Longitudinal Associations between Concurrent Changes in Phenotypic Frailty and Lower Urinary Tract Symptoms among Older Men

BACKGROUND

Lower urinary tract symptoms (LUTS) are associated with prevalent frailty and functional impairment, but longitudinal associations remain unexplored.

OBJECTIVES

To assess the association of change in phenotypic frailty with concurrent worsening LUTS severity among older men without clinically significant LUTS at baseline.

DESIGN

Multicenter, prospective cohort study.

SETTING

Population-based.

PARTICIPANTS

Participants included community-dwelling men age ≥65 years at enrollment in the Osteoporotic Fractures in Men study.

MEASUREMENTS

Data were collected at 4 visits over 7 years. Phenotypic frailty score (range: 0-5) was defined at each visit using adapted Fried criterion and men were categorized at baseline as robust (0), pre-frail (1-2), or frail (3-5). Within-person change in frailty was calculated at each visit as the absolute difference in number of criteria met compared to baseline. LUTS severity was defined using the American Urologic Association Symptom Index (AUASI; range: 0-35) and men with AUASI ≥8 at baseline were excluded. Linear mixed effects models were adjusted for demographics, health-behaviors, and comorbidities to quantify the association between within-person change in frailty and AUASI.

RESULTS

Among 3235 men included in analysis, 48% were robust, 45% were pre-frail, and 7% were frail. Whereas baseline frailty status was not associated with change in LUTS severity, within-person increases in frailty were associated with greater LUTS severity (quadratic P<0.001). Among robust men at baseline, mean predicted AUASI during follow-up was 4.2 (95% CI 3.9, 4.5) among those meeting 0 frailty criteria, 4.6 (95% CI 4.3, 4.9) among those meeting 1 criterion increasing non-linearly to 11.2 (95% CI 9.8, 12.6) among those meeting 5 criteria.

CONCLUSIONS

Greater phenotypic frailty was associated with non-linear increases in LUTS severity in older men over time, independent of age and comorbidities. Results suggest LUTS and frailty share an underlying mechanism that is not targeted by existing LUTS interventions.

A Volumetric Metric for Monitoring Intracranial Aneurysms: Repeatability and Growth Criteria in a Longitudinal MR Imaging Study

BACKGROUND AND PURPOSE

The reliability of contrast-enhanced MRA in monitoring serial volumetric changes of unruptured intracranial aneurysms has not been established. We aimed to determine the coefficient of variance of contrast-enhanced MRA in measuring aneurysm volumes, thus establishing criteria for aneurysm growth and permitting identification of variables predictive of growth.

MATERIALS AND METHODS

Aneurysm volumes were measured from serial contrast-enhanced MRA studies of patients with untreated intracranial aneurysms who underwent >2 sequential MR imaging evaluations. After coregistering all sequential studies in 3D space for each aneurysm and signal intensity normalization, aneurysm volume was determined across all time points. A linear mixed effects model was built to estimate the coefficient of variance of the measurement as well as to determine predictive variables. Growth was defined as relative growth exceeding 2 times the measurement coefficient of variance (sudden growth, as 4 times the coefficient of variance).

RESULTS

A total of 95 patients with 112 aneurysms were included (5.9 scans during 4.0 years on average, 616 scan measurements in total). The coefficient of variance was 5.5% of the aneurysm volume, and the relative growth rate was dependent on the location: anterior cerebral artery, 4.52% per year; vertebral artery, 2.46% per year; middle cerebral artery, 2.74% per year; basilar artery, 2.36% per year; internal carotid artery, 1.14% per year. Thirty-six of 112 (32%) aneurysms were characterized as growing, and 11/36 of them had an episode of sudden growth.

CONCLUSIONS

Volume measurement of unruptured intracranial aneurysms by contrast-enhanced MRA seems a reliable metric for tracking the growth trajectory of aneurysms. Furthermore, the aneurysm growth rate differs among different locations.

995 Clinical Outcomes Following Incomplete Colonoscopy

Introduction

Following incomplete colonoscopy (IC) it is reported that there is up to five-fold increased risk of colorectal cancer. Our aim was to determine the final clinical outcome for patients with a prior IC.

Method

A multi-centre retrospective observational study involving three endoscopy units. All consecutive patients having colonoscopy from over 18 months were analysed. Exclusion criteria included IC was due to obstructing cancer, follow up was not performed due to non-attendance at clinic or investigation and incomplete data set. Electronic notes were analysed to determine patient’s final clinical outcome. All patients were followed up for minimum of six months.

Results

Of the 8,490 colonoscopies, 733 (8.6%) were IC. 86 (11.7%) were excluded. Of the 647 included, 469 (72.4%) were females and 473 (73.1%) has further colonic investigations. Secondary investigations were: CT colonography 169 (35.7%), repeat colonoscopy 161 (34.0%), barium enema 95 (20.1%) and others 48 (10.1%). The repeat colonoscopy group achieved a complete colonoscopy in 111 (68.9%) patients. For those who had further investigations 15 (3.2%) had colorectal cancer and 12 (2.5%) has polyps ≥1cm.

Conclusions

There is significant risk of missing colorectal malignancy and large polyps following IC. Further colonic investigations should be carried out in this cohort of patients.

Spatial distribution and temporal progression of T2 relaxation time values in knee cartilage prior to the onset of cartilage lesions - data from the Osteoarthritis Initiative (OAI)

PURPOSE

To investigate compositional changes of knee cartilage at the site of newly appearing cartilage lesions and the surrounding cartilage 1-4 years prior to lesion onset using quantitative T2-measurements.

METHODS

Fifty-seven cartilage plates with newly appearing cartilage lesions from 45 knees (cases) and 52 plates from 26 control knees from the Osteoarthritis Initiative (OAI) cohort (controls) were evaluated. Using MRI T2-mapping, composition of local (the site of future lesions) and surrounding cartilage (remainder of the cartilage plate) was assessed 1-4 years prior to lesion onset. Analogous cartilage ROIs in control plates without cartilage lesions were assessed over 1-4 years. Mixed models were used to compare T2-means and change rates between local and surrounding cartilage within cases and controls, and to compare change rates in local and surrounding cartilage between cases and controls, adjusting for covariates.

RESULTS

Four years prior to lesion onset, we found that local cartilage ROIs had higher T2-values compared to the surrounding cartilage. No such differences were found in control plates. In cases mean local T2-values were persistantly elevated compared to the surrounding cartilage prior to lesion onset reaching significance 1 year prior (+2.94 ms, p = 0.012). T2-values of the surrounding cartilage were also persistantly higher in cases compared to controls, reaching significance 2 years prior to lesion onset (+3.61 ms, p = 0.003).

CONCLUSION

The findings of our study support the concept of compositional cartilage changes as a mechanism for cartilage degradation and that both diffuse and focal changes of cartilage composition within a cartilage plate precede the development of cartilage lesions.

Association of Physical Activity Measured by Accelerometer, Knee Joint Abnormalities, and Cartilage T2 Measurements Obtained From 3T Magnetic Resonance Imaging: Data From the Osteoarthritis Initiative

OBJECTIVE

To study the cross-sectional association between physical activity measured with an accelerometer, structural knee abnormalities, and cartilage T2 values assessed with 3T magnetic resonance imaging (MRI).

METHODS

We included 274 subjects from the Osteoarthritis Initiative cohort without definite radiographic osteoarthritis (Kellgren/Lawrence grades 0 and 1) and with at most mild pain, stiffness, and functional limitation in the study knee (Western Ontario and McMaster Universities Osteoarthritis Index scale 0-1), which had not limited their activity due to knee pain. Physical activity was measured over 7 days with an ActiGraph GT1M accelerometer. Subjects were categorized by quartile of physical activity based on the average daily minutes of moderate to vigorous physical activity (mv-PA). MRI images of the right knee (at 48-month visit) were assessed for structural abnormalities using a modified Whole-Organ Magnetic Resonance Imaging Score (WORMS) and for T2 relaxation times derived from segmented cartilage of 4 femorotibial regions and the patella. WORMS grades and T2 measurements were compared between activity quartiles using a linear regression model. Covariates included age, sex, body mass index, knee injury, family history of knee replacement, knee symptoms, hip and ankle pain, and daily wear time of the accelerometer.

RESULTS

Higher mv-PA was associated with increased severity (P = 0.0087) and number of lesions of the medial meniscus (P = 0.0089) and with severity of bone marrow edema lesions (P = 0.0053). No association between cartilage lesions and mv-PA was found. T2 values of cartilage (loss, damage, and abnormalities) tended to be greater in the higher quartiles of mv-PA, but the differences were nonsignificant.

CONCLUSION

In knees without radiographic osteoarthritis in subjects with no or mild knee pain, higher physical activity levels were associated with increases in meniscal and bone marrow edema pattern lesions.

Retinal axonal loss in very early stages of multiple sclerosis

BACKGROUND AND PURPOSE

The lack of surrogates of clinical progression has limited the design of neuroprotection trials in multiple sclerosis (MS). Our aim was to study the association between time-domain optical coherence tomography measures and clinical and magnetic resonance imaging outcomes in early MS.

METHODS

Forty-three relapsing-remitting MS patients within 1 year of onset were followed for up to 3 years.

RESULTS

The peripapillary retinal nerve fiber layer (RNFL) decreased annually by 2 μm (95% confidence interval -3.89, -0.11; P = 0.038). The RNFL tended to be associated with normalized normal appearing white matter volume in cross-sectional (P = 0.08) and longitudinal analyses (P = 0.06).

CONCLUSIONS

There is substantial RNFL loss even in very early MS. Our data suggest that retinal axonal atrophy is associated with atrophy in global white matter volume in early MS.

Association of metabolic risk factors with cartilage degradation assessed by T2 relaxation time at the knee: data from the osteoarthritis initiative

OBJECTIVE

To evaluate the association of metabolic risk factors with severity and 2-year progression of early degenerative cartilage changes at the knee, measured with T2 relaxation times in middle-aged subjects from the Osteoarthritis Initiative.

METHODS

Cartilage segmentation and T2 map generation were performed in knee 3T magnetic resonance images from 403 subjects ages 45-60 years without radiographic osteoarthritis (OA). The influence of risk factors on baseline T2 and longitudinal progression of T2 was analyzed using linear regression, adjusting for age, sex, and other OA risk factors.

RESULTS

Four metabolic risk factors, i.e., high abdominal circumference (P < 0.001), hypertension (P = 0.041), high fat consumption (P = 0.023), and self-reported diabetes mellitus (P = 0.010), were individually associated with higher baseline T2. When the 4 metabolic risk factors were considered in a multivariate regression model, higher T2 remained significantly associated with abdominal circumference (P < 0.001) and diabetes mellitus (P = 0.026), and there was a trend for high fat consumption (P = 0.096). For the individual risk factors, only diabetes mellitus remained associated with higher baseline T2 after adjustment for body mass index (BMI). After adjustment for BMI, baseline T2 increased in a dose-response manner with the number of metabolic risk factors present (P = 0.032 for linear trend), and subjects with ≥3 metabolic factors (versus <3) had significantly higher baseline T2 (mean difference 1.2 msec [95% confidence interval 0.3, 2.1]; P = 0.011). Metabolic risk factors were not significantly associated with increases in T2 during followup.

CONCLUSION

Metabolic risk factors are associated with higher T2, suggesting that increased cartilage degeneration may be caused by modifiable metabolic disorders.

A K-nearest neighbors survival probability prediction method

We introduce a nonparametric survival prediction method for right-censored data. The method generates a survival curve prediction by constructing a (weighted) Kaplan-Meier estimator using the outcomes of the K most similar training observations. Each observation has an associated set of covariates, and a metric on the covariate space is used to measure similarity between observations. We apply our method to a kidney transplantation data set to generate patient-specific distributions of graft survival and to a simulated data set in which the proportional hazards assumption is explicitly violated. We compare the performance of our method with the standard Cox model and the random survival forests method.

Longitudinal evaluation of T1ρ and T2 spatial distribution in osteoarthritic and healthy medial knee cartilage

OBJECTIVE

To investigate longitudinal changes in laminar and spatial distribution of knee articular cartilage magnetic resonance imaging (MRI) T1ρ and T2 relaxation times, in individuals with and without medial compartment cartilage defects.

DESIGN

All subjects (at baseline n = 88, >18 years old) underwent 3-Tesla knee MRI at baseline and annually thereafter for 3 years. The MR studies were evaluated for presence of cartilage defects (modified Whole-Organ Magnetic Resonance Imaging Scoring - mWORMS), and quantitative T1ρ and T2 relaxation time maps. Subjects were segregated into those with (mWORMS ≥2) and without (mWORMS ≤1) cartilage lesions at the medial tibia (MT) or medial femur (MF) at each time point. Laminar (bone and articular layer) and spatial (gray level co-occurrence matrix - GLCM) distribution of the T1ρ and T2 relaxation time maps were calculated. Linear regression models (cross-sectional) and Generalized Estimating Equations (GEEs) (longitudinal) were used.

RESULTS

Global T1ρ, global T2 and articular layer T2 relaxation times at the MF, and global and articular layer T2 relaxation times at the MT, were higher in subjects with cartilage lesions compared to those without lesions. At the MT global T1ρ relaxation times were higher at each time point in subjects with lesions. MT T1ρ and T2 became progressively more heterogeneous than control compartments over the course of the study.

CONCLUSION

Spatial distribution of T1ρ and T2 relaxation time maps in medial knee OA using GLCM technique may be a sensitive indicator of cartilage deterioration, in addition to whole-compartment relaxation time data.

Abstract P3-08-18: Association of tamoxifen use and ovarian aging in patients with invasive or pre-invasive breast cancer

Background: The use of tamoxifen has been shown to delay the recovery of chemotherapy-induced amenorrhea, however the independent impact of long-term endocrine therapy on ovarian aging is not known, and to our knowledge, has never been directly investigated. Understanding the effect of endocrine therapy on ovarian aging will help breast cancer patients of reproductive age make more informed and empowered decisions regarding their treatment. The aim of this study is to explore the relationship between tamoxifen therapy and age onset of menopause.

Methods: We conducted a retrospective cohort study using patients identified through the UCSF Cancer Registry and UCSF SPORE database. Women who were diagnosed with Stage 1-3 invasive or in situ breast cancer between 1985 and 2011, who were premenopausal at the time of diagnosis and who did not receive systemic chemotherapy were included. Patients with recurrent disease and prior ovarian surgery were excluded. Eligibility was confirmed by telephone, and online or paper surveys were distributed to eligible subjects only. Age onset of menopause was the primary endpoint of the study and was defined as the age at which a woman had her last period and no menses for 12 months. Age onset of menopause was assessed through surveys. The primary analysis compared age onset of menopause between subjects who received tamoxifen for any duration and control subjects who never received tamoxifen. Secondary analyses were performed using a Cox proportional hazards model to determine whether duration of tamoxifen exposure and age of tamoxifen initiation impacted age onset of menopause in subjects treated with tamoxifen.

Results: A total of 1137 potential subjects believed to meet eligibility criteria were identified and called, and 649 subjects were reached. Eligibility was confirmed by phone in 340 subjects. A total of 336 subjects consented to participate in the study, and 262 (78%) completed and returned the survey. 227 subjects were included in the primary analysis of which 110 subjects received prior tamoxifen, and 117 subjects received no prior tamoxifen. At the time of the survey, 16.3% vs. 20.2% of patients under age 50 that were exposed and not exposed to tamoxifen entered menopause, respectively. The median age onset of menopause was 50.94 and 51.34 for the tamoxifen and no tamoxifen groups, respectively. The hazard ratio between these groups was 1.077 which was not statistically significant (p = 0.6917). No association (p = 0.55) was found between the duration of tamoxifen use and the age onset of menopause. When controlling for tamoxifen duration, there was no significant difference (p = 0.93) in age onset of menopause between subjects who initiated tamoxifen prior to age 45 and those who initiated at age 45 or older.

Conclusion: These data suggest that tamoxifen alone is not associated with an earlier age onset of menopause, and that tamoxifen use, in the absence of systemic chemotherapy, is unlikely to significantly accelerate ovarian aging.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-08-18.

Combined dysfunctions of immune cells predict nosocomial infection in critically ill patients

BACKGROUND

Nosocomial infection occurs commonly in intensive care units (ICUs). Although critical illness is associated with immune activation, the prevalence of nosocomial infections suggests concomitant immune suppression. This study examined the temporal occurrence of immune dysfunction across three immune cell types, and their relationship with the development of nosocomial infection.

METHODS

A prospective observational cohort study was undertaken in a teaching hospital general ICU. Critically ill patients were recruited and underwent serial examination of immune status, namely percentage regulatory T-cells (Tregs), monocyte deactivation (by expression) and neutrophil dysfunction (by CD88 expression). The occurrence of nosocomial infection was determined using pre-defined, objective criteria.

RESULTS

Ninety-six patients were recruited, of whom 95 had data available for analysis. Relative to healthy controls, percentage Tregs were elevated 6-10 days after admission, while monocyte HLA-DR and neutrophil CD88 showed broader depression across time points measured. Thirty-three patients (35%) developed nosocomial infection, and patients developing nosocomial infection showed significantly greater immune dysfunction by the measures used. Tregs and neutrophil dysfunction remained significantly predictive of infection in a Cox hazards model correcting for time effects and clinical confounders {hazard ratio (HR) 2.4 [95% confidence interval (CI) 1.1-5.4] and 6.9 (95% CI 1.6-30), respectively, P=0.001}. Cumulative immune dysfunction resulted in a progressive risk of infection, rising from no cases in patients with no dysfunction to 75% of patients with dysfunction of all three cell types (P=0.0004).

CONCLUSIONS

Dysfunctions of T-cells, monocytes, and neutrophils predict acquisition of nosocomial infection, and combine additively to stratify risk of nosocomial infection in the critically ill.

Provision of long-acting reversible contraception in HIV-prevalent countries: results from nationally representative surveys in southern Africa

OBJECTIVE

To analyse the current provision of long-acting reversible contraception (LARC) and clinician training needs in HIV-prevalent settings.

DESIGN

Nationally representative survey of clinicians.

SETTING

HIV-prevalent settings in South Africa and Zimbabwe.

POPULATION

Clinicians in South Africa and Zimbabwe.

METHODS

Nationally representative surveys of clinicians were conducted in South Africa and Zimbabwe (n = 1444) to assess current clinical practice in the provision of LARC in HIV-prevalent settings. Multivariable logistic regression was used to analyse contraceptive provision and clinician training needs.

MAIN OUTCOME MEASURE

Multivariable logistic regression of contraceptive provision and clinician training needs.

RESULTS

Provision of the most effective reversible contraceptives is limited: only 14% of clinicians provide copper intrauterine devices (IUDs), 4% levonorgestrel-releasing IUDs and 16% contraceptive implants. Clinicians' perceptions of patient eligibility for IUD use were overly restrictive, especially related to HIV risks. Less than 5% reported that IUDs were appropriate for women at high risk of HIV or for HIV-positive women, contrary to evidence-based guidelines. Only 15% viewed implants as appropriate for women at risk of HIV. Most clinicians (82%), however, felt that IUDs were underused by patients, and over half desired additional training on LARC methods. Logistic regression analysis showed that LARC provision was largely restricted to physicians, hospital settings and urban areas. Results also showed that clinicians in rural areas and clinics, including nurses, were especially interested in training.

CONCLUSIONS

Clinician competency in LARC provision is important in southern Africa, given the low use of methods and high rates of unintended pregnancy among HIV-positive and at-risk women. Despite low provision, clinician interest is high, suggesting the need for increased evidence-based training in LARC to reduce unintended pregnancy and associated morbidities.

Individual magnetic resonance imaging and radiographic features of knee osteoarthritis in subjects with unilateral knee pain: the health, aging, and body composition study

OBJECTIVE

Strong associations between radiographic features of knee osteoarthritis (OA) and pain have been demonstrated in persons with unilateral knee symptoms. This study was undertaken to compare radiographic and magnetic resonance imaging (MRI) features of knee OA and assess their ability to discriminate between painful and nonpainful knees in persons with unilateral symptoms.

METHODS

The study population included 283 individuals ages 70-79 years with unilateral knee pain who were enrolled in the Health, Aging, and Body Composition Study, a study of weight-related diseases and mobility. Radiographs of both knees were read for Kellgren/Lawrence (K/L) grade and individual radiographic features, and 1.5T MRIs were assessed using the Whole-Organ Magnetic Resonance Imaging Score. The association between structural features and pain was assessed using a within-person case-control design and conditional logistic regression. Receiver operating characteristic (ROC) analysis was then used to test the discriminatory performance of structural features.

RESULTS

In conditional logistic analyses, knee pain was significantly associated with both radiographic features (any joint space narrowing grade ≥ 1) (odds ratio 3.20 [95% confidence interval 1.79-5.71]) and MRI features (any cartilage defect scored ≥ 2) (odds ratio 3.67 [95% confidence interval 1.49-9.04]). However, in most subjects, MRI revealed osteophytes and cartilage and bone marrow lesions in both knees, and using ROC analysis, no individual structural feature discriminated well between painful and nonpainful knees. The best-performing MRI feature (synovitis/effusion) was not significantly more informative than K/L grade ≥ 2 (P = 0.42).

CONCLUSION

In persons with unilateral knee pain, MRI and radiographic features were associated with knee pain, confirming that structural abnormalities in the knee have an important role in the etiology of pain. However, no single MRI or radiographic finding performed well in discriminating between painful and nonpainful knees. Further work is needed to examine how structural and nonstructural factors influence knee pain.

Abstract P3-05-06: Automated analysis of Her2 FISH using combined Immunofluorescence and FISH signals

Introduction: Qualifying patients for Her2 targeted therapy is currently done by detecting Her2 protein overexpression or gene amplification using immunohistochemistry and/or FISH. We have recently developed a method for detecting both signals on the same tissue section allowing direct correlation of protein expression and gene copy number on a cell by cell basis. Accurate assessment of Her2 gene copy number is critical and can pose a challenge due to tumor heterogeneity. This paper reports the accuracy of a proprietary FISH dot counting algorithm on a cell-by-cell basis, potentially allowing analysis of thousands instead of dozens of tumor cells.

Method: Automatic FISH signal counts were compared to manual counts of 888 cells selected from 19 invasive ductal breast carcinoma samples exhibiting varying degrees of Her2 expression collected between June 2011 and March 2012. Tissue sections (4 µm) were mounted on positively charged slides, baked and processed through deparaffinization, rehydration and antigen retrieval, then stained for immunofluorescence (IF) using Cy5 labeled Her2 and Cy3 labeled cytokeratin antibodies, counterstained with DAPI, and imaged using InCell 2000 analyzer with GE-proprietary acquisition and processing software. Images were collected at 10x magnification and digitally stitched to span the entire tissue section. A pathologist then selected separate tumor and adjacent normal epithelium regions for subsequent imaging at 40x magnification. Slides were subsequently processed for FISH by pepsin digestion and then subjected to FISH by using PathVysion kit (Abbott Molecular, Des Plaines, IL). After hybridization and subsequent high stringency washes, samples were DAPI stained and mounted for microscopy. Samples were imaged at 40x at the same regions recorded for 40x IF acquisition, using filtersets appropriate for FISH fluorophores and DAPI.

A proprietary automated processing algorithm was used to analyze combined IF and FISH signals and derive case specific Her2 score from the tumor and/or adjacent normal epithelium. Cell-level dot counting accuracy was assessed using two metrics comparing automated counts to manual counts: cell classification agreement, where a normal cell was defined as having 3 or less Her2 and Cep17 dots; and dot-counting match, where a difference of more than 20% in absolute counts was considered an error.

Result: Our automatic results gave an overall cell-by-cell classification agreement of 88% (range 71% to 98% by case). Combining classification agreement and counting match, our algorithm gave an overall accuracy of 81% (range 63% to 97% by case). Restricting to tumor tissues (as judged by pathologist review of IF) classification agreement and accuracy were 84% and 72%, respectively.

Conclusion: The observed variability in algorithm performance between the different cases was due to the fact that error root causes were case dependent. For instance, the main cause of over-counting errors was image noise and artifacts. On the other hand, the main cause of under-counting was low image contrast, especially in highly amplified cases. These results are an early indication of the promise of automatic dot counting applied to breast cancer slides multiplexed for Her2 IF and FISH.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-05-06.

Equivalence and precision of knee cartilage morphometry between different segmentation teams, cartilage regions, and MR acquisitions

OBJECTIVE

To compare precision and evaluate equivalence of femorotibial cartilage volume (VC) and mean cartilage thickness over total area of bone (ThCtAB.Me) from independent segmentation teams using identical Magnetic Resonance (MR) images from three series: sagittal 3D Dual Echo in the Steady State (DESS), coronal multi-planar reformat (DESS-MPR) of DESS and coronal 3D Fast Low Angle SHot (FLASH).

DESIGN

Nineteen subjects underwent test-retest MR imaging at 3 T. Four teams segmented the cartilage using prospectively defined plate regions and rules. Mixed models analysis of the pooled data were used to evaluate the effect of acquisition, team and plate on precision and Pearson correlations and mixed models were used to evaluate equivalence.

RESULTS

Segmentation team differences dominated measurement variability in most cartilage regions for all image series. Precision of VC and ThCtAB.Me differed significantly by team and cartilage plate, but not between FLASH and DESS. Mean values of VC and ThCtAB.Me differed by team (P < 0.05) for DESS, FLASH and DESS-MPR. FLASH VC was 4-6% larger than DESS in the medial tibia and lateral central femur, and FLASH ThCtAB.Me was 5-6% larger in the medial tibia, but 4-8% smaller in the medial central femur. Correlations between DESS and FLASH for VC and ThCtAB.Me were high (r = 0.90-0.97), except for DESS vs FLASH medial central femur ThCtAB.Me (r = 0.81-0.83).

CONCLUSIONS

Cartilage morphology metrics from different image contrasts had similar precision, were generally equivalent, and may be combined for cross-sectional analyses if potential systematic offsets are accounted for. Data from different teams should not be pooled unless equivalence is demonstrated for cartilage metrics of interest.

Chlamydial infection during trachoma monitoring: are the most difficult-to-reach children more likely to be infected?

OBJECTIVES

During mass antibiotic distributions for trachoma, certain individuals are difficult to locate and go untreated. These untreated individuals may serve as a source of community reinfection. The importance of this difficult-to-locate, untreated population is unclear. We sought to determine whether individuals who are difficult to locate were more likely to be infected with ocular chlamydia than those who were easier to locate.

METHODS

We monitored 12 Ethiopian communities 1 year after a third annual mass azithromycin treatment for trachoma. Conjunctival swabbing for chlamydial RNA was performed in a random sample of children from each community. If insufficient numbers of children were enrolled on the first monitoring day, we returned on subsequent days.

RESULTS

Of the 12 communities, 10 required more than one monitoring day. On average, 16.1% (95% CI 7.9-30.0) of children were enrolled after the initial day. Evidence of chlamydia was found in 7.1% (95% CI 2.7-17.4) of 0- to 9-year-old children. No ocular swabs collected after the initial day were positive for chlamydial RNA. Children examined after the initial monitoring day were significantly less likely to have ocular chlamydial infection than children seen on the initial day; Mantel-Haenszel common OR = 0 (95% CI 0-0.77).

CONCLUSIONS

In a setting of repeated annual mass azithromycin treatments, after approximately 80% of individuals have been located in a community, extra efforts to find absent individuals may not yield significantly more cases of ocular chlamydia.

Flow residence time and regions of intraluminal thrombus deposition in intracranial aneurysms

Thrombus formation in intracranial aneurysms, while sometimes stabilizing lesion growth, can present additional risk of thrombo-embolism. The role of hemodynamics in the progression of aneurysmal disease can be elucidated by patient-specific computational modeling. In our previous work, patient-specific computational fluid dynamics (CFD) models were constructed from MRI data for three patients who had fusiform basilar aneurysms that were thrombus-free and then proceeded to develop intraluminal thrombus. In this study, we investigated the effect of increased flow residence time (RT) by modeling passive scalar advection in the same aneurysmal geometries. Non-Newtonian pulsatile flow simulations were carried out in base-line geometries and a new postprocessing technique, referred to as "virtual ink" and based on the passive scalar distribution maps, was used to visualize the flow and estimate the flow RT. The virtual ink technique clearly depicted regions of flow separation. The flow RT at different locations adjacent to aneurysmal walls was calculated as the time the virtual ink scalar remained above a threshold value. The RT values obtained in different areas were then correlated with the location of intra-aneurysmal thrombus observed at a follow-up MR study. For each patient, the wall shear stress (WSS) distribution was also obtained from CFD simulations and correlated with thrombus location. The correlation analysis determined a significant relationship between regions where CFD predicted either an increased RT or low WSS and the regions where thrombus deposition was observed to occur in vivo. A model including both low WSS and increased RT predicted thrombus-prone regions significantly better than the models with RT or WSS alone.

Pre-radiographic MRI findings are associated with onset of knee symptoms: the most study

OBJECTIVE

Magnetic resonance imaging (MRI) has greater sensitivity to detect osteoarthritis (OA) damage than radiographs but it is uncertain which MRI findings in early OA are clinically important. We examined MRI abnormalities detected in knees without radiographic OA and their association with incident knee symptoms.

METHOD

Participants from the Multicenter Osteoarthritis Study (MOST) without frequent knee symptoms (FKS) at baseline were eligible if they also lacked radiographic features of OA at baseline. At 15 months, knees that developed FKS were defined as cases while control knees were drawn from those that remained without FKS. Baseline MRIs were scored at each subregion for cartilage lesions (CARTs); osteophytes (OST); bone marrow lesions (BML) and cysts. We compared cases and controls using marginal logistic regression models, adjusting for age, gender, race, body mass index (BMI), previous injury and clinic site.

RESULTS

36 case knees and 128 control knees were analyzed. MRI damage was common in both cases and controls. The presence of a severe CART (P=0.03), BML (P=0.02) or OST (P=0.02) in the whole knee joint was more common in cases while subchondral cysts did not differ significantly between cases and controls (P>0.1). Case status at 15 months was predicted by baseline damage at only two locations; a BML in the lateral patella (P=0.047) and at the tibial subspinous subregions (P=0.01).

CONCLUSION

In knees without significant symptoms or radiographic features of OA, MRI lesions of OA in only a few specific locations preceded onset of clinical symptoms and suggest that changes in bone play a role in the early development of knee pain. Confirmation of these findings in other prospective studies of knee OA is warranted.

Younger children with MS have a distinct CSF inflammatory profile at disease onset

BACKGROUND

The clinical and MRI presentation differs between earlier- and later-onset pediatric multiple sclerosis (MS), whereas the effect of age on the CSF inflammatory profile is unknown and may contribute to delayed diagnosis.

OBJECTIVES

To compare the CSF cellular and immunoglobulin G (IgG) profiles between earlier- and later-onset pediatric MS.

METHODS

We queried the databases of 6 pediatric MS centers for earlier-onset (onset <11 years) and later-onset (> or = 11 and <18 years) patients with MS or clinically isolated syndrome who underwent CSF analysis within the first 3 months of presentation (observational study). We compared CSF white blood cell (WBC) differential count, IgG index, and IgG oligoclonal bands between age groups.

RESULTS

We identified 40 earlier-onset (mean age at onset = 7.2 +/- 2.7 years, 60% females) and 67 later-onset pediatric MS patients (15.1 +/- 1.7 years, 63% females). Although WBC count tended to be higher in earlier-onset patients (median = 9/mm(3) [0-343] vs 6 [0-140], p = 0.15), they had a lower proportion of lymphocytes (70% [0-100] vs 93% [0-100] of WBCs, p = 0.0085; difference = +3% per 1-year increase of age, p = 0.0011) and higher proportion of neutrophils than later-onset patients (0.5% [0-75] vs 0% [0-50] of WBCs, p = 0.16; difference = -1% per 1-year increase of age, p = 0.033). In earlier-onset disease, fewer patients had an elevated IgG index than in the later-onset group (35% vs 68% of patients, p = 0.031).

CONCLUSION

Age modifies the CSF profile at pediatric multiple sclerosis (MS) onset, which may mislead the diagnosis. Our findings suggest an activation of the innate rather than the adaptive immune system in the earlier stages of MS or an immature immune response.

High systemic bone mineral density increases the risk of incident knee OA and joint space narrowing, but not radiographic progression of existing knee OA: the MOST study

OBJECTIVES

Previous studies suggest that high systemic bone mineral density (BMD) is associated with incident knee osteoarthritis (OA) defined by osteophytes but not with joint space narrowing (JSN), and are inconsistent regarding BMD and progression of existing OA. The association of BMD with incident and progressive tibiofemoral OA was tested in a large prospective study of men and women aged 50-79 years with or at risk for knee OA.

METHODS

Baseline and 30-month weight-bearing posteroanterior and lateral knee radiographs were scored for Kellgren-Lawrence (K-L) grade, JSN and osteophytes. Incident OA was defined as the development of K-L grade > or =2 at follow-up. All knees were classified for increases in grade of JSN and osteophytes from baseline. The association of gender-specific quartiles of baseline BMD with risk of incident and progressive OA was analysed using logistic regression, adjusting for covariates.

RESULTS

The mean (SD) age of 1754 subjects was 63.2 (7.8) years and body mass index was 29.9 (5.4) kg/m(2). In knees without baseline OA, higher femoral neck and whole body BMD were associated with an increased risk of incident OA and increases in grade of JSN and osteophytes (p<0.01 for trends); adjusted odds were 2.3-2.9-fold greater in the highest compared with the lowest BMD quartiles. In knees with existing OA, progression was not significantly related to BMD.

CONCLUSIONS

In knees without OA, higher systemic BMD was associated with a greater risk of the onset of JSN and K-L grade > or =2. The role of systemic BMD in early knee OA pathogenesis warrants further investigation.

Sample size calculations for evaluating mediation

This paper presents sample size calculations for testing the mediation of the effect of a primary predictor by an intermediate variable. This problem is related to validating surrogate markers and to testing the effect of a primary predictor in the presence of confounders. For those problems, proposals for sample size calculation exist in the literature and can be adapted to the problem of mediation. Methods based on the variance inflation factor in linear regression provide exact sample size calculations for the linear model and approximations for the logistic, Poisson, and Cox models. We propose another procedure based on simulation of the underlying data structure, with applications to the logistic and Cox models. For the Poisson model, a new analytic method is also proposed. The behavior of the different proposals is investigated by means of simulation studies.

Changing health behaviors to improve health outcomes after angioplasty: a randomized trial of net present value versus future value risk communication

Patients who have undergone angioplasty experience difficulty modifying at-risk behaviors for subsequent cardiac events. The purpose of this study was to test whether an innovative approach to framing of risk, based on 'net present value' economic theory, would be more effective in behavioral intervention than the standard 'future value approach' in reducing cardiovascular morbidity and mortality following angioplasty. At baseline, all patients completed a health assessment, received an individualized risk profile and selected risk factors for modification. The intervention randomized patients into two varying methods for illustrating positive effects of behavior change. For the experimental group, each selected risk factor was assigned a numeric biologic age (the net present value) that approximated the relative potential to improve current health status and quality of life when modifying that risk factor. In the control group, risk reduction was framed as the value of preventing future health problems. Ninety-four percent of patients completed 2-year follow-up. There was no difference between the rates of death, stroke, myocardial infarction, Class II-IV angina or severe ischemia (on non-invasive testing) between the net present value group and the future value group. Our results show that a net present risk communication intervention did not result in significant differences in health outcomes.

Community-based incidence of acute renal failure

There is limited information about the true incidence of acute renal failure (ARF). Most studies could not quantify disease frequency in the general population as they are hospital-based and confounded by variations in threshold and the rate of hospitalization. Earlier studies relied on diagnostic codes to identify non-dialysis requiring ARF. These underestimated disease incidence since the codes have low sensitivity. Here we quantified the incidence of non-dialysis and dialysis-requiring ARF among members of a large integrated health care delivery system - Kaiser Permanente of Northern California. Non-dialysis requiring ARF was identified using changes in inpatient serum creatinine values. Between 1996 and 2003, the incidence of non-dialysis requiring ARF increased from 322.7 to 522.4 whereas that of dialysis-requiring ARF increased from 19.5 to 29.5 per 100,000 person-years. ARF was more common in men and among the elderly, although those aged 80 years or more were less likely to receive acute dialysis treatment. We conclude that the use of serum creatinine measurements to identify cases of non-dialysis requiring ARF resulted in much higher estimates of disease incidence compared with previous studies. Both dialysis-requiring and non-dialysis requiring ARFs are becoming more common. Our data underscore the public health importance of ARF.

Patterns of complementary and alternative medicine use in ED patients and its association with health care utilization

This study characterizes the use of complementary and alternative medicines (CAM) among ED patients and demonstrates patterns of healthcare utilization among users and nonusers of CAM therapies. A cross-sectional observational study was performed by administering questionnaires to ED patients at a university teaching hospital. Of the 356 patients surveyed, more than half (55%) had tried at least one complementary and alternative therapy within the past 12 months and 17% had tried CAM for their presenting medical problem. The use of CAM interventions varied significantly among different demographic groups. The number of ED visits over the past year did not differ between the users and nonusers of CAM, but those using alternative therapies did have more visits to outpatient physicians over the past 12 months (7.8 vs. 5.2; 95% confidence interval [CI], 7-4.6; P <.01). After controlling for age, ethnicity, education level, religion, income, and self-report of overall health status, users of CAM had more frequent visits to outpatient physicians (odds ratio [OR], 1.06; 95% CI, 1.02-1.1; P <.01), had no difference in their rates of hospitalization, but trended toward spending fewer days in the hospital when they were admitted (OR,.96; 95% CI,.92-1.0; P =.06). Complementary and alternative medicines are being used by a majority of ED patients with a significant number having used CAM for their presenting complaint before visiting the ED. CAM users do not differ in their utilization of the ED when compared with nonusers, but do have a significantly increased frequency of outpatient physician visits.

Chondrocyte interactions with porous titanium alloy and calcium polyphosphate substrates

Chondrocytes maintain their phenotype and form cartilagenous tissue when cultured on calcium polyphosphate (CPP) or titanium alloy (Ti alloy), porous three-dimensional materials. To understand how these materials may influence chondrocyte phenotype and matrix synthesis, the early interactions of cultured cells with CPP and titanium alloy were examined. These were compared to chondrocytes grown in monolayer culture on tissue culture polystyrene, conditions in which cultured chondrocytes dedifferentiate and do not form cartilagenous tissue. Scanning electron microscopy of cells up to 72 h in culture showed that bovine chondrocytes on CPP, Ti alloy, and polystyrene were an admixture of round and spread cells. The spread cells on CPP and titanium alloy were not entirely flattened but maintained a polygonal shape. In contrast, spread chondrocytes in monolayer culture were flatter and significantly larger, a difference that was maintained even in the absence of serum. All cells cultured on CPP and Ti alloy exhibited subcortical ring-like distribution of actin filaments whereas the flattened cells on polystyrene showed actin filaments distributed throughout the cytoplasm. Cells on CPP and Ti alloy synthesized significantly less collagen and proteoglycans than cells cultured on polystyrene at 72 h of culture. In summary the cells on the porous three-dimensional materials differed from those on polystyrene in terms of cell morphology and size, actin cytoskeleton organization, and synthesis of selected matrix macromolecules. The data suggests that CPP and titanium alloy may mediate their effect by limiting cell spreading in part by favoring the maintenance of a ring-like actin distribution.

CSF tau protein phosphorylated at threonine 231 correlates with cognitive decline in MCI subjects

In this longitudinal study of 77 patients with mild cognitive impairment (MCI), the authors analyzed whether levels of tau protein phosphorylated at threonine 231 (p-tau(231)) in CSF correlate with progression of cognitive decline. High CSF p-tau(231) levels at baseline, but not total tau protein levels, correlated with cognitive decline and conversion from MCI to AD. Independently, old age and APOE-epsilon 4 carrier status were predictive as well. Our data indicate that an increased p-tau(231) level is a potential risk factor for cognitive decline in patients with MCI.

Discovering subpopulation structure with latent class mixed models

The linear mixed model is a well-known method for incorporating heterogeneity (for example, subject-to-subject variation) into a statistical analysis for continuous responses. However heterogeneity cannot always be fully captured by the usual assumptions of normally distributed random effects. Latent class mixed models offer a way of incorporating additional heterogeneity which can be used to uncover distinct subpopulations, to incorporate correlated non-normally distributed outcomes and to classify individuals. The methodology is motivated with examples in health care studies and a detailed illustration is drawn from the Nutritional Prevention of Cancer trials. Latent class models are used with longitudinal data on prostate specific antigen (PSA) as well as incidence of prostate cancer. The models are extended to accommodate prostate cancer as a survival endpoint; this is compared to treating it as a binary endpoint. Four subpopulations are identified which differ both with regard to their PSA trajectories and their incidence rates of prostate cancer.

Self-efficacy, depressive symptoms, and patients' expectations predict outcomes in asthma

BACKGROUND

Certain psychosocial variables are relatively unexplored as possible predictors of asthma outcomes.

OBJECTIVE

To determine if asthma self-efficacy, depressive symptoms, and unrealistic expectations predict urgent care use and change in health-related quality of life measured by the Asthma Quality of Life Questionnaire and the SF-36 during 2 years.

RESEARCH DESIGN

Prospective cohort study in a primary care internal medicine practice at a tertiary care center in New York City.

PATIENTS

Adults with moderate asthma who were fluent in either English or Spanish.

MEASUREMENTS

At enrollment patients were interviewed in-person and completed a series of questionnaires including the Asthma Quality of Life Questionnaire (AQLQ), the SF-36, the Asthma Self-efficacy Scale, the Geriatric Depression Scale, and open-ended questions regarding their expectations of treatment. Patients also completed the AQLQ and SF-36 at various time intervals throughout the study and were interviewed by telephone every 3 months to record recent hospitalizations, emergency department visits and nonroutine office visits for asthma.

RESULTS

A total of 224 patients were followed for a mean of 23.8 months. In hierarchical analysis, independent predictors of lower AQLQ scores were less self-efficacy, more depressive symptoms, expecting to be cured of asthma, requiring methylxanthines, being Hispanic or black, and having difficult or very difficult access to asthma care (all at P <0.05). Similar predictors were found for lower SF-36 scores. Another outcome, use of urgent care, was required by 60% of patients during the study period. Predictors of using urgent care were having more depressive symptoms, expecting a cure, being female, requiring oral beta-agonists, and having a history of prior hospitalizations for asthma (all at P <0.05).

CONCLUSIONS

Less asthma self-efficacy, more depressive symptoms, and unrealistic expectations predict worse asthma outcomes. These relatively unexplored patient-centered variables in asthma are potentially modifiable and may offer new ways to intervene to improve asthma outcomes.

Genetic control of horizontal virus transmission in the chestnut blight fungus, Cryphonectria parasitica

Vegetative incompatibility in fungi has long been known to reduce the transmission of viruses between individuals, but the barrier to transmission is incomplete. In replicated laboratory assays, we showed conclusively that the transmission of viruses between individuals of the chestnut blight fungus Cryphonectria parasitica is controlled primarily by vegetative incompatibility (vic) genes. By replicating vic genotypes in independent fungal isolates, we quantified the effect of heteroallelism at each of six vic loci on virus transmission. Transmission occurs with 100% frequency when donor and recipient isolates have the same vic genotypes, but heteroallelism at one or more vic loci generally reduces virus transmission. Transmission was variable among single heteroallelic loci. At the extremes, heteroallelism at vic4 had no effect on virus transmission, but transmission occurred in only 21% of pairings that were heteroallelic at vic2. Intermediate frequencies of transmission were observed when vic3 and vic6 were heteroallelic (76 and 32%, respectively). When vic1, vic2, and vic7 were heteroallelic, the frequency of transmission depended on which alleles were present in the donor and the recipient. The effect of heteroallelism at two vic loci was mostly additive, although small but statistically significant interactions (epistasis) were observed in four pairs of vic loci. A logistic regression model was developed to predict the probability of virus transmission between vic genotypes. Heteroallelism at vic loci, asymmetry, and epistasis were the dominant factors controlling transmission, but host genetic background also was statistically significant, indicating that vic genes alone cannot explain all the variation in virus transmission. Predictions from the logistic regression model were highly correlated to independent transmission tests with field isolates. Our model can be used to estimate horizontal transmission rates as a function of host genetics in natural populations of C. parasitica.

Venous gangrene of lower extremities and Staphylococcus aureus sepsis

This is a study of the venous gangrene of lower extremities and Staphylococcus aureus sepsis. We report on a premature infant who developed phlegmasia cerulea dolens (PCD) in both lower extremities in association with S. aureus sepsis, resulting in gangrene of the right foot. Non-pitting edema and cyanosis of the digits of the right lower extremity were noted 48 hours after hypotension and severe shock due to S. aureus sepsis. Intravenous antibiotics, isotonic fluids, and heparin were administered. Twenty-four hours later, edema and ischemic changes of the first and fifth left toes were also noted. Doppler flow study showed flow signals in both right and left popliteal arteries. However, there were no Doppler signals in neither right nor left popliteal vein. Emergency fasciotomies were performed on both lower limbs. The progression of the gangrene was limited to the right foot. There was complete resolution of PCD in both lower extremities. To the best of our knowledge, the association of S. aureus sepsis with PCD and venous gangrene in an infant has not been reported previously. This case illustrates the need for early recognition of PCD and aggressive intervention.

Template mixture models for direct cortical electrical interference data

This paper introduces a statistical approach for high-level spatial analysis when there is little prior information about the shape or location of the region of interest in the underlying image and limited spatial resolution of the available data. Our work was motivated by a functional brain mapping technique called direct cortical electrical interference (DCEI) that gives binary observations at multiple sites throughout the brain. We estimate an underlying, binary spatial response function using a mixture of an unknown number of simple geometrical shapes (e.g. circles) with unknown centers and sizes to be estimated. Inference is made using reversible jump Markov chain Monte Carlo. The approach is illustrated with simulated examples and a real example with DCEI data.

Simultaneously model-unbiased, design-unbiased estimation

This paper proposes a class of inferential procedures (incorporating both design and estimation elements) that yield estimates of means that are simultaneously model unbiased and design unbiased. Classical regression procedures yield conditionally unbiased estimators for the mean (conditioning on the model and choice of observation points). In contrast, design-based methods yield estimators that are unconditionally unbiased on matter what the form of the underlying model. Variance properties of the proposed class are examined, and applications to bioavailability, water quality from mine run-off, and finite population regression estimation are considered. The proposed procedures perform well, especially in the typical case where a model is only approximately correct.