Predicting abnormal laboratory blood test results in the intensive care unit using novel features based on information theory and historical conditional probability (Preprint)

BACKGROUND Redundancy in laboratory blood tests is common in intensive care units (ICU), affecting patients' health and increasing healthcare expenses. Medical communities have made recommendations to order laboratory tests more judiciously. Wise selection can rely on modern data-driven approaches that have been shown to help identify redundant laboratory blood tests in ICUs. However, most of these works have been developed for highly selected clinical conditions such as gastrointestinal bleeding. Moreover, features based on conditional entropy and conditional probability distribution have not been used to inform the need for performing a new test. OBJECTIVE We aimed to address the limitations of previous works by adapting conditional entropy and conditional probability to extract features to predict abnormal laboratory blood test results. METHODS We used an ICU dataset collected across Alberta, Canada which included 55,689 ICU admissions from 48,672 patients with different diagnoses. We investigated conditional entropy and conditional probability-based features by comparing the performances of two machine learning approaches to predict normal and abnormal results for 18 blood laboratory tests. Approach 1 used patients' vitals, age, sex, admission diagnosis, and other laboratory blood test results as features. Approach 2 used the same features plus the new conditional entropy and conditional probability-based features. RESULTS Across the 18 blood laboratory tests, both Approach 1 and Approach 2 achieved a median F1-score, AUC, precision-recall AUC, and Gmean above 80%. We found that the inclusion of the new features statistically significantly improved the capacity to predict abnormal laboratory blood test results in between ten and fifteen laboratory blood tests depending on the machine learning model. CONCLUSIONS Our novel approach with promising prediction results can help reduce over-testing in ICUs, as well as risks for patients and healthcare systems. CLINICALTRIAL N/A

Clinical Characteristics and Outcomes of Severe Pneumonia in Children Under 5 Years Old With and Without Adenovirus Infection in Guangzhou

Objectives: To identify the differences of clinical characteristics and outcomes of severe pneumonia in children under 5 years old with and without adenovirus infection.Methods: A retrospective cohort study was conducted in three pediatric hospitals in Guangzhou, China. In total, 1,595 children under the age of 5 with WHO-defined severe pneumonia had adenovirus testing performed between January 1, 2009 and December 31, 2019. Demographics, complications, the first routine laboratory findings, therapeutic records, and clinical outcome were collected from electronic medical records. We compared characteristics of children with and without adenovirus infection.Results: Adenovirus was detected in 75 (4.7%) out of 1,595 children with severe pneumonia. Cases with adenovirus infection were more likely to be boys (74.7 vs. 63.0%), older than 1 year old (78.7 vs. 25.1%), but less likely to have mixed virus infections (25.3 vs. 92.9%) and combined with cardiovascular disease (12.0 vs. 39.7%), and had more abnormal laboratory results than cases without adenovirus infection. Antiviral therapy (4.9%) was rarely used in children with severe pneumonia, but antibiotic therapy (65.3%) was commonly used, especially in cases with adenovirus infection (91.9%). Children infected with adenovirus (9.3 vs. 2.5%) were also hospitalized longer and had a higher mortality within 30 days of hospitalization.Conclusions: Children with severe pneumonia under 5 years old with adenovirus infection had more abnormal laboratory findings and more severe clinical outcomes than cases without adenovirus infection. More attention should be focused on the harm caused by adenovirus infection.

A Rare Case of Exocrine Pancreatic Insufficiency

Lipomatous pseudohypertrophy (LPH) of the pancreas is an uncommon affection of exocrine pancreatic insufficiency. It is defined as substitution of the pancreatic exocrine gland by a large fat component. We report the case of a young patient with malabsorption syndrome (chronic diarrhoea and steatorrhoea), abnormal laboratory results and normal fibroscopy. Computed tomography revealed characteristic diffuse pancreatic abnormalities.

Difference in Risk Factors Associated with Acute Respiratory Distress Syndrome and Intubation/Death in Patients with Coronavirus Disease 2019: A Two-hospital Retrospective Cohort Study in Hubei, China

Background: The reviews on the risk factors with ARDS and the worse outcomes concluded lacking robust data of risk factors to prevent COVID-19 and identified an urgent need for large sample and high-quality research in this area, as well as the features of the ARDS.Methods: This retrospective cohort study included 333 COVID-19 inpatients at two hospitals in Hubei of China in 2020. The COVID-19-related ARDS was diagnosed according to the Berlin criteria. The outcomes were ARDS development and the intubation or in-hospital death. The cox proportional hazard ratio (HR) models were employed to determine the significant risk factors. Results: The median number of days from symptom onset to ARDS diagnosis was 11.0 (IQR, 8.0–13.0). Up to 84.1% COVID-19-related ARDS patients demonstrated multiple organ injuries. The mortality rates were 41.9% and 85.7% in moderate and severe ARDS. The survival patients on invasive mechanical ventilation (IMV) had been intubated earlier since ARDS diagnosis than those who had not survived (5.5 median days, IQR 4.0-7.0 days versus 11.5 median days, IQR 6.0-14.0 days, P < 0.001). Males and all abnormal laboratory indices associated with the higher risk of ARDS (P<0.05) but were not linked with the risk of intubation or death (P>0.05). The sensitivity analyses found that lymphocyte count of < 1000 per mm3 at hospital admission were still significantly associated with developing ARDS when adjusting for age and male gender (HR, 4.10; 95% CI, 2.40-7.10), and oxygenation index (OI) ratio < 150 were more likely to predict the intubation/death after age adjustment (HR, 2.50; 95% CI, 1.17-5.30). Conclusion: The SARS-CoV-2-caused ARDS was not the typical ARDS according to Berlin criteria. The alive patients with IMV had been intubated earlier since ARDS diagnosis than those who had not survived. We identified male gender and abnormal laboratory indices associated with the ARDS but were not linked with the intubation/death. Sensitivity analysis concluded lymphocyte count of < 1000 per mm3 could predict ARDS while OI ratio less than 150 could predict intubation/death.

602. Do These Labs Really Matter? Searching for the Benefit of Laboratory Monitoring in Outpatient Parenteral Antimicrobial Therapy (OPAT)

Background Weekly laboratory monitoring is routinely performed for patients treated with Outpatient Parenteral Antimicrobial Therapy (OPAT). However, minimal evidence exists to guide this practice. Methods This was a single-center, retrospective cohort study to assess the value of laboratory monitoring in patients being treated with beta-lactam OPAT. This study included adult patients discharged from University of Utah Health (UUH) between January 1, 2018, and July 31, 2019, on beta-lactam OPAT with follow-up care with a UUH Infectious Diseases (ID) Provider. Patients discharged to a skilled nursing facility or long-term acute care hospital, or who received OPAT for a duration less than 7 days, were excluded. The primary aim was to describe how often abnormal laboratory values led to a therapy modification or documented adverse drug reaction (ADR) for patients receiving beta-lactam OPAT. Abnormal laboratory values were defined by consensus criteria for clinical significance (e.g., RIFLE criteria for kidney injury). Therapy modification and ADR occurrence was determined by chart review for UUH ID Provider documentation. Results A total of 346 patients were included; two hundred seventy-four (79%) had abnormal laboratory values during OPAT. Of these, 12 patients had a modification to their OPAT due to abnormal laboratory values. The most common therapy modification due to abnormal laboratory values was a change of antibiotic (9/12). Two hundred thirteen of 274 patients (78%) with abnormal laboratory values were maintained on their OPAT regimen without a modification. Of the 67 therapy modifications observed, 55 (82%) were due to reasons other than abnormal laboratory results (Table 1). Abnormal laboratory values meeting criteria for clinical significance and possible ADR were observed in 469 instances. Of these, 43 (9%) were considered ADRs by the ID provider (Table 2). Table 1 describes therapy modifications for patients on beta-lactam OPAT Table 2 describes documented ADRs in the presence of abnormal labs for patients on beta-lactam OPAT Conclusion Weekly laboratory monitoring was associated with therapy modifications and documented ADRs in a small number of patients receiving beta-lactam agents as OPAT. This supports current guideline recommendations for laboratory monitoring, even for beta-lactam agents, which are considered relatively safe. Further investigation into the cost-effectiveness of this approach is warranted. Disclosures Russell J. Benefield, PharmD, Merck and Co (Grant/Research Support)Paratek Pharmaceuticals (Grant/Research Support)Rempex Pharmaceuticals (Grant/Research Support)