ABSTRACT

OBJECTIVE: We present an illustrative application of methods that account for covariates in receiver operating characteristic (ROC) curve analysis, using individual patient data on D-dimer testing for excluding pulmonary embolism.

STUDY DESIGN AND SETTING: Bayesian nonparametric covariate-specific ROC curves were constructed to examine the performance/positivity thresholds in covariate subgroups. Standard ROC curves were constructed. Three scenarios were outlined based on comparison between subgroups and standard ROC curve conclusion: (1) identical distribution/identical performance, (2) different distribution/identical performance, and (3) different distribution/different performance. Scenarios were illustrated using clinical covariates. Covariate-adjusted ROC curves were also constructed.

RESULTS: Age groups had prominent differences in D-dimer concentration, paired with differences in performance (Scenario 3). Different positivity thresholds were required to achieve the same level of sensitivity. D-dimer had identical performance, but different distributions for YEARS algorithm items (Scenario 2), and similar distributions for sex (Scenario 1). For the later covariates, comparable positivity thresholds achieved the same sensitivity. All covariate-adjusted models had AUCs comparable to the standard approach.

CONCLUSION: Subgroup differences in performance and distribution of results can indicate that the conventional ROC curve is not a fair representation of test performance. Estimating conditional ROC curves can improve the ability to select thresholds with greater applicability.

PMID:37295733 | DOI:10.1016/j.jclinepi.2023.06.001

07:32

PubMed articles on: Cancer & VTE/PE

COVID-19 related acute necrotizing encephalopathy presenting in the early postoperative period

Arch Clin Cases. 2023 Jun 7;10(2):78-85. doi: 10.22551/2023.39.1002.10246. eCollection 2023.

ABSTRACT

Besides respiratory and gastrointestinal symptoms, SARS-CoV-2 also has potential neurotropic effects. Acute hemorrhagic necrotizing encephalopathy is a rare complication of Covid-19. This article presents a case of an 81-year-old female, fully vaccinated, who underwent laparoscopic transhiatal esophagectomy due to gastroesophageal junction cancer. In the early postoperative period, the patient developed persistent fever accompanied by acute quadriplegia, impaired consciousness, and no signs of respiratory distress. Imaging with Computed Tomography and Magnetic Resonance revealed multiple bilateral lesions both in gray and white matter, as well as pulmonary embolism. Covid-19 infection was added to the differential diagnosis three weeks later, after other possible causes were excluded. The molecular test obtained at that time for coronavirus was negative. However, the high clinical suspicion index led to Covid-19 antibody testing (IgG and IgA), which confirmed the diagnosis. The patient was treated with corticosteroids with noticeable clinical improvement. She was discharged to a rehabilitation center. Six months later, the patient was in good general condition, although a neurological deficit was still present. This case indicates the significance of a high clinical suspicion index, based on a combination of clinical manifestations and neuroimaging, and the confirmation of the diagnosis with molecular and antibody testing. Constant awareness of a possible Covid-19 infection among hospitalized patients is mandatory.

PMID:37293685 | PMC:PMC10246599 | DOI:10.22551/2023.39.1002.10246

07:32

PubMed articles on: Cancer & VTE/PE

Incidence and risk factors for venous thromboembolism in patients with ovarian cancer during neoadjuvant chemotherapy: a meta-analysis

Am J Cancer Res. 2023 May 15;13(5):2126-2134. eCollection 2023.