Use of a Shear Reduction Surface for Prehospital Transport: A Randomized Crossover Study

OBJECTIVE

To compare the effectiveness of an antishear mattress overlay (ASMO) with a standard ambulance stretcher surface in reducing pressure and shear and increasing patient comfort.

METHODS

In this randomized, crossover design, adults in three body mass index categories served as their own controls. Pressure/shear sensors were applied to the sacrum, ischial tuberosity, and heel. The stretcher was placed in sequential 0°, 15°, and 30° head-of-bed elevations with and without an ASMO. The ambulance traveled a closed course, achieving 30 mph, with five stops at each head-of-bed elevation. Participants rated discomfort after each series of five runs.

RESULTS

Thirty individuals participated. Each participant had 30 runs (15 with an ASMO, 15 without), for a total of 900 trial runs. The peak-to-peak shear difference between support surfaces was -0.03 N, indicating that after adjustment for elevation, sensor location, and body mass index, peak shear levels at baseline (starting pause) were 0.03 N lower for the ASMO than for the standard surface ( P = .02). The peak-to-peak pressure difference between surfaces was -0.16 mm Hg, indicating that prerun peak-to-peak pressure was 0.16 mm Hg lower with the ASMO versus standard surface ( P = .002). The heel received the most pressure and shear. Discomfort score distributions differed between surfaces at 0° ( P = .004) and 30° ( P = .01); the overall score across all elevations was significantly higher with the standard surface than with the ASMO ( P = .046).

CONCLUSIONS

The ASMO reduced shear, pressure, and discomfort. During transport, the ambulance team should provide additional heel offloading.

Androgen Deprivation Therapy Use and Risk of Mild Cognitive Impairment in Prostate Cancer Patients

INTRODUCTION

We examined the association between androgen deprivation therapy (ADT) use and the risk of mild cognitive impairment (MCI) among prostate cancer patients.

METHODS

We included 241 cognitively unimpaired men, aged 70 to 90, with a history of prostate cancer before enrollment in the population-based Mayo Clinic Study of Aging. Using the Rochester Epidemiology Project medical records-linkage system, ADT use and length of exposure were abstracted. Follow-up visits occurred every 15 months and MCI diagnoses were made based on clinical consensus. Cox proportional hazards models, with age as the timescale, were used to examine the association between ADT use (yes/no) and length of exposure with the risk of MCI adjusting for education, apolipoprotein E, depression, and the Charlson Index score.

RESULTS

There was no association between any ADT use (27.8% of participants) and the risk of MCI in the multivariable model [hazard ratio (HR), 1.25; 95% confidence interval (CI), 0.75-2.10]. Although not significant, there was an ADT dose-response relationship for risk of MCI: <5 years versus no use (HR, 1.08; 95% CI, 0.60-1.96) and ≥5 years versus not use (HR, 1.89; 95% CI, 0.83-4.27).

CONCLUSION

ADT use among prostate cancer patients was not associated with an increased risk of developing MCI.

Limited diagnostic impact of duplications <1 Mb of uncertain clinical significance: a 10-year retrospective analysis of reporting practices at the Mayo Clinic

PURPOSE

Copy-number variants (CNVs) of uncertain clinical significance are routinely reported in a clinical setting only when exceeding predetermined reporting thresholds, typically based on CNV size. Given that very few genes are associated with triplosensitive phenotypes, it is not surprising that many interstitial duplications <1 Mb are found to be inherited and anticipated to be of limited or no clinical significance.

METHODS

In an effort to further refine our reporting criteria to maximize diagnostic yield while minimizing the return of uncertain variants, we performed a retrospective analysis of all clinical microarray cases reported in a 10-year window. A total of 1112 reported duplications had parental follow-up, and these were compared by size, RefSeq gene content, and inheritance pattern. De novo origin was used as a rough proxy for pathogenicity.

RESULTS

Approximately 6% of duplications 500 kb-1 Mb were de novo observations, compared with approximately 14% for 1-2 Mb duplications (p = 0.0005). On average, de novo duplications had higher gene counts than inherited duplications.

CONCLUSION

Our data reveal limited diagnostic utility for duplications of uncertain significance <1 Mb. Considerations for revised reporting criteria are discussed and are applicable to CNVs detected by any genome-wide exploratory methodology, including exome/genome sequencing.

The Cross-sectional and Longitudinal Associations Between IL-6, IL-10, and TNFα and Cognitive Outcomes in the Mayo Clinic Study of Aging

BACKGROUND

Chronic inflammation has been linked with geriatric-related conditions, including dementia. Inflammatory cytokine levels, including interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF) α, in the blood have been associated with cognitive impairment and decline. However, evidence has been mixed.

METHODS

We examined the cross-sectional and longitudinal associations between baseline-measured IL-6, IL-10, and TNFα levels and the ratio of IL-6/IL-10 with cognitive test performance and mild cognitive impairment (MCI) among 1,602 community-dwelling older adults (median age = 72.8) enrolled in the Mayo Clinic Study of Aging. Approximately half (46.5%) of participants were female and 98.6% were white. At baseline and follow-up visits (occurring at 15-month intervals), participants completed neuropsychological testing, blood draws, and had a clinical consensus diagnosis.

RESULTS

In multivariable cross-sectional analyses, we did not observe an association between inflammatory cytokine levels and global or domain-specific cognitive z scores; however, higher IL-6 and IL-10 levels were associated with greater odds of a MCI diagnosis. Longitudinally, we did not observe any association between inflammatory cytokine levels and cognitive test performance or risk of MCI. Sex, age, cognitive status, APOE ε4 genotype, diabetes, depression, and cerebral amyloid-beta deposition were not effect modifiers.

CONCLUSIONS

These results suggest that plasma inflammatory markers may not be useful to ascertain risk for cognitive decline and MCI in the general population.

Association of Cerebrospinal Fluid Neurofilament Light Protein With Risk of Mild Cognitive Impairment Among Individuals Without Cognitive Impairment

Importance

Accumulating data suggest that elevated cerebrospinal fluid (CSF) neurofilament light (NfL) and neurogranin (Ng) levels are associated with cognitive decline and may be useful markers of neurodegeneration. However, to our knowledge, previous studies have not assessed these CSF markers in the community, evaluated them with regards to risk of mild cognitive impairment (MCI), or compared their prognostic value with CSF total tau (T-tau) or phosphorylated tau (P-tau).

Objective

To determine (1) whether CSF NfL and Ng levels were associated with risk of MCI, (2) the effect size of these markers compared with CSF T-tau or P-tau for risk of MCI, and (3) whether CSF amyloid-β (Aβ42) modified these associations.

Design, Setting and Participants

The analyses included 648 participants without cognitive impairment who were enrolled into the prospective population-based Mayo Clinic Study of Aging between January 2004 and December 2015 with available CSF data and at least 1 follow-up visit. Participants were followed up for a median of 3.8 years (interquartile range, 2.6-5.4 years). The CSF NfL and Ng levels were measured using an in-house sandwich enzyme-linked immunosorbent assay. The CSF Aβ42, T-tau, and P-tau levels were measured with automated electrochemiluminescence immunoassays. Cox proportional hazards models, with age as the timescale, were used to assess the association between CSF NfL, Ng, Aβ42, T-tau, or P-tau with risk of MCI after adjusting for sex, education, apolipoprotein E genotype, and the Charlson comorbidity index. To examine CSF Aβ42 as an effect modifier, it was categorized into tertiles; the bottom tertile was defined as having elevated brain amyloid.

Main Outcomes and Measures

Risk of MCI.

Results

At baseline, the median age of the 648 participants without cognitive impairment was 72.3 years (range, 50.7-95.3 years) and 366 (56.5%) were men; 96 (14.8%) developed incident MCI. Compared with the bottom quartile, the top quartile of CSF NfL was associated with a 3.1-fold increased risk of MCI (hazard ratio, 3.13; 95% CI, 1.36-7.18) in multivariate models. Neither CSF T-tau, P-tau, nor Ng was associated with risk of MCI. There was no interaction between Aβ42 and CSF NfL for risk of MCI.

Conclusions and Relevance

Elevated CSF NfL levels but not CSF T-tau, P-tau or Ng are a risk factor for MCI in a community population and are independent of brain amyloid.

Plasma Sphingolipids are Associated With Gait Parameters in the Mayo Clinic Study of Aging

Background

Disrupted gait has been associated with an increased risk of frailty, disability, and death, but the causal molecular pathways are not well understood. Sphingolipids, including ceramides, are associated with multiple age-related diseases. Ceramides promote atrophy, necrosis, and proteolysis in cellular and animal models, and ceramide C16:0 levels are negatively correlated with muscle mass in men. However, there is a paucity of evidence examining sphingolipids and physical function.

Methods

We examined the cross-sectional association between plasma ceramides, sphingosine-1-phosphate (S1P), and ceramide/S1P ratios and gait, a robust measure of physical function, in 340 clinically normal participants aged 70 years and older enrolled in the Mayo Clinic Study of Aging. GAITRite® instrumentation was used to measure gait speed, cadence, step width, double support time, and intra-individual stride time variability. Based on previous studies, we hypothesized that higher plasma levels of ceramide C16:0 would be associated with worse gait.

Results

Multivariable adjusted linear regression models revealed that higher levels of ceramide C16:0 were associated with slower gait speed, decreased cadence, and increased double support time.

Conclusions

These results suggest an association between plasma ceramide C16:0 and physical function. Longitudinal studies are needed to determine whether elevated ceramide C16:0 can be utilized as a prognostic marker for functional decline.

Longitudinal Association Between Brain Amyloid-Beta and Gait in the Mayo Clinic Study of Aging

Background

The longitudinal association between cerebral amyloid-beta (Aβ) and change in gait, and whether this association is mediated by cortical thickness, has yet to be determined.

Methods

We included 439 clinically normal (CN) participants, aged 50-69 years and enrolled in the Mayo Clinic Study of Aging with cerebral Aβ, cortical thickness, and gait measurements. Cerebral Aβ deposition was assessed by Pittsburgh Compound B (PiB)-PET in multiple regions of interest (ROIs) (ie, frontal, orbitofrontal, parietal, temporal, anterior cingulate, posterior cingulate/precuneus, and motor). Cortical thickness was assessed on 3T MRI in corresponding ROIs. Gait parameters (gait speed, cadence, stride length, double support time, and covariance of stance time) were measured with GAITRite. Multivariate-adjusted two level structural equation models were used to examine the longitudinal association between PiB-PET, cortical thickness, and change in gait over a median 15.6 months.

Results

Higher PiB-PET in all ROIs was associated with decreasing cadence and increasing double support time, and in the temporal ROI was associated with declining gait speed. In sex-stratified analyses, higher PiB-PET in all ROIs was associated with declining performance on all gait parameters among women. In contrast, among men, the only association was with higher orbitofrontal ROI PiB-PET and declining cadence. None of the associations were mediated by cortical thickness or attenuated after adjustment of baseline cognition.

Conclusion

Higher PiB-PET was associated with declining gait, particularly among women in this middle-aged CN cohort, independent of cortical thickness and baseline cognitive. Elevated brain Aβ may play a critical role in age-related mobility decline.

Association of antidiabetic medication use, cognitive decline, and risk of cognitive impairment in older people with type 2 diabetes: Results from the population-based Mayo Clinic Study of Aging

OBJECTIVE

To determine the cross-sectional and longitudinal associations between diabetes treatment type and cognitive outcomes among type II diabetics.

METHODS

We examined the association between metformin use, as compared to other diabetic treatment (ie, insulin, other oral medications, and diet/exercise) and cognitive test performance and mild cognitive impairment (MCI) diagnosis among 508 cognitively unimpaired at baseline type II diabetics enrolled in the Mayo Clinic Study of Aging. We created propensity scores to adjust for treatment effects. We used multivariate linear and logistic regression models to investigate the cross-sectional association between treatment type and cognitive test z scores, respectively. Mixed effects models and competing risk regression models were used to determine the longitudinal association between treatment type and change in cognitive test z scores and risk of developing incident MCI.

RESULTS

In linear regression analyses adjusted for age, sex, education, body mass index, APOE ε4, insulin treatment, medical comorbidities, number of medications, duration of diabetes, and propensity score, we did not observe an association between metformin use and cognitive test performance. Additionally, we did not observe an association between metformin use and cognitive test performance over time (median = 3.7-year follow-up). Metformin was associated with an increased risk of MCI (subhazard ratio (SHR) = 2.75; 95% CI = 1.64, 4.63, P < .001). Similarly, other oral medications (SHR = 1.96; 95% CI = 1.19, 3.25; P = .009) and insulin (SHR = 3.17; 95% CI = 1.27, 7.92; P = .014) use were also associated with risk of MCI diagnosis.

CONCLUSIONS

These findings suggest that metformin use, as compared to management of diabetes with other treatments, is not associated with cognitive test performance. However, metformin was associated with incident MCI diagnosis.

Subjective cognitive decline and risk of MCI: The Mayo Clinic Study of Aging

OBJECTIVE

We investigated different dimensions of subjective cognitive decline (SCD) to determine which was the best prognostic risk factor for incident mild cognitive impairment (MCI) among cognitively unimpaired participants.

METHODS

We included 1,167 cognitively unimpaired participants, aged 70 to 95 years, from the Mayo Clinic Study of Aging based on 2 concurrent SCD scales (part of the Blessed memory test and the 39-item Everyday Cognition [ECog] scale, which included a validated 12-item derivative) and a single question assessing worry about cognitive decline. We evaluated multiple ways to dichotomize scores. In continuous models, we compared average scores on 4 ECog domains and multidomain (39- and 12-item) ECog scores. Cox proportional hazards models were used to assess the association between each measure and risk of MCI in models adjusted for objective memory performance, depression, anxiety, sex, APOE ε4 carriership, and medical comorbidities.

RESULTS

It was possible to select a substantial group of participants (14%) at increased risk of incident MCI based on combined baseline endorsement of any consistent SCD on the ECog (any item scored ≥3; 12-item ECog hazard ratio [HR] 2.17 [95% confidence interval 1.51-3.13]) and worry (HR 1.79 [1.24-2.58]) in an adjusted model combining these dimensions. In continuous models, all ECog domains and the multidomain scores were associated with risk of MCI with a small advantage for multidomain SCD (12-item ECog HR 2.13 [1.36-3.35] per point increase in average score). Information provided by the informant performed comparable to self-perceived SCD.

CONCLUSION

Prognostic value of SCD for incident MCI improves when both consistency of SCD and associated worry are evaluated.

Plasma phospho-tau181 increases with Alzheimer's disease clinical severity and is associated with tau- and amyloid-positron emission tomography

INTRODUCTION

We examined and compared plasma phospho-tau181 (pTau181) and total tau: (1) across the Alzheimer's disease (AD) clinical spectrum; (2) in relation to brain amyloid β (Aβ) positron emission tomography (PET), tau PET, and cortical thickness; and (3) as a screening tool for elevated brain Aβ.

METHODS

Participants included 172 cognitively unimpaired, 57 mild cognitively impaired, and 40 AD dementia patients with concurrent Aβ PET (Pittsburgh compound B), tau PET (AV1451), magnetic resonance imaging, plasma total tau, and pTau181.

RESULTS

Plasma total tau and pTau181 levels were higher in AD dementia patients than those in cognitively unimpaired. Plasma pTau181 was more strongly associated with both Aβ and tau PET. Plasma pTau181 was a more sensitive and specific predictor of elevated brain Aβ than total tau and was as good as, or better than, the combination of age and apolipoprotein E (APOE).

DISCUSSION

Plasma pTau181 may have utility as a biomarker of AD pathophysiology and as a noninvasive screener for elevated brain Aβ.

Trajectories of plasma IGF-1, IGFBP-3, and their ratio in the Mayo Clinic Study of Aging

Insulin-like growth factor 1 (IGF-1) has been associated with osteoporosis, cardiovascular disease, cancer, neurodegenerative diseases, and mortality in middle and older aged adults. Cross-sectionally, IGF-1 decreases with age and levels of IGF-1 are markedly different between individuals. However, little is known about intra-individual trajectories of IGF-1. We examined baseline and serial measures of plasma total IGF-1, IGF binding protein (IGFBP)-3, and their ratio, which is a proxy for bioavailable IGF-1, among 1618 adults, aged 50-95, enrolled in the Mayo Clinic Study of Aging. At baseline, IGF-1 and IGFBP-3 were strongly correlated (r = 0.62, p < 0.001). Total IGF-1 and IGFBP-3 decreased across age, while the ratio of IGF-1/IGFBP-3 increased across age. This pattern was consistent across ages at baseline and intra-individually over an average 2.3 years follow-up (range = 10 months-5.6 years). In age-adjusted linear regression models, baseline levels of total IGF-1, IGFBP-3, and IGF-1/IGFBP-3 varied by participant characteristics (sex, BMI, gait speed), medical comorbidities (Charlson comorbidity index score, hypertension, diabetes, and cardiovascular disease), and hormone replacement therapy use in women. High interclass correlation coefficients (ICCs) suggest little intra-individual variability in levels of total IGF-1 (ICC = 0.84), IGFBP-3 (ICC = 0.88), and IGF-1/IGFBP-3 (ICC = 0.81) over time. In mixed effects models that specified age as a time scale, men showed greater decreases in total IGF-1 and IGFBP-3 with age, while more comorbidities and decreasing gait speed were associated with increasing IGFBP-3. In sex-stratified models, trajectories of total IGF-1, IGFBP-3, and IGF-1/IGFBP-3, as a function of participant demographics, health characteristics, and medical conditions, differed between men and women. These results suggest that change in levels of plasma total IGF-1, IGFBP-3, and IGF-1/IGFBP-3 are associated with demographics, health characteristics, and medical conditions, and that the trajectories of change differ by sex. Future research should consider how IGF-1 and IGFBP-3 might be useful in research or clinic, paying particular attention to how sex may impact levels as a function of demographics, health characteristics, and medical conditions.

Serum Adiponectin Levels, Neuroimaging, and Cognition in the Mayo Clinic Study of Aging

BACKGROUND

Adiponectin, a protein involved in inflammatory pathways, may impact the development and progression of Alzheimer's disease (AD). Adiponectin levels have been associated with mild cognitive impairment (MCI) and AD; however, its association with Alzheimer-associated neuroimaging and cognitive outcomes is unknown.

OBJECTIVE

Determine the cross-sectional association between plasma adiponectin and neuroimaging and cognitive outcomes in an older population-based sample.

METHODS

Multivariable adjusted regression models were used to investigate the association between plasma adiponectin and hippocampal volume (HVa), PiB-PET, FDG PET, cortical thickness, MCI diagnosis, and neuropsychological test performance. Analyses included 535 non-demented participants aged 70 and older enrolled in the Mayo Clinic Study of Aging.

RESULTS

Women had higher adiponectin than men (12,631 ng/mL versus 8,908 ng/mL, p < 0.001). Among women, higher adiponectin was associated with smaller HVa (B = -0.595; 95% CI -1.19, -0.005), poorer performance in language (B = -0.676; 95% CI -1.23, -0.121), and global cognition (B = -0.459; 95% CI -0.915, -0.002), and greater odds of a MCI diagnosis (OR = 6.23; 95% CI 1.20, 32.43). In analyses stratified by sex and elevated amyloid (PiB-PET SUVR >1.4), among women with elevated amyloid, higher adiponectin was associated with smaller HVa (B = -0.723; 95% CI -1.43, -0.014), poorer performance in memory (B = -1.02; 95% CI -1.73, -0.312), language (B = -0.896; 95% CI -1.58, -0.212), global cognition (B = -0.650; 95% CI -1.18, -0.116), and greater odds of MCI (OR = 19.34; 95% CI 2.72, 137.34).

CONCLUSION

Higher plasma adiponectin was associated with neuroimaging and cognitive outcomes among women. Longitudinal analyses are necessary to determine whether higher adiponectin predicts neurodegeneration and cognitive decline.

Association of Plasma Total Tau Level With Cognitive Decline and Risk of Mild Cognitive Impairment or Dementia in the Mayo Clinic Study on Aging

Importance

The utility of plasma total tau level as a prognostic marker for cognitive decline and dementia is not well understood.

Objectives

To determine (1) the association between plasma total tau level, cognitive decline, and risk of mild cognitive impairment (MCI) and dementia; (2) whether this association differs by the presence of elevated brain amyloid β (Aβ); and (3) whether plasma total tau level is associated with cognitive decline over a short interval of 15 months.

Design, Setting, and Participants

The present analyses included 458 participants who were enrolled in a population-based cohort study between October 2008 and June 2013. All included participants had available plasma total tau levels, Aβ positron emission tomography imaging, and a complete neuropsychological examine at the same visit, as well as at least 1 follow-up visit.

Exposures

Concentration of plasma total tau.

Main Outcomes and Measures

Risk of MCI and dementia; global and domain-specific cognitive decline.

Results

Of the 458 participants, 287 (62.7%) were men; mean (SD) age was 80.6 (5.6) years. Among cognitively normal (CN) participants oversampled for elevated brain Aβ, both the middle (hazard ratio [HR], 2.43; 95% CI, 1.25-4.72) and highest (HR, 2.02; 95% CI, 1.01-4.06) tertiles of plasma total tau level, compared with the lowest, were associated with an increased risk of MCI. Among participants with MCI, higher plasma total tau levels were not significantly associated with risk of dementia (all-cause dementia or Alzheimer disease). Among all participants, higher levels of plasma total tau, examined as a continuous variable, were associated with significant (P < .05) declines in global cognition, memory, attention, and visuospatial ability over a median follow-up of 3.0 years (range, 1.1-4.9 years). In additional analyses restricting the follow-up to 15 months, plasma total tau did not predict decline among CN participants. However, among participants with MCI, higher plasma total tau levels were associated with greater decline in both visuospatial ability (regression coefficient [b] = -0.50 [0.15], P < .001) and global cognition (b = -0.27 [0.10], P = .009) at 15 months. Adjusting for elevated brain Aβ did not attenuate any association. There was no interaction between plasma total tau level and brain Aβ for prognosis with any outcome.

Conclusions and Relevance

These results suggest that elevated plasma total tau levels are associated with cognitive decline, but the results differ based on cognitive status and the duration of follow-up. The association between plasma total tau levels and cognition is independent of elevated brain Aβ.

Longitudinal association between diabetes and cognitive decline: The National Health and Aging Trends Study

Type II diabetes mellitus (DM) is associated with increased risk of dementia; however, few studies have examined the longitudinal association between DM and cognitive outcomes in large nationally representative cohorts. We investigated these associations in 7605 participants enrolled in the National Health and Aging Trends Study, a nationally representative prospective study of Medicare beneficiaries ≥65, from 2011 to 2015. Participants or proxy respondents reported DM and dementia diagnosis, and participants completed immediate and delayed recall word list learning tests and the Clock Drawing Test. In multivariable-adjusted generalized linear mixed models, baseline DM diagnosis was associated with decline on immediate and delayed word recall and the Clock Drawing Test. In Cox proportional hazards models, DM also predicted incident dementia in older age groups at baseline. These findings further support the notion that DM is associated with cognitive outcomes, suggesting that treatment and prevention of DM may reduce the risk of these outcomes. However, more studies are needed to better understand whether DM treatments affect this relationship.

The impact of postpartum hemorrhage on hospital length of stay and inpatient mortality: a National Inpatient Sample-based analysis

BACKGROUND

Postpartum hemorrhage is a major cause of maternal morbidity and mortality, but the association between postpartum hemorrhage and hospital length of stay has not been rigorously investigated.

OBJECTIVE

We explored the impact of postpartum hemorrhage on hospital length of stay and inpatient mortality, as these outcomes have both clinical and economic significance.

STUDY DESIGN

We performed a retrospective analysis using data from the National Inpatient Sample database during the 2012 through 2013 time period. Deliveries were classified as postpartum hemorrhage due to uterine atony, nonatonic postpartum hemorrhage, or not complicated by postpartum hemorrhage (nonpostpartum hemorrhage). Average length of stay and inpatient mortality rates were compared between groups.

RESULTS

Over the study interval, postpartum hemorrhage occurred in 3% of deliveries. Among deliveries complicated by postpartum hemorrhage, 76.6% were attributed to uterine atony and 23.4% were nonatonic. Women with nonatonic postpartum hemorrhage had the highest average length of stay (3.67 days) followed by atonic postpartum hemorrhage (2.98 days) and nonpostpartum hemorrhage (2.63 days); P < .001, all comparisons. Inpatient mortality rate of nonatonic postpartum hemorrhage over the entire study period was 104 per 100,000 compared to 019 per 100,000 for atonic postpartum hemorrhage and 3 per 100,000 for nonpostpartum hemorrhage deliveries (P < .001).

CONCLUSION

From 2012 through 2013, women with postpartum hemorrhage experienced significantly longer length of stay and higher inpatient mortality rates than women without postpartum hemorrhage, largely attributable to nonatonic causes of postpartum hemorrhage. As hospital length of stay and inpatient mortality are important outcomes from both clinical and societal perspectives, interventions to reduce morbidity and mortality related to postpartum hemorrhage may simultaneously facilitate delivery of more cost-effective care and improve both maternal and population health.

Cerebral Amyloid Deposition Is Associated with Gait Parameters in the Mayo Clinic Study of Aging

OBJECTIVES

To determine the cross-sectional association between cerebral amyloid-beta (Aβ) deposition and gait.

DESIGN

Cross-sectional.

SETTING

Population-based cohort study in Olmsted County, MN.

PARTICIPANTS

Cognitively normal individuals (n = 611), aged 50 to 69 years, enrolled in the Mayo Clinic Study of Aging with concurrent PiB-PET imaging and gait assessment. Participants with a history of stroke, alcoholism, Parkinson's disease, subdural hematoma, traumatic brain injury, or normal pressure hydrocephalus were excluded.

MEASUREMENTS

PiB-PET SUVR was measured in prefrontal, orbitofrontal, parietal, temporal, anterior cingulate, posterior cingulate, and motor-specific regions of interest (ROIs). Gait parameters (speed, cadence, stride length, double support time, and intra-individual stance time variability) were measured using GAITRite® instrumentation. Linear regression models were adjusted for age, sex, body mass index, education, APOE ε4 allele, Charlson comorbidity index, and depression. In secondary analyses, we additionally adjusted for neurodegeneration (hippocampal volume, FDG PET SUVR, and cortical thickness) in AD-associated regions.

RESULTS

In fully adjusted models including neuroimaging measures of neurodegeneration, higher PiB-PET SUVR across all ROIs was associated with slower gait speed (P < .05 except for the parietal ROI), lower cadence and longer double support time (P ≤ .05 except for the motor ROI), and greater stance time variability (P < .05). In sex-stratified analyses, the association between higher PiB-PET SUVR across all ROIs and measures of gait was only present among women.

CONCLUSION

PiB-PET SUVR across ROIs, independent of general measures of AD-associated neurodegeneration, is associated with poorer performance on multiple gait parameters among cognitively normal women, aged 50 to 69 years. Longitudinal studies are needed to determine whether Aβ predicts gait decline in both women and men.

Levels of tau protein in plasma are associated with neurodegeneration and cognitive function in a population-based elderly cohort

INTRODUCTION

Tau protein levels in plasma may be a marker of neuronal damage. We examined associations between plasma tau levels and Alzheimer's disease (AD)-related magnetic resonance imaging (MRI) and positron emission tomography (PET) neuroimaging measures among nondemented individuals.

METHODS

Participants included 378 cognitively normal (CN) and 161 mild cognitive impairment (MCI) individuals enrolled in the Mayo Clinic Study of Aging with concurrent neuropsychological measures and amyloid PET, fluorodeoxyglucose PET, and MRI. Baseline plasma tau levels were measured using the Quanterix Simoa-HD1 tau assay.

RESULTS

Plasma tau levels were higher in MCI compared with CN (4.34 vs. 4.14 pg/mL, P = .078). In regression models adjusted for age, gender, education, and APOE, higher plasma tau was associated with worse memory performance (b = -0.30, P = .02) and abnormal cortical thickness in an AD signature region (odds ratio = 1.80, P = .018).

DISCUSSION

Plasma tau is associated with cortical thickness and memory performance. Longitudinal studies will better elucidate the associations between plasma tau, neurodegeneration, and cognition.

Correlation of the Patient Reported Outcomes Measurement Information System with legacy outcomes measures in assessment of response to lumbar transforaminal epidural steroid injections

BACKGROUND AND PURPOSE

The Patient Reported Outcomes Measurement Information System is a newly developed outcomes measure promulgated by the National Institutes of Health. This study compares changes in pain and physical function-related measures of this system with changes on the Numeric Rating Pain Scale, Roland Morris Disability Index, and the European Quality of Life scale 5D questionnaire in patients undergoing transformational epidural steroid injections for radicular pain.

MATERIALS AND METHODS

One hundred ninety-nine patients undergoing transforaminal epidural steroid injections for radicular pain were enrolled in the study. Before the procedure, they rated the intensity of their pain by using the 0-10 Numeric Rating Pain Scale, Roland Morris Disability Index, and European Quality of Life scale 5D questionnaire. Patients completed the Patient Reported Outcomes Measurement Information System Physical Function, Pain Behavior, and Pain Interference short forms before transforaminal epidural steroid injections and at 3 and 6 months. Seventy and 43 subjects replied at 3- and 6-month follow-up. Spearman rank correlations were used to assess the correlation between the instruments. The minimally important differences were calculated for each measurement tool as an indicator of meaningful change.

RESULTS

All instruments were responsive in detecting changes at 3- and 6-month follow-up (P < .0001). There was significant correlation between changes in Patient Reported Outcomes Measurement Information System scores and legacy questionnaires from baseline to 3 months (P < .05). There were, however, no significant correlations in changes from 3 to 6 months with any of the instruments.

CONCLUSIONS

The studied Patient Reported Outcomes Measurement Information System domains offered responsive and correlative psychometric properties compared with legacy instruments in a population of patients undergoing transforaminal epidural steroid injections for radicular pain.

Synthesis and preliminary evaluation of N-(16-18F-fluorohexadecanoyl)ethanolamine (18F-FHEA) as a PET probe of N-acylethanolamine metabolism in mouse brain

N-Acylethanolamines are lipid signaling molecules found throughout the plant and animal kingdoms. The best-known mammalian compound of this class is anandamide, N-arachidonoylethanolamine, one of the endogenous ligands of cannabinoid CB1 and CB2 receptors. Signaling by N-acylethanolamines is terminated by release of the ethanolamine moiety by hydrolyzing enzymes such as fatty acid amide hydrolase (FAAH) and N-acylethanolamine-hydrolyzing amidase (NAAA). Herein, we report the design and synthesis of N-(16-(18)F-fluorohexadecanoyl)ethanolamine ((18)F-FHEA) as a positron emission tomography (PET) probe for imaging the activity of N-acylethanolamine hydrolyzing enzymes in the brain. Following intravenous administration of (18)F-FHEA in Swiss Webster mice, (18)F-FHEA was extracted from blood by the brain and underwent hydrolysis at the amide bond and incorporation of the resultant (18)F-fluorofatty acid into complex lipid pools. Pretreatment of mice with the FAAH inhibitor URB-597 (1 mg/kg IP) resulted in significantly slower (18)F-FHEA incorporation into lipid pools, but overall (18)F concentrations in brain regions were not altered. Likewise, pretreatment with a NAAA inhibitor, (S)-N-(2-oxo-3-oxytanyl)biphenyl-4-carboxamide (30 mg/kg IV), did not significantly affect the uptake of (18)F-FHEA in the brain. Although evidence was found that (18)F-FHEA behaves as a substrate of FAAH in the brain, the lack of sensitivity of brain uptake kinetics to FAAH inhibition discourages its use as a metabolically trapped PET probe of N-acylethanolamine hydrolyzing enzyme activity.

Detection of recurrent prostate cancer after radical prostatectomy: comparison of 11C-choline PET/CT with pelvic multiparametric MR imaging with endorectal coil

The aim of this study was to compare (11)C-choline PET/CT with pelvic multiparametric MR imaging for detection of recurrent prostate carcinoma in patients with suspected recurrence after radical prostatectomy and to identify an optimal imaging method to restage these patients.

METHODS

This was a retrospective, single-institution study of 115 prostatectomy patients with suspected tumor recurrence who underwent both (11)C-choline PET/CT and multiparametric MR imaging with endorectal coil. The reference standard included histopathology, treatment change, and imaging follow-up for determination of locally recurrent tumor, lymph node (LN) metastases, and skeletal metastases. Two nuclear medicine and 2 genitourinary radiologists independently and in a masked manner reviewed PET/CT and multiparametric MR imaging, respectively. The reviewers assessed for local recurrence in the prostatectomy bed as well as LN and bone metastases, rating their diagnostic confidence with a 5-point scoring system for each location. Receiver-operating-characteristic analysis was used to compare the 2 modalities.

RESULTS

The standard of reference (either positive or negative) for the diagnosis of local recurrence and pelvic LN and bone metastases was met in 87, 70, and 95 patients, respectively. Documented local recurrence and pelvic LN and bone metastases was present in 61 of 87 (70.1%), 50 of 70 (71.4%), and 16 of 95 (16.8%) patients, respectively. Patient-based area under the receiver-operating-characteristic curves of multiparametric MR imaging versus PET/CT for the diagnosis of local recurrence and pelvic LN and bone metastases were 0.909 versus 0.761 (P = 0.0079), 0.812 versus 0.952 (P = 0.0064), and 0.927 versus 0.898 (P = 0.69), respectively. Among 61 patients with local recurrence, 32 patients (52.4%) were correctly diagnosed as having local recurrence by both multiparametric MR imaging and PET/CT, 22 (36.1%) were correctly diagnosed by multiparametric MR imaging only, 6 (9.8%) could not be diagnosed by either modality, and 1 (1.6%) was correctly diagnosed by PET/CT only. The patient-based sensitivity, specificity, and accuracy of multiparametric MR imaging for diagnosing local recurrence were 88.5% (54/61), 84.6% (22/26), and 87.4% (76/87) whereas those of PET/CT for detecting body LN or bone metastases were 92.3% (72/78), 100% (18/18), and 93.8% (90/96), respectively.

CONCLUSION

Multiparametric MR imaging with endorectal coil is superior for the detection of local recurrence, PET/CT is superior for pelvic LN metastasis, and both were equally excellent for pelvic bone metastasis. (11)C-choline PET/CT and pelvic multiparametric MR imaging are complementary for restaging prostatectomy patients with suspected recurrent disease.

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