Psychometrics of the Greek Chronic Liver Disease Questionnaire for Measuring HRQL.

The aim of the present study is to examine psychometric properties such as internal consistency reliability and construct validity of the Greek CLDQ. A sample of 366 eligible patients with chronic liver disease (CLD) self-administered the Greek version of the SF-36 Health Survey, the Chronic Liver Disease Questionnaire (CLDQ), and questions on sociodemographic status and treatment. Child Pugh Score was also collected. Hypothesized scale structure, reliability (Cronbach's alpha), and construct validity (convergent, discriminant, and known groups) were assessed. Multitrait scaling confirmed scale structure of the CLDQ with good item convergence (100%) and discrimination (84.1%) rates. Cronbach's alpha rated >0.70 for all scales. Spearman's correlations between the CLDQ and SF-36 scales assessing similar health-related quality of life dimensions were strong ranging above 0.70 (P < 0.0001). Construct validity was confirmed with satisfactory results for known-group comparisons. Most CLDQ scales discriminated significantly between patients according to disease severity, whereas all CLDQ scales discriminated between treatment receivers and nonreceivers. The overall psychometric results for the Greek version of the CLDQ confirmed it as a reliable and valid questionnaire.

Urine levels of catecholamines in Greek children with obstructive sleep-disordered breathing.

INTRODUCTION: Adults with obstructive sleep apnea have increased sympathetic activity. It was hypothesized that in children with symptoms of obstructive sleep-disordered breathing (SDB), morning urine levels of catecholamines correlate with severity of nocturnal hypoxemia. METHODS: Children with snoring referred for polysomnography and controls without snoring were recruited. Morning urine norepinephrine, epinephrine, normetanephrine, and metanephrine levels were measured (ng/mg urine creatinine). RESULTS: Twelve children (age 5.2 +/- 2.3 years) with severe hypoxemia (oxygen saturation of hemoglobin-SpO2 nadir < or =86%), 20 subjects (age 6.1 +/- 2.1 years) with moderate hypoxemia (SpO2 nadir < or =90% and >86%), 22 children (age 6.6 +/- 1.5 years) with mild nocturnal hypoxemia (SpO2 nadir >90%), and 10 controls (age 7.1 +/- 2.8 years) were studied. Children with severe hypoxemia had significantly higher log-transformed norepinephrine levels (1.63 +/- 0.29) compared to those with moderate hypoxemia (1.43 +/- 0.22; P < 0.05) or compared to controls (1.39 +/- 0.31; P < 0.05). In subjects with SDB, log-transformed oxygen desaturation of hemoglobin index or SpO2 nadir predicted log-transformed norepinephrine levels after adjustment by age, gender and body mass index (r2 = 0.24; and r2 = 0.24, respectively; P < 0.01). CONCLUSIONS: Severity of nocturnal hypoxemia in children with intermittent upper airway obstruction during sleep correlates with morning urine levels of norepinephrine suggesting increased sympathetic tone.

Adiposity in relation to age as predictor of severity of sleep apnea in children with snoring.

Correlation between obesity and obstructive sleep apnea has been documented in both adults and children. This investigation evaluated importance of body mass index (BMI) in relation to age as predictor of severity of obstructive sleep-disordered breathing (SDB). Children with habitual snoring referred for polysomnography were recruited. BMI Z score (> or =1.036 vs <1.036, i.e. at risk for overweight or overweight vs normal) was assessed as predictor of severity of SDB (apnea-hypopnea index [AHI] >five vs < or =five episodes per hour) at different ages (< or =6 vs >6 years). Two hundered eighty-four participants were recruited: 75 young children (4.6 +/- 1 years) with high BMI (1.9 +/- 0.7); 95 young subjects (4.5 +/- 1.1 years) with low BMI (-0.2 +/- 1.3); 55 older children (9.2 +/- 1.8 years) with high BMI (1.8 +/- 0.5); and 59 older participants (9.7 +/- 2.2 years) with low BMI (-0.2 +/- 1.1). Odds ratios for AHI >5 in young/high BMI children, young/low BMI subjects, and older/high BMI subjects relative to older/low BMI participants were: 6.5 (95% confidence interval 2.1-19.9), 7.3 (2.4-22) and 2 (0.6-7.3), respectively. Large tonsil size was associated with young age (odds ratio 1.97; 1.2-3.3). Among children with habitual snoring, adiposity does not predict severity of obstructive SDB in early childhood probably due to the prominent role of adenotonsillar hypertrophy. However, it may have a more important contribution to severity of SDB in older children.

Nocturnal change of circulating intercellular adhesion molecule 1 levels in children with snoring.

Hypoxia promotes adherence of leukocytes to endothelial cells by inducing expression of adhesion molecules like intercellular adhesion molecule 1 (ICAM-1). Increased serum levels of circulating ICAM-1 (cICAM-1) have been reported in adults with sleep apnea and associated hypoxemia. This investigation assessed the hypothesis that the overnight change of cICAM-1 levels in children with snoring is correlated with the severity of obstructive sleep-disordered breathing. Evening and morning serum levels of cICAM-1 were measured in children with snoring referred for polysomnography. Twenty-five children with an apnea-hypopnea index greater than or equal to 5 episodes/h (5.5 +/- 1.8 years), 30 subjects with an index less than 5 and greater than 1 (6.3 +/- 2 years), and 19 children with an index less than or equal to 1 (7.1 +/- 3 years) were recruited. Overnight change in cICAM-1 (log-transformed ratio of morning-to-evening levels) was similar in subjects with an apnea-hypopnea index greater than or equal to 5 episodes/h compared to those with an index less than 5 and greater than 1 or to children with an index less than or equal to 1 (-0.001 +/- 0.08 vs -0.03 +/- 0.09 vs -0.06 +/- 0.1; p > 0.05). When multiple regression analysis was applied, apnea-hypopnea index, respiratory arousal index, and oxygen saturation of hemoglobin nadir were not significant predictors of overnight change in cICAM-1 levels. Thus, in children with snoring, overnight change in cICAM-1 levels is not related to severity of obstructive sleep-disordered breathing.

Overnight change in brain natriuretic peptide levels in children with sleep-disordered breathing.

STUDY OBJECTIVES: Obstructive sleep-disordered breathing is accompanied by episodic increases in left ventricle afterload due to large negative swings in intrathoracic pressure and repetitive surges in arterial pressure. Brain natriuretic peptide (BNP) is released by ventricular myocytes in response to pressure and volume overload. It was hypothesized that in children with snoring, overnight change in BNP levels is correlated with severity of disturbance in respiration. DESIGN: Evening and morning plasma levels of BNP were measured in children with snoring referred for polysomnography. SETTING: A sleep disorders laboratory in a university hospital. PARTICIPANTS: Twenty-two children with apnea-hypopnea index (AHI) > or = 5/h (mean +/- SD age, 6.4 +/- 2.5 years), 60 children with AHI < 5/h (mean age, 7 +/- 2.9 years), and 27 control subjects without snoring (mean age, 7.8 +/- 3.7 years) were recruited. MEASUREMENTS AND RESULTS: Overnight change in BNP (log-transformed ratio of morning-to-evening levels) was larger in children with AHI > or = 5/h, compared to those with AHI < 5/h or to control subjects (0.1 +/- 0.19 vs 0.01 +/- 0.14 vs - 0.06 +/- 0.18; p < 0.05). Children with AHI > or = 5/h had an odds ratio of 4.33 (95% confidence interval, 1.34 to 14) for change in peptide levels > 0.15 relatively to subjects with AHI < 5/h. AHI and oxygen saturation of hemoglobin nadir were significant predictors of overnight change in peptide levels. CONCLUSIONS: In children with snoring, overnight increase in BNP levels is correlated with severity of disturbance in respiration during sleep, which may indicate presence of nocturnal cardiac strain.