Background Despite its popularity, little is known about the measurement invariance of the Patient Health Questionnaire‐9 (PHQ‐9) across U.S. sociodemographic groups. Use of a screener shown not to possess measurement invariance could result in under/over‐detection of depression, potentially exacerbating sociodemographic disparities in depression. Therefore, we assessed the factor structure and measurement invariance of the PHQ‐9 across major U.S. sociodemographic groups. Methods U.S. population representative data came from the 2005–2016 National Health and Nutrition Examination Survey (NHANES) cohorts. We conducted a measurement invariance analysis of 31,366 respondents across sociodemographic factors of sex, race/ethnicity, and education level. Results Considering results of single‐group confirmatory factor analyses (CFAs), depression theory, and research utility, we justify a two‐factor structure for the PHQ‐9 consisting of a cognitive/affective factor and a somatic factor (RMSEA = 0.034, TLI = 0.985, CFI = 0.989). On the basis of multiple‐group CFAs testing configural, scalar, and strict factorial invariance, we determined that invariance held for sex, race/ethnicity, and education level groups, as all models demonstrated close model fit (RMSEA = 0.025–0.025, TLI = 0.985–0.992, CFI = 0.986–0.991). Finally, for all steps ΔCFI was <−0.004, and ΔRMSEA was <0.01. Conclusions We demonstrate that the PHQ‐9 is acceptable to use in major U.S. sociodemographic groups and allows for meaningful comparisons in total, cognitive/affective, and somatic depressive symptoms across these groups, extending its use to the community. This knowledge is timely as medicine moves towards alternative payment models emphasizing high‐quality and cost‐efficient care, which will likely incentivize behavioral and population health efforts. We also provide a consistent, evidence‐based approach for calculating PHQ‐9 subscale scores.

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Objective We investigated whether number of recent stressful life events is associated with incident cardiovascular disease (CVD) and whether this relationship is stronger in adults with a history of clinical depression. Methods Prospective data from 28,583 U.S. adults (mean age = 45 years) initially free of CVD who participated in Waves 1 (2001–2002) and 2 (2004–2005) of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) were examined. Number of past-year stressful life events (Wave 1), lifetime depressive disorder (Wave 1), and incident CVD (Wave 2) were determined by structured interviews. Results There were 1,069 cases of incident CVD. Each additional stressful life event was associated with a 15% increased odds of incident CVD [Odds Ratio (OR) = 1.15, 95% Confidence Interval (CI): 1.11, 1.19]. As hypothesized, a stressful life events by lifetime depressive disorder interaction was detected (P = 0.003). Stratified analyses indicated that stressful life events had a stronger association with incident CVD among adults with (OR = 1.18, 95% CI: 1.10, 1.27, n = 4,908) versus without (OR = 1.10, 95% CI: 1.07, 1.14, n = 23,675) a lifetime depressive disorder. Conclusion Our findings suggest that a greater number of recent stressful life events elevates the risk of new-onset CVD and that this risk is potentiated in adults with a history of clinical depression.

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Pooling urine specimens for testing with the C. trachomatis LCx system is a simple, accurate, and cost-saving approach that can significantly reduce the cost of amplified nucleic acid testing with minimal sacrifice of testing accuracy.

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Nucleic acid amplification assays such as the ligase chain reaction and PCR have encountered reproducibility problems. The initial extract and a newly extracted aliquot of urine specimens (n ‫؍‬ 120) which had signal-to-cutoff (S/CO) ratios above 0.80 by the LCx Chlamydia assay were retested. Nucleic acid was extracted from an additional urine sample for testing by the AMPLICOR PCR Chlamydia assay. Fifteen percent (18 of 120) of the urine specimens were negative by all repeat tests (initial mean S/CO ratio by the LCx Chlamydia assay, 0.93; S/CO ratio range, 0.80 to 3.30). Repeat testing of the 102 specimens with possible positive results by the LCx Chlamydia assay by use of the initially extracted aliquot confirmed the results for 95 (93.1%) of the specimens; repeat testing of a newly extracted aliquot confirmed the results for 87 (85.3%) of the specimens. Twenty specimens had discordant results by the two repeat LCx Chlamydia assays. A total of 78 of 102 (76.5%) of the specimens were positive by the AMPLICOR PCR, and the AMPLICOR PCR confirmed the results for 82.1% (78 of 95) and 89.6% (78 of 87) of the specimens positive by the two repeat LCx Chlamydia assays, respectively. Some of the discrepancies observed by multiple repeat tests may have been due to specimen mislabeling or contamination during performance of the procedure rather than to the LCx Chlamydia assay. Both assays suffered from a lack of reproducibility on repeat testing with a small proportion of specimens, probably due to the presence of low levels of DNA, the presence of variable amounts of amplification inhibitors, and the loss of DNA during extraction.For the past 8 years, clinical laboratories have become accustomed to using nucleic acid amplification (NAA) tests for the detection of Chlamydia trachomatis on swabs and in urine specimens from men and women (1-3, 5, 8, 10). These assays allow the effective management and treatment of C. trachomatis infections. The two NAA assays that have been in routine use the longest, the AMPLICOR PCR Chlamydia assay (Roche Diagnostics Systems, Branchburg, N.J.) and the LCx Chlamydia assay (Abbott Laboratories), have been reported to have reproducibility problems (4, 7).By February 2001, the Abbott Laboratories Diagnostics Division had received customer complaints concerning high rates of positivity for negative controls, resulting in invalid assay runs of the LCx Chlamydia assay, and positive patient specimens which did not test positive upon retesting. Abbott issued a Device Correction letter which stated the following: the specificity of the assay for some on-market lots of the test kit had dropped as low as 92%, but the test sensitivity remained in the normal range. The letter instructed LCx Chlamydia assay users to take the following actions: (i) interpret the results for samples with signal-to-cutoff (S/CO) ratios less than 0.80 as negative and report that C. trachomatis plasmid DNA was not detected and that the sample could be presumed to be negative for C. trachomatis by ligase chain reaction (LCR) ...

Abstract-An important application of binary-level reverse engineering is in reconstructing the internal logic of computer malware. Most malware code is distributed in encrypted (or "packed") form; at runtime, an unpacker routine transforms this to the original executable form of the code, which is then executed. Most of the existing work on analysis of such programs focuses on detecting unpacking and extracting the unpacked code. However, this does not shed any light on the functionality of different portions of the code so obtained, and in particular does not distinguish between code that performs unpacking and code that does not; identifying such functionality can be helpful for reverse engineering the code. This paper describes a technique for identifying and extracting the unpacker code in a self-modifying program. Our algorithm uses offline analysis of a dynamic instruction trace both to identify the point(s) where unpacking occurs and to identify and extract the corresponding unpacker code.