Geographic Progression of Infant Respiratory Syncytial Virus Associated Bronchiolitis Across the United States Before and Since the Onset of COVID-19: Results From Four Health Systems, 2015-2023.

BACKGROUND: Respiratory syncytial virus (RSV) is a substantial cause of infant morbidity and mortality due to seasonal peaks of bronchiolitis across the United States. Clinical and viral surveillance plays a pivotal role in helping hospital systems prepare for expected surges in RSV bronchiolitis. Existing surveillance efforts have shown a geographic pattern of RSV positivity across the United States, with cases typically starting in the southeast and spreading north and west. Public health measures implemented due to the COVID-19 pandemic disrupted viral transmission across the nation and altered the expected seasonality of RSV. The impact of these changes on the geographic progression of infant RSV bronchiolitis across the United States has not been described. METHODS: Here, we used clinical and viral surveillance data from four health care systems located in different regions of the United States to describe the geographic progression of infant RSV bronchiolitis across the country from 2015 to 2023. RESULTS: Prior to widespread circulation of SARS-CoV-2, infant RSV bronchiolitis followed an established geographic pattern associated with seasonal epidemics originating in Florida and spreading north (North Carolina and New York) and later westward (Nevada). Although public health and social measures implemented during the COVID-19 pandemic disrupted the seasonality of RSV disease, infant RSV bronchiolitis epidemics progressed across the nation in a pattern identical to the prepandemic era. CONCLUSIONS: Our findings highlight the importance of ongoing clinical and viral surveillance to optimally track the onset of RSV epidemics and allow health care systems to prepare for expected RSV bronchiolitis surges.

Healthcare Utilization Among Infants Covered by Medicaid and Newly Diagnosed With Respiratory Syncytial Virus.

Background: Infants covered by Medicaid have higher respiratory syncytial virus (RSV) hospitalization rates than those with commercial insurance, but findings are limited to the inpatient setting. This birth cohort study describes healthcare encounters for RSV across all settings among infants covered by Medicaid and the Children's Health Insurance Program. Methods: Medicaid claims for infants born and residing in Arizona (AZ), California (CA), Florida (FL), Michigan (MI), North Carolina (NC), New York (NY), and Texas (TX) were analyzed for first diagnosis of RSV in 2016-2018 using International Classification of Diseases, Tenth Revision codes. Encounters on the day of first diagnosis were examined by setting in 7 states and by setting and race in CA, FL, and NC. Results: A total of 80 945 infants were diagnosed with RSV in 7 states in 2016-2018. The highest encounter rates for first RSV diagnosis were in the emergency department (ED) in 5 states (11.0-33.4 per 1000 in AZ, CA, FL, MI, and NY) and outpatient setting in 2 states (54.8 and 68.5 per 1000 in TX and NC). Significantly higher outpatient encounter rates were found in CA and NC for White infants compared to non-White infants. In NC, ED encounter rates were significantly higher for non-White infants than White infants, whereas in CA, the rates were comparable. In these 2 states, hospitalization rates were similar across groups. In FL, compared with White infants, non-White infants had significantly higher encounter rates in each setting on the day of first RSV diagnosis. Conclusions: This is the first study to describe the burden of RSV by setting and race. Medicaid infants who are newly diagnosed with RSV have the highest burden in ED and outpatient settings.

Trends in RSV testing patterns among infants presenting with bronchiolitis: Results from four United States health systems, 2015-2023.

BACKGROUND: Bronchiolitis due to respiratory syncytial virus (RSV) is the leading cause of hospitalization among American infants. The overall burden of RSV among infants has been historically under-estimated due to variable testing practices, particularly in the outpatient setting. Universal masking and social distancing implemented during the coronavirus disease 2019 (COVID-19) pandemic altered RSV seasonality, however potential consequences on RSV testing practices across different healthcare settings and sociodemographic groups have not been described. Variable testing practices could also affect accurate assessment of the effects of two recently approved RSV preventative agents targeting infants. METHODS: Utilizing real-time clinical and viral surveillance, we examined RSV testing practices among infants with bronchiolitis within four United States healthcare systems across different healthcare settings and sociodemographic groups pre- and post-COVID-19. RESULTS: RSV testing among infants with bronchiolitis increased since 2015 within each healthcare system across all healthcare settings and sociodemographic groups, with a more dramatic increase since the COVID-19 pandemic. Outpatient testing remained disproportionately low compared to hospital-based testing, although there were no major differences in testing frequency among sociodemographic groups in either setting. CONCLUSIONS: Although RSV testing increased among infants with bronchiolitis, relatively low outpatient testing rates remain a key barrier to accurate RSV surveillance.

Epidemiology of RSV Bronchiolitis Among Young Children in Central New York Before and After the Onset of the COVID-19 Pandemic.

BACKGROUND: Respiratory syncytial virus (RSV) bronchiolitis is the leading cause of hospitalizations among infants in the United States. Unpredictability in RSV seasonality has occurred following the onset of the coronavirus disease 2019 (COVID-19) pandemic. Local surveillance networks can enhance the ability to appropriately time prophylaxis when exposure risk is highest. METHODS: A retrospective, cohort study was conducted to describe the epidemiologic patterns of RSV disease among outpatient, emergency department and inpatient encounters in children <5 years in Central New York before and after the onset of the COVID-19 pandemic. Local data were collected from October 2015 to January 2023 and compared to state-level data. Linear regression models were used to identify clinical and sociodemographic differences before and after the pandemic. RESULTS: Local variation in RSV seasonality was noted prior to the COVID-19 pandemic, however highly atypical circulation patterns appeared in the post-COVID-19 era. Since March 2020, patterns for local and state-defined RSV seasons have remained atypical (local season onset in 2021: week 27 and 2022: week 27; state season onset in 2021: week 31 and 2022: week 38). After adjusting for increases in testing, RSV bronchiolitis cases were not significantly different during pre- and post-pandemic eras. In comparison to the 2021 bronchiolitis season, the 2022 season had a higher proportion of RSV cases despite decreased testing. CONCLUSIONS: Temporal patterns for RSV have shifted during the COVID-19 pandemic. Local surveillance networks may be advantageous in trending community-level RSV activity to optimize prophylaxis administration. Changes in RSV testing patterns occurred throughout the study period and should be accounted for when describing infant and childhood RSV disease.

Biomarker expression and survival in patients with non-small cell lung cancer receiving adjuvant chemotherapy in Denmark.

INTRODUCTION: Programmed cell death ligand-1 (PD-L1) expression may help identify patients with non-small cell lung cancer (NSCLC) who would benefit from immunotherapy. We assessed PD-L1 expression, and epidermal growth factor receptor (EGFR) and V-Ki-Ras2 Kirsten rat sarcoma (KRAS) mutations in NSCLC patients receiving adjuvant chemotherapy. METHODS: Data for stage IB/II/IIIA NSCLC patients (diagnosed: 2001-2012) were retrieved from Danish population-based registries. Tumor tissue samples were tested for PD-L1 expression using VENTANA PD-L1 (SP263) Assay in tumor cells (TC) at ≥25% cutoff and immune cells (IC) at ≥1% and ≥25% cutoffs. KRAS and EGFR mutations were tested using PCR-based assays. Follow-up began 120 days after diagnosis until death/emigration/January 1, 2015, whichever came first. Using Cox proportional hazard regression, hazard ratios (HRs) were computed for overall survival (OS) for each biomarker, adjusting for age, sex, histology, comorbidities, and tissue specimen age. RESULTS: Among 391 patients identified, 40.4% had stage IIIA disease, 49.9% stage II, and 8.7% stage IB. PD-L1-TC was observed in 38% of patients, EGFR mutations in 4%, and KRAS mutations in 29%. KRAS mutations were more frequent among patients with PD-L1 TC≥25% versus TC<25% (37% versus 24%). OS was not associated with PD-L1 TC≥25% versus TC<25% (stage II: adjusted HR = 1.15 [95% confidence interval: 0.66-2.01]; stage IIIA: 0.72 [0.44-1.19]). No significant association was observed with OS and PD-L1-IC ≥1% and ≥25%. EGFR and KRAS mutations were not associated with a prognostic impact. CONCLUSION: A prognostic impact for NSCLC patients receiving adjuvant chemotherapy was not associated with PD-L1 expression, or with EGFR and KRAS mutations.

Respiratory Syncytial Virus During the COVID-19 Pandemic Compared to Historic Levels: A Retrospective Cohort Study of a Health System.

BACKGROUND: Surveillance in 2020-2021 showed that seasonal respiratory illnesses were below levels seen during prior seasons, with the exception of interseasonal respiratory syncytial virus (RSV). METHODS: Electronic health record data of infants aged <1 year visiting the Duke University Health System from 4 October 2015 to 28 March 2020 (pre-COVID-19) and 29 March 2020 to 30 October 2021 (COVID-19) were assessed. International Classification of Diseases-Tenth Revision (ICD-10) codes for RSV (B97.4, J12.1, J20.5, J21.0) and bronchiolitis (RSV codes plus J21.8, J21.9) were used to detail encounters in the inpatient (IP), emergency department (ED), outpatient (OP), urgent care (UC), and telemedicine (TM) settings. RESULTS: Pre-COVID-19, 88% of RSV and 92% of bronchiolitis encounters were seen in ambulatory settings. During COVID-19, 94% and 93%, respectively, occurred in ambulatory settings. Pre-COVID-19, the highest RSV proportion was observed in December-January (up to 38% in ED), while the peaks during COVID-19 were seen in July-September (up to 41% in ED) across all settings. RSV laboratory testing among RSV encounters was low during pre-COVID-19 (IP, 51%; ED, 51%; OP, 41%; UC, 84%) and COVID-19 outside of UC (IP, 33%; ED, 47%; OP, 47%; UC, 87%). Full-term, otherwise healthy infants comprised most RSV encounters (pre-COVID-19, up to 57% in OP; COVID-19, up to 82% in TM). CONCLUSIONS: With the interruption of historical RSV epidemiologic trends and the emergence of interseasonal disease during COVID-19, continued monitoring of RSV is warranted across all settings as the changing RSV epidemiology could affect the distribution of health care resources and public health policy.

Mortality Among US Infants and Children Under 5 Years of Age with Respiratory Syncytial Virus and Bronchiolitis: A Systematic Literature Review.

BACKGROUND: A systematic literature review was conducted to summarize the mortality (overall and by disease severity factors) of US infants and children aged <5 years with respiratory syncytial virus (RSV) or all-cause bronchiolitis (ACB). METHODS: Comprehensive, systematic literature searches were conducted; articles were screened using prespecified eligibility criteria. A standard risk of bias tool was used to evaluate studies. Mortality was extracted as the rate per 100 000 or the case fatality ratio (CFR; proportion of deaths among RSV/ACB cases). RESULTS: Among 42 included studies, 36 evaluated inpatient deaths; 10 used nationally representative populations updated through 2013, and only 2 included late-preterm/full-term otherwise healthy infants and children. The RSV/ACB definition varied across studies (multiple International Classification of Diseases [ICD] codes; laboratory confirmation); no study reported systematic testing for RSV. No studies reported RSV mortality rates, while 3 studies provided ACB mortality rates (0.57-9.4 per 100 000). CFRs ranged from 0% to 1.7% for RSV (n = 15) and from 0% to 0.17% for ACB (n = 6); higher CFRs were reported among premature, intensive care unit-admitted, and publicly insured infants and children. CONCLUSIONS: RSV mortality reported among US infants and children is variable. Current, nationally representative estimates are needed for otherwise healthy, late-preterm to full-term infants and children.

Systematic Literature Review of Respiratory Syncytial Virus Laboratory Testing Practices and Incidence in United States Infants and Children <5 Years of Age.

BACKGROUND: Respiratory syncytial virus (RSV) can cause serious illness in those aged <5 years in the United States, but uncertainty remains around which populations receive RSV testing. We conducted a systematic literature review of RSV testing patterns in studies published from 2000 to 2021. METHODS: Studies of RSV, medically attended RSV lower respiratory tract infections (LRTIs), and bronchiolitis were identified using standard methodology. Outcomes were clinical decisions to test for RSV, testing frequency, and testing incidence proportions in inpatient (IP), emergency department (ED), outpatient (OP), and urgent care settings. RESULTS: Eighty good-/fair-quality studies, which reported data from the period 1988-2020, were identified. Twenty-seven described the clinical decision to test, which varied across and within settings. Two studies reported RSV testing frequency for multiple settings, with higher testing proportions in IP (n = 2, range: 83%-85%, 1996-2009) compared with ED (n = 1, 25%, 2006-2009) and OP (n = 2, 15%-25%, 1996-2009). Higher RSV testing incidence proportions were observed among LRTI infant populations in the ED (n = 1, 74%, 2007-2008) and OP (n = 2, 54%-69%, 1995-2008). Incidence proportions in LRTI populations were not consistently higher in the IP setting (n = 13). Across studies and time, there was heterogeneity in RSV testing patterns, which may reflect varying detection methods, populations, locations, time periods, and healthcare settings. CONCLUSIONS: Not all infants and children with LRTI are tested for RSV, highlighting underestimation of RSV burden across all settings.

A Systematic Literature Review of the Burden of Respiratory Syncytial Virus and Health Care Utilization Among United States Infants Younger Than 1 Year.

BACKGROUND: The burden and health care utilization (HCU) of respiratory syncytial virus (RSV) in US infants aged <1 year across health care settings are not well characterized. METHODS: We systematically reviewed studies of RSV and bronchiolitis published 2000-2021 (data years, 1979-2020). Outcomes included RSV hospitalization (RSVH)/bronchiolitis hospitalization rates, emergency department (ED)/outpatient (OP) visit rates, and intensive care unit (ICU) admissions or mechanical ventilation (MV) use among RSV-/bronchiolitis-hospitalized infants. Study quality was determined using standard tools. RESULTS: We identified 141 good-/fair-quality studies. Five national studies reported annual average RSVH rates (range, 11.6 per 1000 per year among infants aged 6-11 months in 2006 to 50.1 per 1000 per year among infants aged 0-2 months in 1997). Two national studies provided RSVH rates by primary diagnosis for the entire study period (range, 22.0-22.7 per 1000 in 1997-1999 and 1997-2000, respectively). No national ED/OP data were available. Among 11 nonnational studies, RSVH rates varied due to differences in time, populations (eg, prematurity), and locations. One national study reported that RSVH infants with high-risk comorbidities had 5-times more MV use compared to non-high-risk infants in 1997-2012. CONCLUSIONS: Substantial data variability was observed. Nationally representative studies are needed to elucidate RSV burden and HCU.

Respiratory Syncytial Virus Is the Leading Cause of United States Infant Hospitalizations, 2009-2019: A Study of the National (Nationwide) Inpatient Sample.

BACKGROUND: This study describes leading causes of hospitalization, including respiratory syncytial virus (RSV), in United States infants (<1 year) from 2009 through 2019. METHODS: Within the National (Nationwide) Inpatient Sample (NIS) data, hospitalizations were determined by primary diagnosis using International Classification of Diseases, Ninth or Tenth Revision codes. RSV was defined as 079.6, 466.11, 480.1, B97.4, J12.1, J20.5, or J21.0. Bronchiolitis was defined as 466.19, J21.8, or J21.9. Leading causes overall and by sociodemographic variables were identified. The Kids' Inpatient Database (KID) was used for confirmatory analyses. RESULTS: Acute bronchiolitis due to RSV (code 466.11 or J21.0) was the leading primary diagnosis, accounting for 9.6% (95% confidence interval [CI], 9.4%-9.9%) and 9.3% (95% CI, 9.0%-9.6%) of total infant hospitalizations from January 2009 through September 2015 and October 2015 through December 2019, respectively; it was the leading primary diagnosis in every year accounting for >10% of total infant hospitalizations from December through March, reaching >15% in January-February. From 2009 through 2011, acute bronchiolitis due to RSV was the leading primary diagnosis in every birth month. Acute bronchiolitis due to RSV was the leading cause among all races/ethnicities, except Asian/Pacific Islanders, and all insurance payer groups. KID analyses confirmed these results. CONCLUSIONS: Acute bronchiolitis due to RSV is the leading cause of US infant hospitalizations.

Mortality Associated With Respiratory Syncytial Virus, Bronchiolitis, and Influenza Among Infants in the United States: A Birth Cohort Study From 1999 to 2018.

BACKGROUND: Infant mortality due to respiratory syncytial virus (RSV) in the United States is not well understood. METHODS: From 1999 to 2018, RSV, bronchiolitis, and influenza deaths were described for infants <1 year using linked birth/death datasets from the National Vital Statistics System. Mortality was described overall and by infant birth and death characteristics. Bronchiolitis was included as the plausible upper limit of RSV, while influenza served as a comparator. RESULTS: Total infant deaths were 561 RSV, 1603 bronchiolitis, and 504 influenza, and rates were 6.9 (95% confidence interval [CI], 6.4-7.5), 19.8 (95% CI, 18.9-20.8), and 6.2 (95% CI, 5.7-6.8) per 1 000 000 live births, respectively. The highest RSV rates were observed among <29 weeks' gestational age infants (103.5; 95% CI, 81.8-129.1), American Indian/Alaskan Native (20.3; 95% CI, 11.6-33.0), and Medicaid-insured (7.3; 95% CI, 5.9-8.9). However, RSV mortality burden was greatest in full-term (53.7%), white (44.9%), and Medicaid-insured (61.7%) infants. Deaths outside the inpatient setting were 21% and 54% for RSV and bronchiolitis; more Medicaid- (58%) and other/unknown-insured (69%) infants with bronchiolitis died outside of the inpatient setting, compared to privately insured infants (48%) (P = .0327). CONCLUSIONS: These national estimates emphasize the importance of considering all infants across all healthcare settings when describing RSV mortality.

Respiratory Syncytial Virus Burden and Healthcare Utilization in United States Infants <1 Year of Age: Study of Nationally Representative Databases, 2011-2019.

BACKGROUND: Respiratory syncytial virus (RSV) is the leading cause of hospitalizations in United States infants aged <1 year, but research has focused on select populations. METHODS: National (Nationwide) Inpatient Sample and National Emergency Department (ED) Sample data (2011-2019) were used to report RSV hospitalization (RSVH), bronchiolitis hospitalization (BH), and ED visit counts, percentage of total hospitalizations/visits, and rates per 1000 live births along with inpatient mortality, mechanical ventilation (MV), and total charges (2020 US dollars). RESULTS: Average annual RSVH and RSV ED visits were 56 927 (range, 43 845-66 155) and 131 999 (range, 89 809-177 680), respectively. RSVH rates remained constant over time (P = .5), whereas ED visit rates increased (P = .004). From 2011 through 2019, Medicaid infants had the highest average rates (RSVH: 22.3 [95% confidence interval {CI}, 21.5-23.1] per 1000; ED visits: 55.9 [95% CI, 52.4-59.4] per 1000) compared to infants with private or other/unknown insurance (RSVH: P < .0001; ED visits: P < .0001). From 2011 through 2019, for all races and ethnicities, Medicaid infants had higher average RSVH rates (up to 7 times) compared to infants with private or other/unknown insurance. RSVH mortality remained constant over time (P = .8), whereas MV use (2019: 13% of RSVH, P < .0001) and mean charge during hospitalization (2019: $21 513, P < .0001) increased. Bronchiolitis patterns were similar. CONCLUSIONS: This study highlights the importance of ensuring access to RSV preventive measures for all infants.

Respiratory Syncytial Virus and All-Cause Bronchiolitis Hospitalizations Among Preterm Infants Using the Pediatric Health Information System (PHIS).

BACKGROUND: In 2014, the American Academy of Pediatrics stopped recommending palivizumab to otherwise healthy 29-34 weeks' gestational age (wGA) infants aged <12 months at respiratory syncytial virus (RSV) season start. Here, we compare the burden of RSV hospitalizations (RSVH) and all-cause bronchiolitis hospitalizations (BH) before and after 2014 among otherwise healthy 29-34 wGA infants hospitalized at ≤6 months of age. METHODS: A historical, observational cohort study was conducted to evaluate RSVH and BH in 29-34 wGA infants during the 2010-2017 RSV seasons using encounter data from 51 United States children's hospitals that comprise the Pediatric Health Information System. RESULTS: The overall cohort included 67 570 RSVH out of 96 281 patients with BH. wGA was known for 22 937 RSVH and 33 289 BH. For 29-34 wGA infants, there were 8.7% and 14.2% RSVH before and after 2014, respectively (P < .0001). Intensive care unit admissions increased for RSVH (from 54.5% to 64.2%; P = .0002) and BH (from 46.7% to 54.5%; P = .0005) after controlling for sex, race, comorbidity, and cluster. The total cost of care increased for RSVH from $37 million to nearly $60 million. CONCLUSIONS: RSVH, BH, and their severity increased among 29-34 wGA infants in the 3 RSV seasons following 2014.

Programmed cell death ligand-1 expression and survival in a cohort of patients with non-small cell lung cancer receiving first-line through third-line therapy in Denmark.

BACKGROUND: PD-L1 expression on tumor cells (TCs) or immune cells (ICs) may be used as a prognostic marker for survival in patients with NSCLC. We characterized PD-L1 expression on TCs or ICs in a patient cohort with NSCLC to determine associations between PD-L1 expression and overall survival (OS), according to EGFR and KRAS mutation status. METHODS: Danish patients aged >18 years diagnosed with NSCLC before 2014 on first- (N = 491), second- (N = 368), or third-line (N = 498) therapy were included. Data were extracted from population-based medical registries. Tumor samples from pathology archives were tested for biomarkers. High PD-L1 expression was defined as expression on ≥25 % of TCs or ICs based on first diagnostic biopsy or surgical resection. KRAS and EGFR mutation status were tested using PCR-based assays. Cox regression analysis was used to compute adjusted HRs and associated 95 % CIs. RESULTS: PD-L1 TC and IC ≥ 25 % were observed in 24.3 %-31.0 % and 11.7-14.7 % of patients, respectively. EGFR and KRAS mutations were detected in 4.7 %-8.8 % and 26.5 %-30.7 % of patients, respectively. PD-L1 TC ≥ 25 % was not associated with survival advantage in first- (HR = 0.96, 95 % CI: 0.75-1.22), second- (1.08, 0.81-1.42), or third-line (0.94, 0.74-1.20) therapy. PD-L1 IC ≥ 25 % was associated with survival advantage in second-line (HR = 0.56, 95 % CI: 0.36-0.86) and third-line (0.69, 0.49-0.97) but not first-line (1.00, 0.70-1.41) therapy. CONCLUSION: No association was observed between PD-L1 TC ≥ 25 % and OS in any therapy line. PD-L1 IC ≥ 25 % may confer survival benefit among some patients who reach second-line therapy.

Healthcare resource utilization among patients with cold agglutinin disease in Denmark.

OBJECTIVES: Cold agglutinin disease (CAD) is a rare form of autoimmune hemolytic anemia that may manifest in complement-mediated chronic hemolytic anemia, profound fatigue, and transient agglutination-mediated circulatory symptoms. This study compared the healthcare resource utilization (HRU) of patients with CAD with a matched non-CAD comparison cohort using national Danish health registry data. METHODS: All cases of CAD were identified from 1 January 1999 to 30 June 2016, in the Danish National Patient Registry using the International Classification of Diseases, Tenth Revision, discharge diagnosis codes. A subcohort of patients with primary CAD was identified based on the absence of secondary predisposing concomitant diseases. CAD cases were matched to individuals without CAD from the general population based on birth year, sex, and 19 disease categories of the Charlson Comorbidity Index. Comparative analyses assessed inpatient hospitalizations, outpatient clinic visits, emergency room visits, transfusion use, and expensive drug use between cohorts 6 months before and 12 months after the admission date of the first hospital visit with CAD diagnosis (index date). RESULTS: A total of 104 patients with CAD were matched to 1003 comparison cohort members. Throughout the 12 months after the index date, patients with CAD were more likely to have at least one inpatient hospitalization (odds ratio [OR], 3.9; 95% confidence interval [CI], 2.5-6.0), outpatient clinic visit (OR, 17.2; 95% CI, 6.8-43.1), and blood transfusion (OR, 93.0; 95% CI, 33.3-259.8) than matched comparisons. HRU was similarly higher among patients with CAD than matched comparisons during the 6 months before the index date. Findings were similar among patients with primary CAD. CONCLUSIONS: Characterization of HRU among European patients with CAD has not previously been conducted. This study shows that patients with CAD utilize significant resources in Denmark. Increased HRU uses among patients with CAD before diagnosis presents opportunities for earlier diagnosis and management.

Relative Dose Intensity of Chemotherapy and Survival in Patients with Advanced Stage Solid Tumor Cancer: A Systematic Review and Meta-Analysis.

BACKGROUND: Chemotherapy-induced toxicities lead to therapy dose reduction or delay, affecting patient outcomes. This systematic review and meta-analysis evaluated the impact of relative dose intensity (RDI) on survival in adult patients with solid tumor cancer on nonadjuvant-based chemotherapy regimens. METHODS: PubMed, Embase, and Web of Science databases were searched for peer-reviewed English journal articles or congress abstracts evaluating association between RDI and survival; observational studies, case series of ≥20 patients, and clinical trials published between 2013 and 2020 were eligible. Meta-analyses were conducted to quantify the association between RDI levels and overall survival (OS) among studies reporting a hazard ratio (HR) for OS by similar tumor types, regimens, and RDI. Forest plots represented summary HR and 95% confidence interval (CI); Cochran's Q and I2 tests evaluated study heterogeneity. RESULTS: Overall, 919 articles were reviewed and 22 included; seven were eligible for meta-analysis. Significantly shorter OS at RDI <80% versus ≥80% and <85% versus ≥85% was observed upon meta-analysis of four carboplatin-based studies for breast, non-small cell lung, or ovarian cancer (HR 1.17; 95% CI: 1.07-1.27) and three FOLFOX-, FOLFIRI-, or FOLFIRINOX-based studies for colorectal or pancreatic cancer (HR 1.39; 95% CI: 1.03-1.89). Grade 3 or higher hematologic toxicities were higher for carboplatin-based regimens (thrombocytopenia: 14%-22%; anemia: 15%-19%; neutropenia: 24%-58%) than FOLFOX-, FOLFIRI-, or FOLFIRINOX-based regimens (thrombocytopenia: 1%-4%; anemia: 5%-19%; neutropenia: 19%-47%). CONCLUSION: The results suggested longer OS with RDI ≥80% or ≥85% for both regimens, indicating that management of toxicities across treatment modalities may contribute to maintenance of higher RDI and benefit survival for patients with advanced solid tumors. IMPLICATIONS FOR PRACTICE: Chemotherapy-induced toxicities lead to dose reduction and/or treatment delay, thus affecting patient outcomes. Results of this systematic review and meta-analysis, evaluating the impact of relative dose intensity (RDI) on survival of patients with solid tumors on nonadjuvant-based chemotherapy regimens, demonstrate a longer overall survival with RDI levels of at least 80% for patients with solid tumors on carboplatin-based and FOLFOX-, FOLFIRI-, or FOLFIRINOX-based chemotherapy regimens, suggesting a protective effect of maintaining RDI ≥80% or ≥ -85%. Although grade 3 or higher hematologic toxicities occurred more in carboplatin-based studies, managing toxicities across treatment regimens may contribute to maintenance of higher RDI and ultimately benefit overall survival.

A Systematic Literature Review and Meta-Analysis Describing the Prevalence of KRAS, NRAS, and BRAF Gene Mutations in Metastatic Colorectal Cancer.

BACKGROUND: Tumors of the metastatic colorectal cancer (mCRC) patients that are wildtype (WT) for KRAS or NRAS mutations respond more favorably to anti-epidermal growth factor receptor (EGFR) treatments. Treatment guidelines now recommend that all mCRC patients have WT KRAS and NRAS tumor status confirmed prior to initiating anti-EGFR therapy. Evidence also suggests that BRAF mutations may predict lack of response to anti-EGFR therapy. As such, there is now a need for comprehensive data on the prevalence of KRAS, NRAS, and BRAF mutations among patients with mCRC. METHODS: A systematic literature review was conducted among studies that described the prevalence of KRAS, NRAS, and BRAF gene mutations in mCRC patients. Observational cohort studies and standard of care arm of randomized clinical trials were included. Random effects meta-analysis models were used to create summary prevalence estimates for each of the mutation types. Subgroup analyses were also conducted to identify potential sources of heterogeneity. Exploratory analyses of overall and progression-free survival by mutation status were also conducted. RESULTS: This systematic review and meta-analysis included 275 studies comprising 77,104 mCRC patients. The summary prevalence estimate was 35.9% for KRAS mutations, 7.1% for BRAF mutations, and 4.1% for NRAS mutations. Female patients had significantly more KRAS and BRAF mutations than males, and significant variation by study location was observed for both KRAS and BRAF mutation prevalence. Overall survival was significantly decreased for patients with KRAS, BRAF, and NRAS mutations compared to those with WT tumors. Progression-free survival was also significantly decreased among patients with KRAS and BRAF mutations. CONCLUSIONS: KRAS, NRAS, and BRAF mutation statuses in patients with mCRC are important predictors of treatment success and may also have prognostic value. In this paper we present the first systematic and comprehensive literature review and meta-analysis of the prevalence of KRAS, BRAF, and NRAS mutations and demonstrate the prognostic impact of mutation status on survival.

Increased risk of thrombotic events in cold agglutinin disease: A 10-year retrospective analysis.

BACKGROUND: Cold agglutinin disease (CAD) is a rare autoimmune hemolytic anemia mediated by IgM autoantibodies that trigger hemolysis via classical complement pathway. Increased incidence of thrombotic events (TEs) has been reported in patients with other forms of hemolysis. The incidence of TEs in patients with CAD is unknown. OBJECTIVE: Evaluate TE risk in patients with CAD. PATIENTS/METHODS: This is a matched cohort comparison study evaluating the risk of TEs in patients with CAD and without CAD over a 10-year period. A total of 608 patients with CAD were identified in the Optum Claims-Clinical data set by reviewing clinical notes for CAD terms and matched with up to 10 patients without CAD (N = 5873). TEs were defined as the first medical claim for a TE using International Classification of Diseases, Ninth and Tenth Revision codes. Cox regression models were used to estimate time to first TE. Sensitivity analyses were conducted to estimate TE risk among patients with primary CAD. RESULTS: At least 1 TE occurred in 29.6% of patients with CAD and 17.6% of patients without CAD. The proportion of patients experiencing venous, arterial, and cerebral TEs were each higher among CAD patients. The overall risk of having TEs was higher in patients with CAD (adjusted hazard ratio [aHR], 1.94; 95% confidence interval [CI], 1.64-2.30). Patients with presumed primary CAD also demonstrated an increased risk of TEs (aHR, 1.80; 95% CI, 1.46-2.22). Patients with CAD with the fewest comorbidities had 2.44-fold higher risk of having a TE (95% CI, 1.70-3.52). CONCLUSIONS: Patients with CAD have an increased risk of TEs when compared with a matched non-CAD population.

Prevalence of RAS and BRAF mutations in metastatic colorectal cancer patients by tumor sidedness: A systematic review and meta-analysis.

Studies have shown that the prevalence of RAS and BRAF mutations may differ by tumor sidedness among metastatic colorectal cancer (mCRC) patients. Both mutation status and tumor sidedness may impact survival and disease progression and RAS mutation status has been shown to predict response to anti-epidermal growth factor receptor (EGFR) therapy. A systematic literature review and meta-analysis were conducted to estimate the pooled prevalence of RAS and BRAF mutations by tumor sidedness in studies of mCRC patients. Forty-four studies comprising 15 981 mCRC patients tested for RAS and/or BRAF mutations were included in the meta-analyses. The prevalence of RAS mutations differed significantly by tumor side (32.4% among left-sided tumors, 41.3% among right-sided tumors; P = .017), as did the prevalence of KRAS mutations (35.8% among left-sided tumors, 46.3% among right-sided tumors; P < .0001) and BRAF mutations (4.3% among left-sided tumors, 16.3% among right-sided tumors; P < .0001). Among right-sided tumors, the prevalence of RAS and KRAS mutations varied significantly by study design, with higher prevalence among observational studies than clinical trials, and there was significant variation by study location for the prevalence of KRAS mutations in left-sided tumors and the prevalence of BRAF mutations in right-sided tumors. These results help to better characterize the mCRC population to better inform clinicians and researchers. Few of the included studies reported overall or progression-free survival (PFS) by both tumor sidedness and mutation status. As both of these factors may have prognostic impact, future studies should consider evaluating survival by these variables.

Occurrence, thromboembolic risk, and mortality in Danish patients with cold agglutinin disease.

Cold agglutinin disease (CAD) is a rare form of autoimmune hemolytic anemia with limited epidemiological and clinical data. We used the Danish National Patient Registries to examine CAD occurrence and risk of thromboembolic events (TEs) and mortality in CAD patients compared with a matched cohort from the general population in Denmark. We identified 72 patients diagnosed with CAD and 720 matched controls between 1999 and 2013. For 2013, the most recent year of study, crude incidence of CAD was 0.18 per 100 000 inhabitants per year and prevalence was 1.26 per 100 000 inhabitants. Risk of TEs was higher in the CAD patient cohort than in the comparison cohort at 1 year (7.2% of CAD patients had TEs vs 1.9% of comparisons), 3 years (9.0% vs 5.3%), and 5 years (11.5% vs 7.8%) after the index date. The median survival was 8.5 years. CAD patients had increased mortality compared with the general population cohort (adjusted hazard ratio [aHR], 1.84; 95% confidence interval [CI], 1.10-3.06; P = .020), with the highest mortality observed during the first 5 years after diagnosis (aHR, 2.27; 95% CI, 1.32-3.89; P = .003). Mortality rates 1 and 5 years after diagnosis were 17% and 39% in the CAD group vs 3% and 18% in the comparison cohort, respectively. CAD is a rare illness characterized by increased risk of TEs and mortality.