A simple method for estimating the odds ratio in matched case-control studies with incomplete paired data.

Paired data from matched case-control studies are commonly used to estimate the association between the exposure to a risk factor and the occurrence of a disease. The odds ratio is typically used to quantify this association. Difficulties in estimating the true odds ratio with matched pairs arise, however, when the exposure status is unknown for one of the individuals in one or more pairs. In this article, we propose a simple method for estimating the odds ratio when the sample consists of a combination of complete and incomplete matched pairs; that is, some of the pairs have exposure data for both the case and the control, some of the pairs have exposure data just for the case, and the remaining pairs have exposure data just for the control. This method uses a weighted average of the odds ratio estimator that is most commonly used when the sample consists entirely of complete paired observations and the odds ratio estimator that is most commonly used when the sample consists entirely of unpaired observations. The proposed estimator has simple closed-form expressions for the estimate of the odds ratio and its approximate variance. We compare our method to existing methods via simulation and show that our method is comparable to or better than the other methods in terms of bias, mean squared error, and confidence interval coverage probability and width.

Rapid HIV testing in a southeastern emergency department serving a semiurban-semirural adolescent and adult population.

OBJECTIVE: We determine the feasibility and yield of universal opt-out HIV screening among adolescents and adults in a southeastern emergency department (ED) serving a semiurban-semirural population. METHODS: Individuals aged 13 to 64 years who visited the ED during specified hours received the OraQuick rapid HIV test (administered by trained counselors) if they did not opt out. Western blot was used to confirm reactive results. Patients were excluded if they had a history of HIV, had been tested within the past year, were physically or mentally incapacitated, did not understand their right to opt out, or did not speak English or Spanish. Basic demographic information was analyzed by using standard descriptive statistics. Measures of diagnostic test performance were calculated for all valid tests. RESULTS: From March 2008 through August 2009, 91% (n=8,493) of eligible patients accepted testing, and results were valid. Of 41 reactive results, 35 were confirmed HIV positive, 2 were indeterminate by Western blot, and 4 were false positive. Blacks accounted for the largest percentage (0.65%) of newly detected infections, and the percentage among black men (1%) was more than twice the percentage among black women (0.42%). Rapid-test specificity was estimated at 99.95% (95% confidence interval 99.88% to 99.98%). Nearly 75% of patients confirmed as HIV positive kept their first HIV clinic appointment. CONCLUSION: High rates of acceptance of testing in an ED and linkage to HIV care for adolescents and adults with newly detected infection can be achieved by using opt-out testing and trained HIV counselors.

Acceptance of rapid HIV screening in a southeastern emergency department.

OBJECTIVES: The objective was to assess the acceptance of an emergency department (ED) human immunodeficiency virus (HIV) screening program based on the Centers for Disease Control and Prevention (CDC) recommendations for routine HIV screening in health care settings. METHODS: Rapid HIV screening was offered on an opt-out basis to patients aged 13 to 64 years presenting to the ED by trained HIV counselors. Patients were excluded if they had a history of HIV, were physically or mentally incapacitated, did not understand their right to opt-out, or did not speak English or Spanish. Statistical analyses, including logistic regression, were performed to assess the associations between the demographics of patients offered testing and their test acceptance or refusal. RESULTS: From March 2008 to January 2009, a total of 5,080 (91%) of the 5,585 patients offered the HIV test accepted, and 506 (9%) refused. White and married patients were less likely to accept testing than those who were African American and unmarried (p < 0.001). Adult patients were almost twice as likely to accept testing as pediatric patients (odds ratio [OR] = 1.95; 95% confidence interval [CI] = 1.50 to 2.53). As age increased among pediatric patients, testing refusal decreased (OR = 0.71; 95% CI = 0.59 to 0.85), and as age increased among adult patients, testing refusal increased (OR = 1.17; 95% CI = 1.12 to 1.22). Two percent of persons accepting the test were considered high risk. Males were more likely to report high-risk behavior than females (OR = 1.83; 95% CI = 1.23 to 2.72). CONCLUSIONS: The opt-out approach results in high acceptance of routine HIV screening. Widespread adoption of the CDC's recommendations, although feasible, will require significant increases in resources.

The phosphorylated axonal form of the neurofilament subunit NF-H (pNF-H) as a blood biomarker of traumatic brain injury.

The detection of neuron-specific proteins in blood might allow quantification of the degree of neuropathology in experimental and clinical contexts. We have been studying a novel blood biomarker of axonal injury, the heavily phosphorylated axonal form of the high molecular weight neurofilament subunit NF-H (pNF-H). We hypothesized that this protein would be released from damaged and degenerating neurons following experimental traumatic brain injury (TBI) in amounts large enough to allow its detection in blood and that the levels detected would reflect the degree of injury severity. An enzyme-linked immunosorbent assay (ELISA) capture assay capable of detecting nanogram amounts of pNF-H was used to test blood of rats subjected to experimental TBI using a controlled cortical impact (CCI) device. Animals were subjected to a mild (1.0 mm), moderate (1.5 mm), or severe (2.0 mm) cortical contusion, and blood samples were taken at defined times post-injury. The assay detected the presence of pNF-H as early as 6 h post-injury; levels peaked at 24-48 h, and then slowly decreased to baseline over several days post-injury. No signal above baseline was detectable in control animals. Analysis of variance (ANOVA) showed a significant effect of lesion severity, and post hoc analysis revealed that animals given a moderate and severe contusion showed higher levels of blood pNF-H than controls. In addition, the peak levels of pNF-H detected at both 24 and 48 h post-injury correlated with the degree of injury as determined by volumetric analysis of spared cortical tissue. Relative amounts of pNF-H were also determined in different areas of the central nervous system (CNS) and were found to be highest in regions containing large-diameter axons, including spinal cord and brainstem, and lowest in the cerebral cortex and hippocampus. These findings suggest that the measurement of blood levels of pNF-H is a convenient method for assessing neuropathology following TBI.

Acute myocardial infarction and race, sex, and insurance types: unequal processes of care.

Cardiovascular disease is the leading cause of death among men and women in the United States. Georgia's death rate from cardiovascular disease is higher than the national rate. Previous studies have suggested that whites and African Americans do not receive the same processes of care for a first episode of acute myocardial infarction, one of many cardiovascular disease pathologies. Patient's insurance type, race, sex, and whether a patient lives in a rural or urban area have also been suggested as explanations for unequal processes of care for the treatment of acute myocardial infarction. Using diagnosis-related group reimbursement data from an academic medical center in Georgia, this study found independent effects for race (p < .001) and payer status (p = .004), after adjusting for fiscal year. Possible causes for these differences, as well as recommendations for further study, are explored.

Hand-assisted laparoscopic nephroureterectomy (HALNU): an assessment of the impact of obesity in 50 procedures.

OBJECTIVE: The aims of this study was to review our experience with hand-assisted laparoscopic nephroureterectomy (HALNU) and to evaluate the impact of body-mass index (BMI) on outcomes. METHODS: We retrospectively analyzed 50 HALNU patients. Twenty had body mass indices (BMIs) <25 (normal cohort), 18 had BMIs between 25 and 29.9 (overweight cohort), and 12 had BMIs >/=30 (obese cohort). RESULTS: The cohorts had similar operative times: 349, 326, and 320 minutes, respectively. Most patients (38) underwent a total HAL distal ureterectomy, but 9 underwent an initial transurethral ureteral dissection (5 [25%], 2 [11%], and 2 [17%]). Five patients were converted to open and 1 had a planned open ureterectomy. The cystotomy was sutured closed in most but left open in 6 (3 [15%], 2 [11%], and 1 [8%]), and a stapled ureteral division was performed in 7 (3 [15%], 2 [11%], and 2 [17%]). Increased BMI was associated with delayed oral intake (P = 0.034). No significant cohort differences were observed for estimated blood loss (EBL), transfusion rate, complication rate, surgical margin status, distant metastases, or death rate. The obese cohort demonstrated trends toward increased hospitalization and bladder cancer recurrence (P = 0.083, P = 0.097). Patients with prior open surgery had longer hospitalizations (P = 0.024). Patients without prior surgery were more commonly alive with persistent disease (P = 0.027). EBL was greater for patients who had transurethral ureteral dissection (P = 0.030). Patients undergoing a stapled ureteral division had delayed oral intake, bowel function, and discharge (P = <0.001, P = 0.034, and P = 0.034). CONCLUSIONS: HALNU is an effective surgical treatment for patients with BMIs as great as 45.

Behavioral assessment of impulsivity: a comparison of children with and without attention deficit hyperactivity disorder.

We conducted a brief computer-based assessment involving choices of concurrently presented arithmetic problems associated with competing reinforcer dimensions to assess impulsivity (choices controlled primarily by reinforcer immediacy) as well as the relative influence of other dimensions (reinforcer rate, quality, and response effort), with 58 children. Results were compared for children with attention deficit hyperactivity disorder (ADHD) who were and were not receiving medication, and with typically developing children without ADHD. Within-subject and between-groups analyses of the ordinal influence of each of the reinforcer dimensions were conducted using both time- and response-allocation measures. In general, the choices of children with ADHD were most influenced by reinforcer immediacy and quality and least by rate and effort, suggesting impulsivity. The choices of children in the non-ADHD group were most influenced by reinforcer quality, and the influence of immediacy relative to the other dimensions was not statistically significant. Results are discussed with respect to the implications for assessment and treatment of ADHD.

Regional distribution of fluoro-jade B staining in the hippocampus following traumatic brain injury.

Fluoro-Jade B (FJB) is an anionic fluorescein derivative that has been reported to specifically stain degenerating neurons. We were interested in applying FJB staining in a well-characterized model of traumatic brain injury (TBI) in order to estimate the total number of neurons in different regions of the hippocampus that die after a mild or moderate injury. Rats were subjected to a mild or moderate unilateral cortical contusion (1.0- or 1.5-mm displacement from the cortical surface) with a controlled cortical impacting device. Animals were allowed to survive for 1, 2, or 7 days and the total number of FJB-positive neurons in hippocampal areas CA1, CA3, and the dentate gyrus granule layer was estimated using sterological methods. The region that had the highest number of FJP-positive neurons after TBI was the dentate gyrus. In both 1- and 1.5-mm injuries, FJB-positive granule cells were observed throughout the rostro-caudal extent of the dentate. In contrast, labeled pyramidal neurons of area CA3 were most numerous after the 1.5-mm injury. The area that had the fewest number of FJB-labeled cells was area CA1 with only scattered neurons seen in the 1.5-mm group. In both injury groups and in all hippocampal regions, more FJB-positive neurons were seen at the earlier times post injury (1 and 2 days) than at 7 days. FJB appears to be a reliable marker for neuronal vulnerability following TBI.