor to compute the individual influenza risk score. The score shows an area under the receiver operating characteristic (ROC) curve of 0.77. The SIHC rate was 1.9 % in the low-risk group, 10.3 % in the intermediate-risk group, and 29.6 % in the high-risk group. The odds ratio for complications was 21.8 for the high-risk group compared with the low-risk group. This easy-to-score influenza A (H1N1) 2009 virus infection risk index accurately stratifies patients hospitalized for H1N1 virus infection into low-, intermediate-, and high-risk groups for SIHC.

Predictive factors of severe multilobar pneumonia and shock in patients with influenza

“… Altered mental status and dyspnoea were predictive of a poor prognosis in any kind of pneumonia and are also reported by other authors as clinical variables independently associated with severe disease 13 14

Patients with influenza in the 2010–2011 season were more likely to develop SPAS, supporting the results from other studies that found that more patients suffered poor outcomes or died than in the pandemic season.

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“…Altered mental status and dyspnoea were predictive of a poor prognosis in any kind of pneumonia and are also reported by other authors as clinical variables independently associated with severe disease 13 14…”

External validation and update of a prognostic model to predict mortality in hospitalized adults with RSV: A retrospective Dutch cohort study

“…We aimed to validate models predicting mortality, but also included studies using a composite outcome including mortality. For the external validation, we applied the included original prognostic models to our study cohort exactly as they were published, with similar definitions of predictor variables and outcomes (Table S2) . If the intercept from the original model was not reported, we calculated a new intercept by recalibration.…”

“…For the external validation, we applied the included original prognostic models to our study cohort exactly as they were published, with similar definitions of predictor variables and outcomes (Table S2). [24][25][26][27] If the intercept from the original model was not reported, we calculated a new intercept by recalibration. We compared the discriminative ability of the models using the Harrell's C-statistic.…”

“…Consequently, we tested the incremental value of the model by adding objectively assessable predefined predictor variables (age, gender, urea, confusion, cardiovascular comorbidities, immunocompromised status, and the number of other comorbidities), based on the existing prognostic models for poor outcomes in patients with positive influenza virus. 26,27,31 We performed backward variable selection based on the Akaike information criterion and Occam's razor principle. Finally, we performed internal validation with optimism correction by bootstrap.…”