Longitudinal patterns and predictors of response to standard-of-care therapy in lupus nephritis: data from the Accelerating Medicines Partnership Lupus Network

BACKGROUND

Leveraging the Accelerating Medicines Partnership (AMP) Lupus Nephritis (LN) dataset, we evaluated longitudinal patterns, rates, and predictors of response to standard-of-care therapy in patients with lupus nephritis.

METHODS

Patients from US academic medical centers with class III, IV, and/or V LN and a baseline urine protein/creatinine (UPCR) ratio ≥ 1.0 (n = 180) were eligible for this analysis. Complete response (CR) required the following: (1) UPCR < 0.5; (2) normal serum creatinine (≤ 1.3 mg/dL) or, if abnormal, ≤ 125% of baseline; and (3) prednisone ≤ 10 mg/day. Partial response (PR) required the following: (1) > 50% reduction in UPCR; (2) normal serum creatinine or, if abnormal, ≤ 125% of baseline; and (3) prednisone dose ≤ 15 mg/day.

RESULTS

Response rates to the standard of care at week 52 were CR = 22.2%; PR = 21.7%; non-responder (NR) = 41.7%, and not determined (ND) = 14.4%. Only 8/180 (4.4%) patients had a week 12 CR sustained through week 52. Eighteen (10%) patients attained a week 12 PR or CR and sustained their responses through week 52 and 47 (26.1%) patients achieved sustained PR or CR at weeks 26 and 52. Week 52 CR or PR attainment was associated with baseline UPCR > 3 (ORadj = 3.71 [95%CI = 1.34-10.24]; p = 0.012), > 25% decrease in UPCR from baseline to week 12 (ORadj = 2.61 [95%CI = 1.07-6.41]; p = 0.036), lower chronicity index (ORadj = 1.33 per unit decrease [95%CI = 1.10-1.62]; p = 0.003), and positive anti-dsDNA antibody (ORadj = 2.61 [95%CI = 0.93-7.33]; p = 0.069).

CONCLUSIONS

CR and PR rates at week 52 were consistent with the standard-of-care response rates observed in prospective registrational LN trials. Low sustained response rates underscore the need for more efficacious therapies and highlight how critically important it is to understand the molecular pathways associated with response and non-response.

Protocol for virtual physical examination in an observational, longitudinal study evaluating virtual outcome measures in SLE

OBJECTIVE

There is a lack of data on the use of telemedicine (TM) in SLE. SLE outcome measures remain complex, and clinicians and clinical trialists have raised concerns about the accuracy of virtual disease activity measures. This study evaluates the level of agreement between virtual SLE outcome measures and face-to-face (F2F) encounter. Here, we describe the study design, virtual physical examination protocol and demographics for the first 50 patients evaluated.

METHODS AND ANALYSIS

This is an observational, longitudinal study of 200 patients with SLE with varying levels of disease activity from 4 academic lupus centres serving diverse populations. Each study participant will be evaluated at a baseline and a follow-up visit. At each visit, participants are evaluated by the same physician first via a videoconference-based TM and then a F2F encounter. For this protocol, virtual physical examination guidelines relying on physician-directed patient self-examination were established. SLE disease activity measures will be completed immediately after the TM encounter and repeated after the F2F encounter for each visit. The degree of agreement between TM and F2F disease activity measures will be analysed using the Bland-Altman method. An interim analysis is planned after the enrolment of the first 50 participants.

ETHICS AND DISSEMINATION

This study has been reviewed by the Columbia University Medical Center Institutional Review Board (IRB Protocol #: AAAT6574). The full results of this study will be published after the final data analysis of 200 patients. The abrupt shift to TM visits due to the COVID-19 pandemic disrupted clinical practice and clinical trials. Establishing a high level of agreement between SLE disease activity measures obtained with videoconference TM and F2F at the same time point, will allow for improved assessment of disease activity when F2F data cannot be acquired. This information may guide both medical decision-making and provide reliable outcome measures for clinical research.

Respiratory microbiome profiles are associated with distinct inflammatory phenotype and lung function in children with asthma

BACKGROUND

Respiratory microbiome studies have fostered our understanding of various phenotypes and endotypes of heterogeneous asthma. However, the relationship between the respiratory microbiome and clinical phenotypes in children with asthma remains unclear. We aimed to identify microbiome-driven clusters reflecting the clinical features of asthma and their dominant microbiotas in children with asthma.

METHODS

Induced sputum was collected from children with asthma, and microbiome profiles were generated via sequencing of the V3-V4 region of the 16S rRNA gene. Cluster analysis was performed using the partitioning around medoid clustering method. The dominant microbiota in each cluster was determined using the Linear Discriminant Effect Size analysis. Each cluster was analyzed for association among the dominant microbiota, clinical phenotype, and inflammatory cytokine.

RESULTS

Eighty-three children diagnosed with asthma were evaluated. Among four clusters reflecting the clinical characteristics of asthma, cluster 1, dominated by Haemophilus and Neisseria, demonstrated lower post-bronchodilator (BD) forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) than that in the other clusters and more mixed granulocytic asthma. Neisseria negatively correlated with pre-BD and post-BD FEV1/FVC. Haemophilus and Neisseria positively correlated with programmed death-ligand (PD-L)1.

CONCLUSION

To our knowledge, this study is the first to analyze the relationship between an unbiased microbiome-driven cluster and clinical phenotype in children with asthma. The cluster dominated by Haemophilus and Neisseria showed fixed airflow obstruction and mixed granulocytic asthma, which correlated with PD-L1 levels. Thus, microbiome-driven unbiased clustering can help identify new asthma phenotypes related to endotypes in childhood asthma.

Adverse pregnancy outcomes in women with systemic lupus erythematosus: can we improve predictions with machine learning?

OBJECTIVES

Nearly 20% of pregnancies in patients with SLE result in an adverse pregnancy outcome (APO). We previously developed an APO prediction model using logistic regression and data from Predictors of pRegnancy Outcome: bioMarkers In Antiphospholipid Antibody Syndrome and Systemic Lupus Erythematosus (PROMISSE), a large multicentre study of pregnant women with mild/moderate SLE and/or antiphospholipid antibodies. Our goal was to determine whether machine learning (ML) approaches improve APO prediction and identify other risk factors.

METHODS

The PROMISSE data included 41 predictors from 385 subjects; 18.4% had APO (preterm delivery due to placental insufficiency/pre-eclampsia, fetal/neonatal death, fetal growth restriction). Logistic regression with stepwise selection (LR-S), least absolute shrinkage and selection operator (LASSO), random forest (RF), neural network (NN), support vector machines (SVM-RBF), gradient boosting (GB) and SuperLearner (SL) were compared by cross-validated area under the ROC curve (AUC) and calibration.

RESULTS

Previously identified APO risk factors, antihypertensive medication use, low platelets, SLE disease activity and lupus anticoagulant (LAC), were confirmed as important with each algorithm. LASSO additionally revealed potential interactions between LAC and anticardiolipin IgG, among others. SL performed the best (AUC=0.78), but was statistically indistinguishable from LASSO, SVM-RBF and RF (AUC=0.77 for all). LR-S, NN and GB had worse AUC (0.71-0.74) and calibration scores.

CONCLUSIONS

We predicted APO with reasonable accuracy using variables routinely assessed prior to the 12th week of pregnancy. LASSO and some ML methods performed better than a standard logistic regression approach. Substantial improvement in APO prediction will likely be realised, not with increasingly complex algorithms but by the discovery of new biomarkers and APO risk factors.

Evaluation of Immune Response and Disease Status in Systemic Lupus Erythematosus Patients Following SARS-CoV-2 Vaccination

OBJECTIVE

To evaluate seroreactivity and disease flares after COVID-19 vaccination in a multiethnic/multiracial cohort of patients with systemic lupus erythematosus (SLE).

METHODS

Ninety SLE patients and 20 healthy controls receiving a complete COVID-19 vaccine regimen were included. IgG seroreactivity to the SARS-CoV-2 spike receptor-binding domain (RBD) and SARS-CoV-2 microneutralization were used to evaluate B cell responses; interferon-γ (IFNγ) production was measured by enzyme-linked immunospot (ELISpot) assay in order to assess T cell responses. Disease activity was measured by the hybrid SLE Disease Activity Index (SLEDAI), and flares were identified according to the Safety of Estrogens in Lupus Erythematosus National Assessment-SLEDAI flare index.

RESULTS

Overall, fully vaccinated SLE patients produced significantly lower IgG antibodies against SARS-CoV-2 spike RBD compared to fully vaccinated controls. Twenty-six SLE patients (28.8%) generated an IgG response below that of the lowest control (<100 units/ml). In logistic regression analyses, the use of any immunosuppressant or prednisone and a normal anti-double-stranded DNA antibody level prior to vaccination were associated with decreased vaccine responses. IgG seroreactivity to the SARS-CoV-2 spike RBD strongly correlated with the SARS-CoV-2 microneutralization titers and correlated with antigen-specific IFNγ production determined by ELISpot. In a subset of patients with poor antibody responses, IFNγ production was similarly diminished. Pre- and postvaccination SLEDAI scores were similar in both groups. Postvaccination flares occurred in 11.4% of patients; 1.3% of these were severe.

CONCLUSION

In a multiethnic/multiracial study of SLE patients, 29% had a low response to the COVID-19 vaccine which was associated with receiving immunosuppressive therapy. Reassuringly, severe disease flares were rare. While minimal protective levels remain unknown, these data suggest that protocol development is needed to assess the efficacy of booster vaccination.

Subgroup discovery in non-inferiority trials

Approaches and guidelines for performing subgroup analysis to assess heterogeneity of treatment effect in clinical trials have been the topic of numerous papers in the statistical and clinical literature, but have been discussed predominantly in the context of conventional superiority trials. Concerns about treatment heterogeneity are the same if not greater in non-inferiority (NI) trials, especially since overall similarity between two treatment arms in a successful NI trial could be due to the existence of qualitative interactions that are more likely when comparing two active therapies. Even in unsuccessful NI trials, subgroup analyses can yield important insights about the potential reasons for failure to demonstrate non-inferiority of the experimental therapy. Recent NI trials have performed a priori subgroup analyses using standard statistical tests for interaction, but there is increasing interest in more flexible machine learning approaches for post-hoc subgroup discovery. The performance and practical application of such methods in NI trials have not been systematically explored, however. We considered the Virtual Twin method for the NI setting, an algorithm for subgroup identification that combines random forest with classification and regression trees, and conducted extensive simulation studies to examine its performance under different NI trial conditions and to devise decision rules for selecting the final subgroups. We illustrate the utility of the method with data from a NI trial that was conducted to compare two acupuncture treatments for chronic musculoskeletal pain.

Evaluation of SARS-CoV-2 IgG antibody reactivity in patients with systemic lupus erythematosus: analysis of a multi-racial and multi-ethnic cohort

Background

Patients with systemic lupus erythematosus (SLE) are at risk of developing COVID-19 due to underlying immune abnormalities and regular use of immunosuppressant medications. We aimed to evaluate the presence of SARS-CoV-2 IgG antibodies in patients with SLE with or without previous COVID-19-related symptoms or RT-PCR-confirmed SARS-CoV-2 infection.

Methods

For this analysis, we included patients with SLE from two cohorts based in New York City: the Web-based Assessment of Autoimmune, Immune-Mediated and Rheumatic Patients during the COVID-19 pandemic (WARCOV) study; and the NYU Lupus Cohort (a prospective registry of patients at NYU Langone Health and NYC Health + Hospitals/Bellevue). Patients in both cohorts were tested for SARS-CoV-2 IgG antibodies via commercially available immunoassays, processed through hospital or outpatient laboratories. Patients recruited from the NYU Lupus Cohort, referred from affiliated providers, or admitted to hospital with COVID-19 were tested for SARS-CoV-2 IgG antibodies as part of routine surveillance during follow-up clinical visits.

Findings

329 patients with SLE were included in this analysis, 146 from the WARCOV study and 183 from the NYU Lupus Cohort, and were tested for SARS-CoV-2 antibodies between April 29, 2020, and Feb 9, 2021. 309 (94%) were women and 91 (28%) were of Hispanic ethnicity. 51 (16%) of 329 patients had a positive SARS-CoV-2 IgG antibody test. Seropositive patients were more likely than seronegative patients to be Hispanic (24 [47%] of 51 vsz 67 [24%] of 278). Other demographic variables, SLE-specific factors, and immunosuppressant use were not associated with SARS-CoV-2 positivity. Of the 29 patients with COVID-19 previously confirmed by RT-PCR, 18 (62%) were on immunosuppressants; 24 (83%) of 29 patients tested positive for SARS-CoV-2 IgG antibodies. Of 17 patients who had symptoms of COVID-19 but negative concurrent RT-PCR testing, one (6%) developed an antibody response. Of 26 patients who had COVID-19-related symptoms but did not undergo RT-PCR testing, six (23%) developed an antibody response. Of 83 patients who had no symptoms of COVID-19 and no RT-PCR testing, four (5%) developed an antibody response. Among 36 patients who were initially SARS-CoV-2 IgG positive, the majority maintained reactivity serially (88% up to 10 weeks, 83% up to 20 weeks, and 80% up to 30 weeks). Seven (70%) of ten patients with confirmed COVID-19 had antibody positivity beyond 30 weeks from disease onset.

Interpretation

Most patients with SLE and confirmed COVID-19 were able to produce and maintain a serological response despite the use of a variety of immunosuppressants, providing reassurance about the efficacy and durability of humoral immunity and possible protection against re-infection with SARS-CoV-2.

Funding

National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, and Bloomberg Philanthropies COVID-19 Response Initiative Grant.

Autoantibody-mediated impairment of DNASE1L3 activity in sporadic systemic lupus erythematosus

Antibodies to double-stranded DNA (dsDNA) are prevalent in systemic lupus erythematosus (SLE), particularly in patients with lupus nephritis, yet the nature and regulation of antigenic cell-free DNA (cfDNA) are poorly understood. Null mutations in the secreted DNase DNASE1L3 cause human monogenic SLE with anti-dsDNA autoreactivity. We report that >50% of sporadic SLE patients with nephritis manifested reduced DNASE1L3 activity in circulation, which was associated with neutralizing autoantibodies to DNASE1L3. These patients had normal total plasma cfDNA levels but showed accumulation of cfDNA in circulating microparticles. Microparticle-associated cfDNA contained a higher fraction of longer polynucleosomal cfDNA fragments, which bound autoantibodies with higher affinity than mononucleosomal fragments. Autoantibodies to DNASE1L3-sensitive antigens on microparticles were prevalent in SLE nephritis patients and correlated with the accumulation of cfDNA in microparticles and with disease severity. DNASE1L3-sensitive antigens included DNA-associated proteins such as HMGB1. Our results reveal autoantibody-mediated impairment of DNASE1L3 activity as a common nongenetic mechanism facilitating anti-dsDNA autoreactivity in patients with severe sporadic SLE.

Leveraging the United States Epicenter to Provide Insights on COVID-19 in Patients With Systemic Lupus Erythematosus

OBJECTIVE

To characterize patients with systemic lupus erythematosus (SLE) affected by coronavirus disease 2019 (COVID-19) and to analyze associations of comorbidities and medications on infection outcomes.

METHODS

Patients with SLE and reverse transcriptase-polymerase chain reaction-confirmed COVID-19 were identified through an established New York University lupus cohort, query of 2 hospital systems, and referrals from rheumatologists. Data were prospectively collected via a web-based questionnaire and review of medical records. Data on baseline characteristics were obtained for all patients with COVID-19 to analyze risk factors for hospitalization. Data were also collected on asymptomatic patients and those with COVID-19-like symptoms who tested negative or were not tested. Statistical analyses were limited to confirmed COVID-19-positive patients.

RESULTS

A total of 226 SLE patients were included: 41 with confirmed COVID-19, 19 who tested negative for COVID-19, 42 with COVID-19-like symptoms who did not get tested, and 124 who remained asymptomatic without testing. Of the SLE patients with confirmed COVID-19, hospitalization was required in 24 (59%) and intensive care unit-level of care in 4, and 4 died. Hospitalized patients tended to be older, nonwhite, Hispanic, have higher body mas index (BMI), history of nephritis, and at least 1 comorbidity. An exploratory (due to limited sample size) logistic regression analysis identified race, presence of at least 1 comorbidity, and BMI as independent predictors of hospitalization.

CONCLUSION

In general, the variables predictive of hospitalization in our SLE patients were similar to those identified in the general population. Further studies are needed to understand additional risk factors for poor COVID-19 outcomes in patients with SLE.

Discontinuation of hydroxychloroquine in older patients with systemic lupus erythematosus: a multicenter retrospective study

Background

Although hydroxychloroquine (HCQ) is a mainstay of treatment for patients with systemic lupus erythematosus (SLE), ocular toxicity can result from accumulated exposure. As the longevity of patients with SLE improves, data are needed to balance the risk of ocular toxicity and the risk of disease flare, especially in older patients with quiescent disease. Accordingly, this study was initiated to examine the safety of HCQ withdrawal in older SLE patients.

Methods

Data were obtained by retrospective chart review at three major lupus centers in New York City. Twenty-six patients who discontinued HCQ and thirty-two patients on HCQ matched for gender, race/ethnicity, and age were included in this study. The primary outcome was the occurrence of a lupus flare classified by the revised version of the Safety of Estrogens in Lupus Erythematosus: National Assessment version of the Systemic Lupus Erythematosus Disease Activity Index (SELENA-SLEDAI) Flare composite index, within 1 year of HCQ withdrawal or matched time of continuation.

Results

Five patients (19.2%) in the HCQ withdrawal group compared to five (15.6%) in the HCQ continuation group experienced a flare of any severity (odds ratio [OR] = 1.28; 95% CI 0.31, 5.30; p = 0.73). There were no severe flares in either group. The results were similar after adjusting for length of SLE, number of American College of Rheumatology criteria, low complement levels, and SELENA-SLEDAI score, and in a propensity score analysis (OR = 1.18; 95% CI 0.23, 6.16; p = 0.84). The analysis of time to any flare revealed a non-significant earlier time to flare in the HCQ withdrawal group (log-rank p = 0.67). Most flares were in the cutaneous and musculoskeletal systems, but one patient in the continuation group developed pericarditis. The most common reason for HCQ withdrawal was retinal toxicity (42.3%), followed by patient’s preference (34.6%), other confirmed or suspected adverse effects (15.4%), ophthalmologist recommendation for macular degeneration (3.8%), and rheumatologist recommendation for quiescent SLE (3.8%).

Conclusions

In this retrospective study of older stable patients with SLE on long-term HCQ, withdrawal did not significantly increase the risk of flares.

Evaluation of hepatic injury in acute carbon monoxide-poisoned patients in emergency department

Introduction:

The affinity of hemoglobin for carbon monoxide (CO) is 250 times higher than that for oxygen. Therefore, exposure to CO leads to a reduction in oxygen delivery to tissues, resulting in cellular hypoxia and affects whole body. Hepatic dysfunction in critically ill patients is related to poor outcome, but few studies have been conducted on this subject that occurs after CO poisoning. This study aims to conduct a study of hepatic injury in CO-poisoned patients in emergency department (ED).

Methods:

This retrospective observational study collected data from patients who were diagnosed with acute CO poisoning at the ED between June 2011 and May 2018 in local tertiary-care hospital (Wonju, Republic of Korea). The primary end point of this study was to describe the prevalence of hepatic injury in acute CO-poisoned patients. The secondary goals were to investigate the recovery trends of hepatic injury caused by acute CO poisoning and the relation to neurologic outcome and mortality.

Results:

Eight hundred ninety-four patients were enrolled in the final analysis, 128 cases (14.3%) had subclinical hepatic injury and 15 (1.6%) cases had hepatic injury. The relationship with mortality was not statistically significant. However, the hepatic injury group was higher incidence of intensive care unit admission and other complications. Patients in the hepatic injury group recovered through conservative management within 1 week of being admitted to the ED.

Conclusions:

While CO-induced hepatic injury is relatively uncommon, it can be associated with complications and poor neurologic outcome. However, CO-induced hepatic injury was not found to have a statistically significant effect on mortality rate.

Low frequency of flares during pregnancy and post-partum in stable lupus patients

Background

Lupus patients are at risk for pregnancy loss, and it has been generally accepted that women with SLE should have low disease activity prior to conception. However, there are conflicting results regarding the effect of pregnancy on SLE flares. This study aims to identify predictors of flares during and after pregnancy in SLE patients with inactive or stable disease activity during the first trimester and to characterize and estimate the frequency of post-partum flares in these patients.

Methods

SLE patients in the multicenter, prospective PROMISSE (Predictors of Pregnancy Outcome: Biomarkers in Antiphospholipid Antibody Syndrome and Systemic Lupus Erythematosus) study were evaluated for flares during and after pregnancy using the SELENA-SLEDAI Flare Index. Flares during pregnancy were assessed in all 384 patients and post-partum flares in 234 patients with study visits 2–6 months post-partum. Logistic regression models were fit to the data to identify independent risk factors for flare.

Results

During pregnancy, 20.8% of patients had mild/moderate flares and 6.25% had severe. Post-partum, 27.7% of patients had mild/moderate flares and 1.7% had severe. The mild flares rarely required treatment. Younger age, low C4 and higher PGA at baseline were independently associated with higher risk of having at least one mild/moderate or severe flare during pregnancy. Older patients were at decreased risk of flare, as well as those with quiescent disease at baseline. No variables evaluated at baseline or the visit most proximal to delivery was significantly associated with risk of flare post-partum. Medications were not associated with flare during or after pregnancy.

Conclusion

In patients with inactive or stable mild disease activity at the time of conception, lupus disease flares during and after pregnancy are typically mild and occur at similar rates. Flares during pregnancy are predicted by the patients’ age and clinical and serological activity at baseline.

Factors associated with long-term cardiac dysfunction in neonatal lupus

OBJECTIVES

Cardiac manifestations of neonatal lupus (NL) have been associated with significant morbidity and mortality; however, there is minimal information on long-term outcomes of affected individuals. This study was initiated to evaluate the presence of and the risk factors associated with cardiac dysfunction in NL after birth in multiple age groups to improve counselling, to further understand pathogenesis and to provide potential preventative strategies.

METHODS

Echocardiogram reports were evaluated in 239 individuals with cardiac NL: 143 from age 0-1 year, 176 from age >1-17 years and 64 from age >17 years. Logistic regression analyses evaluated associations of cardiac dysfunction at each age group with demographic, fetal and postnatal factors, using imputation to address missing data.

RESULTS

Cardiac dysfunction was identified in 22.4% at age 0-1 year, 14.8% at age >1-17 years and 28.1% at age >17 years. Dysfunction in various age groups was significantly associated with male sex, black race, lower fetal heart rates, fetal extranodal cardiac disease and length of time paced. In 106 children with echocardiograms at ages 0-1 year and >1-17 years, 43.8% with dysfunction at age 0-1 year were also affected at age >1-17 years, while the others reverted to normal. Of children without dysfunction at age 0-1 year, 8.9% developed new dysfunction between ages >1 and 17 years. Among 34 with echocardiograms at ages >1-17 years and >17 years, 6.5% with normal function at age >1-17 years developed dysfunction in adulthood.

CONCLUSIONS

Risk factors in fetal life can influence cardiac morbidity into adulthood.Although limited by a small number of cases, cardiac dysfunction in the first year often normalises by later childhood. New-onset dysfunction, although rare, can occur de novo after the first year.

Metabolic syndrome and risk of endometrial cancer in postmenopausal women: a prospective study

BACKGROUND

Obesity is a strong risk factor for endometrial cancer, but it is unclear whether metabolic syndrome (MetS) contributes to endometrial cancer risk over and above the contribution of obesity.

METHODS

We examined the association of MetS and its components with risk of endometrial cancer in a sub-cohort of 24,210 women enrolled in the Women's Health Initiative cohort study. Two variants of the National Cholesterol Education Program Adult Treatment Panel III definition of the MetS were used: one including and one excluding waist circumference (WC). Cox proportional hazards models were used to estimate the association of the study exposures with disease risk.

RESULTS

When WC was included in the definition, MetS showed an approximately two-fold increase in endometrial cancer risk (HR 2.20; 95% CI 1.61-3.02); however, when WC was excluded, MetS was no longer associated with risk. We also observed that women with hyperglycemia, dyslipidemia and hypertension, in combination, had almost a twofold increased risk of endometrial cancer, independent of WC (HR 1.94; 95% CI 1.09, 3.46). Glucose, and, in particular, WC and body mass index were also positively associated with risk.

CONCLUSIONS

Our findings suggest that MetS may predict risk of endometrial cancer independent of obesity among women with the remaining four Mets components.

Abstract OT2-04-02: A phase 3 study of post-lumpectomy radiotherapy to whole breast + regional lymph nodes vs whole breast alone for patients with pN1 breast cancer treated with taxane-based chemotherapy (KROG 1701): Trial in progress

Background

In patients with early stage breast cancer, regional nodal irradiation (RNI) is added to whole breast irradiation (WBI) in order to control microscopic regional disease and to prevent systemic spread of cancer. According to recent randomized trials (MA.20 and EORTC 22922-10925), prophylactic RNI was associated with improvement in disease-free survival (DFS) in the patients with high-risk node negative or pN1 breast cancer. However, systemic agents now known to improve loco-regional control, such as taxane or endocrine therapy, were prescribed to a small percentage of patients in the studies. The benefit of RNI found in the previous studies might be attributed to incorporation of less effective systemic treatments. The impact of prophylactic RNI in pN1 breast cancer should be evaluated in the patients receiving modern systemic treatment. The current study was conducted to compare the effect of post-lumpectomy WBI vs WBI plus RNI on DFS in pN1 breast cancer patients who received adjuvant taxane-based chemotherapy.

Methods

This study is a multicenter, phase 3, randomized controlled non-inferiority trial (NCT03269981). Eligibility criteria are ≥ 20 years female; pathologically proven invasive carcinoma of the breast; one to three positive axillary lymph nodes (pN1) in pathologic specimen; receiving breast-conserving surgery followed by taxane-based chemotherapy; having adjuvant endocrine therapy or anti-HER2 treatment according to molecular subtype of tumor. Patients are randomly assigned in a 1:1 ratio to receive WBI or WBI plus RNI. Patient randomization was stratified by molecular subtype of tumor (i.e. luminal A/luminal B/luminal HER2/HER2-enriched/triple-negative) and methods of axillary management (i.e. sentinel lymph node biopsy/axillary lymph node dissection). The primary outcome is DFS. The secondary outcomes include DFS according to molecular subtype, treatment-related toxicity, and patient's quality of life per EORTC QLQ-C30 and QLQ-BR23. Patients will be followed for survival and disease recurrence for seven years. A total of 1,926 patients are planned to be enrolled, with recruitment initiated in April 2017. As of June 2018, a total of 236 patients were enrolled.

Acknowledgement

This study was supported by a grant from the National R&D Program for Cancer Control, Ministry of Health & Welfare, Republic of Korea (grant number: HA17C0043010018).

Citation Format: Kim H, Park W, Choi DH, Ahn SJ, Kim SS, Kim ES, Lee JH, Lee KC, Kim JH, Lee H-S, Kim JH, Kim MY, Park HJ, Kim K, Song SH, Kwon J, Lee IJ, Kim TH, Kim TG, Chang AR, Cho O, Jeong BK, Ha B, Lee J, Ki Y. A phase 3 study of post-lumpectomy radiotherapy to whole breast + regional lymph nodes vs whole breast alone for patients with pN1 breast cancer treated with taxane-based chemotherapy (KROG 1701): Trial in progress [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT2-04-02.

Adiposity, history of diabetes, and risk of pancreatic cancer in postmenopausal women

PURPOSE

The purpose of this study was to examine the association of type II diabetes and anthropometric variables with risk of pancreatic cancer among postmenopausal women.

METHODS

Weight, height, waist circumference, and hip circumference were measured by trained personnel, whereas history of diabetes and weight earlier in life were self-reported. Pancreatic cancer was ascertained via central review of medical records by physician adjudicators. After exclusions, 1045 cases of pancreatic cancer were diagnosed among 156,218 women over a median follow-up of approximately 18 years. Cox proportional hazards models were used to estimate the associations of study factors with pancreatic cancer risk.

RESULTS

Diabetes (hazards ratio (HR): 1.30; 95% confidence intervals (95% CI): 1.01-1.66), and in particular, waist circumference, waist-to-hip ratio, and waist-to-height ratio showed positive associations with pancreatic cancer risk (HRs for highest vs. lowest level 1.38; 95% CI: 1.14-1.66, 1.40; 1.17-1.68; and 1.36; 1.13-1.64, respectively). Body mass index at the baseline showed only a borderline positive association with risk (HR: 1.21; 95% CI: 0.97-1.51). Body mass index at age 50 years, but not at ages 18 and 35 years, was also associated with increased pancreatic cancer risk.

CONCLUSIONS

In this study of postmenopausal women, central adiposity and, to a lesser extent, general adiposity and a history of diabetes, were associated with increased pancreatic cancer risk.

Metabolic obesity phenotypes and risk of colorectal cancer in postmenopausal women

Obesity has been postulated to increase the risk of colorectal cancer by mechanisms involving insulin resistance and the metabolic syndrome. We examined the associations of body mass index (BMI), waist circumference, the metabolic syndrome, metabolic obesity phenotypes and homeostasis model-insulin resistance (HOMA-IR-a marker of insulin resistance) with risk of colorectal cancer in over 21,000 women in the Women's Health Initiative CVD Biomarkers subcohort. Women were cross-classified by BMI (18.5-<25.0, 25.0-<30.0 and ≥30.0 kg/m² ) and presence of the metabolic syndrome into 6 phenotypes: metabolically healthy normal weight (MHNW), metabolically unhealthy normal weight (MUNW), metabolically healthy overweight (MHOW), metabolically unhealthy overweight (MUOW), metabolically healthy obese (MHO) and metabolically unhealthy obese (MUO). Neither BMI nor presence of the metabolic syndrome was associated with risk of colorectal cancer, whereas waist circumference showed a robust positive association. Relative to the MHNW phenotype, the MUNW phenotype was associated with increased risk, whereas no other phenotype showed an association. Furthermore, HOMA-IR was not associated with increased risk. Overall, our results do not support a direct role of metabolic dysregulation in the development of colorectal cancer; however, they do suggest that higher waist circumference is a risk factor, possibly reflecting the effects of increased levels of cytokines and hormones in visceral abdominal fat on colorectal carcinogenesis.

Complement activation predicts adverse pregnancy outcome in patients with systemic lupus erythematosus and/or antiphospholipid antibodies

OBJECTIVE

Studies in mouse models implicate complement activation as a causative factor in adverse pregnancy outcomes (APOs). We investigated whether activation of complement early in pregnancy predicts APOs in women with systemic lupus erythematosus (SLE) and/or antiphospholipid (aPL) antibodies.

METHODS

The PROMISSE Study enrolled pregnant women with SLE and/or aPL antibodies (n=487) and pregnant healthy controls (n=204) at <12 weeks gestation and evaluated them monthly. APOs were: fetal/neonatal death, preterm delivery <36 weeks because of placental insufficiency or preeclampsia and/or growth restriction <5th percentile. Complement activation products were measured on serial blood samples obtained at each monthly visit.

RESULTS

APO occurred in 20.5% of SLE and/or aPL pregnancies. As early as 12-15 weeks, levels of Bb and sC5b-9 were significantly higher in patients with APOs and remained elevated through 31 weeks compared with those with normal outcomes. Moreover, Bb and sC5b-9 were significantly higher in patients with SLE and/or aPL without APOs compared with healthy controls. In logistic regression analyses, Bb and sC5b-9 at 12-15 weeks remained significantly associated with APO (OR_adj=1.41 per SD increase; 95% CI 1.06 to 1.89; P=0.019 and OR_adj=1.37 per SD increase; 95% CI 1.05 to 1.80; P=0.022, respectively) after controlling for demographic and clinical risk factors for APOs in PROMISSE. When analyses were restricted to patients with aPL (n=161), associations between Bb at 12-15 weeks and APOs became stronger (OR_adj=2.01 per SD increase; 95% CI 1.16 to 3.49; P=0.013).

CONCLUSION

In pregnant patients with SLE and/or aPL, increased Bb and sC5b-9 detectable early in pregnancy are strongly predictive of APOs and support activation of complement, particularly the alternative pathway, as a contributor to APOs.

New methods for estimating follow-up rates in cohort studies

Background

The follow-up rate, a standard index of the completeness of follow-up, is important for assessing the validity of a cohort study. A common method for estimating the follow-up rate, the “Percentage Method”, defined as the fraction of all enrollees who developed the event of interest or had complete follow-up, can severely underestimate the degree of follow-up. Alternatively, the median follow-up time does not indicate the completeness of follow-up, and the reverse Kaplan-Meier based method and Clark’s Completeness Index (CCI) also have limitations.

Methods

We propose a new definition for the follow-up rate, the Person-Time Follow-up Rate (PTFR), which is the observed person-time divided by total person-time assuming no dropouts. The PTFR cannot be calculated directly since the event times for dropouts are not observed. Therefore, two estimation methods are proposed: a formal person-time method (FPT) in which the expected total follow-up time is calculated using the event rate estimated from the observed data, and a simplified person-time method (SPT) that avoids estimation of the event rate by assigning full follow-up time to all events. Simulations were conducted to measure the accuracy of each method, and each method was applied to a prostate cancer recurrence study dataset.

Results

Simulation results showed that the FPT has the highest accuracy overall. In most situations, the computationally simpler SPT and CCI methods are only slightly biased. When applied to a retrospective cohort study of cancer recurrence, the FPT, CCI and SPT showed substantially greater 5-year follow-up than the Percentage Method (92%, 92% and 93% vs 68%).

Conclusions

The Person-time methods correct a systematic error in the standard Percentage Method for calculating follow-up rates. The easy to use SPT and CCI methods can be used in tandem to obtain an accurate and tight interval for PTFR. However, the FPT is recommended when event rates and dropout rates are high.

Electronic supplementary material

The online version of this article (10.1186/s12874-017-0436-z) contains supplementary material, which is available to authorized users.

Rifaximin treatment is associated with reduced risk of cirrhotic complications and prolonged overall survival in patients experiencing hepatic encephalopathy

BACKGROUND

Rifaximin might decrease the risk of portal hypertension-related complications by controlling small intestinal bacterial overgrowth.

AIM

To evaluate whether rifaximin was associated with the risk of death and cirrhotic complications.

METHODS

We conducted a retrospective study that included 1042 patients experiencing hepatic encephalopathy (HE): 421 patients without hepatocellular carcinoma (HCC; the non-HCC cohort) and 621 patients with HCC (the HCC cohort). The primary endpoint was overall survival and secondary endpoints were recurrence of HE and the development of spontaneous bacterial peritonitis (SBP), hepatorenal syndrome (HRS) and variceal bleeding.

RESULTS

In the non-HCC cohort, 145 patients received rifaximin plus lactulose (the rifaximin group) and 276 patients received lactulose alone (the control group). The multivariate analysis revealed that rifaximin was significantly associated with lower risk of death (adjusted hazard ratio [aHR], 0.697; P = .024) and reduced the risk of recurrent HE (aHR, 0.452; P < .001), SBP (aHR, 0.210; P < .001) and variceal bleeding (aHR, 0.425; P = .011) but not HRS (aHR, 0.598; P = .08). In the HCC cohort, 173 patients received rifaximin plus lactulose and 448 patients received lactulose. Rifaximin was not associated with the risk of death (aHR, 1.177; P = .121). Rifaximin was associated with lower risk of SBP (aHR, 0.323; P < .001) but not with variceal bleeding (aHR, 0.660; P = .104) or recurrent HE (aHR, 0.689; P = .057). The risk of Clostridium difficile-associated diarrhoea was not different between the groups (aHR, 0.028; P = .338).

CONCLUSIONS

In patients without HCC, rifaximin treatment was significantly associated with prolonged overall survival and reduced risks of spontaneous bacterial peritonitis, variceal bleeding and recurrent hepatic encephalopathy.

Metabolic Obesity Phenotypes and Risk of Breast Cancer in Postmenopausal Women

Background: Obesity and the metabolic syndrome (MetS) have both been linked to increased risk of postmenopausal breast cancer; however, their relative contributions are poorly understood.Methods: We examined the association of metabolic phenotypes of obesity defined by presence of the MetS (yes and no) and body mass index (BMI; normal, overweight, obese) with risk of postmenopausal breast cancer in a prospective analysis of a cohort of postmenopausal women (n ∼ 21,000) with baseline measurements of blood glucose, triglycerides, HDL-cholesterol, blood pressure, waist circumference, and BMI. Women were classified into 6 metabolic obesity phenotypes according to their BMI (18.5-<25.0, 25.0-<30.0, ≥30.0 kg/m²) and presence of the MetS (≥3 of the following: waist circumference ≥88 cm, triglycerides ≥150 mg/dL, HDL-C <50 mg/dL, glucose ≥100 mg/dL, and systolic/diastolic blood pressure ≥130/85 mmHg or treatment for hypertension). HRs for incident breast cancer and 95% confidence intervals (95% CI) were estimated using Cox proportional hazards models.Results: Over 15 years of follow-up, 1,176 cases of invasive breast cancer were diagnosed. Obesity, regardless of metabolic health, was associated with increased risk of breast cancer. Being obese and metabolically unhealthy was associated with the highest risk: HR, 1.62; 95% CI, 1.33-1.96. These associations were stronger in women who had never used hormone therapy.Conclusions: Our findings suggest that both obesity and metabolic dysregulation are associated with breast cancer risk.Impact: Beyond BMI, metabolic health should be considered a clinically relevant and modifiable risk factor for breast cancer. Cancer Epidemiol Biomarkers Prev; 26(12); 1730-5. ©2017 AACR.

A method to compare the performance of two molecular diagnostic tools in the absence of a gold standard

The paper is motivated by the problem of comparing the accuracy of two molecular tests in detecting genetic mutations in tumor samples when there is no gold standard test. Commonly used sequencing methods require a large number of tumor cells in the tumor sample and the proportion of tumor cells with mutation positivity to be above a threshold level whereas new tests aim to reduce the requirement for number of tumor cells and the threshold level. A new latent class model is proposed to compare these two tests in which a random variable is used to represent the unobserved proportion of mutation positivity so that these two tests are conditionally dependent; furthermore, an independent random variable is included to address measurement error associated with the reading from each test, while existing latent class models often assume conditional independence and do not allow measurement error. In addition, methods for calculating the sample size for a study that is sufficiently powered to compare the accuracy of two molecular tests are proposed and compared. The proposed methods are then applied to a study which aims to compare two molecular tests for detecting EGFR mutations in lung cancer patients.

Brief Report: Changes in Antiphospholipid Antibody Titers During Pregnancy: Effects on Pregnancy Outcomes

OBJECTIVE

To measure variance in antiphospholipid antibody (aPL) levels during pregnancy and to determine if variation affects pregnancy outcomes.

METHODS

We used data from the PROMISSE (Predictors of Pregnancy Outcome: Biomarkers in Antiphospholipid Antibody Syndrome and Systemic Lupus Erythematosus) study, a multicenter prospective study of pregnant women with aPL and/or systemic lupus erythematosus (SLE). Antiphospholipid antibodies were considered present if any of the following were positive: anticardiolipin (aCL), anti-β2 -glycoprotein I (anti-β2 GPI) titers ≥40 IgG phospholipid (GPL) or IgM phospholipid (MPL) units, and/or lupus anticoagulant (LAC). Antiphospholipid antibodies were measured every trimester and postpartum. Adverse pregnancy outcomes were defined as fetal/neonatal death, preterm delivery (<36 weeks) due to preeclampsia or placental insufficiency, or growth restriction.

RESULTS

One hundred fifty-two aPL-positive patients were studied. Fifty-seven percent had clinical antiphospholipid syndrome (APS) and 36% had SLE. IgG aPL levels were significantly lower during the second and third trimesters compared to initial screening, but IgG aCL and anti-β2 GPI remained high-positive through pregnancy in 93% of patients during the second trimester, and in 85% of patients during the third trimester. IgM aPL titers were negative in the majority of patients and decreased modestly during pregnancy among patients who were positive. LAC frequency also decreased, but 75% of patients remained positive through the second trimester. Only 4% of patients with aPL at baseline did not have aPL in either the second or third trimesters. Changes in aPL levels or aPL status were not associated with adverse pregnancy outcomes. LAC was the only aPL associated with adverse pregnancy outcomes.

CONCLUSION

The aPL in the cohort decreased marginally during pregnancy, and changes were not associated with pregnancy outcomes. Our results suggest that, among women with aPL and/or SLE, measuring aPL early in pregnancy is sufficient to assess risk. Repeat aPL testing through pregnancy is unnecessary.

White Blood Cell Count and Total and Cause-Specific Mortality in the Women's Health Initiative

White blood cell (WBC) count appears to predict total mortality and coronary heart disease (CHD) mortality, but it is unclear to what extent the association reflects confounding by smoking, underlying illness, or comorbid conditions. We used data from the Women's Health Initiative to examine the associations of WBC count with total mortality, CHD mortality, and cancer mortality. WBC count was measured at baseline in 160,117 postmenopausal women and again in year 3 in 74,375 participants. Participants were followed for a mean of 16 years. Cox proportional hazards models were used to estimate the relative mortality hazards associated with deciles of baseline WBC count and of the mean of baseline + year 3 WBC count. High deciles of both baseline and mean WBC count were positively associated with total mortality and CHD mortality, whereas the association with cancer mortality was weaker. The association of WBC count with mortality was independent of smoking and did not appear to be influenced by previous disease history. The potential clinical utility of this common laboratory test in predicting mortality risk warrants further study.

Kidney Outcomes and Risk Factors for Nephritis (Flare/De Novo) in a Multiethnic Cohort of Pregnant Patients with Lupus

BACKGROUND AND OBJECTIVES

Kidney disease is a critical concern in counseling patients with lupus considering pregnancy. This study sought to assess the risk of renal flares during pregnancy in women with previous lupus nephritis in partial or complete remission, particularly in those with antidouble-stranded DNA antibodies and low complement levels, and the risk of new-onset nephritis in patients with stable/mildly active SLE.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We assessed active nephritis (renal flares and de novo kidney disease) and associated predictors during pregnancy in patients with lupus with urine protein ≤1000 mg and serum creatinine <1.2 mg/dl at baseline; 373 patients (52% ethnic/racial minorities) enrolled between 2003 and 2012 were prospectively followed in the Predictors of Pregnancy Outcome: Biomarkers in Antiphospholipid Syndrome and Systemic Lupus Erythematosus Study. Active nephritis was defined by proteinuria increase of >500 mg and/or red blood cell casts.

RESULTS

Of 118 patients with previous kidney disease, 13 renal flares (11%) occurred (seven of 89 in complete remission and six of 29 in partial remission) compared with four with de novo kidney involvement (2%) in 255 patients without past kidney disease (P<0.001). Active nephritis was not associated with ethnicity, race, age, creatinine, BP, or antihypertensive and other medications. In multivariable logistic regression analyses, patients with past kidney disease in complete or partial remission more often experienced active nephritis (adjusted odds ratio, 6.88; 95% confidence interval, 1.84 to 25.71; P=0.004 and adjusted odds ratio, 20.98; 95% confidence interval, 4.69 to 93.98; P<0.001, respectively) than those without past kidney disease. Low C4 was associated with renal flares/de novo disease (adjusted odds ratio, 5.59; 95% confidence interval, 1.64 to 19.13; P<0.01) but not low C3 or positive anti-dsDNA alone.

CONCLUSIONS

De novo kidney involvement in SLE, even in ethnic/racial minorities, is uncommon during pregnancy. Past kidney disease and low C4 at baseline independently associate with higher risk of developing active nephritis. Antibodies to dsDNA alone should not raise concern, even in patients with past kidney disease, if in remission.

A statistical method for studying correlated rare events and their risk factors

Longitudinal studies of rare events such as cervical high-grade lesions or colorectal polyps that can recur often involve correlated binary data. Risk factor for these events cannot be reliably examined using conventional statistical methods. For example, logistic regression models that incorporate generalized estimating equations often fail to converge or provide inaccurate results when analyzing data of this type. Although exact methods have been reported, they are complex and computationally difficult. The current paper proposes a mathematically straightforward and easy-to-use two-step approach involving (i) an additive model to measure associations between a rare or uncommon correlated binary event and potential risk factors and (ii) a permutation test to estimate the statistical significance of these associations. Simulation studies showed that the proposed method reliably tests and accurately estimates the associations of exposure with correlated binary rare events. This method was then applied to a longitudinal study of human leukocyte antigen (HLA) genotype and risk of cervical high grade squamous intraepithelial lesions (HSIL) among HIV-infected and HIV-uninfected women. Results showed statistically significant associations of two HLA alleles among HIV-negative but not HIV-positive women, suggesting that immune status may modify the HLA and cervical HSIL association. Overall, the proposed method avoids model nonconvergence problems and provides a computationally simple, accurate, and powerful approach for the analysis of risk factor associations with rare/uncommon correlated binary events.

Superwetting and aptamer functionalized shrink-induced high surface area electrochemical sensors

Electrochemical sensing is moving to the forefront of point-of-care and wearable molecular sensing technologies due to the ability to miniaturize the required equipment, a critical advantage over optical methods in this field. Electrochemical sensors that employ roughness to increase their microscopic surface area offer a strategy to combatting the loss in signal associated with the loss of macroscopic surface area upon miniaturization. A simple, low-cost method of creating such roughness has emerged with the development of shrink-induced high surface area electrodes. Building on this approach, we demonstrate here a greater than 12-fold enhancement in electrochemically active surface area over conventional electrodes of equivalent on-chip footprint areas. This two-fold improvement on previous performance is obtained via the creation of a superwetting surface condition facilitated by a dissolvable polymer coating. As a test bed to illustrate the utility of this approach, we further show that electrochemical aptamer-based sensors exhibit exceptional signal strength (signal-to-noise) and excellent signal gain (relative change in signal upon target binding) when deployed on these shrink electrodes. Indeed, the observed 330% gain we observe for a kanamycin sensor is 2-fold greater than that seen on planar gold electrodes.

Association of Hemoglobin Concentration With Total and Cause-Specific Mortality in a Cohort of Postmenopausal Women

Anemia and low and high levels of hemoglobin have been associated with increased mortality and morbidity. However, most studies have measured hemoglobin at only 1 time point, and few studies have considered possible reverse causation. We used data from the Women's Health Initiative, in which baseline hemoglobin was measured in 160,081 postmenopausal women and year 3 hemoglobin was measured in 75,658 participants, to examine the associations of hemoglobin concentration with total mortality, coronary heart disease mortality, and cancer mortality. Women were enrolled from 1993 to 1998 and followed for a median of 16 years. Cox proportional hazards models were used to estimate the relative mortality hazards associated with deciles of baseline hemoglobin and the mean of baseline + year 3 hemoglobin. Both low and high deciles of baseline hemoglobin were positively associated with all 3 outcomes in the total cohort. In analyses restricted to women with 2 measurements, a low mean hemoglobin level was robustly and positively associated with all 3 outcomes, after exclusion of the early years of follow-up. High mean hemoglobin was also associated with increased risk of total mortality, whereas associations with heart disease mortality and cancer mortality were weaker and inconsistent. Our results provide evidence that low and high levels of hemoglobin are associated with increased risk of mortality in otherwise healthy women.

Common scientific and statistical errors in obesity research

This review identifies 10 common errors and problems in the statistical analysis, design, interpretation, and reporting of obesity research and discuss how they can be avoided. The 10 topics are: 1) misinterpretation of statistical significance, 2) inappropriate testing against baseline values, 3) excessive and undisclosed multiple testing and "P-value hacking," 4) mishandling of clustering in cluster randomized trials, 5) misconceptions about nonparametric tests, 6) mishandling of missing data, 7) miscalculation of effect sizes, 8) ignoring regression to the mean, 9) ignoring confirmation bias, and 10) insufficient statistical reporting. It is hoped that discussion of these errors can improve the quality of obesity research by helping researchers to implement proper statistical practice and to know when to seek the help of a statistician.

Lupus anticoagulant is the main predictor of adverse pregnancy outcomes in aPL-positive patients: validation of PROMISSE study results

Objective

We previously reported that lupus anticoagulant (LAC) is the main predictor of poor pregnancy outcome in antiphospholipid antibody (aPL)-positive patients. We sought to confirm this finding in an independent group of patients who were subsequently recruited into the PROMISSE study.

Methods

The PROMISSE study is a multicentre, prospective, observational study of pregnancy outcomes in women with aPL and/or systemic lupus erythematosus (SLE) that enrolled patients from 2003 to 2015. All consecutive, aPL-positive patients from the PROMISSE study who completed their pregnancy between April 2011 and January 2015 (after the previous PROMISSE report) are included in the current report. Patients were followed monthly until delivery, and aPL was tested at first, second and third trimesters of pregnancy and at 12 weeks post partum. Adverse pregnancy outcomes (APOs) were defined as fetal death after 12 weeks of gestation, neonatal death, delivery prior to 36 weeks of gestation due to pre-eclampsia or placental insufficiency or small-for-gestational age (birth weight <5th percentile).

Results

Forty-four aPL-positive patients are included in this paper. Thirteen patients had APOs, which occurred in 80% of cases during the second trimester of pregnancy. LAC was present in 69% of patients with APOs compared with 27% of patients without APOs (p=0.01). No association was found between anticardiolipin antibodies (aCL) or anti-β2 glycoprotein I antibodies (aβ2GPI) IgG or IgM positivity and APOs. Definite antiphospholipid syndrome (history of thrombosis and/or pregnancy morbidity and aPL) was found in 92% of patients with any APOs compared with 45% of patients without APOs (p=0.004). Conversely, the frequency of SLE was not statistically different between those with and without APOs (30% vs 39%).

Conclusions

Our findings, in an independent group of aPL-positive patients from the PROMISSE study, confirm that LAC, but not aCL and aβ2GPI, is predictive of poor pregnancy outcomes after 12 weeks of pregnancy.

Trial registration number

NCT00198068.

Angiogenic factor imbalance early in pregnancy predicts adverse outcomes in patients with lupus and antiphospholipid antibodies: results of the PROMISSE study

BACKGROUND

Over 20% of pregnancies in patients with systemic lupus erythematosus (SLE) and/or antiphospholipid antibodies (APL) result in an adverse pregnancy outcome (APO) related to abnormal placentation. The ability to identify, early in pregnancy, patients who are destined for poor outcomes would significantly impact care of this high-risk population. In nonautoimmune patients, circulating angiogenic factors are dysregulated in disorders of placentation, such as preeclampsia (PE) and fetal growth restriction.

OBJECTIVE

We sought to determine whether early dysregulation of circulating angiogenic factors can predict APO in high-risk SLE and/or APL pregnancies.

STUDY DESIGN

We used data and samples from the Predictors of Pregnancy Outcome: Biomarkers in APL Syndrome and SLE (PROMISSE), a multicenter prospective study that enrolled 492 pregnant women with SLE and/or APL from September 2003 through August 2013. Patients were followed through pregnancy from <12 weeks gestation. Circulating levels of soluble fms-like tyrosine kinase-1 (sFlt1), placental growth factor (PlGF), and soluble endoglin were measured monthly and subjects followed up for APO, classified as severe (PE <34 weeks, fetal/neonatal death, indicated preterm delivery <30 weeks) or moderate (PE ≥34 weeks, indicated preterm delivery 30-36 weeks, growth restriction without PE).

RESULTS

Severe APOs occurred in 12% and moderate APOs in 10% of patients. By 12-15 weeks, sFlt1, PlGF, and soluble endoglin levels were markedly altered in women who developed severe APO. After adjusting for clinical risk factors, sFlt1 was the strongest predictor of severe APO among 12-15 week measures (odds ratio, 17.3 comparing highest and lowest quartiles; 95% confidence interval [CI], 3.5-84.8; positive predictive value [PPV], 61%; negative predictive value [NPV], 93%). At 16-19 weeks, the combination of sFlt1 and PlGF was most predictive of severe APO, with risk greatest for subjects with both PlGF in lowest quartile (<70.3 pg/mL) and sFlt1 in highest quartile (>1872 pg/mL; odds ratio, 31.1; 95% CI, 8.0-121.9; PPV, 58%; NPV, 95%). Severe APO rate in this high-risk subgroup was 94% (95% CI, 70-99.8%), if lupus anticoagulant or history of high blood pressure was additionally present. In contrast, among patients with both sFlt1 <1872 pg/mL and PlGF >70.3 pg/mL, rate of severe APO was only 4.6% (95% CI, 2.1-8.6%).

CONCLUSION

Circulating angiogenic factors measured during early gestation have a high NPV in ruling out the development of severe adverse outcomes among patients with SLE and/or APL syndrome. Timely risk stratification of patients is important for effective clinical care and optimal allocation of health care resources.

Assessment of fluorinated steroids to avert progression and mortality in anti-SSA/Ro-associated cardiac injury limited to the fetal conduction system

OBJECTIVES

Extension of disease beyond the atrioventricular (AV) node is associated with increased mortality in cardiac neonatal lupus (NL). Treatment of isolated heart block with fluorinated steroids to prevent disease progression has been considered but published data are limited and discordant regarding efficacy. This study evaluated whether fluorinated steroids given to manage isolated advanced block prevented development of disease beyond the AV node and conferred a survival benefit.

METHODS

In this retrospective study of cases enrolled in the Research Registry for NL, inclusion was restricted to anti-SSA/Ro-exposed cases presenting with isolated advanced heart block in utero who either received fluorinated steroids within 1 week of detection (N=71) or no treatment (N=85). Outcomes evaluated were: development of endocardial fibroelastosis, dilated cardiomyopathy and/or hydrops fetalis; mortality and pacemaker implantation.

RESULTS

In Cox proportional hazards regression analyses, fluorinated steroids did not significantly prevent development of disease beyond the AV node (adjusted HR=0.90; 95% CI 0.43 to 1.85; p=0.77), reduce mortality (HR=1.63; 95% CI 0.43 to 6.14; p=0.47) or forestall/prevent pacemaker implantation (HR=0.87; 95% CI 0.57 to 1.33; p=0.53). No risk factors for development of disease beyond the AV node were identified.

CONCLUSIONS

These data do not provide evidence to support the use of fluorinated steroids to prevent disease progression or death in cases presenting with isolated heart block.

Predictors of Pregnancy Outcomes in Patients With Lupus: A Cohort Study

BACKGROUND

Because systemic lupus erythematosus (SLE) affects women of reproductive age, pregnancy is a major concern.

OBJECTIVE

To identify predictors of adverse pregnancy outcomes (APOs) in patients with inactive or stable active SLE.

DESIGN

Prospective cohort.

SETTING

Multicenter.

PATIENTS

385 patients (49% non-Hispanic white; 31% with prior nephritis) with SLE in the PROMISSE (Predictors of Pregnancy Outcome: Biomarkers in Antiphospholipid Antibody Syndrome and Systemic Lupus Erythematosus) study. Exclusion criteria were urinary protein-creatinine ratio greater than 1000 mg/g, creatinine level greater than 1.2 mg/dL, prednisone use greater than 20 mg/d, and multifetal pregnancy.

MEASUREMENTS

APOs included fetal or neonatal death; birth before 36 weeks due to placental insufficiency, hypertension, or preeclampsia; and small-for-gestational-age (SGA) neonate (birthweight below the fifth percentile). Disease activity was assessed with the Systemic Lupus Erythematosus Pregnancy Disease Activity Index and the Physician's Global Assessment (PGA).

RESULTS

APOs occurred in 19.0% (95% CI, 15.2% to 23.2%) of pregnancies; fetal death occurred in 4%, neonatal death occurred in 1%, preterm delivery occurred in 9%, and SGA neonate occurred in 10%. Severe flares in the second and third trimesters occurred in 2.5% and 3.0%, respectively. Baseline predictors of APOs included presence of lupus anticoagulant (LAC) (odds ratio [OR], 8.32 [CI, 3.59 to 19.26]), antihypertensive use (OR, 7.05 [CI, 3.05 to 16.31]), PGA score greater than 1 (OR, 4.02 [CI, 1.84 to 8.82]), and low platelet count (OR, 1.33 [CI, 1.09 to 1.63] per decrease of 50 × 109 cells/L). Non-Hispanic white race was protective (OR, 0.45 [CI, 0.24 to 0.84]). Maternal flares, higher disease activity, and smaller increases in C3 level later in pregnancy also predicted APOs. Among women without baseline risk factors, the APO rate was 7.8%. For those who either were LAC-positive or were LAC-negative but nonwhite or Hispanic and using antihypertensives, the APO rate was 58.0% and fetal or neonatal mortality was 22.0%.

LIMITATION

Patients with high disease activity were excluded.

CONCLUSION

In pregnant patients with inactive or stable mild/moderate SLE, severe flares are infrequent and, absent specific risk factors, outcomes are favorable.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Comparison of computed tomographic findings in pulmonary mucormycosis and invasive pulmonary aspergillosis

Because there are no available molecular markers for pulmonary mucormycosis (PM), which has low culture sensitivity, early diagnosis and treatment rely heavily on imaging modes such as computed tomography (CT). However, there are limited data comparing CT findings for PM with those for invasive pulmonary aspergillosis (IPA). Adult patients who met the modified criteria for proven and probable PM (over an 11-year period) and IPA (over a 6-year period, owing to the availability of the galactomannan assay) according to the modified European Organization for Research and Treatment of Cancer/Mycosis Study Group definitions were retrospectively enrolled. IPA cases were selected at a 1 : 4 (PM/IPA) ratio. Thoracic CT scans were reviewed by two experienced radiologists blinded to the patients' demographics and clinical outcomes. A total of 24 patients with PM, including 20 (83%) with proven PM and four (17%) with probable PM, and 96 patients with IPA, including 12 (13%) with proven IPA and 84 (87%) with probable IPA, were eventually analysed. The reverse halo sign was more common in patients with PM (54%) than in those with IPA (6%, p < 0.001), whereas some airway-invasive features, such as clusters of centrilobular nodules, peribronchial consolidations, and bronchial wall thickening, were more common in patients with IPA (IPA 52% vs. PM 29%, p 0.04; IPA 49% vs. PM 21%, p 0.01; IPA 34% vs. PM 4%, p 0.003, respectively). The reverse halo sign was more common, and airway-invasive features were less common, in patients with PM than in those with IPA. These findings may help physicians to initiate Zygomycetes-active antifungal treatment earlier.

Development of a Model System to Evaluate Local Recurrence in Osteosarcoma and Assessment of the Effects of Bone Morphogenetic Protein-2

PURPOSE

It is increasingly relevant to better define what constitutes an adequate surgical margin in an effort to improve reconstructive longevity and functional outcomes following osteosarcoma surgery. In addition, nonunion remains a challenging problem in some patients following allograft reconstruction. Bone morphogenetic protein-2 (BMP-2) could enhance osseous union, but has been historically avoided due to concerns that it may promote tumor recurrence.

EXPERIMENTAL DESIGN

An orthotopic xenograft murine model was utilized to describe the natural temporal course of osteosarcoma growth. Tumors were treated either with surgery alone, surgery and single-agent chemotherapy, or surgery and dual-agent chemotherapy to assess the relationship between surgical margin and local recurrence. The effect of BMP-2 on local recurrence was similarly assessed.

RESULTS

Osteosarcoma tumor growth was categorized into reproducible phases. Margins greater than 997 μm resulted in local control following surgery alone. Margins greater than 36 μm resulted in local control following surgery and single-agent chemotherapy. Margins greater than 12 μm resulted in local control following surgery and dual-agent chemotherapy. The application of exogenous BMP-2 does not confer an increased risk of local recurrence.

CONCLUSIONS

This model reliably reproduces the clinical, radiographic, and surgical conditions encountered in human osteosarcoma. It successfully incorporates relevant chemotherapy, further paralleling the human experience. Surgical margins required to achieve local control in osteosarcoma can be reduced using single-agent chemotherapy and further decreased using dual-agent chemotherapy. The application of BMP-2 does not increase local recurrence in this model.

Sample size determination for three-level randomized clinical trials with randomization at the first or second level

Clinical trials in the context of comparative effectiveness research (CER) are often conducted to evaluate health outcomes under real-world conditions and standard health care settings. In such settings, three-level hierarchical study designs are increasingly common. For example, patients may be nested within treating physicians, who in turn are nested within an urgent care center or hospital. While many trials randomize the third-level units (e.g., centers) to intervention, in some cases randomization may occur at lower levels of the hierarchy, such as patients or physicians. In this article, we present and verify explicit closed-form sample size and power formulas for three-level designs assuming randomization is at the first or second level. The formulas are based on maximum likelihood estimates from mixed-effect linear models and verified by simulation studies. Results indicate that even with smaller sample sizes, theoretical power derived with known variances is nearly identical to empirically estimated power for the more realistic setting when variances are unknown. In addition, we show that randomization at the second or first level of the hierarchy provides an increasingly statistically efficient alternative to third-level randomization. Power to detect a treatment effect under second-level randomization approaches that of patient-level randomization when there are few patients within each randomized second-level cluster and, most importantly, when the correlation attributable to second-level variation is a small proportion of the overall correlation between patient outcomes.

First Report of Neocosmospora vasinfecta var. vasinfecta Causing Soybean Stem Rot in South Korea

In September 2010, stem rot symptoms were observed on soybean plants (cv. Daepungkong) growing in a field located at Daegu (35.52° N, 128.35° E), South Korea. The first noticeable symptoms, observed on the top leaves, were difficult to distinguish from those of sudden death syndrome (SDS). However, after splitting the stems of symptomatic plants, typical stem rot symptoms appeared as reddish-brown to dark-brown discoloration of the pith. Stem lesions extended 15 to 20 cm upward from the soil surface. To isolate the causal agent, sections of diseased stems were surface disinfected with 1% sodium hypochlorite, placed on potato dextrose agar (PDA) containing streptomycin sulfate, and incubated at 25°C with a 12-h light regime. Two isolates were obtained (SSLNV17 and SSLNV18). Mycelia were white and floccose. Conidia (4.5 to 11.2 × 2.2 to 3.4 μm) were cylindrical to oblong-ellipsoidal, hyaline, and one-celled. Both isolates produced abundant perithecia after 3 to 4 weeks. Perithecia (205 to 331 mm in diameter) were orange to red, globose and ostiolate, with a short neck (80 to 126 mm in diameter). Unitunicate asci (88.6 to 115.3 × 14.5 to 17.3 mm) were cylindrical to clavate, with a short stalk (6.0 to 9.5 × 5.0 to 6.8 mm), and eight spores. Ascospores (13.3 to 17.5 × 10.7 to 12.7 mm) were uniseriately arranged, globose to oval, one-celled, and hyaline to pale brown, with walls with a rugose ornamentation. These morphological features are consistent with those of Neocosmospora vasinfecta var. vasinfecta (1). The internal transcribed spacer (ITS) region, partial translation elongation factor 1-alpha (EF1-α), and β-tubulin genes of rDNA of the two isolates were sequenced using primers ITS4/ITS5 (GenBank Accession Nos. KF662732 and KF662733), EF1-728F/EF1-986R (KF758839 and KF758840), and Bt2a/Bt2b (KF771004 and KF771005), respectively. Sequences of the ITS region, EF1-α, and β-tubulin genes of both isolates showed 99% similarity with several reported N. vasinfecta strains by BLAST analysis. Both morphological and sequence analyses confirmed that the two isolates were N. vasinfecta var. vasinfecta. Pathogenicity tests of both isolates were performed on 15 three-week-old seedlings of soybean cv. Williams inoculated with a spore suspension containing 1.0 × 10⁶ spores/ml, using stem puncture inoculation procedure under controlled conditions (4). Control plants were inoculated in the same way with sterile water. The results were observed by splitting the stem longitudinally and checking for discoloration of the pith 4 to 5 weeks after inoculation. Reddish-brown to dark-brown discoloration was observed in the stem pith of inoculated plants, with occasional chlorosis of the leaves. Moreover, numerous orange-red perithecia were produced on the inoculated stems. However, no symptoms were visible on control plants. The pathogen was re-isolated from the diseased plants, confirming Koch's postulates. Neocosmospora stem rot of soybean was first discovered in Japan and since then it has been reported in the United States and China (2,3,4). To our knowledge, this is the first record of soybean stem rot caused by N. vasinfecta var. vasinfecta in Korea. Our report indicates that Neocosmospora stem rot is a new threat to soybean production in Korea. References: (1) P. F. Cannon and D. L. Hawksworth. Trans. Br. Mycol. Soc. 82:673, 1984. (2) Y. Gai et al. Plant Dis. 95:1031, 2011. (3) F. A. Gray et al. Plant Dis. 64:321, 1980. (4) D. V. Phillips. Phytopathology 62:612, 1972.

Thermoelectric characteristics of the p-type (Bi, Sb)2Te3 nanocomposites processed with silicon nanodispersion

The p-type (Bi0.2Sb0.8)2Te3 powders were mechanically alloyed and hot pressed at 500 degrees C for 30 minutes with dispersion of Si nanopowders up to 3 vol%. The thermal conductivity of the (Bi0.2Sb0.8)2Te3 nanocomposite was substantially reduced with dispersion of 0.3-3 vol% Si nanopowders due to the enhanced phonon scattering. The maximum dimensionless figure-of-merit of 1.32 at 75 degrees C was obtained for the (Bi0.2Sb0.8)2Te3 nanocomposite dispersed with 1 vol% Si nanopowders, compared to 1.08 of the specimen without Si nanopowder dispersion.

Sample size requirements to detect a two- or three-way interaction in longitudinal cluster randomized clinical trials with second-level randomization

BACKGROUND

When randomizations are assigned at the cluster level for longitudinal cluster randomized trials (longitudinal-CRTs) with a continuous outcome, formulae for determining the required sample size to detect a two-way interaction effect between time and intervention are available.

PURPOSE

To show that (1) those same formulae can also be applied to longitudinal trials when randomizations are assigned at the subject level within clusters and (2) this property can be extended to 2-by-2 factorial longitudinal-CRTs with two treatments and different levels of randomization for which testing a three-way interaction between time and the two interventions is of primary interest.

METHODS

We show that slope estimates from different treatment arms are uncorrelated, regardless of whether randomization occurs at the third or second level and also regardless of whether slopes are considered fixed or random in the mixed-effects model for testing two-way or three-way interactions. Sample size formulae are extended to unbalanced designs. Simulation studies were applied to verify the findings.

RESULTS

Sample size formulae for testing two-way and three-way interactions in longitudinal-CRTs with second-level randomization are identical to those for trials with third-level randomization. In addition, the total number of observations required for testing a three-way interaction is demonstrated to be four times as large as that required for testing a two-way interaction, regardless of the level of randomization for both fixed- and random-slope models.

LIMITATIONS

The findings may be only applicable to longitudinal-CRTs with normally distributed continuous outcome.

CONCLUSION

All of the findings are validated by simulation studies and enable the design of longitudinal clinical trials to be more flexible in regard to the level of randomization and allocation of clusters and subjects.

A screen for short-range paracrine interactions

Conventional methods for studying paracrine signaling in vitro may not be sensitive to short-range effects resulting from signal dilution or decay. We employ a microfabricated culture substrate to maintain two cell populations in microscale proximity. Individual populations can be quickly retrieved for cell-specific readouts by standard high-throughput assays. We show that this platform is sensitive to short-range interactions that are not detectable by common methods such as conditioned media transfer or porous cell culture inserts, as revealed by gene expression changes in a tumor-stromal crosstalk model. In addition, we are able to detect population-specific gene expression changes that would have been masked in mixed co-cultures. We thus demonstrate a tool for investigating an important class of intercellular communication that may be overlooked in conventional biological studies.

Implicit bias and its relation to health disparities: a teaching program and survey of medical students

BACKGROUND

The varying treatment of different patients by the same physician are referred to as within provider disparities. These differences can contribute to health disparities and are thought to be the result of implicit bias due to unintentional, unconscious assumptions.

PURPOSES

The purpose is to describe an educational intervention addressing both health disparities and physician implicit bias and the results of a subsequent survey exploring medical students' attitudes and beliefs toward subconscious bias and health disparities.

METHODS

A single session within a larger required course was devoted to health disparities and the physician's potential to contribute to health disparities through implicit bias. Following the session the students were anonymously surveyed on their Implicit Association Test (IAT) results, their attitudes and experiences regarding the fairness of the health care system, and the potential impact of their own implicit bias. The students were categorized based on whether they disagreed ("deniers") or agreed ("accepters") with the statement "Unconscious bias might affect some of my clinical decisions or behaviors." Data analysis focused specifically on factors associated with this perspective.

RESULTS

The survey response rate was at least 69%. Of the responders, 22% were "deniers" and 77% were "accepters." Demographics between the two groups were not significantly different. Deniers were significantly more likely than accepters to report IAT results with implicit preferences toward self, to believe the IAT is invalid, and to believe that doctors and the health system provide equal care to all and were less likely to report having directly observed inequitable care.

CONCLUSIONS

The recognition of bias cannot be taught in a single session. Our experience supports the value of teaching medical students to recognize their own implicit biases and develop skills to overcome them in each patient encounter, and in making this instruction part of the compulsory, longitudinal undergraduate medical curriculum.

A new method to address verification bias in studies of clinical screening tests: cervical cancer screening assays as an example

OBJECTIVES

Studies to evaluate clinical screening tests often face the problem that the "gold standard" diagnostic approach is costly and/or invasive. It is therefore common to verify only a subset of negative screening tests using the gold standard method. However, undersampling the screen negatives can lead to substantial overestimation of the sensitivity and underestimation of the specificity of the diagnostic test. Our objective was to develop a simple and accurate statistical method to address this "verification bias."

STUDY DESIGN AND SETTING

We developed a weighted generalized estimating equation approach to estimate, in a single model, the accuracy (eg, sensitivity/specificity) of multiple assays and simultaneously compare results between assays while addressing verification bias. This approach can be implemented using standard statistical software. Simulations were conducted to assess the proposed method. An example is provided using a cervical cancer screening trial that compared the accuracy of human papillomavirus and Pap tests, with histologic data as the gold standard.

RESULTS

The proposed approach performed well in estimating and comparing the accuracy of multiple assays in the presence of verification bias.

CONCLUSION

The proposed approach is an easy to apply and accurate method for addressing verification bias in studies of multiple screening methods.

Development of a high speed laser scanning confocal microscope with an acquisition rate up to 200 frames per second

There has been an increasing interest for observing fast biological phenomena such as cell movements in circulations and action potentials. The laser scanning confocal microscopy offers a good spatial resolution and optical sectioning ability to observe various in vivo animal models. We developed a high speed laser scanning confocal microscope capable of acquiring 512 by 512 pixel images at 200 fps (frames per second). We have incorporated a fast rotating polygonal scanning mirror with 128 facets for the X-axis scanner. In order to increase the throughput of the Y-axis scanner, we applied a bi-directional scanning method for vertical scanning. This made it possible to scan along the Y-axis two times during each scanner motion cycle. For the image acquisition, we used a custom photomultiplier tube amplifier with a broad frequency band. In addition, custom imaging software was written for the new microscope. In order to verify the acquisition speed of the developed confocal microscope, a resolution target moving at a series of constant speeds and a sedated mouse with slight movements due to heartbeats were observed. By comparing successive frames, the frame acquisition speeds were calculated.

Inhibitory effect of tianeptine on catagen induction in alopecia areata-like lesions induced by ultrasonic wave stress in mice

BACKGROUND

Alopecia areata (AA) is characterized by rapid and complete hair loss in one or multiple areas of the scalp. Stress is an important triggering factor in AA.

AIM

To identify the inhibitory effect of tianeptine on catagen induction in C57BL/6 mice with AA-like lesions induced by ultrasonic wave stress (UWS).

METHODS

The mice were divided into four groups. Group 1 received oral tianeptine before and after UWS; group 2 received oral tianeptine only after UWS; group 3 was given UWS treatment only; and group 4 (negative control group) was not given any treatment. Phototrichigraphy and dermatoscopy were used for assessment. Histological analysis was performed using haematoxylin and eosin, toluidine blue, Masson trichrome and Verhoeff-van Gieson stains. Immunohistochemical analysis was also performed. The level of apoptosis and expression of neuropeptides in the skin were assessed by terminal deoxynucleotidyl transferase dUTP nick end labelling and immunofluorescence assays.

RESULTS

Mice in group 1 had an increased rate of hair growth and greater hair-shaft thickness compared with mice in groups 2 and 3. In addition, mice in group 1 had a higher number of anagen hair follicles, increased synthesis of collagen and elastic fibres, decreased mast-cell degranulation, reduction in cell apoptosis in hair follicles, and recovery of vitamin D receptor expression. Expression of neuropeptides (substance P, calcitonin gene-related peptide) was not altered.

CONCLUSIONS

Tianeptine might play a role in suppressing catagen induction in a stress-induced AA mouse model.

Sample size requirements to detect an intervention by time interaction in longitudinal cluster randomized clinical trials with random slopes

In longitudinal cluster randomized clinical trials (cluster-RCT), subjects are nested within a higher level unit such as clinics and are evaluated for outcome repeatedly over the study period. This study design results in a three level hierarchical data structure. When the primary goal is to test the hypothesis that an intervention has an effect on the rate of change in the outcome over time and the between-subject variation in slopes is substantial, the subject-specific slopes are often modeled as random coefficients in a mixed-effects linear model. In this paper, we propose approaches for determining the samples size for each level of a 3-level hierarchical trial design based on ordinary least squares (OLS) estimates for detecting a difference in mean slopes between two intervention groups when the slopes are modeled as random. Notably, the sample size is not a function of the variances of either the second or the third level random intercepts and depends on the number of second and third level data units only through their product. Simulation results indicate that the OLS-based power and sample sizes are virtually identical to the empirical maximum likelihood based estimates even with varying cluster sizes. Sample sizes for random versus fixed slope models are also compared. The effects of the variance of the random slope on the sample size determinations are shown to be enormous. Therefore, when between-subject variations in outcome trends are anticipated to be significant, sample size determinations based on a fixed slope model can result in a seriously underpowered study.