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Mixed Model Analysis (mixed + model_analysis)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Knee pain reduces joint space width in conventional standing anteroposterior radiographs of osteoarthritic knees

ARTHRITIS & RHEUMATISM, Issue 5 2002
Steven A. Mazzuca
Objective A suspected, but heretofore undemonstrated, limitation of the conventional weight-bearing anteroposterior (AP) knee radiograph, in which the joint is imaged in extension, for studies of progression of osteoarthritis (OA) is that changes in knee pain may affect extension, thereby altering the apparent thickness of the articular cartilage. The present study was undertaken to examine the effect of changes in knee pain of varying magnitudes on radiographic joint space width (JSW) in the weight-bearing extended and the semiflexed AP views, in which radioanatomic positioning of the knee was carefully standardized by fluoroscopy. Methods Fifteen patients with knee OA underwent a washout of their analgesic/nonsteroidal antiinflammatory drug (NSAID) agents (duration 5 half-lives), after which standing AP and semiflexed AP knee radiographs of both knees were obtained. Examinations were repeated 1,12 weeks later (median 4.5 weeks, mean 6.0 weeks), after resumption of analgesic/NSAID therapy. Knee pain was measured with the pain subscale of the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index (Likert scale). JSW was measured with a pair of calipers and a magnifying lens. Mixed model analyses of variance were used to test the significance of changes in pain and JSW within and between 2 groups of knees with mild-to-moderate radiographic severity of OA: (a) "flaring knees," in which the patient rated standing knee pain as severe or extreme after the washout and in which pain decreased to any degree after resumption of analgesics and/or NSAIDs (n = 12) and (b) "nonflaring knees," in which standing knee pain was absent, mild, or moderate after the washout or did not decrease after resumption of treatment (n = 15). Results After reinstitution of treatment, WOMAC pain scores decreased significantly in both flaring and nonflaring knees (,44%; P < 0.0001 and ,18%; P < 0.01, respectively). After adjustment for the within-subject correlation between knees, mean JSW (±SEM) in the extended view of the flaring OA knee increased significantly from the first to second examination (0.20 ± 0.06 mm; P = 0.005). In contrast, the change in adjusted mean JSW in the extended view of the nonflaring OA knee was negligible (,0.04 ± 0.04 mm) and significantly smaller than that observed in flaring knees (P < 0.01). Mean JSW in the semiflexed AP view was unaffected by the severity or responsiveness of standing knee pain in flaring and nonflaring OA knees. Conclusion JSW in weight-bearing extended-view radiographs of highly symptomatic OA knees can be altered significantly by changes in joint pain. In clinical trials and in epidemiologic studies of OA progression that use this radiographic technique, longitudinal variations in pain may confound changes in the apparent thickness of the articular cartilage. [source]

Does presenting with meconium ileus affect the prognosis of children with cystic fibrosis?

PEDIATRIC PULMONOLOGY, Issue 10 2010
Jo-Anne Johnson MBChB
Abstract It is a matter of debate as to what extent the long-term outcome of cystic fibrosis (CF) is affected by presenting with meconium ileus (MI). We compared long-term clinical outcomes of CF children who presented with MI, to those presenting with other symptoms (non-MI) in an era of non new-born-screening (NBS). We collected annual lung function data between the ages of 8,15 years in terms of percent predicted first second forced expired volume (FEV1%pr), percent predicted forced vital capacity (FVC%pr), and between the ages of 2,15 years annual height and weight Z-scores (HtZ and WtZ respectively) for children attending the Royal Brompton Hospital CF clinic. To be included in the study, subjects had to have at least five pulmonary function tests and five anthropometric measurements recorded over this period. Thirty-eight MI and 76 non-MI subjects were compared. There were no significant differences in genotype, sex, chronic Pseudomonas infection, or pancreatic enzyme use between the two groups. The median age of diagnosis was 1 day (MI) versus 7 months (non-MI). There was a decline in spirometry and anthropometric variables over the study period for both MI and non-MI groups apart from WtZ score in the non-MI group. Mixed model analysis adjusting for potential confounders including genotype, pancreatic status, sex, chronic Pseudomonas aeruginosa lung infection, and age of diagnosis revealed no difference between the two groups in terms of lung function and growth during the time period of the study, however there was a non-significant trend for subjects presenting with MI to do better in all four parameters. We conclude that babies presenting with MI have no worse long-term outcome than those presenting symptomatically later in infancy, despite having undergone invasive procedures in the newborn period. This underscores the importance of early diagnosis and treatment in CF. Pediatr Pulmonol. 2010; 45:951,958. © 2010 Wiley-Liss, Inc. [source]

A randomized, placebo-controlled study of the efficacy and safety of sertraline in the treatment of the behavioral manifestations of Alzheimer's disease in outpatients treated with donepezil

INTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 1 2004
Sanford I. Finkel
Abstract Objective To examine the safety and efficacy of sertraline augmentation therapy in the treatment of behavioral manifestations of Alzheimer's disease (AD) in outpatients treated with donepezil. Methods and materials Patients with probable or possible AD, and a Neuropsychiatric Inventory (NPI) total score >5 (with a severity score ,2 in at least one domain), were treated with donepezil (5,10,mg) for 8 weeks, then randomly assigned to 12 weeks of double-blind augmentation therapy with either sertraline (50,200,mg) or placebo. Primary efficacy measures were the 12-item Neuropsychiatric Inventory (NPI) and the Clinical Global Impression Improvement (CGI-I) and Severity (CGI-S) scales. Results 24 patients were treated with donepezil+sertraline and 120 patients with donepezil+placebo. There were no statistically significant differences at endpoint on any of the three primary efficacy measures. However, a linear mixed model analysis found modest but statistically significantly greater improvements in the CGI-I score on donepezil+sertraline. Moreover, in a sub-group of patients with moderate-to-severe behavioral and psychological symptoms of dementia, 60% of patients on sertraline vs 40% on placebo (p,=,0.006) achieved a response (defined as ,;50% reduction in a four-item NPI-behavioral subscale). One adverse event (diarrhea) was significantly (p,<,0.05) more common in the donepezil+sertraline group compared to the donepezil+placebo group. Conclusion Sertraline augmentation was well-tolerated in this sample of AD outpatients. In addition, post hoc analyses demonstrated a modest but statistically significant advantage of sertraline over placebo augmentation in mixed model analyses and a clinically and statistically significant advantage in a subgroup of patients with moderate-to-severe behavioral and psychological symptoms of dementia. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Cognitive Status, Muscle Strength, and Subsequent Disability in Older Mexican Americans

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 9 2005
Mukaila A. Raji MD
Objectives: To examine the association between Mini-Mental State Examination (MMSE) score and subsequent muscle strength (measured using handgrip strength) and to test the hypothesis that muscle strength will mediate any association between impaired cognition and incident activity of daily living (ADL) disability over a 7-year period in elderly Mexican Americans who were initially not disabled. Design: A 7-year prospective cohort study (1993,2001). Setting: Five southwestern states (Texas, New Mexico, Colorado, Arizona, and California). Participants: Two thousand three hundred eighty-one noninstitutionalized Mexican-American men and women aged 65 and older with no ADL disability at baseline. Measurements: In-home interviews in 1993/1994, 1995/1996, 1998/1999, and 2000/2001 assessed social and demographic factors, medical conditions (diabetes mellitus, stroke, heart attack, and arthritis), body mass index (BMI), depressive symptomatology, handgrip muscle strength, and ADLs. MMSE score was dichotomized as less than 21 for poor cognition and 21 or greater for good cognition. Main outcomes measures were mean and slope of handgrip muscle strength over the 7-year period and incident disability, defined as new onset of any ADL limitation at the 2-, 5-, or 7-year follow-up interview periods. Results: In mixed model analyses, there was a significant cross-sectional association between having poor cognition (MMSE<21) and lower handgrip strength, independent of age, sex, and time of interview (estimate=,1.41, standard error (SE)=0.18; P<.001). With the introduction of a cognition-by-time interaction term into the model, there was also a longitudinal association between poor cognition and change in handgrip strength over time (estimate=,0.25, SE=0.06; P<.001), indicating that subjects with poor cognition had a significantly greater decline in handgrip strength over 7 years than those with good cognition, independent of age, sex, and time. This longitudinal association between poor cognition and greater muscle decline remained significant (P<.001) after controlling for age, sex, education, and time-dependent variables of depression, BMI, and medical conditions. In general estimation equation models, having poor cognition was associated with greater risk of 7-year incident ADL disability (odds ratio=2.01, 95% confidence interval (CI)=1.60,2.52); the magnitude of the association decreased to 1.66 (95% CI=1.31,2.10) when adjustment was made for handgrip strength. Conclusion: Older Mexican Americans with poor cognition had steeper decline in handgrip muscle strength over 7 years than those with good cognition, independent of other demographic and health factors. A possible mediating effect of muscle strength on the association between poor cognition and subsequent ADL disability was also indicated. [source]

A randomized, placebo-controlled study of the efficacy and safety of sertraline in the treatment of the behavioral manifestations of Alzheimer's disease in outpatients treated with donepezil

A randomized trial of behavioral management for continence with older rural women,

RESEARCH IN NURSING & HEALTH, Issue 1 2002
Molly C. Dougherty
Abstract Urinary incontinence (UI) is a commonly underreported and underdiagnosed condition. The purpose of this trial was to implement and evaluate behavioral management for continence (BMC), an intervention to manage symptoms of UI with older rural women in their homes. Participants were randomized into BMC or a control group, and 178 were followed for between 6 and 24 months. The intervention involved self-monitoring, bladder training, and pelvic muscle exercise with biofeedback. The primary outcome variable,severity of urine loss,was evaluated by pad test. Secondary variables were episodes of urine loss, micturition frequency, voiding interval, quality of life, and subjective report of severity. Urine loss severity at baseline evaluation was not significantly different in the two groups. But using the generalized linear mixed model analysis, at the four follow-ups, severity of urine loss, episodes of urine loss, quality of life, and subjective report of severity were significantly different. At 2 years the BMC group UI severity decreased by 61%; the control group severity increased by 184%. Self-monitoring and bladder training accounted for most of the improvement. The results support the use of simple strategies based on bladder diaries before implementing more complex treatments. © 2002 John Wiley & Sons, Res Nurs Health 25:3,13, 2002. [source]

Verapamil augmentation of lithium treatment improves outcome in mania unresponsive to lithium alone: preliminary findings and a discussion of therapeutic mechanisms

BIPOLAR DISORDERS, Issue 8 2008
Alan G Mallinger
Objectives:, Attenuation of protein kinase C (PKC) is a mechanism common to both established (lithium, valproate) and some novel (tamoxifen) antimanic agents. Verapamil, although primarily known as a calcium channel blocker, also has PKC inhibitory activity. Verapamil has shown antimanic activity in some but not all studies. Therefore, we investigated verapamil, used alone or as an adjunctive treatment, in manic patients who did not respond to an initial adequate trial of lithium. Methods:, Each study phase lasted three weeks. Subjects were treated openly with lithium in Phase 1 (n = 45). Those who failed to respond were randomly assigned to double-blind treatment in Phase 2 with either verapamil (n = 10) or continued-lithium (n = 8). Phase 2 nonresponders (n = 10) were assigned to combined verapamil/lithium in Phase 3. Results:, Response in Phase 2 did not differ significantly between verapamil and continued-lithium. During Phase 3, response to combined treatment was significantly better than overall response to monotherapy in Phase 2 (Fisher's Exact test, p = 0.043). Mania ratings improved during combined treatment in Phase 3 by 88.2% (linear mixed model analysis, F = 4.34, p = 0.013), compared with 10.5% improvement during Phase 2. Conclusions:, In this preliminary investigation, verapamil monotherapy did not demonstrate antimanic efficacy. By contrast, the combination of verapamil plus lithium was highly efficacious. Our findings thus suggest that verapamil may have potential utility as an adjunct to lithium. This effect may be mediated by additive actions on PKC inhibition, which may be an important mechanism for antimanic agents in general. [source]