The feasibility of using multiple databases to study rare outcomes: the potential effect of long-acting beta agonists with inhaled corticosteroid therapy on asthma mortality

Purpose: Long-acting beta agonists (LABAs) when used without concomitant inhaled corticosteroids (ICS) increase the risk of asthma-related deaths, but the effect on asthma-related death of LABA used in combination with ICS therapy is unknown. To address this question, we explored the feasibility of conducting an observational study using multiple US health care data sources. Methods: Retrospective cohort study to evaluate the likelihood of getting an upper 95% confidence limit ≤1.4 for the asthma mortality rate ratio and ≤0.40 per 10 000 person-years for the mortality rate difference, assuming no effect of new use of combined LABA + ICS (versus non-LABA maintenance therapy) on asthma mortality. Ten research institutions executed centrally distributed analytic code based on a standard protocol using an extracted (2000–2010) persistent asthma cohort (asthma diagnosis and ≥4 asthma medications in 12 months). Pooled results were analyzed by the coordinating center. Asthma deaths were ascertained by linkage with the National Death Index. Results: In a cohort of 994 627 persistent asthma patients (2.4 million person-years; 278 asthma deaths), probabilities of the upper 95% confidence limit for effect estimates being less than targeted values, assuming a null relation, were about 0.05. Modifications in cohort and exposure definitions increased exposed person-time and outcome events, but study size remained insufficient to attain study goals. Conclusions: Even with 10 data sources and a 10-year study period, the rarity of asthma deaths among patients using certain medications made it infeasible to study the association between combined LABA + ICS and asthma mortality with our targeted level of study precision

Folic acid supplementation before and during pregnancy in the Newborn Epigenetics STudy (NEST)

<p>Abstract</p> <p>Background</p> <p>Folic acid (FA) added to foods during fortification is 70-85% bioavailable compared to 50% of folate occurring naturally in foods. Thus, if FA supplements also are taken during pregnancy, both mother and fetus can be exposed to FA exceeding the Institute of Medicine's recommended tolerable upper limit (TUL) of 1,000 micrograms per day (μg/d) for adult pregnant women. The primary objective is to estimate the proportion of women taking folic acid (FA) doses exceeding the TUL before and during pregnancy, and to identify correlates of high FA use.</p> <p>Methods</p> <p>During 2005-2008, pre-pregnancy and pregnancy-related data on dietary supplementation were obtained by interviewing 539 pregnant women enrolled at two obstetrics-care facilities in Durham County, North Carolina.</p> <p>Results</p> <p>Before pregnancy, 51% of women reported FA supplementation and 66% reported this supplementation during pregnancy. Before pregnancy, 11.9% (95% CI = 9.2%-14.6%) of women reported supplementation with FA doses above the TUL of 1,000 μg/day, and a similar proportion reported this intake prenatally. Before pregnancy, Caucasian women were more likely to take FA doses above the TUL (OR = 2.99; 95% = 1.28-7.00), compared to African American women, while women with chronic conditions were less likely to take FA doses above the TUL (OR = 0.48; 95%CI = 0.21-0.97). Compared to African American women, Caucasian women were also more likely to report FA intake in doses exceeding the TUL during pregnancy (OR = 5.09; 95%CI = 2.07-12.49).</p> <p>Conclusions</p> <p>Fifty-one percent of women reported some FA intake before and 66% during pregnancy, respectively, and more than one in ten women took FA supplements in doses that exceeded the TUL. Caucasian women were more likely to report high FA intake. A study is ongoing to identify possible genetic and non-genotoxic effects of these high doses.</p

Polymorphism in the IL18 Gene and Epithelial Ovarian Cancer in Non-Hispanic White Women

Over 22,000 cases of ovarian cancer were diagnosed in 2007 in the United States but only a fraction of them can be attributed to mutations in highly penetrant genes such as BRCA1. To determine whether low penetrance genetic variants contribute to ovarian cancer risk, we genotyped 1,536 single nucleotide polymorphisms (SNPs) in several candidate gene pathways in 848 epithelial ovarian cancer cases and 798 controls in the North Carolina Ovarian Cancer Study (NCO) using a customized Illumina array. The inflammation gene interleukin-18 (IL18) showed the strongest evidence for association with epithelial ovarian cancer in a gene-by-gene analysis (p=0.002) with a <25% chance of being a false positive finding (q-value=0.240). Using a multivariate model search algorithm over eleven IL18 tagging SNPs, we found the association was best modeled by rs1834481. Further, this SNP uniquely tagged a significantly associated IL18 haplotype and there was an increased risk of epithelial ovarian cancer per rs1834481 allele (OR=1.24, 95% CI: 1.06, 1.45). In a replication stage, twelve independent studies from the Ovarian Cancer Association Consortium (OCAC) genotyped rs1834481 in an additional 5,877 cases and 7,791 controls. The fixed effects estimate per rs1834481 allele was null (OR=0.99, 95% CI: 0.94, 1.05) when data from the twelve OCAC studies were combined. The effect estimate remained unchanged with the addition of the initial NCO data. This analysis demonstrates the importance of consortia, like the OCAC, in either confirming or refuting the validity of putative findings in studies with smaller sample sizes

ABSTRACT Slotted Priorities: Supporting Real-Time Computing Within General-Purpose Operating Systems

Recent advances in network technologies, processor capabilities, and micro-computer system hardware, coupled with the explosive growth of the Internet and on-line data access, have created new demands on personal computer operating systems and hardware. In large part, these demands are for the ability to acquire, manipulate, display, and store multimedia data. The computational processes that successfully acquire and display multimedia data necessarily have deadlines. That is, the computation must be complete before a speci ed point in time. Currently, no general-purpose operating systems support such real-time processes. We have developed a software architecture, called slotted priorities, that de nes a way to add support for real-time computation to existing general-purpose operating sys-tems for uniprocessor machine architectures. The slotted priorities architecture shares the resources of a computing system between a general-purpose operating system and a real-time kernel. Software components called executives manage how an instance of a resource is shared. Executives ensure that the RTK can gain ac-cess to the resource at precise times. The resulting operating system will be abl

Incidence of Second Primary Malignancies in Patients with Castration-Resistant Prostate Cancer: An Observational Retrospective Cohort Study in the United States

Background. New therapies for castration-resistant prostate cancer (CRPC) may be associated with increased risk of second primary malignancies (SPM). We therefore estimated the population-based incidence of SPM among patients with CRPC in the Surveillance, Epidemiology, and End Results (SEER)-Medicare database. We also estimated the proportion of men with CRPC with bone metastases and overall survival. Methods. We conducted a retrospective cohort study of United States (US) men aged ≥ 65 years with CRPC. Cohort entry was from January 1, 2000, to December 31, 2011, with follow-up through December 31, 2013. Castration resistance was defined by treatment with second-line systemic therapy (after surgical or medical castration). SPM were diagnoses of primary cancers (other than prostate) in SEER or Medicare data. Results. Altogether 2,234 patients met eligibility criteria. Most (1,887; 84.5%) had evidence of bone metastases in Medicare claims. SPM occurred in 172 patients (incidence rate 5.9 per 100 person-years; 95% confidence interval [CI], 5.0-6.8; standardized incidence ratio = 3.1, 95% CI, 2.8-3.6, based on SEER incidence rate of all malignancies except prostate cancer among men aged ≥ 65 years). The most common SPM were lung/bronchus (n = 29, 16.9%), urinary bladder (n = 22, 12.8%), and colon/rectum (n = 21, 12.2%). Median survival was 1.2 years (95% CI, 1.1-1.3); 5-year survival was 9% (95% CI, 7-11%). Conclusions. This study provides the first estimate of SPM risk in older men with CRPC in the US. The incidence rate is approximately threefold higher than the population-based cancer incidence among men without prostate cancer