Interplay between Comorbidities and Long COVID: Challenges and Multidisciplinary Approaches.

Long COVID, a name often given to the persistent symptoms following acute SARS-CoV-2 infection, poses a multifaceted challenge for health. This review explores the intrinsic relationship between comorbidities and autoimmune responses in shaping the trajectory of long COVID. Autoantibodies have emerged as significant players in COVID-19 pathophysiology, with implications for disease severity and progression. Studies show immune dysregulation persisting months after infection, marked by activated innate immune cells and high cytokine levels. The presence of autoantibodies against various autoantigens suggests their potential as comorbid factors in long COVID. Additionally, the formation of immune complexes may lead to severe disease progression, highlighting the urgency for early detection and intervention. Furthermore, long COVID is highly linked to cardiovascular complications and neurological symptoms, posing challenges in diagnosis and management. Multidisciplinary approaches, including vaccination, tailored rehabilitation, and pharmacological interventions, are used for mitigating long COVID's burden. However, numerous challenges persist, from evolving diagnostic criteria to addressing the psychosocial impact and predicting disease outcomes. Leveraging AI-based applications holds promise in enhancing patient management and improving our understanding of long COVID. As research continues to unfold, unravelling the complexities of long COVID remains paramount for effective intervention and patient care.

Anemia, Iron Deficiency, and Cause-Specific Mortality: The Atherosclerosis Risk in Communities (ARIC) Study.

INTRODUCTION: Anemia is a risk factor for all-cause mortality in older adults. Iron deficiency may also be associated with adverse outcomes, independent of its role in causing anemia. This study tested the hypotheses that anemia, and low ferritin among non-anemic participants, were associated with all-cause and cause-specific mortality in a community-based cohort of older adults. METHODS: Fasting blood was obtained from 5,070 ARIC participants (median age: 75) in 2011-2013. Anemia was defined by hemoglobin concentrations <12 g/dL in women and <13 g/dL in men. We classified 4,020 non-anemic participants by quartiles of plasma ferritin, measured by the SomaScan proteomics platform. Cox proportional hazards regression was used. RESULTS: Over a median of 7.5 years, there were 1147 deaths, including 357 due to cardiovascular disease (CVD), 302 to cancer and 132 to respiratory disease. Compared to those with normal hemoglobin, participants with anemia had a higher risk of all-cause mortality [hazard ratio 1.81 (95% CI: 1.60-2.06)], and mortality due to CVD [1.77 (1.41-2.22)], cancer [1.81 (1.41-2.33)], and respiratory disease [1.72 (1.18-2.52)] in demographics-adjusted models. In fully adjusted models, associations with all-cause mortality [1.37 (1.19-1.58)] and cause-specific mortality were attenuated. In non-anemic participants, lower ferritin levels were not associated with all-cause or cause-specific mortality, though associations were observed among participants with lesser evidence of inflammation and for cancer mortality in men only. CONCLUSION: Anemia is an important risk factor in older adults and may contribute to mortality due to CVD, cancer, and respiratory disease. Our results do not provide evidence that iron deficiency, independent of anemia, is a risk factor for mortality in this population.

Plasma Ferritin Levels, Incident Heart Failure, and Cardiac Structure and Function: The ARIC Study.

BACKGROUND: Whether iron deficiency contributes to incident heart failure (HF) and cardiac dysfunction has important implications given the prevalence of iron deficiency and the availability of several therapeutics for iron repletion. OBJECTIVES: The aim of this study was to estimate the associations of plasma ferritin level with incident HF overall, HF phenotypes, and cardiac structure and function measures in older adults. METHODS: Participants in the ongoing, longitudinal ARIC (Atherosclerosis Risk In Communities) study who were free of prevalent HF and anemia were studied. The associations of plasma ferritin levels with incident HF overall and heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF) were estimated using Cox proportional hazards regression models. Linear regression models estimated the cross-sectional associations of plasma ferritin with echocardiographic measures of cardiac structure and function. RESULTS: The cohort included 3,472 individuals with a mean age of 75 ± 5 years (56% women, 14% Black individuals). In fully adjusted models, lower ferritin was associated with higher risk for incident HF overall (HR: 1.20 [95% CI: 1.08-1.34] per 50% lower ferritin level) and higher risk for incident HFpEF (HR: 1.28 [95% CI: 1.09-1.50]). Associations with incident HFrEF were not statistically significant. Lower ferritin levels were associated with higher E/e' ratio and higher pulmonary artery systolic pressure after adjustment for demographics and HF risk factors but not with measures of left ventricular structure or systolic function. CONCLUSIONS: Among older adults without prevalent HF or anemia, lower plasma ferritin level is associated with a higher risk for incident HF, HFpEF, and higher measures of left ventricular filling pressure.