Representing visual classification as a linear combination of words

Explainability is a longstanding challenge in deep learning, especially in high-stakes domains like healthcare. Common explainability methods highlight image regions that drive an AI model's decision. Humans, however, heavily rely on language to convey explanations of not only "where" but "what". Additionally, most explainability approaches focus on explaining individual AI predictions, rather than describing the features used by an AI model in general. The latter would be especially useful for model and dataset auditing, and potentially even knowledge generation as AI is increasingly being used in novel tasks. Here, we present an explainability strategy that uses a vision-language model to identify language-based descriptors of a visual classification task. By leveraging a pre-trained joint embedding space between images and text, our approach estimates a new classification task as a linear combination of words, resulting in a weight for each word that indicates its alignment with the vision-based classifier. We assess our approach using two medical imaging classification tasks, where we find that the resulting descriptors largely align with clinical knowledge despite a lack of domain-specific language training. However, our approach also identifies the potential for 'shortcut connections' in the public datasets used. Towards a functional measure of explainability, we perform a pilot reader study where we find that the AI-identified words can enable non-expert humans to perform a specialized medical task at a non-trivial level. Altogether, our results emphasize the potential of using multimodal foundational models to deliver intuitive, language-based explanations of visual tasks.Comment: To be published in the Proceedings of the 3rd Machine Learning for Health symposium, Proceedings of Machine Learning Research (PMLR

Diagnostic concordance of clinical diagnosis, tissue culture, and histopathology testing for skin and soft tissue infections: A single-center retrospective study

BACKGROUND: Tissue culture and histopathology are the conventional diagnostic modalities for skin and soft tissue infections (SSTIs), but few studies have investigated their concordance. OBJECTIVE: Determine concordance between histopathology and tissue culture in the diagnosis of suspected SSTIs. METHODS: Single-center retrospective study of 355 cases with suspected SSTIs identified from the dermatology inpatient consultation log January 2014-July 2017. RESULTS: Overall concordance between histopathology testing and tissue culture results was high (76.1%). Concordance was high for cases defined as no evidence of infection, fungal infection and mycobacterial infection by histopathology (77.8%, 74.2%, and 80.0%) and tissue culture (92.1%, 67.7%, and 83.3%). Concordance was lower for suspected SSTIs with bacterial infection by histopathology (61.9%) and tissue culture (28.4%). Concordance rates were not significantly affected by age, sex, race, antimicrobial agent use, immunologic status, or biopsy size. LIMITATIONS: Retrospective and single-institution nature of the study. CONCLUSION: This study demonstrated a high concordance between histopathology and tissue culture in SSTIs with no clinical evidence of infection and suspected fungal and mycobacterial SSTIs, though concordance was lower for suspected SSTIs with evidence of bacterial infection. Clinicians should not be deterred from relying on initial histopathological results based on patients\u27 immunosuppressed status, antimicrobial agent use, age, or biopsy tissue size

Vestibular Function and Activities of Daily Living

Objective: Vestibular dysfunction increases with age and is associated with mobility difficulties and fall risk in older individuals. We evaluated whether vestibular function influences the ability to perform activities of daily living (ADLs). Method: We analyzed the 1999 to 2004 National Health and Nutrition Examination Survey of adults aged older than 40 years ( N = 5,017). Vestibular function was assessed with the Modified Romberg test. We evaluated the association between vestibular function and difficulty level in performing specific basic and instrumental ADLs, and total number of ADL impairments. Results: Vestibular dysfunction was associated with significantly higher odds of difficulty with nine ADLs, most strongly with difficulty managing finances (odds ratio [ OR ] = 2.64, 95% confidence interval [CI] = [1.18, 5.90]). In addition, vestibular dysfunction was associated with a significantly greater number of ADL impairments (β = .21, 95% CI = [0.09, 0.33]). This effect size was comparable with the influence of heavy smoking (β = .21, 95% CI = [0.06, 0.36]) and hypertension (β = .10, 95% CI = [0.02, 0.18]) on the number of ADL impairments. Conclusion: Vestibular dysfunction significantly influences ADL difficulty, most strongly with a cognitive rather than mobility-based task. These findings underscore the importance of vestibular inputs for both cognitive and physical daily activities

Cutaneous adverse events of immune checkpoint inhibitor therapy: incidence and types of reactive dermatoses

Background Dermatoses are common and potentially serious complications of programmed cell death receptor PD-1 immune checkpoint inhibitor (anti-PD-1 ICI) therapy. Understanding their incidence is necessary to support clinical awareness, diagnosis, and management. Objective To examine the incidence and odds of reported non-cancerous dermatoses in the setting of anti-PD-1 ICI therapy. Methods Cross-sectional study of anti-PD-1 (pembrolizumab or nivolumab) treated patients at a tertiary healthcare institution. Selected dermatologic events following immunotherapy were identified in the electronic medical record. Comparator arm were patients that developed these same dermatoses without receiving anti-PD-1 ICI therapy. Results There were 13.7% (254/1857) patients that developed one of 28 dermatoses. Compared with the general population, patients treated with anti-PD-1 had a greater risk for development of mucositis (OR 65.7, 95% CI 35.0–123.3), xerostomia (OR 11.9, 95% CI 8.4–16.8), pruritus (11.3, 95% CI 8.9–14.3), and lichen planus/lichenoid dermatitis (OR 10.7, 95% CI 5.6–20.7). Conclusions We report the frequency of dermatoses encountered in the setting of ICI therapy, both common (pruritus, rash, vitiligo) and uncommon (scleroderma, urticaria)

Racial Disparities in the Clinical Presentation and Prognosis of Patients with Mycosis Fungoides

Objective: Racial and gender disparities in mycosis fungoides (MF) are understudied. The objective of this study was to test the hypothesis that worse prognosis in blacks with MF is mediated by higher disease stage at diagnosis and by earlier disease onset in black females. Methods: We conducted retrospective chart review of 337 patients with clinically-suspected MF seen at Johns Hopkins between 2003 and 2018, requiring biopsy-proven disease for study inclusion. Patient demographics, initial stage/percent body surface area (BSA) involvement, pathology type, flow cytometry results, and treatment regimens were recorded. Results: Of 303 patients with confirmed MF, 166 (55%) were white, 107 (35%) black, 10 (3.3%) Middle Eastern, 6 (2.0%) Asian, and 14 (4.6%) Hispanic/other. Blacks were 3 times as likely (95% CI: 1.2, 8.0) to have Stage 2 disease to have Stage 2 disease at diagnosis as compared to whites as whites. In females, blacks were younger at diagnosis (p = 0.003) and at death (p = 0.008) compared to whites. In males, blacks had 4 times the odds of late-stage disease (p = 0.017) and presented with 19% greater BSA involvement on average compared to whites (p \u3c 0.001). Conclusions: Compared to their white counterparts in this cohort, black males were diagnosed with MF at a higher stage with greater skin involvement while black females were diagnosed and died earlier. Earlier recognition of MF in skin of color and closer follow-up of black females with early-onset, aggressive disease may help to mitigate disparities in outcomes

Psoriasis and mortality in the United States: Data from the National Health and Nutrition Examination Survey

Background: Psoriasis is a multifactorial disease that has been associated with multiple systemic disorders. Despite its role in mediating cardiovascular, metabolic, and pulmonary disorders, few studies have examined the independent mortality risk associated with psoriasis. Objective: To determine the independent relationship between psoriasis and all-cause mortality in a nationally representative sample of the US population. Methods: Retrospective population-based cohort study of adults and adolescents older than 10 years (N = 13 031) who participated in National Health and Nutrition Examination Surveys (2003-2006 and 2009-2010). Psoriasis status was determined from a self-reported medical history questionnaire. Mortality data are linked from national databases. Results: Psoriasis was present in 2.7% of the study population. Over an average median follow-up of 52.3 months, psoriasis was significantly associated with increased mortality risk (HR, 1.99; 95% CI, 1.01-3.93; P = .047) with adjustment for demographics, smoking, and comorbidities including cardiovascular disease, diabetes, chronic obstructive pulmonary disease, cancer, chronic kidney disease, and stroke. These comorbidities mediated 15.5%, 5.9%, 8.7%, 11.7%, 4.2%, and 4.7% of the association between psoriasis and mortality, respectively. Conclusion: Psoriasis is independently associated with an increased risk of mortality. This relationship is partially mediated by an increased prevalence of the cardiovascular, infectious, and neoplastic disorders seen among patients with psoriasis

Prediction of severe immune-related adverse events requiring hospital admission in patients on immune checkpoint inhibitors: study of a population level insurance claims database from the USA

Background Immune-related adverse events (irAEs) are a serious side effect of immune checkpoint inhibitor (ICI) therapy for patients with advanced cancer. Currently, predisposing risk factors are undefined but understanding which patients are at increased risk for irAEs severe enough to require hospitalization would be beneficial to tailor treatment selection and monitoring.Methods We performed a retrospective review of patients with cancer treated with ICIs using unidentifiable claims data from an Aetna nationwide US health insurance database from January 3, 2011 to December 31, 2019, including patients with an identified primary cancer and at least one administration of an ICI. Regression analyses were performed. Main outcomes were incidence of and factors associated with irAE requiring hospitalization in ICI therapy.Results There were 68.8 million patients identified in the national database, and 14 378 patients with cancer identified with at least 1 administration of ICI in the study period. Patients were followed over 19 117 patient years and 504 (3.5%) developed an irAE requiring hospitalization. The incidence of irAEs requiring hospitalization per patient ICI treatment year was 2.6%, rising from 0% (0/71) in 2011 to 3.7% (93/2486) in 2016. Combination immunotherapy (OR: 2.44, p<0.001) was associated with increased odds of developing irAEs requiring hospitalization, whereas older patients (OR 0.98 per additional year, p<0.001) and those with non-lung cancer were associated with decreased odds of irAEs requiring hospitalization (melanoma OR: 0.70, p=0.01, renal cell carcinoma OR: 0.71, p=0.03, other cancers OR: 0.50, p<0.001). Sex, region, zip-code-imputed income, and zip-code unemployment were not associated with incidence of irAE requiring hospitalization. Prednisone (72%) and methylprednisolone (25%) were the most common immunosuppressive treatments identified in irAE hospitalizations.Conclusions We found that 3.5% of patients initiating ICI therapy experienced irAEs requiring hospitalization and immunosuppression. The odds of irAEs requiring hospitalization were higher with younger age, treatment with combination ICI therapy (cytotoxic T lymphocyte-associated 4 and programmed cell death protein 1 (PD-1) or programmed death-ligand 1 (PD-L1)), and lower for other cancers compared with patients on PD-1 or PD-L1 inhibitors with lung cancer. This evidence from the first nationwide study of irAEs requiring hospitalization in the USA identified the real-world epidemiology, risk factors, and treatment patterns of these irAEs which may guide treatment and management decisions