Men, women with less common diagnoses for their sex face poorer outcomes in ICU
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Men and women admitted to the ICU with diagnoses uncommon for their sex faced poorer outcomes, according to study results published in American Journal of Respiratory and Critical Care Medicine.
This was especially true for women undergoing cardiac surgery, according to researchers.
“It’s fairly well-established that heart disease affects men more often than women, yet women affected by heart disease have worse outcomes than men,” Lucy J. Modra, MPH, FCICM, FACEM, intensivist at Austin Health and senior clinical fellow in the department of critical care at The University of Melbourne, told Healio. “Our study again demonstrated that women with heart disease have worse outcomes than men, particularly following cardiac surgery. We also observed an overall association between sex balance and the mortality of women compared with men — so in some conditions, like metabolic disorders or orthopedic surgery, men are less commonly affected yet have worse outcomes than women.”
In a retrospective cross-sectional study, Modra and colleagues analyzed 1,450,782 ICU patients (mean age, 62.3 years; 42.1% women) from the Australian and New Zealand Intensive Care Society’s Adult Patients Database between 2011 and 2020 to evaluate whether sex balance, classified as the percentage of female ICU patients for each diagnostic category, impacted hospital mortality and illness severity compared with men with identical diagnoses.
Researchers adjusted for sex, illness severity, ICU lead time, admission year and hospital site in mixed effects logistic regression when assessing hospital mortality. Additionally, they used weighted linear regression to compare the sex balance with adjusted hospital mortality of women to men for each diagnosis.
Mortality differences
Between women and men, researchers found no differences in adjusted hospital mortality overall (OR = 0.99; 99% CI, 0.97-1); however, when evaluating diagnostic categories of ICU admissions, researchers observed mortality sex differences in five of the nine groups.
Women had a greater likelihood of dying in two categories — cardiac surgery and other cardiovascular diagnoses — whereas men had higher adjusted mortality in three categories: respiratory, sepsis and metabolic/hematologic/renal disorders. Researchers observed no differences between the sexes in the categories of neurological; trauma; musculoskeletal, soft tissue and skin diagnoses; and gastrointestinal.
Researchers found inverse associations between sex balance and mortality (weighted linear regression coefficient, –0.015; 99% CI, –0.2 to –0.011; P < .001; r2 = 38%) and illness severity (weighted linear regression coefficient, –0.0026; 99% CI, –0.0035 to –0.0018; P < .001; r2 = 38%), indicating that women had higher chances of dying or experiencing more severe disease if the percentage of women in their diagnostic category was lower than that of men, and vice versa.
“Surprisingly, the association between sex balance and mortality of women compared with men persisted across individual ICUs, after adjusting for diagnosis and other confounders,” Modra told Healio. “ICUs that admitted relatively few women had higher mortality among their female patients compared with male patients, and vice versa.”
Additionally, researchers found that patients with an illness that occurs less frequently in their sex spent a longer time in the hospital before moving into the ICU.
“Overall, our study shows that patient sex impacts upon outcomes from different critical illnesses,” Modra said. “Our findings suggest that clinicians more effectively recognize and treat ‘familiar’ presentations of critical illness, for example when a patient presents with an illness that is ‘expected’ for their sex. Clinicians should take particular care when treating sex-based minority groups, like women with heart disease.”
Role of biases
This study by Modra and colleagues suggests preconceived notions may delay diagnosis and “raises urgent questions” about the influence of cognitive and implicit biases on medical decision-making in the ICU, according to an accompanying editorial by Elizabeth M. Viglianti, MD, MPH, MSc, assistant professor in the department of internal medicine at University of Michigan, and colleagues.
“The findings by Modra and colleagues should give pause to clinicians, educators, researchers and trialists as they imply that variation in ICU mortality is not solely explained by biology but perhaps, because of systemic, implicit and cognitive biases,” Viglianti and colleagues wrote. “Notably, these biases are hurting our patients when they are diagnosed with a condition more prevalent in the opposite sex. The authors clearly show us the limits of our heuristic algorithms and when cognitive biases (eg, ascertainment, anchoring and availability biases) are more likely to influence our decision-making, contributing to a delay in diagnosis (eg, longer pre-ICU admission stays), delay in care (eg, higher severity of illness on ICU admission) and ultimately resulting in higher adjusted mortality within that diagnosis.”
For more information:
Lucy J. Modra, MPH, FCICM, FACEM, can be reached at lucy.modra@austin.org.au.