Comprehensive Association Analyses of Extraintestinal Manifestations in Inflammatory Bowel Disease

BACKGROUND & AIMS

Patients with inflammatory bowel disease (IBD) frequently develop extraintestinal manifestations (EIMs) that contribute substantially to morbidity. We assembled the largest multicohort data set to date to investigate the clinical, serologic, and genetic factors associated with EIM complications in IBD.

METHODS

Data were available in 12,083 unrelated European ancestry IBD cases with presence or absence of EIMs (eg, ankylosing spondylitis [ankylosing spondylitis and sacroiliitis], primary sclerosing cholangitis [PSC], peripheral arthritis, and skin and ocular manifestations) across 4 cohorts (Cedars-Sinai Medical Center, National Institute for Diabetes and Digestive and Kidney Diseases IBD Genetics Consortium, Sinai Helmsley Alliance for Research Excellence Consortium, and Risk Stratification and Identification of Immunogenetic and Microbial Markers of Rapid Disease Progression in Children with Crohn's Disease cohort). Clinical and serologic parameters were analyzed by means of univariable and multivariable regression analyses using a mixed-effects model. Within-case logistic regression was performed to assess genetic associations.

RESULTS

Most EIMs occurred more commonly in female subjects (overall EIM: P = 9.0E-05, odds ratio [OR], 1.2; 95% CI, 1.1-1.4), with CD (especially colonic disease location; P = 9.8E-09, OR, 1.7; 95% CI, 1.4-2.0), and in subjects who required surgery (both CD and UC; P = 3.6E-19, OR, 1.7; 95% CI, 1.5-1.9). Smoking increased risk of EIMs except for PSC, where there was a "protective" effect. Multiple serologic associations were observed, including with PSC (IgG and IgA, perinuclear anti-nuclear cytoplasmic antibody; anti-Saccharomyces cerevisiae antibodies; and anti-flagellin) and any EIM (IgG and IgA, perinuclear anti-nuclear cytoplasmic antibody; anti-Saccharomyces cerevisiae antibodies; and anti-Pseudomonas fluorescens-associated sequence). We identified genome-wide significant associations within major histocompatibility complex (ankylosing spondylitis and sacroiliitis, P = 1.4E-15; OR, 2.5; 95% CI, 2.0-3.1; PSC, P = 2.7E-10; OR, 2.8; 95% CI, 2.0-3.8; ocular, P = 2E-08, OR, 3.6; 95% CI, 2.3-5.6; and overall EIM, P = 8.4E-09; OR, 2.2; 95% CI, 1.7-2.9) and CPEB4 (skin, P = 2.7E-08; OR, 1.5; 95% CI, 1.3-1.8). Genetic associations implicated tumor necrosis factor, JAK-STAT, and IL6 as potential targets for EIMs. Contrary to previous reports, only 2% of our subjects had multiple EIMs and most co-occurrences were negatively correlated.

CONCLUSIONS

We have identified demographic, clinical, and genetic associations with EIMs that revealed underlying mechanisms and implicated novel and existing drug targets-important steps toward a more personalized approach to IBD management.

Serum Lipidomic Screen Identifies Key Metabolites, Pathways, and Disease Classifiers in Crohn's Disease

BACKGROUND

There is an unmet medical need for biomarkers that capture host and environmental contributions in inflammatory bowel diseases (IBDs). This study aimed at testing the potential of circulating lipids as disease classifiers given their major roles in inflammation.

METHODS

We applied a previously validated comprehensive high-resolution liquid chromatography-mass spectrometry-based untargeted lipidomic workflow covering 25 lipid subclasses to serum samples from 100 Crohn's disease (CD) patients and 100 matched control subjects. Findings were replicated and expanded in another 200 CD patients and 200 control subjects. Key metabolites were tested for associations with disease behavior and location, and classification models were built and validated. Their association with disease activity was tested using an independent cohort of 42 CD patients.

RESULTS

We identified >70 metabolites with strong association (P < 1 × 10-4, q < 5 × 10-4) to CD. Highly performing classification models (area under the curve > 0.84-0.97) could be built with as few as 5 to 9 different metabolites, representing 6 major correlated lipid clusters. These classifiers included a phosphatidylethanolamine ether (O-16:0/20:4), a sphingomyelin (d18:1/21:0) and a cholesterol ester (14:1), a very long-chain dicarboxylic acid [28:1(OH)] and sitosterol sulfate. These classifiers and correlated lipids indicate a dysregulated metabolism in host cells, notably in peroxisomes, as well as dysbiosis, oxidative stress, compromised inflammation resolution, or intestinal membrane integrity. A subset of these were associated with disease behavior or location.

CONCLUSIONS

Untargeted lipidomic analyses uncovered perturbations in the circulating human CD lipidome, likely resulting from multiple pathogenic mechanisms. Models using as few as 5 biomarkers had strong disease classifier characteristics, supporting their potential use in diagnosis or prognosis.

Breast sensorisexual function: a novel patient-reported outcome measure of sexual sensory functions of the breast

BACKGROUND

A validated measure assessing sexual sensory functions of the breast is needed to optimize sexual and other health outcomes after breast procedures.

AIM

To describe the development of a patient-reported outcome measure (PROM) to assess breast sensorisexual function (BSF).

METHODS

We applied the PROMIS standards (Patient Reported Outcomes Measurement Information System) for measure development and evaluation of validity. An initial conceptual model of BSF was developed with patients and experts. A literature review yielded a pool of 117 candidate items that underwent cognitive testing and iteration. Forty-eight items were administered to an ethnically diverse, national panel-based sample of sexually active women with breast cancer (n = 350) or without (n = 300). Psychometric analyses were performed.

OUTCOMES

The main outcome was BSF, a measure that assesses affective (satisfaction, pleasure, importance, pain, discomfort) and functional (touch, pressure, thermoreception, nipple erection) sensorisexual domains.

RESULTS

A bifactor model fit to 6 domains-excluding 2 domains with only 2 items each and 2 pain-related domains-revealed a single general factor representing BSF that may be adequately measured by the average of the items. This factor, with higher values denoting better function and with the standard deviation set to 1, was highest among women without breast cancer (mean, 0.24), intermediate among women with breast cancer but not bilateral mastectomy and reconstruction (-0.01), and lowest among those with bilateral mastectomy and reconstruction (-0.56). Between women with and without breast cancer, the BSF general factor accounted for 40%, 49%, and 100% of the difference in arousal, ability to orgasm, and sexual satisfaction, respectively. Items in each of 8 domains demonstrated unidimensionality (ie, they measured 1 underlying BSF trait) and high Cronbach's alphas for the entire sample (0.77-0.93) and the cancer group (0.71-0.95). Correlations with sexual function, health, and quality of life were positive for the BSF general factor and mostly negative for the pain domains.

CLINICAL IMPLICATIONS

The BSF PROM can be used to assess the impact of breast surgery or other procedures on the sexual sensory functions of the breast in women with and without breast cancer.

STRENGTHS AND LIMITATIONS

The BSF PROM was developed by using evidence-based standards, and it applies to sexually active women with and without breast cancer. Generalizability to sexually inactive women and other women warrants further study.

CONCLUSION

The BSF PROM is a measure of women's breast sensorisexual function with evidence of validity among women affected and unaffected by breast cancer.

Short-Interval Pregnancy in the Illinois Medicaid Population Following Delivery in Catholic vs non-Catholic Hospitals

OBJECTIVE

Catholic hospitals restrict access to comprehensive reproductive health services that could impact patient outcomes. We sought to determine whether delivery at a Catholic hospital is associated with shorter pregnancy intervals among patients insured by Medicaid in Illinois.

STUDY DESIGN

We used Illinois Medicaid data files to conduct a retrospective cohort study. We used billing codes to identify deliveries in 2010 and 2011 and classified each by hospital of delivery, maternal age, race/ethnicity, and residential zip code. We calculated the interval from index birth to subsequent conception using an established method, and used Cox proportional hazards regression to compare the rate of subsequent pregnancy between enrollees who delivered in Catholic vs non-Catholic hospitals, adjusting for individual characteristics. We also computed differences in the rates of conception within 6, 12 and 18 month intervals.

RESULTS

We identified 96,293 index births and 18,627 subsequent conceptions. Twenty eight percent (26,775) of index births occurred in a Catholic hospital. Women who delivered in a Catholic hospital had a 12% greater risk of conception in the following 18 months (HR 1.12, 95% CI 1.09-1.16) after adjusting for age, race/ethnicity and rural residence. At 18 months, 23.9% of enrollees delivering in a Catholic hospital had become pregnant as compared to 21.2% for enrollees delivering in a non-Catholic hospital (difference of 2.6%, 95% CI 1.8-3.6).

CONCLUSION

Illinois Medicaid enrollees who deliver at Catholic hospitals have an increased risk of short-interval pregnancy. As the market share of Catholic hospitals grows, providers must work with patients to acknowledge and address these potential impacts on reproductive health outcomes and policies must change to promote equitable access.

IMPLICATIONS

Delivery at a Catholic hospital is associated with increased risk of short-interval pregnancy. Further attention from providers, researchers and policy makers alike, is necessary to identify the mechanisms through which these differences manifest such that effective interventions can be developed.

Socio-Structural and Neighborhood Predictors of Incident Criminal Justice Involvement in a Population-Based Cohort of Young Black MSM and Transgender Women

Black men who have sex with men (MSM) and transgender women are disproportionately affected by criminal justice involvement (CJI) and HIV. This study recruited 618 young Black MSM and transgender women in Chicago, IL, using respondent-driven sampling between 2013 and 2014. Random effects logistic regression evaluated predictors of incident CJI over 18 months of follow-up. Controlling for respondent age, gender and sexual identity, spirituality (aOR 0.56, 95% CI 0.33-0.96), and presence of a mother figure (aOR 0.41, 95% CI 0.19-0.89) were protective against CJI. Economic hardship (financial or residential instability vs. neither aOR 2.23, 95% CI 1.10-4.51), two or more past episodes of CJI vs. none (aOR 2.66, 95% CI 1.40-5.66), and substance use (marijuana use vs. none aOR 2.79, 95% CI 1.23-6.34; other drug use vs. none aOR 4.49, 95% CI 1.66-12.16) were associated with CJI during follow-up. Research to identify and leverage resilience factors that can buffer the effects of socioeconomic marginalization may increase the effectiveness of interventions to address the socio-structural factors that increase the risk for CJI among Black MSM and transgender women. Given the intersection of incarceration, HIV and other STIs, and socio-structural stressors, criminal justice settings are important venues for interventions to reduce health inequities in these populations.

NUMBER OF FRIENDS AND THE RISK OF DEVELOPING DIABETES: A REPLICATION USING NSHAP AND HRS

The epidemic increase in diabetes prevalence (primarily type 2) is a public health crisis. We hypothesized that the rates of movement among diabetic states depend in part on one’s social relationships and environment. Using population-based samples from both NSHAP and HRS, collected in 2005–15, we found that having more friends was associated with a lower risk for acquiring diabetes over the next 4-5 years. As an independent replication, separate logistic models for NSHAP and HRS data yielded similar odds-ratios for the protective effect of having friends (OR = 0.82 and 0.92 respectively), adjusting for gender, age, race/ethnicity, and BMI. This effect was concentrated entirely between 0–4 friends; differences in the number of friends above 4 were not associated with differences in diabetes risk.

Neighbourhoods, networks and pre-exposure prophylaxis awareness: a multilevel analysis of a sample of young black men who have sex with men

OBJECTIVE

Young black men who have sex with men (YBMSM) in the USA represent a subgroup that has the highest HIV incidence among the overall population. In the USA, pre-exposure prophylaxis (PrEP) is an effective prevention intervention to prevent HIV acquisition when taken regularly. Neighbourhood and network factors may relate to PrEP awareness, but have not been studied in YBMSM. This study aimed to examine the relationship of neighbourhood and network characteristics with PrEP awareness among YBMSM.

METHODS

We used data collected from a sample of 618 YBMSM in Chicago (2013-2014). Home addresses were collected for participants and enumerated network members. Administrative data (eg, 2014 American Community Survey, Chicago Department of Public Health) were used to describe residence characteristics. Network member characteristics were also collected (eg, sexual partners' sex-drug use, confidant network members who were also MSM). Multilevel analysis was performed to examine the relationships of neighbourhood and network characteristics to PrEP awareness.

RESULTS

Higher neighbourhood-level educational attainment (adjusted odds ratio (aOR) 1.02, p=0.03) and greater primary care density (aOR 1.38, p=0.01) were associated with greater PrEP awareness; greater neighbourhood alcohol outlet density (aOR 0.52, p=0.004) was associated with less PrEP awareness. Sexual network members residing in the same neighbourhood as the participants (aOR 2.58, p=0.03) and discussions around avoiding HIV acquisition with confidants (aOR 2.26, p=0.04) were associated with greater PrEP awareness.

CONCLUSIONS

The results suggest that neighbourhood and network characteristics can influence PrEP awareness in YBMSM. Additional studies are needed to understand the influences of neighbourhood (eg, MSM serving venues) and network (eg, peer to peer communication) characteristics on dissemination of PrEP information, uptake and adherence and the related mechanisms behind the associations.

At the intersection of criminal justice involvement and sexual orientation: Dynamic networks and health among a population-based sample of young Black men who have sex with men

Mass incarceration of young Black men has a significant impact on their network composition and stability that, in turn, may have major implications for health and well-being. A sub-group of young Black men with criminal justice involvement (CJI) identify as gay, bisexual or are non-identified men who have sex with men (hereafter MSM). This paper focuses on the potential effects of CJI on the composition of Black MSM social and sexual networks, their stability over time, and concomitant health and social outcomes. We use data from the UConnect study, a population-based cohort of young Black MSM 16-29 years of age (n=618) selected using respondent-driven sampling in Chicago from 2013-2016. Both confidant and sexual network name generators and interpreters were administered at 9-month intervals over three waves of data collection. Ego and dyadic-level data were collected on behaviors prevalent among MSM and including factors associated with network CJI, network stability, and health outcomes. Generalized Structural Equation Models (GSEM) were utilized to determine the relationship between CJI network composition, network stability and behaviors prevalent among young Black MSM and their networks. In the UConnect cohort, 46% had at least once been detained, arrested or spent time in jail or prison. In addition, 20% of participants reported incident CJI over the study period. Respondents with a history of CJI were significantly more likely to have CJI homophily in their confidant and sexual networks. Multivariate analyses demonstrate that the association between one's history of CJI, housing instability and drug use is partially explained by one's network CJI. In addition, a higher prevalence of network CJI is associated with increased turnover in the confidant network, and this network instability is also related to important health and social outcomes. This analysis describes the networks of criminal justice involved men among a representative sample of young Black MSM and demonstrates the relationship between CJI network homophily, network stability and their impact on several key health and social outcomes relevant to this population.

PrEP Chicago: A randomized controlled peer change agent intervention to promote the adoption of pre-exposure prophylaxis for HIV prevention among young Black men who have sex with men

BACKGROUND/AIMS

Advances in biomedical prevention strategies such as pre-exposure prophylaxis (PrEP) represent a new opportunity for reducing HIV incidence among young Black men who have sex with men, for whom the number of new HIV infections continues to rise. However, studies have documented low rates of PrEP uptake in this community. Research suggests that the peer networks of young Black men who have sex with men play important roles in their sexual health decisions. PrEP Chicago is a randomized controlled trial network intervention designed to increase PrEP uptake among young Black men who have sex with men living in Chicago. The aims of this study are twofold. Aim 1 is to estimate the effectiveness of a peer change agent intervention for (1) increasing the number of referrals made to a PrEP information line, (2) increasing the rate of PrEP adoption among non-participant peers, and (3) increasing PrEP knowledge, attitudes, and intentions among participants. Aim 2 is to determine the individual and network variables that explain peer change agent effectiveness.

METHODS

PrEP Chicago is a social network intervention that utilizes the influence of peer change agents to link young Black men who have sex with men in Chicago to PrEP. Young Black men who have sex with men were recruited using respondent-driven sampling. Once screened for eligibility, participants were randomly assigned to either one of two treatment sequences: (1) intervention treatment in Year 1 followed by a minimal contact attention control in Year 2 or (2) the minimal contact attention control in Year 1 followed by treatment in Year 2. The treatment consists of a PrEP/peer change agent training workshop followed by booster calls for 12 months. The attention control consists of a sex diary activity designed to help participants assess sexual risk. Psychosocial, sexual health, and network data are collected from all participants at baseline and at 12- and 24-month follow-ups.

RESULTS

In total, 423 participants aged 18-35 have been enrolled (more than 100% target enrollment) and have completed baseline data collection. A majority of participants in both intervention and control groups reported having heard of PrEP before enrolling in the study, yet also reported having had no current or prior experience taking PrEP. Statistical analyses await completion of Year 1 of the trial in March 2018.

CONCLUSION

PrEP Chicago addresses a gap in HIV prevention research and intervention design by utilizing the existing social networks among young Black men who have sex with men as mechanisms for information diffusion, behavioral influence, social support, and empowerment. Therefore, interventions that leverage peer influence processes to facilitate PrEP uptake are promising strategies to improve sexual health engagement and overcome disparities in outcomes among this at-risk population.

Appendectomy does not decrease the risk of future colectomy in UC: results from a large cohort and meta-analysis

OBJECTIVES

Early appendectomy is inversely associated with the development of UC. However, the impact of appendectomy on the clinical course of UC is controversial, generally favouring a milder disease course. We aim to describe the effect appendectomy has on the disease course of UC with focus on the timing of appendectomy in relation to UC diagnosis.

DESIGN

Using the National Institute of Diabetes and Digestive and Kidney Diseases Inflammatory Bowel Disease Genetics Consortium database of patients with UC, the risk of colectomy was compared between patients who did and did not undergo appendectomy. In addition, we performed a meta-analysis of studies that examined the association between appendectomy and colectomy.

RESULTS

2980 patients with UC were initially included. 111 (4.4%) patients with UC had an appendectomy; of which 63 were performed prior to UC diagnosis and 48 after diagnosis. In multivariable analysis, appendectomy performed at any time was an independent risk factor for colectomy (OR 1.9, 95% CI 1.1 to 3.1), with appendectomy performed after UC diagnosis most strongly associated with colectomy (OR 2.2, 95% CI 1.1 to 4.5). An updated meta-analysis showed appendectomy performed either prior to or after UC diagnosis had no effect on colectomy rates.

CONCLUSIONS

Appendectomy performed at any time in relation to UC diagnosis was not associated with a decrease in severity of disease. In fact, appendectomy after UC diagnosis may be associated with a higher risk of colectomy. These findings question the proposed use of appendectomy as treatment for UC.

Facebook network structure and awareness of preexposure prophylaxis among young men who have sex with men

BACKGROUND

Young Black men who have sex with men (YBMSM) are the only population in the United States who have experienced rising human immunodeficiency virus incidence over the past decade. Consistent pre-exposure prophylaxis (PrEP) use can substantially reduce the risk of human immunodeficiency virus acquisition. What differentiates those who become aware of PrEP, and those who do not, remains largely unknown.

METHODS

The social networks of YBMSM can impact their awareness of PrEP; to examine this impact, we used two waves of Facebook data from "uConnect"-a longitudinal cohort study of YBMSM in Chicago (n = 266).

RESULTS

While PrEP awareness increased from 45% at baseline to 75% at follow-up, its use remained low (4% and 6%). There were 88 PrEP-unaware individuals at baseline who became aware (BA) by follow-up, and 56 who remained persistently unaware. While the persistently unawares had a higher median number of total Facebook friends, the BAs had a higher median numbers of friends who participated in uConnect, who were PrEP-aware, and who practiced behaviors previously found to be associated with individual-level awareness of PrEP at baseline. The BAs also had substantially more "influential" friends.

CONCLUSION

These findings demonstrate the potential of social networks in raising PrEP awareness and use among YBMSM.

Network Characteristics of People Who Inject Drugs Within a New HIV Epidemic Following Austerity in Athens, Greece

BACKGROUND

Greece experienced an unprecedented increase in HIV cases among drug injectors in 2011 after economic crisis. Network-level factors are increasingly understood to drive HIV transmission in emerging epidemics.

METHODS

We examined the relationship between networks, risk behaviors, and HIV serostatus among 1404 people who inject drugs in Athens, Greece. We generated networks using the chain-referral structure within a large HIV screening program. Network proportions, the proportion of a respondent's network with a given characteristic, were calculated. Multiple logistic regression models were used to assess the relationship between network proportions and individual HIV seroprevalence, injection frequency and unprotected sex.

RESULTS

Of note, 1030 networks were generated. Respondent HIV seroprevalence was associated with greater proportions of network members who were HIV infected (ie, those with ≥ 50% of network members HIV positive vs. those with no network members HIV positive) (AOR: 3.11; 95% CI: 2.10 to 4.62), divided drugs (AOR: 1.60; 95% CI: 1.10 to 2.35), or injected frequently (AOR: 1.50; 95% CI: 1.02 to 2.21). Homelessness was the only sociodemographic characteristic associated with a risk outcome measure--high-frequency injecting (AOR: 1.41; 95% CI: 1.03 to 1.93). These associations were weaker for more distal second- and third-degree networks and not present when examined within random networks.

CONCLUSIONS

Networks are an independently important contributor to the HIV outbreak in Athens, Greece. Network associations were strongest for the immediate network, with residual associations for distal networks. Homelessness was associated with high-frequency injecting. Prevention programs should consider including network-level interventions to prevent future emerging epidemics.

Abstract WP283: Medical Treatment Matters: Using Headdfirst Results To Enhance The Lessons From The European Hemicraniectomy Trials For Stroke

Introduction: HeADDFIRST was a randomized trial to evaluate the benefit of surgical decompression for brain swelling from large supratentorial cerebral hemispheric infarction (LSCHI). Subsequently, several similar European trials have been completed. Several unique aspects about HeADDFIRST findings provide specific lessons about patient selection and the significance of medical management to outcome, particularly in the context of these trials.

Methods: All patients were screened for eligibility (age 18-75, NIHSS > 18, and CT demonstrating at least compete MCA territory infarction by specific imaging criteria). Those without exclusions and consented were treated by a standardized medical treatment protocol. Those with > 4 mm of pineal shift or > 7.5 mm of anteroseptal shift within 96 hours of stroke onset were randomized to the medical treatment only (MTO) or surgical + medical treatment (SMT) arms with struct adherence.

Results: 40 patients were registered, and 26 developed the requisite brain swelling for randomization. All of those consented who failed to develop the degree of brain swelling required for randomization survived. The 180-day mortality was 40% and 35.7% in the MTO and SMT arms, respectively. From the pooled meta-analysis of the European trials’ the 12-month mortality was 71% and 22% in the medical and surgical arms.

Conclusion: 1. HeADDFIRST medical treatment outcomes were profoundly better than the European trials, suggesting some significance to our medical treatment protocol differences and the strict adherence.

2. HeADDFIRST randomization criteria accurately differentiates between survivors vs. those with a high risk of non-survival with LSCHI.

Network mixing and network influences most linked to HIV infection and risk behavior in the HIV epidemic among black men who have sex with men

OBJECTIVES

We evaluated network mixing and influences by network members upon Black men who have sex with men.

METHODS

We conducted separate social and sexual network mixing analyses to determine the degree of mixing on risk behaviors (e.g., unprotected anal intercourse [UAI]). We used logistic regression to assess the association between a network "enabler" (would not disapprove of the respondent's behavior) and respondent behavior.

RESULTS

Across the sample (n = 1187) network mixing on risk behaviors was more assortative (like with like) in the sexual network (r(sex), 0.37-0.54) than in the social network (r(social), 0.21-0.24). Minimal assortativity (heterogeneous mixing) among HIV-infected men on UAI was evident. Black men who have sex with men reporting a social network enabler were more likely to practice UAI (adjusted odds ratio = 4.06; 95% confidence interval = 1.64, 10.05) a finding not observed in the sexual network (adjusted odds ratio = 1.31; 95% confidence interval = 0.44, 3.91).

CONCLUSIONS

Different mixing on risk behavior was evident with more disassortativity among social than sexual networks. Enabling effects of social network members may affect risky behavior. Attention to of high-risk populations' social networks is needed for effective and sustained HIV prevention.

Deep resequencing of GWAS loci identifies independent rare variants associated with inflammatory bowel disease

More than 1,000 susceptibility loci have been identified through genome-wide association studies (GWAS) of common variants; however, the specific genes and full allelic spectrum of causal variants underlying these findings have not yet been defined. Here we used pooled next-generation sequencing to study 56 genes from regions associated with Crohn's disease in 350 cases and 350 controls. Through follow-up genotyping of 70 rare and low-frequency protein-altering variants in nine independent case-control series (16,054 Crohn's disease cases, 12,153 ulcerative colitis cases and 17,575 healthy controls), we identified four additional independent risk factors in NOD2, two additional protective variants in IL23R, a highly significant association with a protective splice variant in CARD9 (P < 1 × 10(-16), odds ratio ≈ 0.29) and additional associations with coding variants in IL18RAP, CUL2, C1orf106, PTPN22 and MUC19. We extend the results of successful GWAS by identifying new, rare and probably functional variants that could aid functional experiments and predictive models.

Spectral graph analysis of modularity and assortativity

Expressions and bounds for Newman's modularity are presented. These results reveal conditions for or properties of the maximum modularity of a network. The influence of the spectrum of the modularity matrix on the maximum modularity is discussed. The second part of the paper investigates how the maximum modularity, the number of clusters, and the hop count of the shortest paths vary when the assortativity of the graph is changed via degree-preserving rewiring. Via simulations, we show that the maximum modularity increases, the number of clusters decreases, and the average hop count and the effective graph resistance increase with increasing assortativity.

Use of prescription and over-the-counter medications and dietary supplements among older adults in the United States

CONTEXT

Despite concerns about drug safety, current information on older adults' use of prescription and over-the-counter medications and dietary supplements is limited.

OBJECTIVE

To estimate the prevalence and patterns of medication use among older adults (including concurrent use), and potential major drug-drug interactions.

DESIGN, SETTING, AND PARTICIPANTS

Three thousand five community-residing individuals, aged 57 through 85 years, were drawn from a cross-sectional, nationally representative probability sample of the United States. In-home interviews, including medication logs, were administered between June 2005 and March 2006. Medication use was defined as prescription, over-the-counter, and dietary supplements used "on a regular schedule, like every day or every week." Concurrent use was defined as the regular use of at least 2 medications.

MAIN OUTCOME MEASURE

Population estimates of the prevalence of medication use, concurrent use, and potential major drug-drug interactions, stratified by age group and gender.

RESULTS

The unweighted survey response rate was 74.8% (weighted response rate, 75.5%). Eighty-one percent (95% confidence interval [CI], 79.4%-83.5%) used at least 1 prescription medication, 42% (95% CI, 39.7%-44.8%) used at least 1 over-the-counter medication, and 49% (95% CI, 46.2%-52.7%) used a dietary supplement. Twenty-nine percent (95% CI, 26.6%-30.6%) used at least 5 prescription medications concurrently; this was highest among men (37.1%; 95% CI, 31.7%-42.4%) and women (36.0%; 95% CI, 30.2%-41.9%) aged 75 to 85 years. Among prescription medication users, concurrent use of over-the-counter medications was 46% (95% CI, 43.4%-49.1%) and concurrent use of dietary supplements was 52% (95% CI, 48.8%-55.5%). Overall, 4% of individuals were potentially at risk of having a major drug-drug interaction; half of these involved the use of nonprescription medications. These regimens were most prevalent among men in the oldest age group (10%; 95% CI, 6.4%-13.7%) and nearly half involved anticoagulants. No contraindicated concurrent drug use was identified.

CONCLUSIONS

In this sample of community-dwelling older adults, prescription and nonprescription medications were commonly used together, with nearly 1 in 25 individuals potentially at risk for a major drug-drug interaction.

Phenotype-stratified genetic linkage study demonstrates that IBD2 is an extensive ulcerative colitis locus

OBJECTIVES

The complete elucidation of genetic variants that contribute to inflammatory bowel disease (IBD) will likely include variants that increase risk to both Crohn's disease and ulcerative colitis as well as variants that increase risk for particular phenotypic subsets. The purpose of this study was to assess phenotypic subsets that contribute to the major IBD susceptibility loci.

METHODS

This linkage study encompassed 904 affected relative pairs, representing the largest combined phenotyped cohort to date, and allowing for meaningful subset analyses. Genetic linkage data were stratified by disease location and age at diagnosis.

RESULTS

We establish that some loci, notably the IBD3 and chromosome 3q linkage regions demonstrate contributions from both small intestine and colon cohorts, whereas others, notably the IBD1 (NOD2/CARD15) and IBD2 regions increase risk for small intestine or colon inflammation, respectively. The strongest linkage evidence in this study was for the subset of extensive ulcerative colitis in the region of IBD2 (lod 3.27; p < 0.001). Evidence for linkage in the region of NOD2/CARD15 (IBD1) was stronger for the subset of Crohn's patients with ileal disease (lod 2.56; p= 0.035) compared to the overall Crohn's group, consistent with previous findings that NOD2/CARD15 variants are associated with ileal disease.

CONCLUSIONS

Analyses incorporating disease location in IBD increase the power and enhance the accuracy of genomic localization. Our data provide strong evidence that extensive ulcerative colitis represents a pathophysiologic subset of IBD.

The Effect of Reconstruction Algorithm on Conspicuity of Polyps in CT Colonography

OBJECTIVE

CT colonography studies to date have used a standard CT algorithm. To determine whether nonstandard algorithms may result in better performance of CT colonography, we conducted a prospective, blinded-observer study of the effect of the reconstruction algorithm on the conspicuity of colonic polyps and folds.

SUBJECTS AND METHODS

CT colonography of patients with proven polyps, masses, or polypoid folds was performed on an MDCT scanner, and the images were reconstructed using the standard, soft, lung, and detail algorithms. Two experiments were performed. The first used four patient data sets of a short segment of colon (30-60 images), each reconstructed using all four algorithms and then viewed on a workstation in a four-on-one format that allowed all four reconstructions to be viewed simultaneously. The second used six sets of cut-film images (four or eight images each); images within each set differed only in the reconstruction algorithm used to generate them (eight-image sets were prepared with two different level settings). Twenty-one reviewers with varying levels of experience who were unaware of the purpose of the study were asked to rank the images within each set according to their value in the detection of either polyps or masses.

RESULTS

Reviewers showed statistically significant differences in preference for the four algorithms (p = 0.037 in the computer-based experiment; for the cut-film experiment, p = 0.029 for the four-image sets and p = 0.041 for the eight-image sets). In the computer-based experiment, reviewers preferred the detail algorithm to the standard algorithm with an estimated probability of 0.67 (95% confidence interval [CI], 0.57-0.75) and the soft algorithm over the standard algorithm with an estimated probability of 0.59 (95% CI, 0.51-0.66). However, reviewers with the most experience (having interpreted at least 250 cases) preferred the soft algorithm over the standard algorithm by the same two-to-one margin as observed for the detail algorithm. In contrast, the standard and detail algorithms were ranked similarly in the cut-film experiment, with the soft and lung algorithms ranked worst.

CONCLUSION

To our knowledge, ours is the first observer study on the effect of the reconstruction algorithm on conspicuity of folds and polyps in CT colonography. Our results indicate significant differences in the reconstruction algorithms, with the soft and detail algorithms being preferred over the standard algorithm by experienced reviewers when interpreting images on a workstation. These results indicate the need for further research into the effect of reconstruction algorithms on CT colonography.

Phase I Trial of ISIS 5132, an antisense oligonucleotide inhibitor of c-raf-1, administered by 24-hour weekly infusion to patients with advanced cancer

Raf-1 is a serine/threonine kinase that functions as a critical effector of Ras-mediated signal transduction via the mitogen-activated protein kinase pathway. Constitutive activation of this pathway directly contributes to malignant transformation in many human tumors. A 20-base phosphorothioate oligonucleotide complementary to c-raf-1 mRNA (ISIS 5132; CGP 69846A) has been shown to specifically suppress Raf-1 expression both in vitro and in vivo. This Phase I trial, involving 22 patients with advanced cancer, was designed to evaluate the safety, feasibility, and maximum tolerated dose of ISIS 5132 administration as a weekly 24-h i.v. infusion. Pharmacokinetic analysis was performed, and c-raf-1 mRNA levels in peripheral blood mononuclear cells were assessed using quantitative reverse transcription-PCR. This trial defined a maximum tolerated dose of 24 mg/kg/week on this schedule. Two of four patients treated at 30 mg/kg/week had serious adverse events after the first dose of ISIS 5132, including acute hemolytic anemia and acute renal failure and anasarca. There were no major responses documented. Dose-dependent complement activation was demonstrated on this schedule, but not on previously evaluated schedules, of ISIS 5132 administration. In contrast to other trials of ISIS 5132, there appeared to be no consistent suppression of peripheral blood mononuclear cell c-raf-1 mRNA level on this schedule at any of the dose levels analyzed. These data suggest that the efficacy and toxicity profiles of antisense oligonucleotides may be highly dependent on the schedule of administration and support the analysis of the putative molecular target in the evaluation of novel therapeutics.

Prevalence of BRCA1 and BRCA2 mutations among clinic-based African American families with breast cancer

To define the prevalence and relative contributions of BRCA1 and BRCA2 mutations among African American families with breast cancer, we analyzed 28 DNA samples from patients identified through two oncology clinics. The entire coding regions of BRCA1 and BRCA2 were screened by protein truncation test, heteroduplex analysis, or single-stranded conformation polymorphism followed by DNA sequencing of variant bands. Deleterious protein-truncating BRCA1 and BRCA2 mutations were identified in five patients or 18% of the entire cohort. Only 8% (1 of 13) of women with a family history of breast cancer, but no ovarian cancer, had mutations. The mutation rates were higher for women from families with a history of breast cancer and at least one ovarian cancer (three of six, 50%). One woman with a family history of undocumented cancers was also found to carry a deleterious mutation in BRCA2. The spectrum of mutations was unique in that one novel BRCA1 mutation (1625del5) and three novel BRCA2 mutations (1536del4, 6696delTC, and 7795delCT) were identified. No recurrent mutations were identified in this cohort, although one BRCA2 (2816insA) mutation had been previously reported. In addition, two BRCA1 and four BRCA2 missense mutations of unknown significance were identified, one of which was novel. Taken together with our previous report on recurrent mutations seen in unrelated families, we conclude that African Americans have a unique mutation spectrum in BRCA1 and BRCA2 genes, but recurrent mutations are likely to be more widely dispersed and therefore not readily identifiable in this population.

Quality of life and performance in advanced head and neck cancer patients on concomitant chemoradiotherapy: a prospective examination

PURPOSE

To prospectively evaluate performance and quality of life (QOL) in advanced-stage head and neck cancer (HNC) patients on a curative-intent, concomitant-chemoradiotherapy (CT/XRT) (twice-daily radiation, fluorouracil, hydroxyurea, and cisplatin) regimen aimed at improving locoregional control, survival, and QOL.

PATIENTS AND METHODS

Sixty-four patients were assessed before, during, and at 3-month intervals after treatment. Standardized measures of QOL (Functional Assessment of Cancer Therapy-Head and Neck), performance (Performance Status Scale for Head and Neck Cancer Patients and Karnofsky Performance Status Rating Scale), and patient-reported symptoms (McMaster University Head and Neck Radiotherapy Questionnaire) were administered.

RESULTS

Acute treatment toxicities were severe, with declines in virtually all QOL and functional domains. Marked improvement was seen by 12 months; general functional and physical measures returned to baseline levels of good to excellent. Although up to a third of the patients continued to report problems with swallowing, hoarseness, and mouth pain, these difficulties were present in similar magnitudes before treatment. The following symptoms were more frequent at 12 months: dry mouth (58% v 17%), difficulties tasting (32% v 8%), and soft food diet (82% v 42%). Twelve-month diet was not related to pretreatment functioning, disease, treatment, or patient characteristics. Twelve-month QOL was best predicted by pretreatment QOL, with very little relationship to residual side effects or functional impairments. Small numbers of patients in four of the five disease sites precluded examination of outcome by site.

CONCLUSION

These data support the feasibility of intense CT/XRT as primary treatment for advanced HNC. Results confirm acute toxicity but indicate that many of the treatment-related performance and QOL declines resolve by 12 months. The persistent inability to eat a full range of foods warrants further attention and monitoring.