Altered Mental Status: An Important but Overlooked Presenting Symptom of COVID-19 in Older Adults

Since its discovery, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has led to nearly one million deaths globally. Several studies have indicated that the older adult population makes up a large percentage of patients that are hospitalized, intubated, and ultimately die.

In older adults, altered mental status (AMS) is a well-recognized presenting symptom in infections, particularly pneumonia. It is well known that AMS can serve as a gauge of disease severity in older adults. Despite this, there has been a lack of attention paid to AMS as a presenting symptom of COVID-19 in older adults. The purpose of this study is to elucidate the association of AMS as a presenting symptom of COVID-19 and adverse outcomes in older adult COVID-19 positive patients.

Of the total sample (n = 421), 202 (48.0%) patients died and 219 (52%) were discharged. 161 (38.2%) patients had AMS on admission. 58.4% of patients that presented with AMS died during hospitalization compared to 41.5% of those that presented without AMS. Of the total patients, 29 (6.2%) of patients presented with AMS as their sole presenting symptom and 47 (11.2%) presented with AMS lacking typical symptoms including fever and shortness of breath. Patients that presented with AMS were older, had lower median admission temperature, and had significantly more history of CVA and CKD than the non-AMS presentation group (Supplemental Table 1).

Multivariate regression analysis revealed that AMS and age were independently associated with mortality, AMS and obesity were independently associated with intubation, and AMS and male sex were independently associated with AKI (Table 1). AMS did not demonstrate an association with the outcomes of ACI or ARDS.

To our knowledge, this is one of the first studies to report the increased risk for mortality, intubation, and AKI in an older adult subset presenting with AMS. The causes of AMS in the setting of COVID-19 are likely due to a multitude of factors, including dehydration, cytokine storm, hypoxia, fevers, metabolic imbalances, and possibly more directly through viral invasion of the central nervous system. Several studies have postulated that the disruption of brain stem neurons, either through direct infection or systemic complications of the virus may result in respiratory dysregulation. Although further investigation is needed, the association of AMS with mortality and intubation found in our study may be explained by the ensuing respiratory collapse and hypoxia caused by such a manifestation of the virus. Furthermore, several studies have reported the incidence of AKI in the setting of COVID-19. It is hypothesized that AKI occurs due to both direct viral infiltration of tubular epithelium and podocytes, as well as indirectly, through systemic complications caused by the virus. AKI is a known cause of delirium and coma in patients that are severely ill, and it is plausible that the association between AMS and AKI found in our study is due to AMS being an early finding of kidney injury in patients with COVID-19.

While the cause of AMS in the setting of COVID-19 has yet to be determined, its impact on mortality, intubation, and AKI in our study was significant and should be interpreted as a prognostic indicator of adverse outcomes in older adults. A study by Chen et al. reported that patients with “disorder of consciousness” were more prevalent in patients that died from the infection (20%) than in those that did not (1%). In our study we noted higher numbers; 58.4% of patients that succumbed to illness presented with AMS. Additionally, the risk of dying in patients with COVID-19 presenting with AMS was 29% greater compared to those that did not present with AMS, even after adjusting for possible influencing factors such as comorbidities and age. We also found that the risk of intubation in older adults presenting with AMS in the setting of COVID-19 was 58% greater when compared to those that did not, a finding that is yet to be reported. Although the aforementioned risk values are not very large, given the gravity of the outcomes of interest (mortality and intubation), and the impact of such outcomes on public health in the setting of the COVID-19 pandemic, these findings should be considered clinically significant and addressed as such. Furthermore, we also found that the risk of developing AKI was 42% greater in patients that presented with AMS compared to those that did not, another novel finding. Finally, 6.2% of our older adult patients presented with AMS as their only symptom, while 11.1% presented with AMS while lacking typical symptoms of fever and SOB, giving some credence to the hypothesis of Ward et al that in some older adults, AMS may be the earliest sign of COVID-19 infection even before respiratory symptoms develop.

There are several limitations to this study. First, probable delirium has been found to be associated with frailty in older adults with COVID-19, and it is possible that our patients that presented with AMS may have had higher frailty scores which resulted in adverse outcomes. We were unable to assess clinical frailty scale due to insufficient data recorded in charts during the peak of the pandemic. Second, the baseline mental status was unknown in our patient population, which could contribute to a change in the rate of AMS documented. Lastly, our study sample is not generalizable to the U.S. population because our patients are from a single hospital system in a predominantly low-resourced community with poor access to social determinants of health. Yet, this allows it to be generalizable to similar communities.

Despite these limitations, our study also has notable strengths. We are among the first to report an association between AMS and mortality, intubation and AKI in an older adult patient population with COVID-19. Additionally, we supplement the growing literature on disorders of consciousness such as delirium as a predictor of adverse outcomes in older adults with COVID-19, but focus on the broader presenting symptom of AMS, thereby aiding clinicians that may be unable to screen using DSM-5 criteria in time constricted surge situations. Given these findings, it is imperative that AMS be recognized as an alarming presenting symptom of COVID-19 and prognostic indicator of adverse outcomes in older adults. National guidelines, such as the United States Centers for Disease Control and Prevention (CDC) make no mention of AMS in their screening criteria. This is especially concerning given that routine screening for COVID-19 such as temperature checks can have limited efficacy in older adults. Cardinal signs of infection such as fever can be absent or blunted in older adult patients with infection. Adding AMS as an important presenting symptom of COVID-19 will ensure early identification and treatment of disproportionately affected patient populations such as older adults.

Alvin Oommen*: Study Conceptualization, Design, Contribution of Intellectual Content, Literature Search, Data Acquisition, Manuscript Preparation, Editing, Review, Guarantor.

Joel Thomas*: Study Conceptualization, Design, Contribution of Intellectual Content, Literature Search, Data Acquisition, Manuscript Preparation, Editing, Review, Guarantor.

Priyanka Parmar: Study Design, Literature Search, Data Acquisition, Manuscript Preparation, Editing, Review.

Sabrina Rosengarten: Data Acquisition, Literature Search, Data Analysis, Statistical Analysis, Manuscript editing, Review.

Clara Wilson: Study Design, Literature Search, Data Acquisition, Manuscript editing, Review.

Rohan Maini: Study Design, Literature Search, Data Acquisition, Manuscript preparation, Editing.

Julie Minjae Kim: Study Design, Literature Search, Data Acquisition, Manuscript Editing, Review.

Max Mecklenburg: Literature Search, Data Acquisition, Manuscript preparation, Editing, Review.

Pia Daniel: Study design, Contribution of Intellectual Content, Manuscript Editing, Review, Guarantor.

Igal Brietman: Study Design, Contribution of Intellectual Content, Manuscript Preparation, Editing, Review, Guarantor.