Using a data-driven approach to define post-COVID conditions in US electronic health record data

OBJECTIVE

To create a data-driven definition of post-COVID conditions (PCC) by directly measure changes in symptomatology before and after a first COVID episode.

MATERIALS AND METHODS

Retrospective cohort study using Optum® de-identified Electronic Health Record (EHR) dataset from the United States of persons of any age April 2020-September 2021. For each person with COVID (ICD-10-CM U07.1 "COVID-19" or positive test result), we selected up to 3 comparators. The final COVID symptom score was computed as the sum of new diagnoses weighted by each diagnosis' ratio of incidence in COVID group relative to comparator group. For the subset of COVID cases diagnosed in September 2021, we compared the incidence of PCC using our data-driven definition with ICD-10-CM code U09.9 "Post-COVID Conditions", first available in the US October 2021.

RESULTS

The final cohort contained 588,611 people with COVID, with mean age of 48 years and 38% male. Our definition identified 20% of persons developed PCC in follow-up. PCC incidence increased with age: (7.8% of persons aged 0-17, 17.3% aged 18-64, and 33.3% aged 65+) and did not change over time (20.0% among persons diagnosed with COVID in 2020 versus 20.3% in 2021). For cases diagnosed in September 2021, our definition identified 19.0% with PCC in follow-up as compared to 2.9% with U09.9 code in follow-up.

CONCLUSION

Symptom and U09.9 code-based definitions alone captured different populations. Maximal capture may consider a combined approach, particularly before the availability and routine utilization of specific ICD-10 codes and with the lack consensus-based definitions on the syndrome.

Risk of Major Bleeding Associated with Concomitant Direct-Acting Oral Anticoagulant and Clopidogrel Use: A Retrospective Cohort Study

BACKGROUND AND AIM

Combined anticoagulant-antiplatelet therapy is often indicated in adults with cardiovascular disease and atrial fibrillation or venous thromboembolism. The study aim was to assess the comparative risk of bleeding between rivaroxaban and apixaban when combined with clopidogrel.

METHODS

We conducted a retrospective cohort study of commercially insured US adults newly treated with a combination of rivaroxaban+clopidogrel or apixaban+clopidogrel (2015-2018) using Merative™ Marketscan Research Databases. We used propensity score-based inverse probability of treatment weighting (IPTW) to balance the treatment groups. Weighted Cox proportional hazards regression was used to estimate the risk of major bleeding.

RESULTS

The study cohort included 2895 rivaroxaban+clopidogrel users and 3628 apixaban+clopidogrel users. The median (range) duration of follow up was 61 (73) days. Rivaroxaban+clopidogrel users had a similar risk of major bleeding compared with apixaban+clopidogrel users (IPTW incidence rate per 100 person-years 7.96 vs 7.38; IPTW hazard ratio [HR] 1.13 [95% CI 0.78-1.63]). In the subcohort of adults who were treated with DOAC or clopidogrel monotherapy prior to the combined therapy, the risk of major bleeding did not differ by the drug of monotherapy (IPTW HR for rivaroxaban+clopidogrel group: 0.66 [95% CI 0.33-1.32]; IPTW HR for apixaban+clopidogrel group: 1.10 [95% CI 0.55-2.23]) CONCLUSIONS: In our study of commercially insured US adults, the concomitant use of rivaroxaban+clopidogrel and apixaban+clopidogrel conferred a similar risk of major bleeding. DOAC versus clopidogrel monotherapy prior to the concomitant therapy did not influence the risk of major bleeding.

Health Care Resource Utilization and Costs Associated With COVID-19 Among Pediatrics Managed in the Community or Hospital Setting in England: A Population-based Cohort Study

BACKGROUND

Although COVID-19 morbidity is significantly lower in pediatrics than in adults, the risk of severe COVID-19 may still pose substantial health care resource burden. This study aimed to describe health care resource utilization (HCRU) and costs associated with COVID-19 in pediatrics 1-17 years old in England.

METHODS

A population-based retrospective cohort study of pediatrics with COVID-19 using Clinical Practice Research Datalink (CPRD Aurum) primary care data and, where available, linked Hospital Episode Statistics Admitted Patient Care secondary care data. HCRU and associated costs to the National Health Service were stratified by age, risk of severe COVID-19 and immunocompromised status, separately for those with and without hospitalization records (hospitalized cohort: COVID-19 diagnosis August 2020-March 2021; primary care cohort: COVID-19 diagnosis August 2020-January 2022).

RESULTS

This study included 564,644 patients in the primary care cohort and 60 in the hospitalized cohort. Primary care consultations were more common in those 1-4 years of age (face-to-face: 4.3%; telephone: 6.0%) compared with those 5-11 (2.0%; 2.1%) and 12-17 years of age (2.2%; 2.5%). In the hospitalized cohort, mean (SD) length of stay was longer [5.0 (5.8) days] among those 12-17 years old (n = 24) than those 1-4 [n = 15; 1.8 (0.9) days] and 5-11 years old [n = 21; 2.8 (2.1) days].

CONCLUSIONS

Most pediatrics diagnosed with COVID-19 were managed in the community. However, hospitalizations were an important driver of HCRU and costs, particularly for those 12-17 years old. Our results may help optimize the management and resource allocation of COVID-19 in this population.

Persons diagnosed with COVID-19 in England in the Clinical Practice Research Datalink (CPRD): a cohort description

OBJECTIVE

To create case definitions for confirmed COVID-19 diagnoses, COVID-19 vaccination status and three separate definitions of high risk of severe COVID-19, as well as to assess whether the implementation of these definitions in a cohort reflected the sociodemographic and clinical characteristics of COVID-19 epidemiology in England.

DESIGN

Retrospective cohort study.

SETTING

Electronic healthcare records from primary care (Clinical Practice Research Datalink, CPRD) linked to secondary care data (Hospital Episode Statistics) data covering 24% of the population in England.

PARTICIPANTS

2 271 072 persons aged 1 year and older diagnosed with COVID-19 in CPRD Aurum between 1 August 2020 and 31 January 2022.

MAIN OUTCOME MEASURES

Age, sex and regional distribution of COVID-19 cases and COVID-19 vaccine doses received prior to diagnosis were assessed separately for the cohorts of cases identified in primary care and those hospitalised for COVID-19 (primary diagnosis code of ICD-10 U07.1 'COVID-19'). Smoking status, body mass index and Charlson Comorbidity Index were compared for the two cohorts, as well as for three separate definitions of high risk of severe disease used in the UK (National Health Service Highest Risk, PANORAMIC trial eligibility, UK Health Security Agency Clinical Risk prioritisation for vaccination).

RESULTS

Compared with national estimates, CPRD case estimates under-represented older adults in both the primary care (age 65-84: 6% in CPRD vs 9% nationally) and hospitalised (31% vs 40%) cohorts, and over-represented people living in regions with the highest median wealth areas of England (20% primary care and 20% hospital admitted cases in South East vs 15% nationally). The majority of non-hospitalised cases and all hospitalised cases had not completed primary series vaccination. In primary care, persons meeting high-risk definitions were older, more often smokers, overweight or obese, and had higher Charlson Comorbidity Index score.

CONCLUSIONS

CPRD primary care data are a robust real-world data source and can be used for some COVID-19 research questions, however, limitations of the data availability should be carefully considered. Included in this publication are supplemental files for a total of over 28 000 codes to define each of three definitions of high risk of severe disease.

Economic burden of COVID-19 for employers and employees in the United States

OBJECTIVE

Describe the economic burden of COVID-19 on employers and employees in the United States (US).

METHODS

A targeted literature review was conducted to evaluate the impact of COVID-19 on US-based employers and employees in terms of healthcare resource utilization (HCRU), medical costs, and costs associated with work-loss. Searches were conducted in MEDLINE, Embase, and EconLit using a combination of disease terms, populations, and outcomes to identify articles published from January 2021 to November 4, 2022. As data from the employer perspective were lacking, additional literature related to influenza were included to contextualize the impact of COVID-19, as it shifts into an endemic state, within the existing respiratory illness landscape.

RESULTS

A total of 41 articles were included in the literature review. Employer and employee perspectives were not well represented in the literature, and very few articles overlapped on any given outcome. HCRU, costs, and work impairment vary by community transmission levels, industry type, population demographics, telework ability, mitigation implementation measures, and company policies. Work-loss among COVID-19 cases were higher among the unvaccinated and in the week following diagnosis and for some, these continued for 6 months. HCRU is increased in those with COVID-19 and COVID-19-related HCRU can also continue for 6 months.

CONCLUSIONS

COVID-19 continues to be a considerable burden to employers. The majority of COVID-19 cases impact working age adults. HCRU is mainly driven by outpatient visits, while direct costs are driven by hospitalization. Productivity loss is higher for unvaccinated individuals. An increased focus to support mitigation measures may minimize hospitalizations and work-loss. A data-driven approach to implementation of workplace policies, targeted communications, and access to timely and appropriate therapies for prevention and treatment may reduce health-related work-loss and associated cost burden.

National Trends in Anticoagulation Therapy for COVID-19 Hospitalized Adults in the United States: Analyses of the National COVID Cohort Collaborative

BACKGROUND

Anticoagulation (AC) utilization patterns and their predictors among hospitalized coronavirus disease 2019 (COVID-19) patients have not been well described.

METHODS

Using the National COVID Cohort Collaborative, we conducted a retrospective cohort study (2020-2022) to assess AC use patterns and identify factors associated with therapeutic AC employing modified Poisson regression.

RESULTS

Among 162 842 hospitalized COVID-19 patients, 64% received AC and 24% received therapeutic AC. Therapeutic AC use declined from 32% in 2020 to 12% in 2022, especially after December 2021. Therapeutic AC predictors included age (relative risk [RR], 1.02; 95% confidence interval [CI], 1.02-1.02 per year), male (RR, 1.29; 95% CI, 1.27-1.32), non-Hispanic black (RR, 1.16; 95% CI, 1.13-1.18), obesity (RR, 1.48; 95% CI, 1.43-1.52), increased length of stay (RR, 1.01; 95% CI, 1.01-1.01 per day), and invasive ventilation (RR, 1.64; 95% CI, 1.59-1.69). Vaccination (RR, 0.88; 95% CI, 84-.92) and higher Charlson Comorbidity Index (CCI) (RR, 0.98; 95% CI, .97-.98) were associated with lower therapeutic AC.

CONCLUSIONS

Overall, two-thirds of hospitalized COVID-19 patients received any AC and a quarter received therapeutic dosing. Therapeutic AC declined after introduction of the Omicron variant. Predictors of therapeutic AC included demographics, obesity, length of stay, invasive ventilation, CCI, and vaccination, suggesting AC decisions driven by clinical factors including COVID-19 severity, bleeding risks, and comorbidities.

Drug-drug interaction between dexamethasone and direct-acting oral anticoagulants: a nested case-control study in the National COVID Cohort Collaborative (N3C)

OBJECTIVE

The goal of this work is to evaluate if there is an increase in the risk of thromboembolic events (TEEs) due to concomitant exposure to dexamethasone and apixaban or rivaroxaban. Direct oral anticoagulants (DOACs), as well as corticosteroid dexamethasone, are commonly used to treat individuals hospitalised with COVID-19. Dexamethasone induces cytochrome P450-3A4 enzyme that also metabolises DOACs apixaban and rivaroxaban. This raises a concern about possible interaction between dexamethasone and DOACs that may reduce the efficacy of the DOACs and result in an increased risk of TEE.

DESIGN

We used nested case-control study design.

SETTING

This study was conducted in the National COVID Cohort Collaborative (N3C), the largest electronic health records repository for COVID-19 in the USA.

PARTICIPANTS

Study participants were adults over 18 years who were exposed to a DOAC for 10 or more consecutive days. Exposure to dexamethasone was at least 5 or more consecutive days.

PRIMARY AND SECONDARY OUTCOME MEASURES

Our primary exposure variable was concomitant exposure to dexamethasone for 5 or more days after exposure to either rivaroxaban or apixaban for 5 or more consecutive days. We used McNemar's Χ² test and adjusted logistic regression to evaluate association between concomitant use of dexamethasone with either apixaban or rivaroxaban.

RESULTS

McNemar's Χ² test did not find a discernible association of TEE in patients concomitantly exposed to dexamethasone and a DOAC (χ²=0.5, df=1, p=0.48). In addition, a conditional logistic regression model did not find an increase in the risk of TEE (adjusted OR 1.15, 95% CI 0.32 to 4.18).

CONCLUSION

This nested case-control study did not find evidence of an association between concomitant exposure to dexamethasone and a DOAC with an increase in risk of TEE. Due to small sample size, an association cannot be completely ruled out.

Coronavirus Disease 2019 Severity and Risk of Subsequent Cardiovascular Events

BACKGROUND

Little is known about the relationship between coronavirus disease 2019 (COVID-19) severity and subsequent risk of experiencing a cardiovascular event (CVE) after COVID-19 recovery. We evaluated this relationship in a large cohort of United States adults.

METHODS

Using a claims database, we performed a retrospective cohort study of adults diagnosed with COVID-19 between 1 April 2020 and 31 May 2021. We evaluated the association between COVID-19 severity and risk of CVE >30 days after COVID-19 diagnosis using inverse probability of treatment-weighted competing risks regression. Severity was based on level of care required for COVID-19 treatment: intensive care unit (ICU) admission, non-ICU hospitalization, or outpatient care only.

RESULTS

A total of 1 357 518 COVID-19 patients were included (2% ICU, 3% non-ICU hospitalization, and 95% outpatient only). Compared to outpatients, there was an increased risk of any CVE for patients requiring ICU admission (adjusted hazard ratio [aHR], 1.80 [95% confidence interval {CI}, 1.71-1.89]) or non-ICU hospitalization (aHR, 1.28 [95% CI, 1.24-1.33]). Risk of subsequent hospitalization for CVE was even higher (aHRs, 3.47 [95% CI, 3.20-3.76] for ICU and 1.96 [95% CI, 1.85-2.09] for non-ICU hospitalized vs outpatient only).

CONCLUSIONS

COVID-19 patients hospitalized or requiring critical care had a significantly higher risk of experiencing and being hospitalized for post-COVID-19 CVE than patients with milder COVID-19 who were managed solely in the outpatient setting, even after adjusting for differences between these groups. These findings underscore the continued importance of preventing severe acute respiratory syndrome coronavirus 2 infection from progressing to severe illness to reduce potential long-term cardiovascular complications.

Thromboprophylaxis in people hospitalized with COVID-19: Assessing intermediate or standard doses in a retrospective cohort study

Background and Objectives

Current clinical guidelines recommend thromboprophylaxis for adults hospitalized with coronavirus disease 2019 (COVID-19), yet it is unknown whether higher doses of thromboprophylaxis offer benefits beyond standard doses.

Methods

We studied electronic health records from 50 091 adults hospitalized with COVID-19 in the United States between February 2020 and February 2021. We compared standard (enoxaparin 30 or 40 mg/day, fondaparinux 2.5 mg, or heparin 5000 units twice or thrice per day) versus intermediate (enoxaparin 30 or 40 mg twice daily, or up to 1.2 mg/kg of body weight daily, heparin 7500 units thrice per day or heparin 10 000 units twice or thrice per day) thromboprophylaxis. We separately examined risk of escalation to therapeutic anticoagulation, severe disease (first occurrence of high-flow nasal cannula, noninvasive positive pressure ventilation or invasive mechanical ventilation), and death. To summarize risk, we present hazard ratios (HRs) with 95% confidence intervals (CIs) using adjusted time-dependent Cox proportional hazards regression models.

Results

People whose first dose was high intensity were younger, more often obese, and had greater oxygen support requirements. Intermediate dose thromboprophylaxis was associated with increased risk of therapeutic anticoagulation (HR, 3.39; 95% CI, 3.22-3.57), severe disease (HR, 1.22; 95% CI, 1.17-1.28), and death (HR, 1.37; 95% CI, 1.21-1.55). Increased risks associated with intermediate-dose thromboprophylaxis persisted in subgroup and sensitivity analyses varying populations and definitions of exposures, outcomes, and covariates.

Conclusions

Our findings do not support routine use of intermediate-dose thromboprophylaxis to prevent clinical worsening, severe disease, or death among adults hospitalized with COVID-19.

The Expert Next Door: Interactions With Friends and Family During the COVID-19 Pandemic

The coronavirus disease 2019 (COVID-19) pandemic thrust the field of public health into the spotlight. For many epidemiologists, biostatisticians, and other public health professionals, this caused the professional aspects of our lives to collide with the personal, as friends and family reached out with concerns and questions. Learning how to navigate this space was new for many and required refining our communication depending on context, setting, and audience. Some of us took to social media, utilizing our existing personal accounts to share information after sorting through and summarizing the rapidly emerging literature to keep loved ones safe. However, those in our lives sometimes asked unanswerable questions, or began distancing themselves when we suggested more stringent guidance than they hoped, causing additional stress during an already traumatic time. We often had to remind ourselves that we are also individuals experiencing this pandemic, and that our time-intensive efforts were meaningful, relevant, and impactful. As this pandemic and other public health crises continue, we encourage our discipline to consider how we can best use shared lessons from this period, and recognize that our professional knowledge, when used in our personal lives, can promote, protect, and bolster confidence in public health.

Long-term use of immunosuppressive medicines and in-hospital COVID-19 outcomes: a retrospective cohort study using data from the National COVID Cohort Collaborative

BACKGROUND

Many individuals take long-term immunosuppressive medications. We evaluated whether these individuals have worse outcomes when hospitalised with COVID-19 compared with non-immunosuppressed individuals.

METHODS

We conducted a retrospective cohort study using data from the National COVID Cohort Collaborative (N3C), the largest longitudinal electronic health record repository of patients in hospital with confirmed or suspected COVID-19 in the USA, between Jan 1, 2020, and June 11, 2021, within 42 health systems. We compared adults with immunosuppressive medications used before admission to adults without long-term immunosuppression. We considered immunosuppression overall, as well as by 15 classes of medication and three broad indications for immunosuppressive medicines. We used Fine and Gray's proportional subdistribution hazards models to estimate the hazard ratio (HR) for the risk of invasive mechanical ventilation, with the competing risk of death. We used Cox proportional hazards models to estimate HRs for in-hospital death. Models were adjusted using doubly robust propensity score methodology.

FINDINGS

Among 231 830 potentially eligible adults in the N3C repository who were admitted to hospital with confirmed or suspected COVID-19 during the study period, 222 575 met the inclusion criteria (mean age 59 years [SD 19]; 111 269 [50%] male). The most common comorbidities were diabetes (23%), pulmonary disease (17%), and renal disease (13%). 16 494 (7%) patients had long-term immunosuppression with medications for diverse conditions, including rheumatological disease (33%), solid organ transplant (26%), or cancer (22%). In the propensity score matched cohort (including 12 841 immunosuppressed patients and 29 386 non-immunosuppressed patients), immunosuppression was associated with a reduced risk of invasive ventilation (HR 0·89, 95% CI 0·83-0·96) and there was no overall association between long-term immunosuppression and the risk of in-hospital death. None of the 15 medication classes examined were associated with an increased risk of invasive mechanical ventilation. Although there was no statistically significant association between most drugs and in-hospital death, increases were found with rituximab for rheumatological disease (1·72, 1·10-2·69) and for cancer (2·57, 1·86-3·56). Results were generally consistent across subgroup analyses that considered race and ethnicity or sex, as well as across sensitivity analyses that varied exposure, covariate, and outcome definitions.

INTERPRETATION

Among this cohort, with the exception of rituximab, there was no increased risk of mechanical ventilation or in-hospital death for the rheumatological, antineoplastic, or antimetabolite therapies examined.

FUNDING

None.

First Biologic Drug Persistence in Patients With Ankylosing Spondylitis and Nonradiographic Axial Spondyloarthritis: A Real-World Canadian Physicians' Experience

METHODS

Data were obtained from persons enrolled in the SpondyloArthritis Research Consortium of Canada registry between 2003 and 2018. Kaplan-Meier curves were constructed from the time of biologic initiation until discontinuation and compared using the log-rank test. Subanalyses were performed according to calendar year and disease activity. Cox proportional hazards models were used to identify factors associated with discontinuation.

RESULTS

We identified 385 biologic-naive persons. Overall, the 349 AS participants had longer persistence to their first biologic than the 36 nr-axSpA subjects (p < 0.01). The Bath Ankylosing Spondylitis Disease Activity Index and Bath Ankylosing Spondylitis Functional Index decreased by 2.3 points (95% confidence interval [CI], 1.9-2.7) and 3.2 points (95% CI, 2.6-3.7), respectively, in the first year and were stable thereafter. Adjusting for sex, human leukocyte antigen B27, and smoking status, nr-axSpA patients were more likely to discontinue their biologic than AS patients (hazards ratio, 1.65; 95% CI, 1.03-2.62).

CONCLUSIONS

In this real-world study, AS patients had longer persistence to their first biologic compared with nr-axSpA, with disease subtype being the most significant predictor of treatment persistence. Future studies should be targeted at assessing long-term clinical outcome of axSpA in the real-world setting.

Curating the Evidence About COVID-19 for Frontline Public Health and Clinical Care: The Novel Coronavirus Research Compendium

The public health crisis created by the COVID-19 pandemic has spurred a deluge of scientific research aimed at informing the public health and medical response to the pandemic. However, early in the pandemic, those working in frontline public health and clinical care had insufficient time to parse the rapidly evolving evidence and use it for decision-making. Academics in public health and medicine were well-placed to translate the evidence for use by frontline clinicians and public health practitioners. The Novel Coronavirus Research Compendium (NCRC), a group of >60 faculty and trainees across the United States, formed in March 2020 with the goal to quickly triage and review the large volume of preprints and peer-reviewed publications on SARS-CoV-2 and COVID-19 and summarize the most important, novel evidence to inform pandemic response. From April 6 through December 31, 2020, NCRC teams screened 54 192 peer-reviewed articles and preprints, of which 527 were selected for review and uploaded to the NCRC website for public consumption. Most articles were peer-reviewed publications (n = 395, 75.0%), published in 102 journals; 25.1% (n = 132) of articles reviewed were preprints. The NCRC is a successful model of how academics translate scientific knowledge for practitioners and help build capacity for this work among students. This approach could be used for health problems beyond COVID-19, but the effort is resource intensive and may not be sustainable in the long term.

Changing patterns of use of implantable cardiac monitors from 2011 to 2018 for a large commercially-insured U.S. population

Implantable cardiac monitors (ICMs) provide long-term electrocardiographic monitoring for a number of indications. However, frequencies of use by indication and temporal changes have not been characterized on a national scale. We sought to characterize overall use and changes between 2011 and 2018. We used generalized linear models to characterize the incidence rate per 1,000,000 patient-quarters at risk and an autoregressive integrated moving average model to account for autocorrelation in this time series data. We studied commercially-insured patients and their insured dependents in the IBM MarketScan Commercial Database who had an ICM placed. We described the characteristics of individuals who received ICMs and the frequency of placements into 3 guideline concordance groups. We estimated the mean change per quarter in ICM placements (mean quarterly change in incidence rate per 1,000,000 patient-quarters at risk) for quarter (Q)1 2011 through Q1 2014, Q1 2014 to Q2 2014, and Q2 2014 through Q4 2018 for each guideline concordance group. The most common indications for categorizable ICM placement were syncope (24%), atrial fibrillation (11%), and stroke (11%). For each of the 3 guideline concordance groups except guideline unaddressed inpatient ICM placements, there was a significant increase in use either during the Q1 2014 to Q2 2014 or the Q2 2014 through Q4 2018 periods. A significant portion of ICM placements were for indications that lack strong evidence, such as established atrial fibrillation. The incidence of ICM placement for most of the indications and settings increased after miniaturization and technical improvements.

Real-World Effectiveness Of Remdesivir In Adults Hospitalized With Covid-19: A Retrospective, Multicenter Comparative Effectiveness Study

Background

There is an urgent need to understand the real-world effectiveness of remdesivir in the treatment of SARS-CoV-2.

Methods

This was a retrospective comparative effectiveness study. Individuals hospitalized in a large private healthcare network in the US from February 23, 2020 through February 11, 2021 with a positive test for SARS-CoV-2 and ICD-10 diagnosis codes consistent with symptomatic COVID-19 were included. Remdesivir recipients were matched to controls using time-dependent propensity scores. The primary outcome was time to improvement with a secondary outcome of time to death.

Results

Of 96,859 COVID-19 patients, 42,473 (43.9%) received at least one remdesivir dose. The median age of remdesivir recipients was 65 years, 23,701 (55.8%) were male and 22,819 (53.7%) were non-white. Matches were found for 18,328 patients (43.2%). Remdesivir recipients were significantly more likely to achieve clinical improvement by 28 days (adjusted hazard ratio [1.19, 95% confidence interval (CI), 1.16-1.22]). Remdesivir patients on no oxygen (aHR 1.30, 95% CI 1.22-1.38) or low-flow oxygen (aHR 1.23, 95% CI 1.19-1.27) were significantly more likely to achieve clinical improvement by 28 days. There was no significant impact on the likelihood of mortality overall (aHR 1.02, 95% CI 0.97-1.08). Remdesivir recipients on low-flow oxygen were significantly less likely to die than controls (aHR 0.85, 95% CI 0.77-0.92; 28-day mortality 8.4% [865 deaths] for remdesivir patients, 12.5% [1,334 deaths] for controls).

Conclusions

These results support the use of remdesivir for hospitalized COVID-19 patients on no or low-flow oxygen. Routine initiation of remdesivir in more severely ill patients is unlikely to be beneficial.

Association Between Chronic Use of Immunosuppresive Drugs and Clinical Outcomes From Coronavirus Disease 2019 (COVID-19) Hospitalization: A Retrospective Cohort Study in a Large US Health System

BACKGROUND

It is unclear whether chronic use of immunosuppressive drugs worsens or improves the severity of coronavirus disease 2019 (COVID-19), with plausible mechanisms for both.

METHODS

Retrospective cohort study in 2121 consecutive adults with acute inpatient hospital admission between 4 March and 29 August 2020 with confirmed or suspected COVID-19 in a large academic health system, with adjustment for confounding with propensity score-derived stabilized inverse probability of treatment weights. Chronic immunosuppression was defined as prescriptions for immunosuppressive drugs current at the time of admission. Outcomes included mechanical ventilation, in-hospital mortality, and length of stay.

RESULTS

There were 2121 patients admitted with laboratory-confirmed (1967, 93%) or suspected (154, 7%) COVID-19 during the study period, with a median age of 55 years (interquartile range, 40-67). Of these, 108 (5%) were classified as immunosuppressed before COVID-19, primarily with prednisone (>7.5 mg/day), tacrolimus, or mycophenolate mofetil. Among the entire cohort, 311 (15%) received mechanical ventilation; the median (interquartile range) length of stay was 5.2 (2.5-10.6) days, and 1927 (91%) survived to discharge. After adjustment, there were no significant differences in the risk of mechanical ventilation (hazard ratio [HR], .79; 95% confidence interval [CI], .46-1.35), in-hospital mortality (HR, .66; 95% CI, .28-1.55), or length of stay (HR, 1.16; 95% CI, .92-1.47) among individuals with immunosuppression and counterparts.

CONCLUSIONS

Chronic use of immunosuppressive drugs was neither associated with worse nor better clinical outcomes among adults hospitalized with COVID-19 in one US health system.

A Bridge Too Far? Real-World Practice Patterns of Early Glucocorticoid Use in the Canadian Early Arthritis Cohort

OBJECTIVE

To describe patterns of glucocorticoid use in a large real-world cohort with early rheumatoid arthritis (RA) and assess the impact on disease activity and treatment.

METHODS

Data are from adults with new RA (≤1 year) recruited to the Canadian Early Arthritis Cohort (CATCH) and are stratified on the basis of whether a person was prescribed oral glucocorticoids within 3 months of study entry. Disease activity was compared over 24 months. Mixed-effects logistic regression was used for adjusted odds ratios (aORs) of escalation to biologics separately for 12 and 24 months, with random effects terms to account for prescribing patterns clustering by study site.

RESULTS

Among 1891 persons, 30% received oral steroids. Users were older, were less often employed, and had shorter disease duration and higher disease activity. Disease activity improved over time, with early glucocorticoid users starting at higher levels of disease activity. Participants with early oral glucocorticoids were more likely to be on a biologic at 12 months (aOR = 2.4; 95% confidence interval [CI], 1.5-3.7) and 24 months (aOR = 1.9; 95% CI, 1.3-3.0). Despite Canadian clinical practice guidelines to limit corticosteroid use to short-term or 'bridge' therapy, 30% of patients who used oral glucocorticoids still used them 2 years later.

CONCLUSION

Early steroids were prescribed sparingly in CATCH and were often indicative of more active baseline disease as well as the need for progression to biologics.

Use of Hydroxychloroquine, Remdesivir, and Dexamethasone Among Adults Hospitalized With COVID-19 in the United States : A Retrospective Cohort Study

BACKGROUND

Relatively little is known about the use patterns of potential pharmacologic treatments of COVID-19 in the United States.

OBJECTIVE

To use the National COVID Cohort Collaborative (N3C), a large, multicenter, longitudinal cohort, to characterize the use of hydroxychloroquine, remdesivir, and dexamethasone, overall as well as across individuals, health systems, and time.

DESIGN

Retrospective cohort study.

SETTING

43 health systems in the United States.

PARTICIPANTS

137 870 adults hospitalized with COVID-19 between 1 February 2020 and 28 February 2021.

MEASUREMENTS

Inpatient use of hydroxychloroquine, remdesivir, or dexamethasone.

RESULTS

Among 137 870 persons hospitalized with confirmed or suspected COVID-19, 8754 (6.3%) received hydroxychloroquine, 29 272 (21.2%) remdesivir, and 53 909 (39.1%) dexamethasone during the study period. Since the release of results from the RECOVERY (Randomised Evaluation of COVID-19 Therapy) trial in mid-June, approximately 78% to 84% of people who have had invasive mechanical ventilation have received dexamethasone or other glucocorticoids. The use of hydroxychloroquine increased during March 2020, peaking at 42%, and started declining by April 2020. By contrast, remdesivir and dexamethasone use gradually increased over the study period. Dexamethasone and remdesivir use varied substantially across health centers (intraclass correlation coefficient, 14.2% for dexamethasone and 84.6% for remdesivir).

LIMITATION

Because most N3C data contributors are academic medical centers, findings may not reflect the experience of community hospitals.

CONCLUSION

Dexamethasone, an evidence-based treatment of COVID-19, may be underused among persons who are mechanically ventilated. The use of remdesivir and dexamethasone varied across health systems, suggesting variation in patient case mix, drug access, treatment protocols, and quality of care.

PRIMARY FUNDING SOURCE

National Center for Advancing Translational Sciences; National Heart, Lung, and Blood Institute; and National Institute on Aging.

COVID-19 Disease Severity among People with HIV Infection or Solid Organ Transplant in the United States: A Nationally-representative, Multicenter, Observational Cohort Study

Background

Individuals with immune dysfunction, including people with HIV (PWH) or solid organ transplant recipients (SOT), might have worse outcomes from COVID-19. We compared odds of COVID-19 outcomes between patients with and without immune dysfunction.

Methods

We evaluated data from the National COVID-19 Cohort Collaborative (N3C), a multicenter retrospective cohort of electronic medical record (EMR) data from across the United States, on. 1,446,913 adult patients with laboratory-confirmed SARS-CoV-2 infection. HIV, SOT, comorbidity, and HIV markers were identified from EMR data prior to SARS-CoV-2 infection. COVID-19 disease severity within 45 days of SARS-CoV-2 infection was classified into 5 categories: asymptomatic/mild disease with outpatient care; mild disease with emergency department (ED) visit; moderate disease requiring hospitalization; severe disease requiring ventilation or extracorporeal membrane oxygenation (ECMO); and death. We used multivariable, multinomial logistic regression models to compare odds of COVID-19 outcomes between patients with and without immune dysfunction.

Findings

Compared to patients without immune dysfunction, PWH and SOT had a greater likelihood of having ED visits (adjusted odds ratio [aOR]: 1.28, 95% confidence interval [CI] 1.27-1.29; aOR: 2.61, CI: 2.58-2.65, respectively), requiring ventilation or ECMO (aOR: 1.43, CI: 1.43-1.43; aOR: 4.82, CI: 4.78-4.86, respectively), and death (aOR: 1.20, CI: 1.19-1.20; aOR: 3.38, CI: 3.35-3.41, respectively). Associations were independent of sociodemographic and comorbidity burden. Compared to PWH with CD4>500 cells/mm3, PWH with CD4<350 cells/mm3 were independently at 4.4-, 5.4-, and 7.6-times higher odds for hospitalization, requiring ventilation, and death, respectively. Increased COVID-19 severity was associated with higher levels of HIV viremia.

Interpretation

Individuals with immune dysfunction have greater risk for severe COVID-19 outcomes. More advanced HIV disease (greater immunosuppression and HIV viremia) was associated with higher odds of severe COVID-19 outcomes. Appropriate prevention and treatment strategies should be investigated to reduce the higher morbidity and mortality associated with COVID-19 among PWH and SOT.

Identifying Minimal and Meaningful Change in PROMIS® for Rheumatoid Arthritis: Use of Multiple Methods and Perspectives

BACKGROUND

Rheumatoid arthritis (RA) is chronic, painful, disabling condition resulting in significant impairments in physical, emotional, and social health. We used different methods and perspectives to evaluate the responsiveness of PROMIS® short forms (SFs) and identify minimal and meaningful score changes.

METHODS

Adults with RA enrolled in a multi-site prospective observational cohort completed PROMIS Physical Function, Pain Interference, Fatigue, Participation in Social Roles/Activities SFs, PROMIS-29, and pain, patient global, and rated change in specific symptoms and RA (a little vs. lot better or worse) at the second visit. Physicians recorded joint counts, MD Global Assessment, and change in RA at visit 2. We compared mean score differences for minimal and meaningful improvement/worsening using patient and MD change ratings and distribution-based methods, and visually inspected empirical cumulative distribution function curves by change categories.

RESULTS

The 348 adults were mostly (81%) female with longstanding RA. Using patient ratings, generally 1-3 point differences were observed for minimal change and 3-7 points for meaningful change. Larger differences were observed with patient vs. physician ratings and for symptom-specific vs. RA change. Mean differences were similar among SF versions. Prespecified hypotheses about change in PROMIS Physical Function, Pain Interference, Fatigue and Participation and legacy scales were supported.

CONCLUSIONS

PROMIS SFs and the PROMIS-29 Profile are responsive to change and generally distinguish between minimal and meaningful improvement and worsening in key RA domains. These data add to a growing body of evidence demonstrating robust psychometric properties of PROMIS and supporting use in RA care, research, and decision-making.

Comparative risk of serious infections among real-world users of biologics for psoriasis or psoriatic arthritis

OBJECTIVE

To examine whether initiation of interleukin (IL)-17, IL-12/23 or tumour necrosis factor (TNF) inhibitor is associated with an increased risk of serious infection among real-world psoriasis (PsO) or psoriatic arthritis (PsA) patients.

METHODS

We assembled a retrospective cohort of commercially insured adults in the USA diagnosed with PsO or PsA between 2015 and 2018. Exposure was dispensation for IL-17 (ixekizumab or secukinumab), IL-12/23 (ustekinumab) or TNF (adalimumab, certolizumab pegol, etanercept, golimumab and infliximab). The outcome was infection requiring hospitalisation after biologic initiation. Incidence rates (IRs) per 100 person-years were computed, and hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated using Cox proportional hazards regression models, adjusted for inverse probability of treatment-weighted propensity scores.

RESULTS

A total of 11 560 new treatment episodes were included. Overall, 190 serious infections (2% of treatment episodes) were identified in 9264 person-years of follow-up. Class-specific IRs were similar among IL-17 and TNF, yet significantly lower for IL-12/23. After adjustment for propensity scores, there was no increased risk with IL-17 compared with either TNF (HR=0.89, 95% CI 0.48 to 1.66) or IL-12/23 (HR=1.12, 95% CI 0.62 to 2.03). By contrast, IL-23/23 were associated with a lower risk of infections than TNF (HR=0.59, 95% CI 0.39 to 0.90).

CONCLUSIONS

Relative to TNF and IL-17, IL-12/23 inhibitors were associated with a reduced risk of serious infection in biologic-naïve patients with PsO or PsA. In biologic-experienced individuals, there was no difference in infection risk across TNF, IL-17 or IL-12/23 inhibitors.

Identifying Possible Outcome Domains from Existing Outcome Measures to Inform an OMERACT Core Domain Set for Safety in Rheumatology Trials

OBJECTIVE

The Outcome Measures in Rheumatology (OMERACT) Safety Working Group objective was to identify harm domains from existing outcome measurements in rheumatology.

METHODS

Systematically searching the MEDLINE database on January 24, 2017, we identified full-text articles that could be used for harm outcomes in rheumatology. Domains/items from the identified instruments were described and the content synthesized to provide a preliminary framework for harm outcomes.

RESULTS

From 435 possible references, 24 were read in full text and 9 were included: 7 measurement instruments were identified. Investigation of domains/items revealed considerable heterogeneity in the grouping and approach.

CONCLUSION

The ideal way to assess harm aspects from the patients' perspective has not yet been ascertained.

Patient Perspectives on DMARD Safety Concerns in Rheumatology Trials: Results from Inflammatory Arthritis Patient Focus Groups and OMERACT Attendees Discussion

OBJECTIVE

The Outcome Measures in Rheumatology (OMERACT) Safety Working Group is identifying core safety domains that matter most to patients with rheumatic disease.

METHODS

International focus groups were held with 39 patients with inflammatory arthritis to identify disease-modifying antirheumatic drug (DMARD) experiences and concerns. Themes were identified by pragmatic thematic coding and discussed in small groups by meeting attendees.

RESULTS

Patients view DMARD side effects as a continuum and consider the cumulative effect on day-to-day function. Disease and drug experiences, personal factors, and life circumstances influence tolerance of side effects and treatment persistence.

CONCLUSION

Patients weigh overall adverse effects and benefits over time in relation to experiences and life circumstances.

Improving Benefit-harm Assessment of Therapies from the Patient Perspective: OMERACT Premeeting Toward Consensus on Core Sets for Randomized Controlled Trials

Objective.

Outcome Measures in Rheumatology (OMERACT) convened a premeeting in 2018 to bring together patients, regulators, researchers, clinicians, and consumers to build upon previous OMERACT drug safety work, with patients fully engaged throughout all phases.

Methods.

Day 1 included a brief introduction to the history of OMERACT and methodology, and an overview of current efforts within and outside OMERACT to identify patient-reported medication safety concerns. On Day 2, two working groups presented results; after each, breakout groups were assembled to discuss findings.

Results.

Five themes pertaining to drug safety measurement emerged.

Conclusion.

Current approaches have failed to include data from the patient’s perspective. A better understanding of how individuals with rheumatic diseases view potential benefits and harms of therapies is essential.

Effect of Employment Status on Physical Activity and Sedentary Behavior Long-Term Post-Bariatric Surgery

INTRODUCTION

Inactivity and weight regain are serious problems post-bariatric surgery. Nearly half of waking time is spent at work, representing an opportunity to accumulate physical activity and help avoid weight regain.

PURPOSE

The purpose of this study is to evaluate potential differences in physical activity and sedentary time by employment status post-bariatric surgery.

METHODS

A total of 48 adults (employed (n = 19), unemployed (n = 29)) aged 50.7 ± 9.4 years, BMI = 34.4 ± 10.1 kg/m², and 10 ± 3 years post-surgery participated. ActivPAL accelerometers measured transitions, steps, and sedentary time for 7 days.

RESULTS

Participants worked on average 8.7 ± 1.8 h/day. Twenty-one percent of employed met step/day guidelines on work-days compared to 10% of unemployed. Employed persons transitioned from sitting-to-standing more on work-days (58.6 ± 17.8) than unemployed (45.0 ± 15.4). Employment status did not influence activity or sedentarism on weekend/non-working-days.

CONCLUSION

Employment status may be associated with meaningful improvements in activity post-bariatric surgery.

Overweight, Obesity, and the Likelihood of Achieving Sustained Remission in Early Rheumatoid Arthritis: Results From a Multicenter Prospective Cohort Study

OBJECTIVE

Obesity is implicated in rheumatoid arthritis (RA) development, severity, outcomes, and treatment response. We estimated the independent effects of overweight and obesity on ability to achieve sustained remission (sREM) in the 3 years following RA diagnosis.

METHODS

Data were from the Canadian Early Arthritis Cohort, a multicenter observational trial of early RA patients treated by rheumatologists using guideline-based care. sREM was defined as Disease Activity Score in 28 joints (DAS28) <2.6 for 2 consecutive visits. Patients were stratified by body mass index (BMI) as healthy (18.5-24.9 kg/m² ), overweight (25-29.9 kg/m² ), and obese (≥30 kg/m² ). Cox regression was used to estimate the effect of the BMI category on the probability of achieving sREM over the first 3 years, controlling for age, sex, race, education, RA duration, smoking status, comorbidities, baseline DAS28, Health Assessment Questionnaire disability index, C-reactive protein level, and initial treatment.

RESULTS

Of 982 patients, 315 (32%) had a healthy BMI, 343 (35%) were overweight, and 324 (33%) were obese; 355 (36%) achieved sREM within 3 years. Initial treatment did not differ by BMI category. Compared to healthy BMI, overweight patients (hazard ratio [HR] 0.75 [95% confidence interval (95% CI) 0.58-0.98]) and obese patients (HR 0.53 [95% CI 0.39-0.71]) were significantly less likely to achieve sREM.

CONCLUSION

Rates of overweight and obesity were high (69%) in this early RA cohort. Overweight patients were 25% less likely, and obese patients were 47% less likely, to achieve sREM in the first 3 years, despite similar initial disease-modifying antirheumatic drug treatment and subsequent biologic use. This is the largest study demonstrating the negative impact of excess weight on RA disease activity and supports a call to action to better identify and address this risk in RA patients.

Identification of Three Rheumatoid Arthritis Disease Subtypes by Machine Learning Integration of Synovial Histologic Features and RNA Sequencing Data

OBJECTIVE

In this study, we sought to refine histologic scoring of rheumatoid arthritis (RA) synovial tissue by training with gene expression data and machine learning.

METHODS

Twenty histologic features were assessed in 129 synovial tissue samples (n = 123 RA patients and n = 6 osteoarthritis [OA] patients). Consensus clustering was performed on gene expression data from a subset of 45 synovial samples. Support vector machine learning was used to predict gene expression subtypes, using histologic data as the input. Corresponding clinical data were compared across subtypes.

RESULTS

Consensus clustering of gene expression data revealed 3 distinct synovial subtypes, including a high inflammatory subtype characterized by extensive infiltration of leukocytes, a low inflammatory subtype characterized by enrichment in pathways including transforming growth factor β, glycoproteins, and neuronal genes, and a mixed subtype. Machine learning applied to histologic features, with gene expression subtypes serving as labels, generated an algorithm for the scoring of histologic features. Patients with the high inflammatory synovial subtype exhibited higher levels of markers of systemic inflammation and autoantibodies. C-reactive protein (CRP) levels were significantly correlated with the severity of pain in the high inflammatory subgroup but not in the others.

CONCLUSION

Gene expression analysis of RA and OA synovial tissue revealed 3 distinct synovial subtypes. These labels were used to generate a histologic scoring algorithm in which the histologic scores were found to be associated with parameters of systemic inflammation, including the erythrocyte sedimentation rate, CRP level, and autoantibody levels. Comparison of gene expression patterns to clinical features revealed a potentially clinically important distinction: mechanisms of pain may differ in patients with different synovial subtypes.

Effects of Neighborhood Walkability on Physical Activity and Sedentary Behavior Long-Term Post-Bariatric Surgery

ᅟ: Chronic inactivity and weight regain are serious health concerns following bariatric surgery. Neighborhood walkability is associated with higher physical activity and lower obesity rates in normal weight populations.

PURPOSE

Explore the influence of neighborhood walkability on physical activity and sedentarism among long-term post-bariatric surgery patients.

METHODS

Fifty-eight adults aged 50.5 ± 9.1 years, with a BMI of 34.6 ± 9.7 kg/m² having undergone surgery 9.8 ± 3.15 years earlier participated in this study. Participants were asked to wear an ActivPAL™ tri-axial accelerometer attached to their mid-thigh for 7-consecutive days, 24 hours/day. The sample was separated into those that live in Car-Dependent (n = 23), Somewhat Walkable (n = 14), Very Walkable (n = 16), and Walker's Paradise (n = 5) neighborhoods as defined using Walk Score®. ANCOVA was performed comparing Walk Score® categories on steps and sedentary time controlling for age and sex.

RESULTS

Neighborhood walkability did not influence either daily steps (F (3, 54) = 0.921, p = 0.437) or sedentary time (F (3, 54) = 0.465, p = 0.708), Car-Dependent (6359 ± 2712 steps, 9.54 ± 2.46 hrs), Somewhat Walkable (6563 ± 2989 steps, 9.07 ± 2.70 hrs), Very Walkable (5261 ± 2255 steps, 9.97 ± 2.06 hrs), and Walker's Paradise (6901 ± 1877 steps, 10.14 ± 0.815 hrs).

CONCLUSION

Walkability does not appear to affect sedentary time or physical activity long-term post-surgery. As the built-environment does not seem to influence activity, sedentarism, or obesity as it does with a normal weight population, work needs to be done to tailor physical activity programming after bariatric surgery.

Malocclusion model of temporomandibular joint osteoarthritis in mice with and without receptor for advanced glycation end products

OBJECTIVE

This study has two aims: 1. Validate a non-invasive malocclusion model of mouse temporomandibular joint (TMJ) osteoarthritis (OA) that we developed and 2. Confirm role of inflammation in TMJ OA by comparing the disease in the presence and absence of the receptor for advanced glycation end products (RAGE).

DESIGN

The malocclusion procedure was performed on eight week old mice, either wild type (WT) or without RAGE.

RESULTS

We observed TMJ OA at two weeks post-misalignment/malocclusion. The modified Mankin score used for the semi-quantitative assessment of OA showed an overall significantly higher score in mice with malocclusion compared to control mice at all times points (2, 4, 6 and 8 weeks). Mice with malocclusion showed a decrease in body weight by the first week after misalignment but returned to normal weight for their ages during the following weeks. The RAGE knock out (KO) mice had statistically lower modified Mankin scores compared to WT mice of the same age. The RAGE KO mice had statistically lower levels of Mmp-13 and HtrA1 but higher Tgf-β1, as measured by immunohistochemistry, compared to WT mice at eight weeks post malocclusion.

CONCLUSIONS

We demonstrate an inexpensive, efficient, highly reproducible and non-invasive model of mouse TMJ OA. The mechanical nature of the malocclusion resembles the natural development of TMJ OA in humans, making this an ideal model in future studies that aim to elucidate the pathogenesis of the disease leading to the discovery of a treatment. The RAGE plays a role in mouse TMJ OA.

Physical activity and sedentary behavior in bariatric patients long-term post-surgery

BACKGROUND

To measure sedentary behaviors and physical activity using accelerometry in participants who have undergone bariatric surgery 8.87 ± 3.78 years earlier and to compare these results with established guidelines.

METHODS

Participants' weight and height were measured, an ActivPAL™3 accelerometer and sleeping journal were used to determine day sedentary time, transitions from sitting to standing, as well as steps/day, and participants were asked to indicate if they felt that they were currently less, the same, or more active than before surgery.

RESULTS

Participants averaged 48 ± 15 transitions/day, 6375 ± 2690 steps/day, and 9.7 ± 2.3 h/day in sedentary positions. There was a negative correlation between steps/day and sedentary time (r = -.466, p ≤ .001), 11.27 % of participants achieved 10,000 steps/day. Participants who reported being more active prior to surgery averaged 6323.4 ± 2634.79 steps/day, which was not different from the other two groups of self-perceived change in level of physical activity (F (2, 68) = .941, p ≤ .05) from pre- to post-surgery.

CONCLUSIONS

Participants were inadequately active and overly sedentary compared to established guidelines and norms. Healthcare workers should be taking physical activity and sedentary time into account when creating post-surgical guidelines for this population to ensure the best long-term weight loss maintenance and health outcomes.

Association of a microsatellite in FASL to type II diabetes and of the FAS-670G>A genotype to insulin resistance

Type II diabetes is caused by a failure of the pancreatic beta-cells to compensate for insulin resistance leading to hyperglycaemia. There is evidence for an essential role of an increased beta-cell apoptosis in type II diabetes. High glucose concentrations induce IL-1beta production in human beta-cells, Fas expression and concomitant apoptosis owing to a constitutive expression of FasL. FASL and FAS map to loci linked to type II diabetes and estimates of insulin resistance, respectively. We have tested two functional promoter polymorphisms, FAS-670 G>A and FASL-844C>T as well as a microsatellite in the 3' UTR of FASL for association to type II diabetes in 549 type II diabetic patients and 525 normal-glucose-tolerant (NGT) control subjects. Furthermore, we have tested these polymorphisms for association to estimates of beta-cell function and insulin resistance in NGT subjects. We found significant association to type II diabetes for the allele distribution of the FASL microsatellite (P-value 0.02, Bonferroni corrected). The FAS-670G>A was associated with homeostasis model assessment insulin resistance index and body mass index (P-values 0.02 and 0.02). We conclude that polymorphisms of FASL and FAS associate with type II diabetes and estimates of insulin resistance in Danish white subjects.

Maintaining the patency of peripherally inserted central catheters with 10 units/cc heparin

To maintain the patency of a peripherally inserted central catheter (PICC) line, it has been common practice to use 100 units of heparin as a flush. In this study, it was hypothesized that 10 units of heparin would maintain the patency of the PICC line as effectively as 100 units. To test this hypothesis, 46 patients who had PICC lines placed were retrospectively identified. Twenty patients received 100 units of heparin and had a PICC indwelling time ranging from 4 to 52 days (mean = 12 days) for a total of 314 indwelling days. Twenty-six patients received 10 units of heparin and had PICC indwelling time ranging from 2 to 54 days (mean = 11 days) for a total of 440 indwelling days. In two patients who received 100 units of heparin, PICC lines clotted after 2 days and 16 days, respectively. In four patients who received 10 units of heparin, PICC lines clotted after 5, 9, 29, and 36 days, respectively. Given the fact that this study was retrospective and uncontrolled, a statistical analysis was inappropriate; however, as a descriptive study, there appears to be evidence to support the original hypothesis. A controlled, blinded study must be performed to test the hypothesis statistically.