Development and validation of a predictive model algorithm to identify anaphylaxis in adults with type 2 diabetes in U.S. administrative claims data.

PURPOSE: To use medical record adjudication and predictive modeling methods to develop and validate an algorithm to identify anaphylaxis among adults with type 2 diabetes (T2D) in administrative claims. METHODS: A conventional screening algorithm that prioritized sensitivity to identify potential anaphylaxis cases was developed and consisted of diagnosis codes for anaphylaxis or relevant signs and symptoms. This algorithm was applied to adults with T2D in the HealthCore Integrated Research Database (HIRD) from 2016 to 2018. Clinical experts adjudicated anaphylaxis case status from redacted medical records. We used confirmed case status as an outcome for predictive models developed using lasso regression with 10-fold cross-validation to identify predictors and estimate the probability of confirmed anaphylaxis. RESULTS: Clinical adjudicators reviewed medical records with sufficient information from 272 adults identified by the anaphylaxis screening algorithm, which had an estimated Positive Predictive Value (PPV) of 65% (95% confidence interval [CI]: 60%-71%). The predictive model algorithm had a c-statistic of 0.95. The model's probability threshold of 0.60 excluded 89% (84/94) of false positives identified by the screening algorithm, with a PPV of 94% (95% CI: 91%-98%). The model excluded very few true positives (15 of 178), and identified 92% (95% CI: 87%-96%) of the cases selected by the screening algorithm. CONCLUSIONS: Predictive modeling techniques yielded an accurate algorithm with high PPV and sensitivity for identifying anaphylaxis in administrative claims. This algorithm could be considered in future safety studies using similar claims data to reduce potential outcome misclassification.

Clinical Utility of Fluid Volume Assessment in Heart Failure Patients Using Bioimpedance Spectroscopy.

Background: Bioimpedance spectroscopy (BIS) is a non-invasive method used to measure fluid volumes. In this report, we compare BIS measurements from patients with heart failure (HF) to those from healthy adults, and describe how these point-of-care fluid volume assessments may be applied to HF management. Methods and results: Fluid volumes were measured in 64 patients with NYHA class II or III HF and 69 healthy control subjects. BIS parameters including extracellular fluid (ECF), intracellular fluid (ICF), total body water (TBW), and ECF as a percentage of TBW (ECF%TBW) were analyzed. ECF%TBW values for the HF and control populations differed significantly (49.2 ± 3.2% vs. 45.2 ± 2.1%, respectively; p < 0.001); both distributions satisfied criteria for normality. Interquartile ranges did not overlap (46.7-51.0% vs. 43.8-46.4%, respectively; p < 0.001). Subgroup analyses of HF patients who underwent transthoracic echocardiography showed that impedance measurements correlated with inferior vena cava size (Pearson correlation -0.73, p < 0.0001). A case study is presented for illustrative purposes. Conclusions: BIS-measured ECF%TBW values were significantly higher in HF patients as compared to adults without HF. We describe three strata of ECF%TBW (normal, elevated, fluid overload) that may aid in clinical risk stratification and fluid volume monitoring of HF patients. Clinical Trial Registration: COMPARE - www.ClinicalTrials.gov; IMPEL - www.ClinicalTrials.gov; Heart Failure at Home - www.ClinicalTrials.gov, identifier: NCT02939053; NCT02857231; NCT04013373.

Enhanced diagnosis of narrow complex tachycardias with increased electrocardiograph speed.

The objective of this study was to determine if the addition of rapid speed (50 mm/s) electrocardiograms (EKGs) improves the clinician's diagnostic accuracy of narrow complex tachycardias when compared to standard speed (25 mm/s) EKGs. We conducted a prospective, comparative trial. Forty-five difficult narrow complex tachycardias (heart rate range: 150-250 beats per minute) were printed at both 25 mm/s and 50 mm/s. Eight board certified emergency physicians initially interpreted the standard speed EKG (standard group) and chose a therapy for the hypothetical patient. These eight participants later interpreted the same 45 EKGs by using both the standard and rapid speed EKGs (rapid group) and again chose a therapy. The gold standard for each EKG was based on the patient's clinical diagnosis and was independently confirmed in all cases by a board-certified cardiologist. The rhythm distribution was as follows: atrial flutter (17), atrial fibrillation (11), paroxysmal supraventricular tachycardia (15), and sinus tachycardia (2). Participants were masked to all clinical information and EKG ratios. Diagnostic accuracy was compared by using McNemar's chi(2) test. Correct diagnosis improved from 226/360 (63%), in the standard group to 257/360 (71%) in the rapid group (difference in means 8.6%, p = 0.002). The incorrect use of adenosine was decreased from 43/240 (18%) in the standard group to 32/240 (13%) in the rapid group (difference in means 4.5%, p = 0.06). In conclusion, correct diagnosis of difficult narrow complex tachycardias was improved when EKGs at both 25 mm/s and 50 mm/s were used for interpretation. It appears that the simple technique of increasing the EKG paper speed, and thus effectively spacing out the rhythm, enhances the diagnostic ability of the observer.