Gender-specific anthropometric markers of adiposity, metabolic syndrome and visceral adiposity index (VAI) in patients with obstructive sleep apnea

Association between the triglyceride glucose index and obstructive sleep apnea and its symptoms: results from the NHANES

BACKGROUND

Certain studies have indicated a link between obstructive sleep apnea and insulin resistance in specific populations. To gain more clarity, extensive research involving a broad sample of the overall population is essential. The primary objective of this study was to investigate this correlation by utilizing data from the National Health and Nutrition Examination Survey database.

METHODS

The analysis incorporated data from the National Health and Nutrition Examination Survey database spanning the time periods from 2005 to 2008 and from 2015 to 2018, with a focus on American adults aged 18 years and older after applying weight adjustments. Key variables such as obstructive sleep apnea, triglyceride glucose index, and various confounding factors were considered. A generalized linear logistic regression model was used to investigate the association between obstructive sleep apnea and the triglyceride glucose index, with additional exploration of the consistency of the results through hierarchical analysis and other techniques.

RESULTS

The study included participants aged between 18 and 90 years, with an average age of 46.75 years. Among the total sample, 50.76% were male. The triglyceride glucose index demonstrated a diagnostic capability for obstructive sleep apnea, with an AUC of 0.701 (95% CI: 0.6619-0.688). According to the fully adjusted model, individuals in the fourth quartile of the triglyceride glucose index showed an increased likelihood of having obstructive sleep apnea compared to those in the first quartile (OR: 1.45; 95% CI: 1.02-2.06; P < 0.05). Subgroup analysis indicated that male sex (OR: 2.09; 95% CI: 1.76-2.45; P < 0.05), younger age (OR: 2.83; 95% CI: 2.02-3.96; P < 0.05), white ethnicity (OR: 2.29; 95% CI: 1.93-2.73; P < 0.05), and obesity (OR: 1.54; 95% CI: 1.28-1.85; P < 0.05) were correlated with an elevated risk of OSA.

CONCLUSIONS

This study demonstrated a strong association between an elevated TG index and OSA. Additionally, the triglyceride glucose index could serve as an independent predictor of obstructive sleep apnea.

Overall Obesity Not Abdominal Obesity Has a Causal Relationship with Obstructive Sleep Apnea in Individual Level Data

Objective

Both obstructive sleep apnea (OSA) and obesity are highly prevalent worldwide, and are intrinsically linked. Previous studies showed that obesity is one of the major risk factors for OSA, but the causality of the relationship is still unclear. The study was to investigate the causal relationships of overall obesity and abdominal obesity with OSA and its quantitative traits.

Methods

In this case-control study, a total of 7134 participants, including 4335 moderate-to-severe OSA diagnosed by standard polysomnography and 2799 community-based controls were enrolled. Anthropometric and biochemical data were collected. Mendelian randomization (MR) analyses were performed using the genetic risk score, based on 29 body mass index (BMI)- and 11 waist-hip-ratio (WHR)-associated single nucleotide polymorphisms as instrumental variables. The causal associations of these genetic scores with OSA and its quantitative phenotypes were analyzed.

Results

Obesity was strongly correlated with OSA in observational analysis (β= 0.055, P = 3.7 × 10-5). In MR analysis, each increase by one standard deviation in BMI was associated with increased OSA risk [odds ratio (OR): 2.21, 95% confidence interval (CI): 1.62-3.02, P = 5.57 × 10-7] and with 2.72-, 4.68-, and 3.25-fold increases in AHI, ODI, and MAI, respectively (all P < 0.05) in men. However, no causal associations were found between WHR and OSA risk or OSA quantitative traits in men and women.

Conclusion

Compared to abdominal obesity, overall obesity showed a causal relationship with OSA and its quantitative traits, especially in men.

Association of adiposity with risk of obstructive sleep apnea: a population-based study

BACKGROUND

Obesity is a crucial risk factor for obstructive sleep apnea (OSA), but the association between adiposity deposition and OSA risk has not reached a consistent conclusion. This study sought to reveal the association of multiple adiposity indicators with OSA risk.

METHODS

This cross-sectional study included 9,733 participants aged 35-74 years, recruited from an ongoing population-based cohort. OSA was assessed by the Berlin Questionnaire. Six adiposity indicators, including neck circumference (NC), body fat percentage (BF%), waist-to-hip ratio (WHR), visceral adiposity index (VAI), lipid accumulation product (LAP), and resting metabolic rate (RMR), were selected. Multivariate logistic regression models were used to examine the association of adiposity indicators with OSA risk.

RESULTS

One thousand six hundred twenty-six participants (16.71%) were classified into the OSA group. NC, BF%, WHR, VAI, LAP, and RMR were all positively associated with the risk of OSA after adjusting for confounders, regardless of age, sex, and history of dyslipidemia. Every 1-unit increment of NC, BF%, and VAI was associated with a 13%, 9%, and 14% increased risk of OSA, respectively; every 0.01-unit increment of WHR was associated with a 3% increased risk of OSA; every 10-unit increment of LAP and RMR was associated with 2% and 4% increased risk of OSA, respectively.

CONCLUSIONS

NC, BF%, WHR, VAI, LAP, and RMR were all independently and positively associated with OSA risk, regardless of age, sex, history of dyslipidemia, and menopausal status. Application of these new indicators could help to more comprehensively reflect and predict the risk of OSA in the general population.

Composite lipid indices in patients with obstructive sleep apnea: a systematic review and meta-analysis

BACKGROUND

One of the most prevalent sleep disorders affecting the individual's daily life is obstructive sleep apnea (OSA), for which obesity is a major risk factor. Several novel lipid indices have been suggested to have associations with OSA, among which visceral adiposity index (VAI), atherogenic index of plasma (AIP), and lipid accumulation product (LAP) are the most important ones. Herein, the current study aimed to systematically investigate the association between these indices and OSA.

METHODS

Four international databases, including PubMed, Scopus, the Web of Science, and Embase were searched in order to find relevant studies that investigated LAP, VAI, or AIP in OSA and compared them with non-OSA cases or within different severities of OSA. Random-effect meta-analysis was used to generate the standardized mean difference (SMD) and 95% confidence interval (CI) of the difference in lipid indices between OSA and non-OSA cases. Moreover, the pooled area under the receiver operating characteristic curves (AUCs) observed in individual studies for diagnosis of OSA based on these lipid indices were calculated by random-effect meta-analysis.

RESULTS

Totally 14 original studies were included, comprised of 14,943 cases. AIP, LAP, and VAI were assessed in eight, five, and five studies, respectively. Overall, these lipid indices had acceptable diagnostic ability (AUC 0.70, 95% CI 0.67 to 073). Meta-analysis revealed that AIP was significantly higher in patients with OSA (SMD 0.71, 95% CI 0.45 to 0.97, P < 0.01). Moreover, AIP also increased in higher severities of OSA. Regarding LAP, a higher LAP was observed in OSA/patients with high risk for OSA rather than in controls/low risk for OSA (SMD 0.53, 95% CI 0.25 to 0.81, P < 0.01). VAI was also increased in OSA based on results from two studies.

CONCLUSION

These findings suggest that composite lipid indices are increased in OSA. Also, these indices can have the potential beneficiary diagnostic and prognostic ability in OSA. Future studies can confirm these findings and enlighten the role of lipid indices in OSA.

Sex differences in variables associated with excessive daytime sleepiness in patients with epilepsy

OBJECTIVE

Excessive daytime sleepiness (EDS) is common in patients with epilepsy (PWE). The Epworth Sleepiness Scale (ESS) is a self-reported measure of sleepiness in widespread use. The purpose of this study was to identify contributors to the ESS score in PWE and to identify variables associated with a high score indicative of EDS.

METHODS

A cross-sectional study was performed on 115 PWE presenting to the epilepsy clinic. Self-reported questionnaires were administered and demographic and clinical information was gathered from the electronic medical record. Regression analyses were performed.

RESULTS

A high ESS score was found in nearly 20% of the cohort. Obstructive sleep apnea (OSA) risk, standardized anti-seizure drug (ASD) dose, and female sex were associated with an increased likelihood of a high ESS score. Assessment of the ESS without the use of a cutpoint showed that standardized ASD dose and OSA risk were associated with the ESS in men, but standardized ASD dose was not associated with the ESS in women. Higher use of valproic acid and oxcarbazepine in men and higher use of lamotrigine in women may be contributing factors.

SIGNIFICANCE

Sex is likely to be a key factor in determining contributors to EDS in PWE.

Validation of GOAL questionnaire as screening tool for clinical obstructive sleep apnea: A large sample study in China

Background

Obstructive sleep apnea (OSA) is a serious disease with a high prevalence in the general population. The purpose of this study is to explore the effectiveness of the GOAL questionnaire in the clinical screening of OSA and compare it with other existing screening tools.

Materials and methods

Outpatients and inpatients who underwent polysomnography (PSG) examination at the Sleep Medicine Center of the First Affiliated Hospital of Guangzhou Medical University from January 2013 to November 2016 were analyzed retrospectively. The basic data such as demographic, medical history, etc., and PSG data of the patients were collected, and the sensitivity, specificity, positive predictive value, negative predictive value and area under the curve (AUC) of GOAL and five other screening scales (the NoSAS score, Epworth Sleepiness Scale, the Berlin questionnaire, STOP, and STOP-Bang questionnaire) were calculated.

Results

Data from 2,171 participants (1,644 male; 78%) were analyzed there were 1,507 OSA patients [Apnea Hypopnea Index (AHI) ≥ 5 events/h] among them, accounting for about 69.415%. No matter which cut-off point (AHI ≥ 5, 15 and 30 events/h), the AUC score reveals that GOAL questionnaire had comparable screening ability to the NoSAS and STOP-BANG, and performed better than the ESS, and the AUC scores of the STOP questionnaire and Epworth Sleepiness Scale (ESS) were both lower than 0.7. When the cut-off point of the AHI was 5 events/h, the AUC of GOAL was the highest at 0.799 (0.781–0.816), and its sensitivity was the highest at 89.1%. The sensitivity levels of the NoSAS score and STOP-Bang questionnaire were 67.4 and 78.8% respectively, while ESS and the Berlin questionnaire have higher specificity (70.2 and 72.3% respectively) but lower sensitivity (49.3 and 60.0% respectively).

Conclusion

GOAL is a free, efficient and easy to manage tool with a screening ability comparable to NoSAS and STOP-Bang, and better than that of ESS.

Obesity and Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is characterized by upper airway collapse during sleep. Chronic intermittent hypoxia, sleep fragmentation, and inflammatory activation are the main pathophysiological mechanisms of OSA. OSA is highly prevalent in obese patients and may contribute to cardiometabolic risk by exerting detrimental effects on adipose tissue metabolism and potentiating the adipose tissue dysfunction typically found in obesity. This chapter will provide an update on: (a) the epidemiological studies linking obesity and OSA; (b) the studies exploring the effects of intermittent hypoxia and sleep fragmentation on the adipose tissue; (c) the effects of OSA treatment with continuous positive airway pressure (CPAP) on metabolic derangements; and (d) current research on new anti-diabetic drugs that could be useful in the treatment of obese OSA patients.

Comparison of Composite Lipid Indices in Patients with Obstructive Sleep Apnoea

PURPOSE

Obstructive sleep apnoea (OSA) is a recognised risk factor for cardiovascular disease. However, it is difficult to evaluate the risk of cardiovascular disease in patients with OSA due to multiple shared risk factors. Composite lipid indices, such as atherogenic index of plasma (AIP), visceral adiposity index (VAI) and lipid accumulation product (LAP) have been shown to predict cardiovascular disease better than their individual lipid components. This study aimed to evaluate these indices in patients with OSA.

PATIENTS AND METHODS

Six hundred sixty-seven (667) patients with OSA and 139 non-OSA control volunteers participated in the study. Fasting serum triglycerides, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol (HDL-C) levels were measured, and AIP, LAP and VAI were calculated following cardiorespiratory polygraphy. The relationship between lipid parameters, OSA and its comorbidities was evaluated using receiver operating curve (ROC) analysis.

RESULTS

We found a significant difference in all lipid parameters between OSA patients and controls. Comparing ROCs, LAP was significantly more strongly associated with OSA compared to all the other parameters. The optimal cut-off value for LAP to detect OSA was 76.4, with a sensitivity of 63% and a specificity of 76%. In addition, LAP was the best parameter to predict hypertension and diabetes in patients with OSA, and it was predictive for ischaemic heart disease together with HDL-C.

CONCLUSION

Our results support the use of LAP in clinical practice when evaluating cardiovascular risk in patients with OSA. However, the optimal cut-off value should be determined in large-scale follow-up studies.

Nonlinear relationship between visceral adiposity index and lung function: a population-based study

Background

As one of the critical indicators of obesity, the interaction between visceral fat content and lung disease is the focus of current research. However, the exact relationship between Visceral adipose index (VAI) and lung function is not fully understood. The purpose of this study was to evaluate the relationship between VAI and lung function,

Methods

Our study included all participants from the baseline survey population in Xinjiang in the Natural Population Cohort Study in Northwest China. A field survey was conducted in rural areas of Moyu County, Xinjiang, China, between 35 and 74 years old from June to December 2018. We collected standard questionnaires and completed physical examinations, visceral fat tests, and lung function measurements.

Results

The study included 2367 participants with a mean VAI of 10.35 ± 4.35, with males having a significantly higher VAI than females: 13.17 ± 3.91 vs. 7.58 ± 2.65. The piecewise linear spline models indicated a significant threshold effect between lung function and VAI in the general population and the males population, showing an inverted U-shaped curve. But there was no significant association between VAI and lung function in females. FEV1% predicted and FVC% predicted increased with the increase of VAI (β 0.76; 95% CI 0.30, 1.21) and (β 0.50; 95% CI 0.06, 0.94) in males with VAI ≤ 14, while FEV1% predicted and FVC% predicted decreased with the increase of VAI (β − 1.17; 95% CI − 1.90, − 0.45) and (β − 1.36; 95% CI − 2.08, − 0.64) in males with VAI ≥ 15.

Conclusions

The relationship between lung function and VAI in male participants showed an inverted U-shaped curve, with the turning point of VAI between 14 and 15. The association between visceral fat and lung function was more robust in males than in females.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01751-7.

Using anthropometric measures to screen for obstructive sleep apnea in the Sleep Heart Health Study cohort

STUDY OBJECTIVES

To evaluate predictions of moderate-to-severe-obstructive sleep apnea (MS-OSA) by the neck circumference height ratio (NHR) and waist circumference height ratio (WHR) and compare to the derived STOP-Bang Questionnaire (dSBQ) prediction.

METHODS

Included were 6,167 participants from the Sleep Heart Health Study (SHHS) baseline evaluation who completed polysomnograms, had anthropometric measurements, and data to compute proxy dSBQ item answers. The sample was divided randomly into derivation (n = 2,035) and validation (n = 4,132) subsets. The derivation sample was used to estimate the NHR and WHR cut points to detect MS-OSA; the validation sample was used to evaluate sensitivity (SN) and specificity (SP).

RESULTS

Mean age was 63.1 years, and 47.2% were male for the overall sample. In the derivation sample, a cut point ≥ 0.21 for NHR yielded a SN of 92.0% and SP of 25.0%; a cut point ≥ 0.52 for WHR yielded a SN of 91.2% and SP of 25.0% for MS-OSA. Using the validation sample, the NHR, WHR, and dSBQ areas under the receiver operator curves (AUCs) were 69.8%, 65.2%, and 70.5% respectively for MS-OSA. There was no statistical difference with listwise comparison of the NHR and dSBQ AUCs (p = 0.997); however, there was a significant difference between the WHR and dSBQ AUCs (p = 0.015) for MS-OSA.

CONCLUSIONS

The NHR is a viable OSA screening tool comparable to the dSBQ, independent of witnessed apneas and BMI, that can be used for different body types.

Visceral adiposity index and its association with Dietary Approaches to Stop Hypertension (DASH) diet scores among older adults: National Health and Nutrition Examination Surveys 2011-2014

BACKGROUND & AIMS

The visceral adiposity index (VAI) has been shown to be a reliable estimate of visceral adiposity, but little is known about its association with specific dietary patterns such as the Dietary Approaches to Stop Hypertension (DASH) diet, particularly in older adults. Many studies have shown the DASH diet to be beneficial for cardiometabolic health. The purpose of this study was to investigate the relationship between DASH diet scores and the VAI in older adults using a nationally representative dataset.

METHODS

Using the National Health and Nutrition Examination Surveys (NHANES) from 2011 to 2014, data from 508 community-dwelling older adults were examined, and dietary intake was evaluated using the Dixon's DASH diet index. Using multiple linear regression analysis, the relationship between VAI and DASH diet score was assessed while controlling for demographic variables.

RESULTS

Participants' average DASH diet score was 2.41 (SE = 0.07), and the average VAI was 1.55 (SE = 0.08). The results suggest a significant inverse relationship between the DASH diet and VAI (β = -0.19, t = -2.73, p = 0.009).

CONCLUSIONS

Results of this study suggest that protective properties of the DASH diet pattern may be due in part to its inverse relationship with visceral adiposity. This information supports practitioners' use of the VAI with older adults in addition to providing nutrition counseling with the DASH diet to reduce patients' cardiometabolic risk.

Visceral adiposity index is associated with lung function impairment: a population-based study

Background

The effects of visceral adiposity on decreased lung function have drawn much attention. Recently, the visceral adiposity index (VAI) has been proposed as a visceral fat distribution and dysfunction marker. However, the relationship between the VAI and lung function has not been investigated. The objective of the study was to analyze the association between the VAI and lung function and evaluate the potential of VAI as a predictor of lung function.

Methods

We collected data from a population-based study of 1786 subjects aged 40 years or older. All subjects completed a questionnaire and underwent anthropometric measurements and laboratory tests. Linear and logistic regression models were developed to assess the association between the VAI and lung function.

Results

The VAI was inversely related to FVC%predicted in men and negatively associated with both FVC%predicted and FEV1%predicted in women. In the linear regression analysis, the decrease in FVC%predicted associated with each 10% increase in the VAI was 1.127% in men and 1.943% in women; the decrease in FEV1%predicted associated with each 10%increase in the VAI was 0.663% in men and 1.738% in women. Further regression analysis revealed that the VAI was positively correlated with FVC and FEV1 impairment in women.

Conclusions

We were the first to show a clear correlation between the VAI and lung function impairment in the Chinese population. The VAI could be a simple and reliable approach in daily practice, and individuals, especially women with a high VAI, should receive additional screening and preventive interventions for respiratory disease.

Importance of Measured Body Fat, Visceral Adiposity Index, and Lipid Accumulation Product Index in Predicting Cardiometabolic Risk Factors

Background: Obesity, which is defined as excessive fat accumulation in the body, is an important public health problem. Objective: The aim of this study was to compare measured body fat and the visceral adiposity index (VAI) and lipid accumulation product (LAP) index used to predict cardiometabolic risk (CMR) factors. Methods: This study was performed retrospectively by scanning the files of 817 participants who had bioelectrical impedance analysis (BIA) results and routine blood tests. The VAI and the LAP index were calculated using the appropriate formulas. Results: Of the 817 participants included in the study, 67.9% (n = 555) were female, 32.1% (n = 262) were male, and the mean age was 36.14 ± 11.4 (18-65) years. The mean body mass index (BMI) was 29.90 ± 6.6 kg/m² and 24.2% (n = 198) of the participants were of normal weight (BMI <25 kg/m²), while 75.8% (n = 619) were overweight or obese (BMI ≥25 kg/m²). Body fat quantity was higher in females than in males. As BMI increased, the body fat quantity measured by BIA also increased (P < 0.001). The mean LAP index of men was higher than the mean LAP index of women in both the normal-weight group and the obese group (P = 0.025 and P = 0.033, respectively). One unit increase in visceral fat percentage resulted in a 77.9% increase in CMR. Conclusions: It may not be sufficient to use only BMI to predict obesity and related cardiometabolic diseases. According to the study findings, it was determined that the increase in visceral fat percentage significantly increases the CMR.

The Role of Visceral Adiposity Index as Predictor of Metabolic Syndrome in Obese and Nonobese Women with Polycystic Ovary Syndrome

Background: To evaluate anthropometric-metabolic biomarkers as predictors of metabolic syndrome (MS) in women with polycystic ovary syndrome (PCOS) with and without obesity. Methods: This was an observational cross-sectional study. Patients were classified as nonobese-PCOS (body mass index, BMI <30 kg/m², n = 385), and obese-PCOS (BMI ≥30 kg/m², n = 261). The anthropometric parameters waist circumference, waist/hip ratio, lean body mass, fat body mass, visceral adiposity index (VAI), lipid accumulating product, and biomarkers of glucose and lipid metabolisms were compared between groups. Binominal logistic regression analyses were performed to identify predictors of MS. Results: Obesity was diagnosed in 40% of all PCOS women (P < 0.001). Blood pressure and anthropometric abnormalities were significantly more frequent in obese-PCOS women (P < 0.001, for all comparisons). Glucose metabolism markers were higher in obese-PCOS compared with nonobese-PCOS (P < 0.001, for all comparisons). High-density lipoprotein cholesterol was lower in obese group than in nonobese group (1.26 mM vs. 1.08 mM, P < 0.001). MS was found in 23 of 385 (6%) nonobese-PCOS and in 116 of 261 (44.4%) obese-PCOS (P < 0.001). VAI was the best predictor of MS in both nonobese-PCOS (OR = 4.1, 95% CI 1.5-11.1) and obese-PCOS (OR = 12.9, 95% CI 5.7-29.0). Conclusions: MS is more prevalent in PCOS women with obesity. VAI was the strongest predictor of MS in both obese and nonobese PCOS women, and can be applied in clinical practice for early detection of risk for MS and precocious intervention in women with PCOS, particularly in obese women.

The use of visceral adiposity variables in the prediction of obstructive sleep apnea: evidence from a large cross-sectional study

PURPOSE

The purposes of this study were to evaluate the ability of visceral adiposity variables [the lipid accumulation product (LAP), the visceral adiposity index (VAI), and the triglyceride-glucose index (TyG)] in predicting obstructive sleep apnea hypopnea syndrome (OSAHS) and to determine the effect of sex on the prediction.

METHODS

A total of 5539 subjects admitted to the sleep center for suspected OSAHS were consecutively recruited from 2007 to 2016. Anthropometric measurements, biological indicators, Epworth sleepiness scale score, and polysomnographic variables were collected. Prediction models for diagnosing OSAHS were established in the test group by logistic regression and verified in the validation group by receiver operating characteristic (ROC) curves.

RESULTS

A total of 4703 patients were included in total. LAP and TyG were of moderate diagnostic accuracy for OSAHS, with the diagnostic efficiency differing between men and women. A prediction model was developed that combined visceral adiposity indicators with waist circumstance and the lowest SpO₂. The sensitivity of those indicators were both 84% in men and women, respectively, and their specificity were both 90%. In addition, the model was confirmed in the validation group with a sensitivity and specificity of 83% and 85% in men and 85% and 84% in women.

CONCLUSIONS

LAP and TyG were of moderate efficiency in screening for OSAHS. The prediction model provides a simple and practical screening tool for OSAHS.

Diagnostic Accuracy of a Modified STOP-BANG Questionnaire with National Anthropometric Obesity Indexes

OBJECTIVES

Obstructive sleep apnea (OSA) is a very common sleep-related disorder and has many medical complications. Although the STOP-BANG questionnaire is an attractive screening tool because of high sensitivity, it lacks power in specificity. The aim of the present study was to evaluate and compare the diagnostic accuracy of standard STOP-BANG and a modified STOP-BANG questionnaire, using national cut-off values for neck circumference that determined OSA, in a sleep center population.

MATERIALS AND METHODS

One hundred eighty-five participants who were referred to the sleep-disordered breathing clinic were consecutively enrolled. We used 40 cm and 36 cm as the cut-off values for neck circumference, thus scoring patients accordingly and creating a modified STOP-BANG score with national anthropometric obesity indexes.

RESULTS

The median neck circumferences were 41 (39-44) cm, 40 (37-42) cm, and 43 (40-45) cm for total population, female gender, and male gender, respectively. The mean STOP-BANG score was 4.5±1.5, and the mean modified STOP-BANG score was 4.9±1.5. Discrimination of OSA measured by area under the curve for both questionnaires is comparable (p>0.05). Sensitivity to define OSA (apnea-hypopnea index (AHI)≥5) was 92.2% and 93.8% for original and modified STOP-BANG questionnaire, respectively. Sensitivity for moderate (AHI≥15) and severe OSA (AHI≥30) was identical for both questionnaires.

CONCLUSION

The STOP-BANG questionnaire has an excellent sensitivity, but modest specificity and adding national obesity indexes for neck circumference achieved similar results in terms of sensitivity and specificity with the original questionnaire.

Visceral adiposity index in female with type 2 diabetic mellitus and its association with the glycemic control

AIMS

Visceral Adiposity Index (VAI) is suggested as a surrogate marker for visceral adipose tissue dysfunction. It is an empirical-mathematical model, sex-specific, based on metabolic and anthropometric parameters. Diabetes mellitus is growing in an expanding fashion globally. The aim of this study to study the association between VAI and glycemic control in women with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

A total of 300 T2DM female aged (25-60 years) were enrolled in this cross-sectional study. Subjects were recruited from Baghdad medical city during the period from January 2017 to July 2018. Body mass index (BMI), waist circumference (WC), blood pressure was measured and fasting blood sample was analyzed for blood glucose, glycated hemoglobin(HbA1c), and lipid profile. VAI was calculated in addition to triglyceride-glucose (TyG) derived indices. Statistical analysis was done by SPSS version 23. The study was ethically approved.

RESULTS

Patients with high VAI showed poor glycemic control, dyslipidemia, elevated TYG index, TYGWC and TYGBMI. The number of diabetics with poor glycemic control increased across the VAI quartiles. The area under the curve in ROC analysis demonstrated that VAI had a good predictive ability to identify the state of glycemic control as compared to other anthropometric measures (WC, BMI) or combined metabolic and anthropometric measures (TyGWC, TyGBMI).

CONCLUSION

increased VAI adversely affects the glycemic control in women with T2DM.

Gender differences in the application of anthropometric measures for evaluation of obstructive sleep apnea

This study aims to investigate anthropometric measures and their effectiveness as screening method for diagnosing obstructive sleep apnea (OSA) in each gender. We also evaluated which measures were associated with OSA in the adult population of a large metropolitan city, Sao Paulo, Brazil. 552 women and 450 men were submitted to polysomnography (PSG), and the anthropometric measurements as body mass index (BMI), waist-to-height ratio, neck and waist circumference were collected. The measurements were then compared with the OSA classification established by the PSG. In women, waist circumference and waist-to-height ratio were found to be the best predictor, while in men, the factors with great potential for identification varied according to severity of the disease, highlighting waist-to-height ratio, neck circumference and BMI had strongest association. The accuracy of the classification in relation to mild-to-severe OSA based on cut-off values of 92.5cm for waist circumference was greater than 72.9% in men, and 78.9% in women based on cut off values of 95cm. Regarding severe OSA, cut-off values of 116.1cm were greater than 91.3% accurate in the male population, and 95.1% in the female population with a cut-off value of 126.5cm. The study found waist circumference and waist-to-height ratio to be the best measure to assess sleep-disordered breathing in women. Waist-to-height ratio and neck circumferences were the best measures in men with mild OSA, but BMI was more closely associated with severe OSA. The present study identified the anthropometric variables with the highest risk for OSA and their respective cutoff value, according to gender.

Indicadores de adiposidade como método de rastreamento para polissonografia em trabalhadores de turno

Resumo Objetivo: verificar o potencial discriminatório dos indicadores de adiposidade na predição da apneia obstrutiva do sono (AOS) em trabalhadores de turnos. Métodos: estudo transversal realizado em uma empresa de extração de minério de ferro, em Minas Gerais, Brasil. Dados antropométricos foram coletados e polissonografia (PSG) foi realizada em 118 trabalhadores de turno do sexo masculino que possuíam ao menos um fator de risco global para doença cardiovascular. Resultados: a prevalência de AOS na amostra foi de 84,7%. Entre os indicadores de adiposidade usados para predizerem a AOS (≥ 5 eventos/hora), o índice de massa corporal (IMC), a circunferência da cintura (CC), a relação cintura/estatura (RCE) e a gordura corporal total (GCT), revelaram valores de sensibilidade acima de 70%. Gordura visceral (GV), circunferência do pescoço (CP) e relação pescoço-estatura (RPE) foram as mais efetivas em identificar corretamente trabalhadores sem AOS (valores de especificidade acima de 70%). As áreas sob a curva de Característica de Operação do Receptor (COR) para CC e RPE foram maiores que 0,7, o que indicou que o teste foi eficaz na discriminação de indivíduos com AOS. Conclusões: alterações nos indicadores de adiposidade abdominal e cervical têm relação significativa com a presença de AOS e demostraram eficácia como método de rastreamento para PSG. CC e RPE são considerados bons indicadores para predizerem a AOS.

Association between Obstructive Sleep Apnea and Cardiovascular Risk Factors: Variation by Age, Sex, and Race. The Multi-Ethnic Study of Atherosclerosis

RATIONALE

The association between obstructive sleep apnea (OSA) and cardiovascular disease (CVD) is complex, bidirectional, and may vary across groups. Understanding which cardiovascular risk factors vary in their relationship to OSA across population groups may improve knowledge of OSA-related CVD susceptibility.

OBJECTIVES

To better understand the heterogeneity of associations, we assessed whether associations of OSA with cardiovascular risk factors vary by age, sex, and race/ethnicity.

METHODS

We performed cross-sectional analyses of 1,344 Multi-Ethnic Study of Atherosclerosis participants who underwent overnight full polysomnography, assays of fasting blood, and assessments of cardiovascular risk factors. Risk factors considered were blood pressure, glucose/lipid concentrations, white blood cell (WBC) total and subset counts, and cystatin C. The outcome was the apnea-hypopnea index (AHI). Linear regression analyses with tests for interactions were conducted.

RESULTS

The sample had a mean age of 68 ± 9 years. Forty-seven percent of the sample was male, and 32% had moderate or severe OSA (AHI, ≥15). Multivariable adjusted analysis showed significant associations between higher AHI with lower high-density lipoprotein cholesterol and higher diastolic blood pressure and neutrophil counts. Significant interactions with demographic factors were observed. Stronger associations were shown between AHI and higher total WBC count (Pint = 0.006) and glucose concentrations (Pint = 0.006) in younger (<65 yr) than in older individuals, higher triglyceride concentrations in men than in women (Pint = 0.006), and higher total WBC (Pint = 0.07) and monocyte counts (Pint = 0.03) in African American individuals than in other racial groups.

CONCLUSIONS

In a multiethnic cohort, we found increased levels of cardiovascular risk factors in association with OSA, including elevated neutrophil counts, a marker of inflammation. Furthermore, several associations were stronger in men, younger individuals, and African American individuals, highlighting pathways for CVD risk that may explain heterogeneity in the associations between CVD and OSA across population groups.

Clinical surrogate markers for predicting metabolic syndrome in middle-aged and elderly Chinese

AIMS/INTRODUCTION

The present study evaluated the ability of lipid accumulation product (LAP), visceral adiposity index (VAI), and the product of triglycerides and glucose (TyG), three novel markers, in identifying metabolic syndrome (MetS) with different criteria in middle-aged and elderly Chinese.

MATERIALS AND METHODS

During June 2012 to January 2013, 992 consecutive patients (age ≥40 years) were enrolled at Daping Hospital. The criteria of MetS were based on the International Diabetes Federation and the modified National Cholesterol Education Program's Adult Treatment Panel III. VAI, LAP and TyG were computed based on a published mathematical model.

RESULTS

The prevalence of MetS was 42.8%. The receiver operating characteristic curve found LAP, VAI and TyG were positively related to MetS in both criteria. The optimal cut-offs of VAI, LAP and TyG for the modified National Cholesterol Education Program's Adult Treatment Panel III and International Diabetes Federation criteria were 2.015, 31.465 and 8.706, and 2.035, 37.99 and 8.697, respectively. After adjustment of potential confounding factors, VAI, LAP and TyG were significantly correlated with MetS in all criteria according to optimal cut-offs. For MetS, reliable predictive value was observed in different subgroups (age and sex). LAP showed the greatest area under the curve in MetS with the International Diabetes Federation definition (area under the curve 0.887, 95% confidence interval 0.852-0.922).

CONCLUSIONS

AP, VAI and TyG were reliable surrogate markers for identifying MetS in middle-aged and elderly Chinese. LAP could be a better parameter than VAI and TyG for predicting MetS in the present study.

Visceral adiposity index is strongly associated with hyperuricemia independently of metabolic health and obesity phenotypes

Visceral adiposity index (VAI) is a novel sex-specific index for visceral adipose function; however the association between VAI and hyperuricemia in China is unknown. We aimed to investigate this association, also whether it was independent of metabolic health and obesity phenotypes. 7632 adult subjects from the China Health and Nutrition Survey 2009 were retained. Subjects were categorized into four obesity phenotypes based on a cross-classification of BMI and metabolic health status by two representative criteria. VAI was the best predictors for hyperuricemia irrespective of obesity phenotypes, with area under curve (AUC) ranging 0.665–0.719. The odd ratio (OR) for hyperuricemia in the highest quartile of the VAI were 6.93 (95% CI 5.79–8.29) after adjusting for age and gender. Following further adjustments for metabolic obesity phenotypes and lifestyle confounders, the ORs were 4.88 (3.92–6.09) and 5.65 (4.68–6.82) according to these two criteria, respectively. A similar significant pattern was still found even after adjustment for blood pressure and other cardiovascular risks. Within each metabolic obesity phenotype, the significant association between VAI and hyperuricemia was consistently evident. In conclusion, the association of the VAI with hyperuricemia was significant, especially this association was independent of metabolic health and obesity phenotypes in the Chinese population.

Increased inflammation from childhood to adolescence predicts sleep apnea in boys: A preliminary study

While chronic systemic inflammation in obstructive sleep apnea (OSA) has been traditionally considered a consequence of intermittent hypoxia, several treatment studies targeting inflammation suggest that this process may precede the development of the disorder. A recent cross-sectional study in the Penn State Child Cohort (PSCC) revealed that inflammation largely mediates the association between visceral adiposity and OSA in adolescence. The purpose of this study was to examine for the first time whether, longitudinally, inflammation precedes OSA during this developmental period. A subsample of the PSCC with longitudinal sleep and inflammation data (n=51) was included in this study. Participants underwent 9-h polysomnography (22:00-7:00), physical exam, and fasting morning blood draw at both time points. Plasma C-reactive protein (CRP) was measured via ELISA. At follow-up, visceral, subcutaneous, and total fat area were assessed via dual X-ray absorptiometry. Sex differences in body composition emerged in adolescence, with boys having more visceral adiposity than girls. Longitudinal increases in waist circumference from childhood to adolescence were associated with increases in CRP (ΔCRP) and follow-up CRP in boys, but not girls. Furthermore, in boys, ΔCRP was associated with higher follow-up apnea/hypopnea index (AHI). When ΔCRP was entered into a model predicting follow-up AHI, Δwaist circumference was no longer significant, indicating that inflammation largely explains the association between increasing central obesity and OSA severity. These preliminary findings, in a longitudinal, non-clinical sample of children developing OSA, suggest that inflammation derived from visceral adipose tissue precedes the development of the disorder, suggesting a potential causal mechanism.

Prediction of the severity of obstructive sleep apnea by anthropometric features via support vector machine

To develop an applicable prediction for obstructive sleep apnea (OSA) is still a challenge in clinical practice. We apply a modern machine learning method, the support vector machine to establish a predicting model for the severity of OSA. The support vector machine was applied to build up a prediction model based on three anthropometric features (neck circumference, waist circumference, and body mass index) and age on the first database. The established model was then valided independently on the second database. The anthropometric features and age were combined to generate powerful predictors for OSA. Following the common practice, we predict if a subject has the apnea-hypopnea index greater then 15 or not as well as 30 or not. Dividing by genders and age, for the AHI threhosld 15 (respectively 30), the cross validation and testing accuracy for the prediction were 85.3% and 76.7% (respectively 83.7% and 75.5%) in young female, while the negative likelihood ratio for the AHI threhosld 15 (respectively 30) for the cross validation and testing were 0.2 and 0.32 (respectively 0.06 and 0.1) in young female. The more accurate results with lower negative likelihood ratio in the younger patients, especially the female subgroup, reflect the potential of the proposed model for the screening purpose and the importance of approaching by different genders and the effects of aging.

Gender differences in clinical and polysomnographic features of obstructive sleep apnea: a clinical study of 2827 patients

PURPOSE

Obstructive sleep apnea (OSA) is underdiagnosed in females due to different clinical presentation. We aimed to determine the effect of gender on clinical and polysomnographic features and identify predictors of OSA in women.

METHODS

Differences in demographic, clinical, and polysomnographic parameters between 2052 male and 775 female OSA patients were compared.

RESULTS

In female OSA patients, age (56.1 ± 9.7 vs. 50.4 ± 11.6 years, p < 0.0001) and body mass index (36.3 ± 8.6 vs. 31.8 ± 5.9 kg/m², p < 0.0001) were increased, whereas men had higher waist-to-hip ratio and neck circumference (p < 0.0001). Hypertension, diabetes mellitus, thyroid disease, and asthma were more common in females (p < 0.0001). Men reported more witnessed apnea (p < 0.0001), but nocturnal choking, morning headache, fatigue, insomnia symptoms, impaired memory, mood disturbance, reflux, nocturia, and enuresis were more frequent in women (p < 0.0001). The indicators of OSA severity including apnea-hypopnea index (AHI) (p < 0.0001) and oxygen desaturation index (p = 0.007) were lower in women. REM AHI (p < 0.0001) was higher, and supine AHI (p < 0.0001) was lower in females. Besides, women had decreased total sleep time (p = 0.028) and sleep efficiency (p = 0.003) and increased sleep latency (p < 0.0001). In multivariate logistic regression analysis, increased REM AHI, N3 sleep, obesity, age, morning headache, and lower supine AHI were independently associated with female gender.

CONCLUSIONS

These data suggest that frequency and severity of sleep apnea is lower in female OSA patients, and they are presenting with female-specific symptoms and increased medical comorbidities. Therefore, female-specific questionnaires should be developed and used for preventing underdiagnosis of OSA.

Prevalence and Predictors of Atherogenic Serum Lipoprotein Dyslipidemia in Women with Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is associated with dyslipidemia. However, no study has focused on dyslipidemia in women with OSA. The aim of this study was to determine the prevalence and risk factors for dyslipidemia in women with OSA. Between 2007 and 2013, 570 eligible female patients with suspected OSA were consecutively recruited. The analyzed data consisted of polysomnography parameters, biochemical indicators, and anthropometric measurements. Serum lipid levels and dyslipidemia were compared. Binary logistic regression and multivariate linear regression models were used to determine the independent risk factors influencing serum lipids. After multivariate adjustment, there were essentially no major differences in serum lipid levels among patients with no to mild, moderate, and severe OSA nor did serum lipid levels change with OSA severity. Dyslipidemia in total cholesterol, triglycerides, low-density lipoprotein cholesterol, apolipoproteins(apo) B and apoE increased with OSA severity, but only in non-obese subjects and those <55 years of age. Age, body mass index, waist to hip ratio, glucose and insulin were major risk factors for most serum lipids after multivariate adjustments. Our results indicate that, in women with OSA, age, obesity/central obesity, and insulin resistance are major determinants of dyslipidemia.

Association Between the Visceral Adiposity Index and Homeostatic Model Assessment of Insulin Resistance in Participants With Normal Waist Circumference

We assessed the correlation between the visceral adiposity index (VAI; a useful indicator of adipose distribution and function) and homeostatic model assessment of insulin resistance (HOMA-IR) in participants with normal waist circumference. A cross-sectional study was conducted, which included 1834 Chinese adults. The blood pressure, anthropometric measurements, fasting and postprandial blood glucose, fasting insulin, and lipid profiles were measured. The VAI and HOMA-IR were calculated. Participants were divided into 4 groups according to the HOMA-IR level, and the correlation between the VAI and HOMA-IR was analyzed. The VAI gradually increased across the HOMA-IR quartiles ( P < .05), and a Pearson correlation analysis showed that VAI was positively related to the HOMA-IR ( P < .001) in males and females. After adjusting for the other covariates, VAI was independently correlated with the HOMA-IR. A logistic regression analysis indicated that VAI elevation was the main risk factor for the increased HOMA-IR in both genders. Overall, the VAI was closely correlated with the HOMA-IR in a population without central obesity.

Effect of orlistat alone or in combination with Garcinia cambogia on visceral adiposity index in obese patients

Aim:

The objective of this study was to estimate the effect of orlistat alone and in combination with Garcinia cambogia on visceral adiposity index (VAI) in obese patients.

Patients and Methods:

A total of 99 obese male patients were recruited with aged range between 37 and 46 years. They were randomized into three equal groups, first group treated with orlistat 120 mg/day, second group treated with G. cambogia 166 mg/day, and third group treated with orlistat 120 mg/day plus G. cambogia 166 mg/day. The duration of the treatments was three consecutive months. Body mass index (BMI), VAI, blood pressure, blood glucose, total lipid profile, atherogenic index, and cardiac risk ratio were recorded at baseline and after 3 months.

Results:

The treatment with G. cambogia leads to reduction in VAI P < 0.05, whereas orlistat has a beneficial effect on cardiometabolic profiles without a reduction in VAI P > 0.05. Combined therapy of G. cambogia plus orlistat showed the more significant effect in reduction of VAI P < 0.05, cardiometabolic profiles and anthropometric measures P < 0.01 compared to pretreatment period.

Conclusion:

Combination of G. cambogia with orlistat lead to more significant effect than orlistat alone in amelioration of cardiometabolic profile and VAI in obese patients.

Applicability of visceral adiposity index in predicting metabolic syndrome in adults with obstructive sleep apnea: a cross-sectional study

Background

Obstructive sleep apnea (OSA) is severely affected by visceral adiposity (VA) that correlates to another disorder—metabolic syndrome (MetS). However, little is known concerning the relation of visceral adiposity index (VAI)—a novel and simple indicator of VA, with OSA and MetS. The objective of the study was to analyze the association of VAI with both disorders and applicability to identify OSA patients at risk of MetS.

Methods

Consecutive individuals undergoing polysomnography and biochemical tests were enrolled, and differences in all subjects grouped by apnea-hypopnea index (AHI) were analyzed. Spearman correlation was performed for assessing the relationship between VAI, OSA-related indices and metabolic score—total number of the positive diagnostic criteria of MetS. Receiver operating characteristic (ROC) curve was conducted to obtain a cut-off value of VAI for predicting incident MetS by sex. Then, the risk of MetS in OSA patients according to the cut-offs was attained by logistic regression.

Results

A total of 411 individuals were enrolled. Of whom, 361 subjects were diagnosed OSA (mild in 67 patients, moderate in 89 and severe in 205, respectively). A significant increasing trend based on AHI was observed in the variables of blood pressure, triglycerides, fasting glucose, incident MetS, metabolic score and VAI (all p < 0.05). Irrespective of gender, VAI was all significantly correlated with PSG characteristics as AHI, mean nocturnal oxygen saturation, the lowest oxygen saturation, metabolic score(all p < 0.05). A VAI of 2.282, 2.105, 2.511 (for all subjects, males and females, separately) were calculated to determine the occurrence of MetS. According to the cut-offs, OSA patients tended to suffer from greater risk in MetS (odds ratio [OR] = 10.237, p = 0.000; OR = 13.556, p = 0.000; OR = 21.458, p = 0.000).

Conclusions

The present study suggested that VAI was significantly associated with MetS and OSA. As a simple and alternative approach obtained in everyday practice, it may offer a powerful tool to identify patients with OSA at risk of MetS.

Meta-analyses of the Association of Sleep Apnea with Insulin Resistance, and the Effects of CPAP on HOMA-IR, Adiponectin, and Visceral Adipose Fat

OBJECTIVE

We sought to conduct an updated meta-analysis of randomized controlled trials (RCTs) on the effect of continuous positive airway pressure (CPAP) on insulin resistance, as measured by homeostasis model assessment of insulin resistance (HOMA-IR), visceral abdominal fat (VAF), and adiponectin. Additionally, we performed a separate meta-analysis and meta-regression of studies on the association of insulin resistance and obstructive sleep apnea (OSA).

METHODS

All included studies were searched from PubMed (from conception to March 15, 2014). Data were pooled across all included RCTs as the mean difference in HOMA-IR and VAF, and as the standardized mean difference in the case of adiponectin analysis. From the included case-control studies, data on the difference of HOMA-IR between cases and controls were pooled across all studies, as the standardized mean difference (SMD).

RESULTS

There was a significant difference in HOMA-IR (-0.43 [95% CIs: -0.75 to -0.11], p = 0.008) between CPAP treated and non CPAP treated participants. However, there was no significant difference in VAF or adiponectin; (-47.93 [95% CI: -112.58 to 16.72], p = 0.14) and (-0.06 [95% CI: -0.28 to 0.15], p = 0.56), respectively. Meta-analysis of 16 case-control studies showed a pooled SMD in HOMA-IR of 0.51 (95% CI: 0.28 to 0.75), p ≤ 0.001, between cases and controls.

CONCLUSIONS

The results of our meta-analyses show that CPAP has a favorable effect on insulin resistance. This effect is not associated with any significant changes in total adiponectin levels or amount of VAF. Our findings also confirm a significant association between OSA and insulin resistance.

Significantly increased visceral adiposity index in prehypertension

Background

The prevalence of prehypertension has increased in China, and prehypertension frequently progress to hypertension over a short time period; both have become public health problems. Therefore, this study was conducted to determine the relationship between the Visceral Adiposity Index (VAI) and blood pressure (BP) in China.

Methods

A cross-sectional epidemiological survey was conducted in China using a stratified random cluster sampling method. Sex-specific VAI quartile cut-off points were used as follows: 0.88, 1.41, 2.45 in males and 0.85, 1.33, 2.22 in females. Prehypertension and hypertension were each defined according to The Seventh Report of the Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) guidelines. A multivariate logistic analysis was conducted to analyze the relationship among VAI, prehypertension and hypertension.

Results

The ORs for prehypertension and hypertension in the upper quartiles of the VAI were 1.514 (1.074-2.133), P=0.018 and 1.660 (1.084-2.542), P=0.020, in males, after adjusting for age, education, smoking habits, alcohol consumption, physical activity, serum creatinine, fasting glucose, and plasma insulin. Following further adjustments for the above confounders, chronic kidney disease, and diabetes, the ORs for prehypertension and hypertension in the upper quartile of the VAI were 1.660 1.533 (1.086-2.165), P=0.015, and 1.743 (1.133-2.680), P=0.011, in males. The ORs for prehypertension and hypertension in the upper quartile of the VAI were 1.691 (1.223-2.338), P=0.001, and 1.682 (1.162-2.435), P=0.006, in females, after adjusting for age, education, smoking habits, alcohol consumption, physical activity, serum creatinine, fasting glucose, and plasma insulin. Following further adjustments for the above confounders, chronic kidney disease, and diabetes, the ORs for prehypertension and hypertension in the upper quartile of the VAI were 1.688 (1.220-2.334), P=0.002, and 1.657 (1.141-2.406), P=0.008, in females.

Conclusions

A higher VAI was positively associated with both prehypertension and hypertension in both males and females. It is both essential and urgent that clinicians take steps to control and prevent visceral adiposity.

Surrogate markers of visceral adiposity in young adults: waist circumference and body mass index are more accurate than waist hip ratio, model of adipose distribution and visceral adiposity index

Surrogate indexes of visceral adiposity, a major risk factor for metabolic and cardiovascular disorders, are routinely used in clinical practice because objective measurements of visceral adiposity are expensive, may involve exposure to radiation, and their availability is limited. We compared several surrogate indexes of visceral adiposity with ultrasound assessment of subcutaneous and visceral adipose tissue depots in 99 young Caucasian adults, including 20 women without androgen excess, 53 women with polycystic ovary syndrome, and 26 men. Obesity was present in 7, 21, and 7 subjects, respectively. We obtained body mass index (BMI), waist circumference (WC), waist-hip ratio (WHR), model of adipose distribution (MOAD), visceral adiposity index (VAI), and ultrasound measurements of subcutaneous and visceral adipose tissue depots and hepatic steatosis. WC and BMI showed the strongest correlations with ultrasound measurements of visceral adiposity. Only WHR correlated with sex hormones. Linear stepwise regression models including VAI were only slightly stronger than models including BMI or WC in explaining the variability in the insulin sensitivity index (yet BMI and WC had higher individual standardized coefficients of regression), and these models were superior to those including WHR and MOAD. WC showed 0.94 (95% confidence interval 0.88-0.99) and BMI showed 0.91 (0.85-0.98) probability of identifying the presence of hepatic steatosis according to receiver operating characteristic curve analysis. In conclusion, WC and BMI not only the simplest to obtain, but are also the most accurate surrogate markers of visceral adiposity in young adults, and are good indicators of insulin resistance and powerful predictors of the presence of hepatic steatosis.

Visceral adiposity index and risks of cardiovascular events and mortality in prevalent hemodialysis patients

Background

The visceral adiposity index (VAI) is a newly-derived measure of visceral adiposity with well-validated predictive power for cardiovascular (CV) outcomes in the general population. However, this predictability has not been investigated in hemodialysis patients, and whether VAI is superior to waist circumference (WC) and waist-to-height ratio (WHtR) in predicting CV outcomes and survival in hemodialysis patients remains unknown.

Methods

We performed a prospective study including 464 prevalent hemodialysis patients. The composite outcome was the occurrence of death and CV events during follow-up. Using multivariate Cox regression analysis, VAI, WC and WHtR were tested for the predictive power of outcomes. To evaluate the predictive performance of the VAI, WC and WHtR, time-dependent receiver operating characteristic curve (ROC) analysis was performed.

Results

VAI, WC and WHtR positively correlated with each other. Patients with a higher VAI (tertile 3 vs. tertile 1, adjusted hazard ratio (HR), 1.65; 95% confidence interval (CI), 1.12-2.42; tertile 2 vs. tertile 1, adjusted HR, 1.52; 95% CI, 1.1-2.18) had more composite outcomes. VAI had a similar predictive power of all-cause mortality to WC and WHtR, but superior predictive power of composite and CV outcomes to WC when analyzed by a stepwise forward likelihood ratio test. In time-dependent ROC analysis, VAI, WC and WHtR showed similar predictive performance for outcomes.

Conclusion

VAI is an optimal method to measure visceral adiposity to assess long-term CV outcomes and all-cause mortality in prevalent hemodialysis patients. VAI may provide a superior predictive power of CV outcomes to WC and WHtR.

Trial registration

ClinicalTrials.gov NCT01457625

Visceral adiposity index: an indicator of adipose tissue dysfunction

The Visceral Adiposity Index (VAI) has recently proven to be an indicator of adipose distribution and function that indirectly expresses cardiometabolic risk. In addition, VAI has been proposed as a useful tool for early detection of a condition of cardiometabolic risk before it develops into an overt metabolic syndrome. The application of the VAI in particular populations of patients (women with polycystic ovary syndrome, patients with acromegaly, patients with NAFLD/NASH, patients with HCV hepatitis, patients with type 2 diabetes, and general population) has produced interesting results, which have led to the hypothesis that the VAI could be considered a marker of adipose tissue dysfunction. Unfortunately, in some cases, on the same patient population, there is conflicting evidence. We think that this could be mainly due to a lack of knowledge of the application limits of the index, on the part of various authors, and to having applied the VAI in non-Caucasian populations. Future prospective studies could certainly better define the possible usefulness of the VAI as a predictor of cardiometabolic risk.