Pulmonary function is associated with frailty, hospitalization and mortality in older people: 5-year follow-up

BACKGROUND

The relationship between pulmonary impairment and frailty has rarely been studied in community-dwelling older adults.

OBJECTIVE

This study aimed to analyze the association between pulmonary function and frailty (prevalent and incident), identifying the best cut-off points to detect frailty and its association with hospitalization and mortality.

METHODS

A longitudinal observational cohort study with 1188 community-dwelling older adults was taken from the Toledo Study for Healthy Aging. The forced expiratory volume in the first second (FEV₁) and the forced vital capacity (FVC) were measured with spirometry. Frailty was evaluated using the Frailty Phenotype and Frailty Trait Scale 5. Associations between pulmonary function and frailty, hospitalization and mortality in a 5-year follow-up and the best cut-off points for FEV₁ and FVC were analyzed.

RESULTS

FEV₁ and FVC were associated with frailty prevalence (OR from 0.25 to 0.60), incidence (OR from 0.26 to 0.53), and hospitalization and mortality (HR from 0.35 to 0.85). The cut-off points of pulmonary function identified in this study: FEV1 (≤1.805 L for male and ≤1.165 L for female) and FVC (≤2.385 L for male and ≤1.585 L for female) were associated with incident frailty (OR: 1.71-4.06), hospitalization (HR: 1.03-1.57) and mortality (HR: 2.64-5.17) in individuals with and without respiratory diseases (P < 0.05 for all).

CONCLUSION

Pulmonary function was inversely associated with the risk of frailty, hospitalization and mortality in community-dwelling older adults. The cut-off points for FEV₁ and FVC to detect frailty were highly associated with hospitalization and mortality in the 5-year follow-up, regardless of the existence of pulmonary diseases.

Physical activity scaled to preferred walking speed as a predictor of walking difficulty in older adults: a 2-year follow-up

Background

The usual accelerometry-based measures of physical activity (PA) are dependent on physical performance. We investigated the associations between PA relative to walking performance and the prevalence and incidence of early and advanced walking difficulties compared to generally used measures of PA.

Methods

Perceived walking difficulty was evaluated in 994 community-dwelling participants at baseline (age 75, 80, or 85 years) and 2 years later over 2 km (early difficulty) and 500 m (advanced difficulty). We used a thigh-mounted accelerometer to assess moderate-to-vigorous PA, daily mean acceleration, and relative PA as movement beyond the intensity of preferred walking speed in a 6-minute walking test (PA_rel). Self-reported PA was assessed using questionnaires.

Results

The prevalence and incidence were 36.2% and 18.9% for early and 22.4% and 14.9% for advanced walking difficulty, respectively. PA_rel was lower in participants with prevalent (mean 42 [SD 45] vs 69 [91] min/week, p < .001) but not incident early walking difficulty (53 [75] vs 72 [96] min/week, p = .15) compared to those without difficulty. The associations between absolute measures of PA and incident walking difficulty were attenuated when adjusted for preferred walking speed.

Conclusions

The variation in habitual PA may not explain the differences in the development of new walking difficulty. Differences in physical performance explain a meaningful part of the association of PA with incident walking difficulty. Scaling of accelerometry to preferred walking speed demonstrated independence on physical performance and warrants future study as a promising indicator of PA in observational studies among older adults.

Individual Scaling of Accelerometry to Preferred Walking Speed in the Assessment of Physical Activity in Older Adults

BACKGROUND

Walking forms a large portion of physical activity (PA) of older adults. We assessed free-living PA using acceleration corresponding to preferred walking speed as a relative cut-point and studied how it relates to age. We compared the relative cut-point to a common absolute cut-point of moderate-to-vigorous physical activity (MVPA).

METHOD

Four hundred forty-four community-dwelling adults aged 75, 80, and 85 years wore an accelerometer on the thigh during a PA surveillance period and a modified 6-minute walking test (6MWT) at preferred speed. Each individual's mean acceleration (g) during the 6MWT was used as a cut-point for relative PA. Acceleration corresponding to three metabolic equivalents (METs) was used as the cut-point for absolute MVPA.

RESULTS

When using the acceleration of preferred walking speed as a cut-point, 62 (SD 82) minutes a week of relative PA was detected, compared to 228 (163) minutes of absolute MVPA. For 96% of the participants, the acceleration generated by their preferred walking speed exceeded the common absolute cut-point for MVPA. Absolute MVPA was lower in the older age groups, and 6MWT speed explained 22% of its variation (p < .001), whereas relative PA was independent of walking speed and age.

CONCLUSIONS

Preferred walking speed was a significant contributor to absolute MVPA and those who walked the slowest accumulated the least MVPA. Assessing relative PA using the intensity of preferred walking speed as a cut-point eliminated the dependency of PA on age and walking speed, and may be a feasible scaling option to evaluate relative PA among older people.

ADC cut points for chronic kidney disease in pathologically-proven cholangiocarcinoma

Purpose

Apparent diffusion coefficient (ADC) has been shown to indicate renal function in various conditions. As cholangiocarcinoma may have renal involvement due to immune complex-mediated glomerulonephritis, this study aimed to determine whether or not there is any association between ADC values and renal function in these patients.

Methods

This was a retrospective, analytical study. The inclusion criteria were age over 18 years, pathologically proven cholangiocarcinoma diagnosis and having undergone either 1.5 T or 3.0 T diffusion-weighted MRI. Chronic kidney disease (CKD) was defined as eGFR less than 60 mL/min/1.73m². Patients’ ADC levels in the CKD and non-CKD groups were compared, and subgroup analysis was performed by MRI field strength and type of cholangiocarcinoma.

Results

One hundred fifty-eight patients participated in the study. Most were male (66.46 %), and the average age (SD) was 61.59 years (7.91). Average ADC levels in the CDK and non-CDK group differed significantly, regardless of MRI field strength or type of cholangiocarcinoma (2.11 mm/s² in the ADC group vs 1.91 mm/s² in the non-ADC group; P < 0.001). An ADC cut-point of 1.75 mm/s² yielded sensitivities ranging from 66.67–90.00 in almost all study populations. The distal cholangiocarcinoma group had a perfect cut-point at 1.78 mm/s² with 100 % sensitivity and area under the ROC curve.

Conclusions

Radiologists can use ADC to detect CKD in cholangiocarcinoma patients regardless of MRI field strength or type of cholangiocarcinoma.

The external validity and performance of the no-laboratory American Diabetes Association screening tool for identifying undiagnosed type 2 diabetes among the Iranian population

AIMS

The aim of this study is to assess the American Diabetes Association (ADA) risk score as a self-assessment screening tool for undiagnosed type 2 diabetes (T2DM) in Iran.

METHODS

In a national survey of risk factors for non-communicable diseases, we included 3458 Iranian adults. The discrimination and validity were assessed using the area under the curve (AUC), sensitivity, specificity, Youden's index, positive and negative predictive values (PPV and NPV). The frequency of high-risk Iranian population who need a glucose test and those who need intervention were also estimated.

RESULTS

The AUC was 73.7% and the suggested ADA score of ≥5 yielded a sensitivity of 51.6%, specificity 82.4%, NPV 98.3%, and PPV 7.9%. This threshold results in classifying 18.6% of the Iranians, equals to 8.5 million, as high-risk and 1.5% of the population, about 700,000, would need intervention. However, our study suggested score ≥4 that identified 34% of the population as high-risk and 2% of the population would need intervention.

CONCLUSION

Our findings support the ADA suggested threshold for identifying high-risk individuals for undiagnosed T2DM; however, a lower threshold is also recommended for higher sensitivity. The ADA screening tool could help the public health system for low-cost screening.

Clarifying acromial distance: Standardisation and association between supine and sitting positions

OBJECTIVES

To define a standardised acromial distance (AD) in relaxed, supine position and its cut-point with sensitivity and specificity for classifying pectoralis minor (PMI) shortness. To clarify a predictive value of AD while relaxed, supine (AD2) from AD while sitting (AD1), adjusted by the effect of body mass index (BMI).

DESIGN

Cross-sectional; SETTING: Laboratory of Physical Therapy Faculties.

PARTICIPANTS

Eighty-five participants aged 18-38 years.

MAIN OUTCOME MEASURES

A standardised-AD was proportionate of AD at scapular retraction (AD3) to AD2. AD1 was clarified as a predictive variable for AD2 in circumstances of adjusted BMI.

RESULTS

The cut-point of standardised-AD for PMI shortness was equal to or above 0.61. The sensitivity and specificity were 75.64% and 85.71%. AD2 was 0.355 time of AD1 when adjusted for effect of BMI. This cumulative effect may be able to explain AD2 for 41.4% of the variation in the AD1 and BMI around its mean.

CONCLUSIONS

Standardised-AD may be suitable to reflect PMI shortness while supine. Application for clinical practise may estimate AD2 from AD1 by summation of the effect of BMI. When designing postural education for correcting PMI shortness while lying, efficacy may be a concern in transfer to upright or functional position.

A Smooth Nonparametric Approach to Determining Cut-Points of A Continuous Scale

The problem of determining cut-points of a continuous scale according to an establish categorical scale is often encountered in practice for the purposes such as making diagnosis or treatment recommendation, determining study eligibility, or facilitating interpretations. A general analytic framework was recently proposed for assessing optimal cut-points defined based on some pre-specified criteria. However, the implementation of the existing nonparametric estimators under this framework and the associated inferences can be computationally intensive when more than a few cut-points need to be determined. To address this important issue, a smoothing-based modification of the current method is proposed and is found to substantially improve the computational speed as well as the asymptotic convergence rate. Moreover, a plug-in type variance estimation procedure is developed to further facilitate the computation. Extensive simulation studies confirm the theoretical results and demonstrate the computational benefits of the proposed method. The practical utility of the new approach is illustrated by an application to a mental health study.

A cut-off of daily sedentary time and all-cause mortality in adults: a meta-regression analysis involving more than 1 million participants

BACKGROUND

The appropriate limit to the amount of daily sedentary time (ST) required to minimize mortality is uncertain. This meta-analysis aimed to quantify the dose-response association between daily ST and all-cause mortality and to explore the cut-off point above which health is impaired in adults aged 18-64 years old. We also examined whether there are differences between studies using self-report ST and those with device-based ST.

METHODS

Prospective cohort studies providing effect estimates of daily ST (exposure) on all-cause mortality (outcome) were identified via MEDLINE, PubMed, Scopus, Web of Science, and Google Scholar databases until January 2018. Dose-response relationships between daily ST and all-cause mortality were examined using random-effects meta-regression models.

RESULTS

Based on the pooled data for more than 1 million participants from 19 studies, the results showed a log-linear dose-response association between daily ST and all-cause mortality. Overall, more time spent in sedentary behaviors is associated with increased mortality risks. However, the method of measuring ST moderated the association between daily ST and mortality risk (p < 0.05). The cut-off of daily ST in studies with self-report ST was 7 h/day in comparison with 9 h/day for those with device-based ST.

CONCLUSIONS

Higher amounts of daily ST are log-linearly associated with increased risk of all-cause mortality in adults. On the basis of a limited number of studies using device-based measures, the findings suggest that it may be appropriate to encourage adults to engage in less sedentary behaviors, with fewer than 9 h a day being relevant for all-cause mortality.

Analysis of liquid bead microarray antibody assay data for epidemiologic studies of pathogen-cancer associations

BACKGROUND

Liquid bead microarray antibody (LBMA) assays are used to assess pathogen-cancer associations. However, studies analyze LBMA data differently, limiting comparability.

METHODS

We generated 10,000 Monte Carlo-type simulations of log-normal antibody distributions (exposure) with 200 cases and 200 controls (outcome). We estimated type I error rates, statistical power, and bias associated with t-tests, logistic regression with a linear exposure and with the exposure dichotomized at 200 units, 400 units, the mean among controls plus two standard deviations, and the value corresponding to the optimal sensitivity and specificity. We also applied these models, and data visualizations (kernel density plots, receiver operating characteristic (ROC) curves, predicted probability plots, and Q-Q plots), to two empirical datasets to assess the consistency of the exposure-outcome relationship.

RESULTS

All strategies had acceptable type I error rates (0.03 ≤ P ≤ 0.048), except for the dichotomization according to optimal sensitivity and specificity, which had a type I error rate of 0.27. Among the remaining methods, logistic regression with a linear predictor (Power=1.00) and t-tests (Power=1.00) had the highest power to detect a mean difference of 1.0 MFI (median fluorescence intensity) on the log scale and were unbiased. Dichotomization methods upwardly biased the risk estimates.

CONCLUSION

These results indicate that logistic regression with linear predictors and unpaired t-tests are superior to logistic regression with dichotomized predictors for assessing disease associations with LBMA data. Logistic regression with continuous linear predictors and t-tests are preferable to commonly used LBMA dichotomization methods.

Sample size and threshold estimation for clinical trials with predictive biomarkers

With the increasing availability of newly discovered biomarkers personalized drug development is becoming more commonplace. Unless evidence of the dependence of clinical benefit on biomarker classification is a priori unequivocal, personalized drug development needs to jointly investigate treatments and biomarkers in clinical trials. Motivated by the development of contemporary cancer treatments, we propose targeting three main questions sequentially in order to determine (1) whether a drug is efficacious, (2) whether a biomarker can personalize treatment, and (3) how to define personalization. For time-to-event data satisfying the Cox proportional hazards model, we show that (1) and (2) may not directly involve the variance of an interaction term but of a contrast with smaller variance. An asymptotically exact covariance matrix for the parameter vector in the CPH model is derived to construct sample size formulae and an inference approach for thresholds of continuous biomarkers. The covariance matrix also reveals strategies for greater efficiency in trial design, for example, when the biomarker is binary or does not modulate the effect of treatment in the control arm. We motivate our approach by studying the outcome of a contemporary cancer study.

Obesity and metabolic syndrome in Korea

In Korea, a person with a body mass index (BMI) ≥25 kg/m(2) is considered obese, and a person with a BMI ≥30 kg/m(2) is classified as severely obese. Central obesity is defined as a waist circumference ≥90 cm for Korean men and ≥85 cm for Korean women. Recent epidemiologic data show that the prevalence of severe obesity and metabolic syndrome is steadily increasing. These epidemics increased morbidity and mortality of type 2 diabetes, cardiovascular diseases, and obesity-related cancers such as breast, colorectal, and other cancers in Korea. Decreased physical activity, increased fat and alcohol consumption, heavy smoking, and stress/depressed mood are the primary modifiable life-style risk factors for Koreans. Recently, public health interventions to encourage life-style changes have shown promising results in reducing the prevalence of severe obesity and metabolic syndrome.