key: cord-1055366-xisa01ps
authors: FISHER, Stephanie A.; GOLDSTEIN, Jeffery A.; MITHAL, Leena B.; ISAIA, Alexandra L.; SHANES, Elisheva D.; OTERO, Sebastian; MILLER, Emily S.
title: Laboratory Analysis of Symptomatic and Asymptomatic Pregnant Patients with SARS-CoV-2 Infection
date: 2021-08-14
journal: Am J Obstet Gynecol MFM
DOI: 10.1016/j.ajogmf.2021.100458
sha: 32ba7c5458486cc8c6bd8c6b58c3ffe66d1177aa
doc_id: 1055366
cord_uid: xisa01ps

BACKGROUND: : Inflammatory biomarkers have been utilized to portend disease severity in non-pregnant individuals with SARS-CoV-2 infection. However, currently limited data are available, and with mixed results, to elucidate which inflammatory biomarkers may be most associated with clinical phenotype in pregnant patients. OBJECTIVE: : We aimed to compare laboratory findings among pregnant patients with severe acute respiratory syndrome coronavirus (SARS-CoV-2) by symptom status and disease severity. STUDY DESIGN: : We retrospectively evaluated pregnant patients at an urban academic U.S. hospital with positive polymerase-chain reaction SARS-CoV-2 testing between March and October 2020, performed for reported symptoms or universal screening on admission. In our hospital, all patients with SARS-CoV-2 were recommended to have baseline laboratory testing, including leukocyte, neutrophil and lymphocyte counts; aspartate and alanine aminotransferase; high sensitivity C-reactive protein (hsCRP); procalcitonin (PCT); lactate dehydrogenase (LDH); D-dimer; and ferritin. We performed multivariable logistic regression to evaluate peak laboratory abnormalities significantly associated with symptomatic SARS-CoV-2 infection and disease severity with gestational age at diagnosis, maternal age, and obesity as covariates. The sensitivity and specificity of laboratory abnormalities to identify symptomatic versus asymptomatic infection, and severe to critical disease versus mild to moderate disease, were calculated. RESULTS: : We identified 175 pregnant patients with SARS-CoV-2, of whom 100 (57%) were symptomatic; 17 (17%) of those who were symptomatic had severe to critical disease. Laboratory data was available for 128 patients, of whom 67 (52%) were symptomatic. Compared to asymptomatic people, symptomatic people were more likely to exhibit elevated hsCRP after adjusting for gestational age (aOR 5.67, 95% CI 1.42-22.52, sensitivity 81%, specificity 43%). In symptomatic individuals, transaminitis (aOR 5.67, 95% CI 1.27-25.43), elevated PCT (aOR 16.60, 95% CI 2.61-105.46), and elevated LDH (aOR 17.55, 95% CI 2.51-122.78) were independently associated with severe to critical disease compared to mild to moderate disease after adjusting for maternal age and obesity. Sensitivity for transaminitis, PCT elevation and LDH elevation was 47%, 87% and 53%, while specificity was 89%, 63% and 90%, respectively, for differentiating disease severity. CONCLUSION: : Inflammatory biomarkers in pregnant patients with SARS-CoV-2 exhibit vast heterogeneity, poor discriminative ability, and thereby limited clinical utility. Larger registry studies should evaluate which inflammatory biomarkers, accounting for pregnancy physiology, may be most useful for risk stratification and prognostication of pregnant patients with SARS-CoV-2 infection.

and specificity of laboratory abnormalities to identify symptomatic versus asymptomatic

Pregnant individuals are more likely to experience severe sequelae after infection with 72 severe acute respiratory syndrome coronavirus (SARS-CoV-2), presumably due to physiologic 73 changes in pregnancy that alter immune function. [1] [2] [3] [4] In the United States, from March to August 74 2020, approximately one in four reproductive-aged patients who were hospitalized for SARS-75

CoV-2 infection was pregnant, and as of October 29, 2020, SARS-CoV-2 has infected nearly 76 35,000 pregnant individuals resulting in 50 maternal deaths. 5, 6 In the midst of a rapidly evolving 77 pandemic, several small case series have determined that the majority of pregnant individuals 78 with SARS-CoV-2 infection will have a mild clinical phenotype, but a clinically significant 79 minority will develop severe illness. 3,7-10 80

In the non-pregnant population, several inflammatory biomarkers show promise in 81 facilitating risk stratification and prognostication of patients with severe SARS-CoV-2 infection, 82 including leukocyte, neutrophil and lymphocyte counts; aspartate and alanine aminotransferase; 83 C-reactive protein (CRP); procalcitonin (PCT); lactate dehydrogenase (LDH); D-dimer; and 84 ferritin. [11] [12] [13] [14] [15] However, several of these biomarkers, especially white blood cell count and 85 differential, D-dimer, CRP and ferritin, are physiologically altered in pregnancy, challenging the 86 clinical integration of these results. While some studies have evaluated subsets of biomarkers to 87 clinically distinguish pregnant individuals based on symptoms or severity of symptoms, the 88 small sample sizes have precluded meaningful conclusions. [16] [17] [18] [19] [20] [21] As such, we remain without a 89 clear laboratory-based approach to evaluate pregnant patients with SARS-CoV-2. 90

As inflammatory biomarkers may provide insight into disease severity in individuals with Symptomatic people were admitted if they had unstable vital signs, required oxygen 116 supplementation, reported significant shortness of breath or respiratory symptoms, or were felt to 117 be at risk for subsequent clinical deterioration. Otherwise clinically stable pregnant individuals 118 not warranting admission had outpatient telehealth follow-up for monitoring of symptoms. In our 119

hospital, all patients who tested positive for SARS-CoV-2, irrespective of pregnancy, were 120 recommended to have baseline labs with a complete blood cell count with differential to assess 121 neutrophil and lymphocyte percentage as well as leukocyte counts; chemistry panel to evaluate 122 aspartate aminotransferase (AST) and alanine aminotransferase (ALT); and additional testing for 123 the following biomarkers that were selected a priori based on their potential to stratify disease 124 severity: high-sensitivity C-reactive protein (hsCRP), PCT, LDH, D-dimer, and ferritin. Labs 125 were repeated daily if hospital admission was required, and providers were recommended to 126 trend all inflammatory markers on symptomatic patients throughout the study period until they 127 demonstrated clinical improvement. If patients were not hospitalized, then only laboratory values 128 from a single outpatient office, emergency room, or triage visit at the time of SARS-CoV-2 129 testing were available. Notably, for many asymptomatic patients with positive SARS-CoV-2 130 testing, laboratory assessment was not performed. A chest x-ray was not routinely obtained on 131 admission for SARS-CoV-2; rather, the clinical suspicion of worsening pulmonary disease or 132 concern for superimposed bacterial pneumonia were used to guide the decision for radiographic 133 fourteen days of a positive COVID-19 test result, were also compared according to symptom status and the severity of illness using independent samples t-tests and Mann Whitney U tests in 162 bivariable analyses. As SARS-CoV-2 infection has been associated with leukopenia in non-163 pregnant patients, we also compared the nadir of neutrophil percentage, lymphocyte percentage 164 and leukocyte count between groups. 23 The data included were cross-sectional; only the highest 165 (or lowest) biomarker level was analyzed for each patient. Analysis of laboratory values obtained 166 at initial presentation was similarly performed. Multiple lab values for the same patient were not 167 analyzed. No corrections were made for multiple comparison testing. (Table 1) . Of note, 46% and 23% of symptomatic and asymptomatic 205 people, respectively, reported known exposure to a positive case contact (p=0.003). There were between those who were symptomatic versus asymptomatic. Among symptomatic individuals, 208 pregnant patients with severe to critical disease were older (p=0.03) and more likely to be obese 209 (p=0.004) compared to those with mild to moderate disease; baseline characteristics were 210 otherwise similar between those with mild to moderate disease and those with severe to critical 211 disease. The most common medical comorbidities reported by disease severity are described in 212 Table 1 . 213

Among symptomatic pregnant patients, 60% had mild disease, 23% had moderate 214 disease, 16% had severe disease and one person (1%) had critical disease. The most commonly 215 reported symptoms were cough (63%), fever (41%), and shortness of breath (40%, Figure 2 ). 216

Thirty symptomatic pregnant individuals (30%) were hospitalized for supportive care and further 217 management of SARS-CoV-2 infection, 13 (43%) of whom had mild to moderate disease and the 218 remaining 17 (57%) with severe to critical disease. The majority of asymptomatic women 219 (94.6%) were identified during a hospitalization for delivery, whereas only 26.5% of 220 symptomatic women were identified during a hospitalization for delivery. 221

Laboratory data was available for 128 patients, of whom 61 (48%) were asymptomatic 222 and 67 (52%) were symptomatic. When peak (vs. nadir) laboratory markers as continuous 223 variables were compared between symptomatic and asymptomatic pregnant patients, those with 224 symptomatic infection had decreased leukocyte nadir and increased peak ferritin, ALT, AST, 225 hsCRP, D-dimer, and PCT (Table 2) . When peak (vs. nadir) laboratory markers as continuous 226 variables were compared between pregnant patients with mild to moderate disease and those 227 with severe to critical disease, pregnant patients with severe to critical disease had reduced analysis for laboratory values obtained at initial presentation. 231

Laboratory markers were then dichotomized as normal versus abnormal. For both peak 232 (vs nadir) laboratory values and those obtained at initial presentation, only leukocytosis 233 (compared to the absence of leukocytosis, with leukocytosis defined as white blood cell count 234 greater than 10.5K/µL); leukopenia (compared to the absence of leukopenia, with leukopenia 235 defined as white blood cell count less than 4K/µL); and an elevated hsCRP (compared to a 236 normal hsCRP, defined as less than 10 mg/L) were significantly associated with symptomatic 237 infection (Table 3, Supplementary Table 2 ). Neutrophil percentage, lymphocyte percentage, 238 transaminitis, and elevations in ferritin, D-Dimer, LDH and PCT were not associated with 239 symptomatic disease. After adjusting the peak value for gestational age at diagnosis, pregnant 240 patients with an elevated hsCRP had an over four-fold odds of having symptomatic disease. 241

Within the subgroup of pregnant patients who had symptoms, lymphopenia (compared to the 242 absence of lymphopenia, with lymphopenia defined as lymphocyte percentage less than 20%); 243 transaminitis (compared to normal liver transaminases, with elevated ALT defined as greater 244 than 52 units/L and elevated AST defined as greater than 39 units/L); an elevated PCT 245 (compared to normal PCT, defined as less than 0.065 ng/mL); and an elevated LDH (compared 246 to normal LDH, defined as less than 271 units/L), were associated with severe to critical disease 247 (Table 4) and an elevated LDH were each associated with having severe to critical disease. In analysis of laboratory values obtained at initial presentation, elevated procalcitonin was no longer significant 253 (Supplementary Table 3) . 254

Regarding test characteristics for peak laboratory values, hsCRP showed moderate 255 sensitivity (81%), but poor specificity (43%) for distinguishing symptomatic versus 256 asymptomatic infection. The sensitivity and specificity for each of these biomarkers to 257 differentiate disease severity among symptomatic patients were also suboptimal, with a 258 sensitivity of 47%, 87% and 53% for transaminitis, procalcitonin elevation and LDH elevation, 259 while specificity was 89%, 63% and 90%, respectively ( 15, 20, 24 However, we must consider that normal reference ranges for laboratory results may be 300 altered by physiologic changes in pregnancy. 24 In particular, D-dimer is typically elevated during 301 pregnancy, albeit with inconsistent reference ranges. 21,24-26 Normal reference ranges for hsCRP 302 and PCT have not been identified for pregnancy, although PCT is basally expressed at very low 303 levels in pregnancy while median CRP values in normal pregnancies appear to be higher than 304 standardized values for nonpregnant individuals. 21,24-28 Pregnancy itself does not affect LDH 305 levels or liver enzymes, though these can be elevated in the setting of pre-eclampsia or other 306 liver diseases associated with pregnancy. 29-31 Leukocytosis, primarily related to increased 307 circulation of neutrophils, without significant alteration in lymphocyte count is also associated 308 with the normal pregnancy state. 32,33,34 Finally, although elevated ferritin level can be an 309 indicator of infection in pregnancy, ferritin levels can also be reduced as a result of hemodilution 310 that is characteristic of pregnancy. 35 Therefore, it is possible certain biomarker levels in our 311 cohort may be labeled -normal‖ or -abnormal'‖ merely due to pregnancy physiology and not 312 solely due to SARS-CoV-2 infection. We must interpret the trends in laboratory markers 313 identified and their clinical significance with caution in our pregnant cohort given baseline 314 alterations due to normal pregnancy physiology. 315

Prior evaluation of inflammatory biomarkers in pregnant patients with SARS-CoV-2 316 infection according to symptomatology and disease severity is limited and demonstrates mixed 317 results (Table 6) . 17, 18, 20, 21, 25, 26 . Two studies compared biomarkers in pregnant versus nonpregnant 318 women with SARS-CoV-2 infection, though these did not include subgroups for symptomatic 319 disease or disease severity. 17 While this cohort is the largest cohort to our knowledge to analyze laboratory markers of 363 disease in pregnant individuals with clinically phenotyped SARS-CoV-2 infection, the small 364 sample size and missing data, particularly within smaller subgroups and among asymptomatic 365 patients, may lead to type II error. Missing data, specifically as it is not missing at random, 366 further introduces additional selection bias, limiting our ability to firmly conclude the frequency of abnormal lab results and the validity of comparisons between groups. Changes in criteria for 368 testing over the course of the pandemic also limit our ability to determine the proportion of 369 pregnant individuals tested who will have symptomatic infection. Changes in the care and 370 management of patients with SARS-CoV-2 infection also occurred throughout the study period 371 with different treatments having the potential to affect peak biomarker levels; however, our study 372 conclusions are less likely to be impacted by the evolving treatment methods given the relative 373 consistency in findings in our analysis of laboratory values obtained on initial presentation with 374 that of peak laboratory values. 375

It is important to note this is an epidemiologic, cross-sectional analysis evaluating peak 376 laboratory values, or nadir in the case of leukocyte count and differential, based on available 377 laboratory data captured among pregnant patients in the hospital setting as a proxy for the most 378 severe point in the clinical course of patients' disease. We cannot comment on biomarker trends 379 overtime throughout the course of a patient's disease, nor are we able to fully capture laboratory 380 data for pregnant patients managed primarily in the outpatient setting. Particularly in 381 asymptomatic patients identified on admission, but also among symptomatic individuals, the 382 actual timing of infection is unknown and it is plausible that peak biomarker levels could have 383 occurred prior to, or even after, admission. 

Characteristics of people of reproductive age with laboratory-confirmed SARS-CoV-2 415 infection by pregnancy status-United States

SARS-CoV-2 infection among hospitalized pregnant women: reasons for admission and 419 pregnancy characteristics-eight U.S. health care centers

Clinical characteristics and 422 intrauterine vertical transmission potential of COVID-19 infection in nine pregnant 423 women: a retrospective review of medical records

The immune system in pregnancy: a unique complexity

Characteristics and Maternal and Birth Outcomes of Hospitalized Pregnant Women with

Laboratory-confirmed COVID-19-COVID-NET, 13 States

analysis of potential biomarkers associated with severity of coronavirus disease 2019 456 (COVID-19)

COVID-19 disease progression

Prognostic Value of Cardiovascular 461

Biomarkers in COVID-19: A Review

COVID-19 and acute coagulopathy in pregnancy

Clinical characteristics and laboratory results of pregnant 466 women with COVID-19 in Wuhan, China

Clinical and CT imaging features of the

COVID-19 pneumonia: Focus on pregnant women and children

Clinical characteristics of pregnant women with COVID-19

Laboratory abnormalities in pregnant women

OR-unadjusted odds ratio, aOR-odds ratio adjusted for maternal age and obesity, CI-confidence interval; 594 hsCRP-high-sensitivity C-reactive protein, PCT-procalcitonin

Figure 2. The most commonly reported symptoms among symptomatic pregnant patients with SARS-CoV-2 infection