Introduction: Both blood pressure and heart rate (HR) are important factors that constitute hemodynamic status. Hypothesis: We aimed to determine whether HR was independently associated with all-cause mortality and whether HR modified the association between systolic blood pressure (SBP) and all-cause mortality. Methods: We included adults aged ≥20 years from the 1999-2018 National Health and Nutrition Examination Surveys without cardiovascular disease, chronic kidney disease, chronic obstructive pulmonary disease, cancer, asthma, or beta blocker use. Resting HR was categorized into 10 beats-per-min increments, and SBP in 10-20 mmHg increments as shown in Table 1. Our primary outcome was all-cause mortality, determined using linkage to the National Death Index through 2019. We used multivariable Cox regression, stratified by HTN status and adjusted for the survey design. Results: Among 27,369 participants, 5984 (22%) had diagnosed HTN. A HR ≥80 was associated with at least a 30% increase in mortality risk, regardless of HTN status (Table 1). Among normotensive participants, a HR ≥80 was associated with higher mortality risk compared to HR <80 at all SBPs except for SBP ≥180 (Table 1). While there was significant interaction between continuous HR and SBP on all-cause mortality (p=0.02), there was no evidence of significant effect modification within individual SBP categories. Conclusions: A HR ≥80 was independently associated with increased all-cause mortality risk, regardless of HTN diagnosis. HR may be a surrogate for cardiorespiratory fitness. Further studies understanding the joint associations between SBP and HR are needed in both normotensive and hypertensive individuals.

Background: The second wave of the COVID-19 pandemic has led to considerable morbidity and mortality in India, in part due to lack of healthcare access, low health literacy, and poor disease surveillance. In this retrospective, descriptive ecological study, we utilized Google Trends (GT) to characterize the second COVID-19 wave and its association with official case counts based on search terms related to symptoms, testing, disease complications, medications, preventive behaviors, and healthcare utilization. Methods: GT is a publicly available, online tracking system of Google searches. Searches are presented as relative search volumes (RSV) from 0 (least) to 100 (most number of searches). We performed pre-defined Web searches in India from 2/12/2021 to 5/09/2021. We characterized the peak RSV, RSV doubling rates, and Spearman rank correlation of selected search terms with official case counts. We also used date-adjusted linear regression to estimate the association between highly correlated search terms and official case counts. We then qualitatively classified public search queries into thematic groups to better understand public awareness and needs related to COVID-19. Results: We observed that searches for symptoms (most searched terms in order: fever, cough, headache, fatigue, chest pain), disease states (infection, pneumonia), COVID-19-related medications (remdesivir, ivermectin, azithromycin, Fabiflu, dexamethasone), testing modalities (PCR, CT Scan, D-dimer, C-reactive protein, oxygen saturation), healthcare utilization (oxygen cylinders, hospital, physician), and preventive behaviors (lockdown, mask, pulse oximetry, hand sanitizer, quarantine) all demonstrated increases, in line with increases in official case counts. Symptoms, PCR testing, outpatient medications, and preventive behaviors peaked around April 24th, approximately two weeks prior to the peak RSV in official case counts. Contrarily, healthcare utilization factors, including searches for hospital, physicians, beds, disease states, and inpatient medications did not peak until the first week of May. There were highly significant correlations between "Coronavirus Disease 2019" (r=0.959), "fever" (r=0.935), "pulse oximetry" (r=0.952), "oxygen saturation" (r=0.944), "C-reactive protein" (r=0.955), "D-Dimer" (r=0.945), & "Fabiflu" (r=0.943) and official case counts. Conclusion: GT search terms related to symptoms, testing, and medications are highly correlated with official case counts in India, suggesting need for further studies examining GT's potential use as a disease surveillance and public informant tool for public health officials.