keyword
MENU ▼
Read by QxMD icon Read
search

Missing at random

keyword
https://www.readbyqxmd.com/read/28230909/a-general-instrumental-variable-framework-for-regression-analysis-with-outcome-missing-not-at-random
#1
Eric J Tchetgen Tchetgen, Kathleen E Wirth
The instrumental variable (IV) design is a well-known approach for unbiased evaluation of causal effects in the presence of unobserved confounding. In this article, we study the IV approach to account for selection bias in regression analysis with outcome missing not at random. In such a setting, a valid IV is a variable which (i) predicts the nonresponse process, and (ii) is independent of the outcome in the underlying population. We show that under the additional assumption (iii) that the IV is independent of the magnitude of selection bias due to nonresponse, the population regression in view is nonparametrically identified...
February 23, 2017: Biometrics
https://www.readbyqxmd.com/read/28225198/adjunctive-steroid-therapy-versus-antibiotics-alone-for-acute-endophthalmitis-after-intraocular-procedure
#2
REVIEW
Carole H Kim, Monica F Chen, Anne L Coleman
BACKGROUND: Endophthalmitis refers to severe infection within the eye that involves the aqueous humor or vitreous humor, or both, and threatens vision. Most cases of endophthalmitis are exogenous (i.e. due to inoculation of organisms from an outside source), and most exogenous endophthalmitis is acute and occurs after an intraocular procedure. The mainstay of treatment is emergent administration of broad-spectrum intravitreous antibiotics. Due to their anti-inflammatory effects, steroids in conjunction with antibiotics have been proposed to be beneficial in endophthalmitis management...
February 22, 2017: Cochrane Database of Systematic Reviews
https://www.readbyqxmd.com/read/28222101/costs-and-effects-of-a-state-wide-health-promotion-program-in-primary-schools-in-germany-the-baden-w%C3%A3-rttemberg-study-a-cluster-randomized-controlled-trial
#3
Dorothea Kesztyüs, Romy Lauer, Tibor Kesztyüs, Reinhold Kilian, Jürgen M Steinacker
AIM: To evaluate the cost-effectiveness of the state-wide implementation of the health promotion program "Join the Healthy Boat" in primary schools in Germany. METHODS: Cluster-randomized intervention trial with wait-list control group. Anthropometric data of 1733 participating children (7.1 ± 0.6 years) were taken by trained staff before and after a one year intervention period in the academic year 2010/11. Parents provided information about the health status, and the health behaviour of their children and themselves, parental anthropometrics, and socio-economic background variables...
2017: PloS One
https://www.readbyqxmd.com/read/28219348/distribution-based-nearest-neighbor-imputation-for-truncated-high-dimensional-data-with-applications-to-pre-clinical-and-clinical-metabolomics-studies
#4
Jasmit S Shah, Shesh N Rai, Andrew P DeFilippis, Bradford G Hill, Aruni Bhatnagar, Guy N Brock
BACKGROUND: High throughput metabolomics makes it possible to measure the relative abundances of numerous metabolites in biological samples, which is useful to many areas of biomedical research. However, missing values (MVs) in metabolomics datasets are common and can arise due to both technical and biological reasons. Typically, such MVs are substituted by a minimum value, which may lead to different results in downstream analyses. RESULTS: Here we present a modified version of the K-nearest neighbor (KNN) approach which accounts for truncation at the minimum value, i...
February 20, 2017: BMC Bioinformatics
https://www.readbyqxmd.com/read/28217883/clinical-and-radiographic-outcome-following-immediate-loading-and-delayed-loading-of-single-tooth-implants-randomized-clinical-trial
#5
Björn Gjelvold, Jenö Kisch, Bruno Ramos Chrcanovic, Tomas Albrektsson, Ann Wennerberg
BACKGROUND: Immediate loading of single implants is generally considered a reliable procedure. PURPOSE: The objective of the present prospective randomized clinical study was to compare the overall treatment outcome following immediate loading (IL) and delayed loading (DL) of single implants after 1 year of follow-up. MATERIALS AND METHODS: Patients with a missing maxillary tooth (15-25) were randomly assigned to IL or DL. The protocol included implant installation in healed sites, immediate loading, delayed loading, temporary screw-retained restoration, and replacement with a permanent single implant crown...
February 19, 2017: Clinical Implant Dentistry and related Research
https://www.readbyqxmd.com/read/28211087/semiparametric-pseudoscore-for-regression-with-multidimensional-but-incompletely-observed-regressor
#6
Zonghui Hu, Jing Qin, Dean Follmann
We study the regression fβ (Y|X,Z), where Y is the response, Z∈Rd is a vector of fully observed regressors and X is the regressor with incomplete observation. To handle missing data, maximum likelihood estimation via expectation-maximisation (EM) is the most efficient but is sensitive to the specification of the distribution of X. Under a missing at random assumption, we propose an EM-type estimation via a semiparametric pseudoscore. Like in EM, we derive the conditional expectation of the score function given Y and Z, or the mean score, over the incompletely observed units under a postulated distribution of X...
February 16, 2017: Statistics in Medicine
https://www.readbyqxmd.com/read/28183702/glycated-hemoglobin-is-associated-with-the-growth-rate-of-abdominal-aortic-aneurysms-a-substudy-from-the-viva-viborg-vascular-randomized-screening-trial
#7
Katrine Lawaetz Kristensen, Marie Dahl, Lars Melholt Rasmussen, Jes Sanddal Lindholt
OBJECTIVE: An inverse association between abdominal aortic aneurysms (AAAs) and diabetes mellitus exists; however, the cause remains unknown. This study aimed to evaluate whether the degree of glycemia is associated with aneurysm growth. APPROACH AND RESULTS: The study was based on VIVA trial (Viborg Vascular), the randomized clinically controlled screening trial for abdominal aortic aneurysm in men aged 65 to 74 years in the Central Denmark Region. The screening included measurement of the abdominal aorta by ultrasound, analysis of glycated hemoglobin (HbA1c), and follow-up for ≤5 years for aneurysms <5 cm...
February 9, 2017: Arteriosclerosis, Thrombosis, and Vascular Biology
https://www.readbyqxmd.com/read/28182830/order-restricted-inference-for-means-with-missing-values
#8
Heng Wang, Ping-Shou Zhong
Missing values appear very often in many applications, but the problem of missing values has not received much attention in testing order-restricted alternatives. Under the missing at random (MAR) assumption, we impute the missing values nonparametrically using kernel regression. For data with imputation, the classical likelihood ratio test designed for testing the order-restricted means is no longer applicable since the likelihood does not exist. This article proposes a novel method for constructing test statistics for assessing means with an increasing order or a decreasing order based on jackknife empirical likelihood (JEL) ratio...
February 9, 2017: Biometrics
https://www.readbyqxmd.com/read/28181393/blepharocheilodontic-bcd-syndrome-new-insights-on-craniofacial-and-dental-features
#9
Wael Awadh, Anu Kiukkonen, Pekka Nieminen, Sirpa Arte, Kirsti Hurmerinta, David P Rice
Blepharocheilodontic (BCD) syndrome is a rare condition characterized by bilateral cleft lip and palate (BCLP), eyelid abnormalities, and oligodontia. Despite orofacial clefting and oligodontia being central features of the condition, detailed reports of dental and craniofacial characteristics are scarce. The aim of this study was to analyze the dental and craniofacial features in a group of patients with BCD syndrome (three of which were related). Cephalometric radiographic analyses were performed on BCD syndrome patients (all radiographs taken at age 8 years) and compared to 40 randomly selected age-matched controls (20 non-syndromic BCLP, 20 non-cleft)...
February 9, 2017: American Journal of Medical Genetics. Part A
https://www.readbyqxmd.com/read/28176953/survival-status-and-predictors-of-mortality-among-severely-acute-malnourished-children-5-years-of-age-admitted-to-stabilization-centers-in-gedeo-zone-a-retrospective-cohort-study
#10
Tadele Girum, Mesfin Kote, Befikadu Tariku, Henok Bekele
Despite the existence of standard protocol, many stabilization centers (SCs) continue to experience high mortality of children receiving treatment for severe acute malnutrition. Assessing treatment outcomes and identifying predictors may help to overcome this problem. Therefore, a 30-month retrospective cohort study was conducted among 545 randomly selected medical records of children <5 years of age admitted to SCs in Gedeo Zone. Data was entered by Epi Info version 7 and analyzed by STATA version 11. Cox proportional hazards model was built by forward stepwise procedure and compared by the likelihood ratio test and Harrell's concordance, and fitness was checked by Cox-Snell residual plot...
2017: Therapeutics and Clinical Risk Management
https://www.readbyqxmd.com/read/28166735/what-impact-do-assumptions-about-missing-data-have-on-conclusions-a-practical-sensitivity-analysis-for-a-cancer-survival-registry
#11
M Smuk, J R Carpenter, T P Morris
BACKGROUND: Within epidemiological and clinical research, missing data are a common issue and often over looked in publications. When the issue of missing observations is addressed it is usually assumed that the missing data are 'missing at random' (MAR). This assumption should be checked for plausibility, however it is untestable, thus inferences should be assessed for robustness to departures from missing at random. METHODS: We highlight the method of pattern mixture sensitivity analysis after multiple imputation using colorectal cancer data as an example...
February 6, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28158157/successful-long-term-nerve-root-stimulation-for-chronic-neuropathic-pain-a-real-world-single-center-canadian-experience
#12
Adrian B Levine, David A Steven, Andrew G Parrent, Keith W MacDougall
BACKGROUND: Spinal cord stimulation (SCS) is a well-established treatment for chronic neuropathic pain in the lower limbs. However, some patients have pain in distributions that are difficult to target specifically and consistently with SCS. This often involves pain in the groin or upper limbs, or pain limited to a specific dermatome. We hypothesized that dorsal nerve root stimulation (DNRS) would provide similar pain relief for these patients, compared to our results using SCS. OBJECTIVES: In this study we report our experience treating patients with chronic neuropathic pain using SCS and DNRS...
February 2017: Pain Physician
https://www.readbyqxmd.com/read/28156551/effect-of-early-integrated-palliative-care-on-family-caregivers-fc-outcomes-for-patients-with-gastrointestinal-and-lung-cancer
#13
Vicki A Jackson, Joseph A Greer, William F Pirl, Elyse R Park, Anthony Back, Alona Muzikansky, Mihir Kamdar, Simone Rinaldi, Juliet Jacobsen, Joel Fishbein, Justin Eusebio, Harry VanDusen, Ryan David Nipp, David P Ryan, Jennifer S Temel
: 234 Background: Patients with newly diagnosed advanced cancers who receive early palliative care (PC) integrated with oncology care report improvement in their quality of life (QOL) and mood. While a telephone-based psycho-educational intervention for FC decrease depression, the impact of early, integrated outpatient PC models on FC outcomes remains unknown. METHODS: We conducted a randomized trial of early PC integrated with oncology care versus oncology care alone for newly diagnosed patients with incurable lung and gastrointestinal cancers and their FC...
October 9, 2016: Journal of Clinical Oncology: Official Journal of the American Society of Clinical Oncology
https://www.readbyqxmd.com/read/28152999/a-participatory-supportive-return-to-work-program-for-workers-without-an-employment-contract-sick-listed-due-to-a-common-mental-disorder-an-economic-evaluation-alongside-a-randomized-controlled-trial
#14
Lieke Lammerts, Johanna M van Dongen, Frederieke G Schaafsma, Willem van Mechelen, Johannes R Anema
BACKGROUND: Mental disorders are associated with high costs for productivity loss, sickness absence and unemployment. A participatory supportive return to work (RTW) program was developed in order to improve RTW among workers without an employment contract, sick-listed due to a common mental disorder. The program contained a participatory approach, integrated care and direct placement in a competitive job. The aim of this study was to evaluate the cost-effectiveness and cost-utility of this new program, compared to usual care...
February 2, 2017: BMC Public Health
https://www.readbyqxmd.com/read/28152969/utilizing-an-a3-project-to-improve-assessment-of-oral-chemotherapy-adherence-across-a-five-site-enterprise
#15
Kathleen Dunn, Debra Kay Allen, Diane Denny, Maurie Markman
: 136 Background: Cancer Treatment Centers of America, Inc. (CTCA) is a national network of five hospitals that specialize in treating patients fighting complex or advanced-stage cancer. During the fall of 2013, two of the five centers began the pursuit of Quality Oncology Practice Initiative (QOPI) certification. A third site began QOPI certification the spring of 2014 and the remaining two sites followed suit the spring of 2015. This process brought attention to the patient population receiving oral chemotherapy and the importance of careful monitoring of those self-administering their cancer treatment regimens...
March 2016: Journal of Clinical Oncology: Official Journal of the American Society of Clinical Oncology
https://www.readbyqxmd.com/read/28152856/the-influence-of-treatment-facility-volume-on-the-mortality-of-multiple-myeloma-patients
#16
Adam C Bartley, Cynthia S Crowson, Nilay D Shah, Elizabeth B Habermann, Sara Holton, David R Holmes
: 284 Background: MM is an uncommon cancer with annual incidence of only 27,000 cases in the US. Our study determined the extent to which the number of MM patients treated annually in a treatment facility affected all-cause mortality. METHODS: We used the National Cancer Data Base (NCDB) to identify adult patients with MM diagnosed from 2003-2011. NCDB is sourced from over 1,500 Commission on Cancer-accredited cancer registries representing 70% of cancer cases in the US...
March 2016: Journal of Clinical Oncology: Official Journal of the American Society of Clinical Oncology
https://www.readbyqxmd.com/read/28142036/handling-missing-mini-mental-state-examination-mmse-values-results-from-a-cross-sectional-long-term-care-study
#17
Judith Godin, Janice Keefe, Melissa K Andrew
BACKGROUND: Missing values are commonly encountered on the Mini Mental State Examination (MMSE), particularly when administered to frail older people. This presents challenges for MMSE scoring in research settings. We sought to describe missingness in MMSEs administered in long-term-care facilities (LTCF) and to compare and contrast approaches to dealing with missing items. METHODS: As part of the Care and Construction project in Nova Scotia, Canada, LTCF residents completed an MMSE...
December 27, 2016: Journal of Epidemiology
https://www.readbyqxmd.com/read/28141913/systemic-corticosteroid-regimens-for-prevention-of-bronchopulmonary-dysplasia-in-preterm-infants
#18
REVIEW
Wes Onland, Anne Pmc De Jaegere, Martin Offringa, Anton van Kaam
BACKGROUND: Cochrane systematic reviews show that systemic postnatal corticosteroids reduce the risk of bronchopulmonary dysplasia (BPD) in preterm infants. However, corticosteroids have also been associated with an increased risk of neurodevelopmental impairment. It is unknown whether these beneficial and adverse effects are modulated by differences in corticosteroid treatment regimens. OBJECTIVES: To assess the effects of different corticosteroid treatment regimens on mortality, pulmonary morbidity, and neurodevelopmental outcome in very low birth weight (VLBW) infants...
January 31, 2017: Cochrane Database of Systematic Reviews
https://www.readbyqxmd.com/read/28137247/a-randomised-controlled-trial-of-dietary-improvement-for-adults-with-major-depression-the-smiles-trial
#19
Felice N Jacka, Adrienne O'Neil, Rachelle Opie, Catherine Itsiopoulos, Sue Cotton, Mohammedreza Mohebbi, David Castle, Sarah Dash, Cathrine Mihalopoulos, Mary Lou Chatterton, Laima Brazionis, Olivia M Dean, Allison M Hodge, Michael Berk
BACKGROUND: The possible therapeutic impact of dietary changes on existing mental illness is largely unknown. Using a randomised controlled trial design, we aimed to investigate the efficacy of a dietary improvement program for the treatment of major depressive episodes. METHODS: 'SMILES' was a 12-week, parallel-group, single blind, randomised controlled trial of an adjunctive dietary intervention in the treatment of moderate to severe depression. The intervention consisted of seven individual nutritional consulting sessions delivered by a clinical dietician...
January 30, 2017: BMC Medicine
https://www.readbyqxmd.com/read/28123747/improving-visual-assessment-documentation-in-patients-with-periorbital-trauma-through-an-eye-assessment-teaching-session-and-a-proforma-sticker
#20
Tharsika Myuran
Up to 30% of patients who have periorbital trauma will have ocular injury with devastating consequences if missed. All staff working with acutely injured Oral and Maxillofacial Surgery (OMFS) patients should be competent in a basic eye examination with documentation of visual acuity, gross visual fields, eye movements, diplopia, and pupillary responses at a minimum. As a standard we adapted guidance published by the Emergency Care Institute New South Wales to assess the documentation of the eye examination in OMFS patients at King's College Hospital with any periorbital injury...
2017: BMJ Quality Improvement Reports
keyword
keyword
55439
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"