Boliang Guo

Relative effectiveness of clinic and home blood pressure monitoring compared with ambulatory blood pressure monitoring in diagnosis of hypertension: Systematic review

Objective To determine the relative accuracy of clinic measurements and home blood pressure monitoring compared with ambulatory blood pressure monitoring as a reference standard for the diagnosis of hypertension. Design Systematic review with meta-analysis with hierarchical summary receiver operating characteristic models. Methodological quality was appraised, including evidence of validation of blood pressure measurement equipment. Data sources Medline (from 1966), Embase (from 1980), Cochrane Database of Systematic Reviews, DARE, Medion, ARIF, and TRIP up to May 2010. Eligibility criteria for selecting studies Eligible studies examined diagnosis of hypertension in adults of all ages using home and/or clinic blood pressure measurement compared with those made using ambulatory monitoring that clearly defined thresholds to diagnose hypertension. Results The 20 eligible studies used various thresholds for the diagnosis of hypertension, and only seven studies (clinic) and three studies (home) could be directly compared with ambulatory monitoring. Compared with ambulatory monitoring thresholds of 135/85 mm Hg, clinic measurements over 140/90 mm Hg had mean sensitivity and specificity of 74.6% (95% confidence interval 60.7% to 84.8%) and 74.6% (47.9% to 90.4%), respectively, whereas home measurements over 135/85 mm Hg had mean sensitivity and specificity of 85.7% (78.0% to 91.0%) and 62.4% (48.0% to 75.0%). Conclusions Neither clinic nor home measurement had sufficient sensitivity or specificity to be recommended as a single diagnostic test. If ambulatory monitoring is taken as the reference standard, then treatment decisions based on clinic or home blood pressure alone might result in substantial overdiagnosis. Ambulatory monitoring before the start of lifelong drug treatment might lead to more appropriate targeting of treatment, particularly around the diagnostic threshold.

Association of COMT Val108/158Met genotype with smoking cessation

Objectives We attempted to extend a previous finding of an association of COMT genotype with response to nicotine-replacement therapy (NRT), in a larger cohort of treatment-seeking smokers, with greater statistical power to detect possible moderating effects of sex. We also investigated the association of the COMT genotype with withdrawal and mood symptoms, to identify possible mediating mechanisms by which the COMT genotype might influence response to NRT. Methods Participants were eligible if they were aged 18 years or older, and if they smoked 10 cigarettes per day or more; they were recruited from 26 general practice clinics in Buckinghamshire and Oxfordshire in the United Kingdom. All participants received 8 weeks of 15-mg NRT transdermal patch. Confirmation of abstinence was defined as an exhaled CO of less than 10 parts per million (ppm), or salivary cotinine concentration of less than 15 ng/ml. Results Cox regression analysis indicated a significant effect of the COMT genotype on relapse into smoking (P=0.001), with shorter times to relapse being observed among the AG (Val/Met) and GG (Val/Val) genotype groups. These effects were observed both during active treatment and as soon as active treatment had ended. The effect, however, was greater, once active treatment had ended, in the subgroup of smokers who had abstained up to this point. We did not observe any evidence of a sex difference in the effect of the COMT genotype. These effects did not seem to be mediated by self-reported withdrawal or mood symptoms. Conclusions Our results indicate that the COMT genotype is associated with the likelihood of smoking cessation in smokers treated with the NRT transdermal patch. Future large-scale studies will be required to afford sufficient power to simultaneously investigate the role of multiple genetic variants in treatment responses, and the effects of potential moderating variables on these associations.

Performance of methods for meta-analysis of diagnostic test accuracy with few studies or sparse data:

Hierarchical models such as the bivariate and hierarchical summary receiver operating characteristic (HSROC) models are recommended for meta-analysis of test accuracy studies. These models are challenging to fit when there are few studies and/or sparse data (for example zero cells in contingency tables due to studies reporting 100% sensitivity or specificity); the models may not converge, or give unreliable parameter estimates. Using simulation, we investigated the performance of seven hierarchical models incorporating increasing simplifications in scenarios designed to replicate realistic situations for meta-analysis of test accuracy studies. Performance of the models was assessed in terms of estimability (percentage of meta-analyses that successfully converged and percentage where the between study correlation was estimable), bias, mean square error and coverage of the 95% confidence intervals. Our results indicate that simpler hierarchical models are valid in situations with few studies or sparse data. For synthesis of sensitivity and specificity, univariate random effects logistic regression models are appropriate when a bivariate model cannot be fitted. Alternatively, an HSROC model that assumes a symmetric SROC curve (by excluding the shape parameter) can be used if the HSROC model is the chosen meta-analytic approach. In the absence of heterogeneity, fixed effect equivalent of the models can be applied.

Individual participant data meta-analyses should not ignore clustering

Objectives Individual participant data (IPD) meta-analyses often analyze their IPD as if coming from a single study. We compare this approach with analyses that rather account for clustering of patients within studies. Study Design and Setting Comparison of effect estimates from logistic regression models in real and simulated examples. Results The estimated prognostic effect of age in patients with traumatic brain injury is similar, regardless of whether clustering is accounted for. However, a family history of thrombophilia is found to be a diagnostic marker of deep vein thrombosis [odds ratio, 1.30; 95% confidence interval (CI): 1.00, 1.70; P = 0.05] when clustering is accounted for but not when it is ignored (odds ratio, 1.06; 95% CI: 0.83, 1.37; P = 0.64). Similarly, the treatment effect of nicotine gum on smoking cessation is severely attenuated when clustering is ignored (odds ratio, 1.40; 95% CI: 1.02, 1.92) rather than accounted for (odds ratio, 1.80; 95% CI: 1.29, 2.52). Simulations show models accounting for clustering perform consistently well, but downwardly biased effect estimates and low coverage can occur when ignoring clustering. Conclusion Researchers must routinely account for clustering in IPD meta-analyses; otherwise, misleading effect estimates and conclusions may arise.

Genetic variation in the serotonin pathway and smoking cessation with nicotine replacement therapy: new data from the Patch in Practice trial and pooled analyses.

The serotonin pathway has been implicated in nicotine dependence and may influence smoking cessation. Therefore, 792 cigarette smokers from the Patch in Practice trial were genotyped for the tryptophan hydroxylase (TPH1 A779C), serotonin transporter (SLC6A45-HTTLPR), and 5-HT1A (HTR1A C-1019G) polymorphisms. Cox regression analysis did not demonstrate significant effects of any of the three genotypes on relapse to smoking: TPH1 (Reference AA; AC: hazard ratio (HR) 0.99, 95% confidence interval (CI) 0.78, 1.24, p=0.90; CC: HR 0.93, 95% CI 0.73, 1.18, p=0.55); 5-HTTLPR (Reference LL; SL: HR 1.01, 95% CI 0.85, 1.20, p=0.90; SS: HR 1.13, 95% CI 0.91, 1.39, p=0.27); HTR1A (Reference CC; CG: HR 1.04, 95% CI 0.86, 1.25, p=0.70; GG: HR 1.01, 95% CI 0.82, 1.24, p=0.93). Moreover, pooled analyses of data from all three extant pharmacogenetic NRT trials (N=1398) found no significant effect of 5-HTTLPR genotype on continuous abstinence at 12-week (Reference LL; SL: odds ratio (OR)=1.25, 95% CI 0.89, 1.74, p=0.19; SS: OR=1.31, 95% CI 0.86, 1.98, p=0.21) or 26-week follow-up (Reference LL; SL: OR=0.93, 95% CI 0.64, 1.33, p=0.68; SS: OR=1.00, 95% CI 0.63, 1.58, p=1.00). These data do not support a statistically or clinically significant moderating effect of these specific 5-HT pathway genetic variants on smoking cessation. However, the possibility remains that other variants in these or other 5-HT genes may influence NRT efficacy for smoking cessation in treatment seeking smokers.

Testing the convergent and discriminant validity of the Decisional Balance Scale of the Transtheoretical Model using the Multi-Trait Multi-Method approach.

The authors extended research on the construct validity of the Decisional Balance Scale for smoking in adolescence by testing its convergent and discriminant validity. Hierarchical confirmatory factor analysis multi-trait multi-method approach (HCFA MTMM) was used with data from 2,334 UK adolescents, both smokers and non-smokers. They completed computerized and paper versions of the questionnaire on 3 occasions over 2 years. The results indicated a 3-factor solution; Social Pros, Coping Pros, and Cons fit the data best. The HCFA MTMM model fit the data well, with correlated methods and correlated trait factors. Subsequent testing confirmed discriminant validity between the factors and convergent validity of both methods of administering the questionnaire. There was, however, clear evidence of a method effect, which may have arisen due to different response formats or may be a function of the method of presentation. Taken with other data, there is strong evidence for construct validity of Decisional Balance for smoking in adolescence, but evidence of predictive validity is required.

Preliminary studies of the ICD-11 classification of personality disorder in practice

OBJECTIVE This study aims to compare ICD-10 and putative ICD-11 classifications of personality disorder in different clinical populations. DESIGN Prospective recording of ICD-10 and ICD-11 personality disorder classifications was carried out in (1) an anxious medical population, (2) an acute psychiatric in-patient population and (3) a retrospective recording of a mixed anxiety depression cohort in which all baseline data were scored from baseline information using the ICD-11 classification and compared with the original ICD-10 assessments. METHOD Comparison of ICD-10 and ICD-11 prevalence of personality disorder in each population was carried out. RESULTS Data from 722 patients were recorded. Using the ICD-10 criteria, the prevalence of generic personality disorder was 33.8% compared with 40.4% using the ICD-11 ones (χ2  = 6.7; P < 0.01), with 103 (14.3%) discordant assessments. Using the severity definitions in ICD-11, 34.3% of patients had personality difficulty. Severity level varied greatly by population; severe personality disorder was five times more common in the inpatient group. The four domain traits originally denoted as qualifying severity in ICD-11, negative affective, dissocial, anankastic and detached, were linked to anxious, borderline, dissocial, anankastic and schizoid personality disorders in ICD-10. Many patients had pathology in two or more domains. CONCLUSIONS The ICD-11 classification of personality disorder yields somewhat higher levels of personality dysfunction than ICD-10, possibly because the age range for the onset of diagnosis is now flexible. The range of severity levels make the classification more useful than ICD-10 in clinical practice as it identifies the greater pathology necessary for intervention.

Health promotion in older Chinese: a 12-month cluster randomized controlled trial of pedometry and "peer support".

PURPOSE Aging, in conjunction with decreasing physical activity, is associated with a range of health problems. Simple, low-maintenance, population-based means of promoting activity to counteract the age-associated decline are required. We therefore assessed the effect of pedometry and buddy support to increase physical activity. METHODS We undertook a clustered randomized trial (HKCTR-346) of 24 community centers involving 399 older Chinese participants (≥ 60 yr). Centers were randomly allocated to 1) pedometry and buddy, 2) pedometry and no buddy, 3) no pedometry and buddy, and 4) no pedometry and no buddy with a 2 × 2 factorial design. The trial simultaneously tested the individual and combined effects of the interventions. The intervention groups also received monthly organized group activities to provide encouragement and support. Outcome measures were assessed at 6 and 12 months, including physical fitness and activity and cardiovascular disease risk factors (anthropometry and blood pressure). RESULTS From the 24 centers, 356 volunteers (89.2%) completed the study. Those receiving the interventions had higher mean physical activity levels at 12 months of 1820 (95% confidence interval (CI) = 1360-2290) and 1260 (95% CI = 780-1740) MET·min·wk(-1), respectively relative to the decrease in the control groups. The buddy peer support intervention significantly improved mean aerobic fitness (12% [95% CI = 4%-21%]) and reduced both body fat (-0.6% [95% CI = -1.1% to 0.0%]) and time to complete the 2.5-m get-up-and-go test (-0.27 [95% CI = -0.53 to -0.01] s). No other improvements in the cardiovascular disease risk factors were observed. The combination of motivational tools was no better than the individual interventions. CONCLUSIONS Both motivational interventions increased physical activity levels, and the buddy style improved fitness. These tools could be useful adjuncts in the prevention of obesity and age-related complications.

Is attributing smoking to genetic causes associated with a reduced probability of quit attempt success? A cohort study

Aims Pharmacogenetic smoking cessation interventions would involve smokers being given information about the influence of genes on their behaviour. However, attributing smoking to genetic causes may reduce perceived control over smoking, reducing quit attempt success. This study examines whether attributing smoking to genetic influences is associated with reduced quitting and whether this effect is mediated by perceived control over smoking. Design Cohort study. Participants A total of 792 smokers, participating in a trial of nicotine replacement therapy (NRT)-assisted smoking cessation. Participants were informed that the trial investigated relationships between genetic markers and smoking behaviour, but personalized genetic feedback was not provided. Setting Primary care in Oxfordshire and Buckinghamshire, UK. Measurements Perceived control over smoking and perceived importance of genetic factors in causing smoking assessed pre-quit; abstinence 4, 12, 26 and 52 weeks after the start of treatment. Findings A total of 515 smokers (65.0%) viewed genetic factors as playing some role in causing their smoking. They had lower perceived control over smoking than smokers who viewed genetic factors as having no role in causing their smoking. Attributing smoking to genetic causes was not associated significantly with a lower probability of quit attempt success. Conclusions Attributing smoking to genetic factors was associated with lower levels of perceived control over smoking but not lower quit rates. This suggests that learning of ones genetic predisposition to smoking during a pharmacogenetically tailored smoking cessation intervention may not deter quitting. Further research should examine whether the lack of impact of genetic attributions on quit attempt success is also found in smokers provided with personalized genetic feedback.

Do the Transtheoretical Model processes of change, decisional balance and temptation predict stage movement? Evidence from smoking cessation in adolescents

AIMS To examine the effects of processes of change (POC) on forward stage movement directly, indirectly through decisional balance and temptation, and total effects as a test of the key hypothesis of the Transtheoretical Model (TTM). DESIGN Prospective cohort study. SETTING United Kingdom. PARTICIPANTS A total of 1160 adolescents aged 13-14 years who were current or former smokers at baseline. MEASUREMENTS Stage was assessed with the standard algorithm three times, once every 3 months. On each occasion the POC, decisional balance and temptation were measured with the standard questionnaires. Path analysis was used to examine the direct, indirectly mediated and total contribution of POC and the other constructs to stage movement 3 months later. FINDINGS Four of the 24 analyses showed evidence that the theoretically appropriate POC predicted stage transition, with statistically significant total effects. Effect sizes were small. When the POC were summarized to experiential and behavioural process means, one transition from pre-contemplation was predicted by experiential processes and, contrary to the TTM, one transition predicted by behavioural processes. There was slightly more evidence that decisional balance (attitudes towards smoking) and temptation (ability to resist the urge to smoke) was associated with stage transition. CONCLUSIONS POC use was not associated generally with stage transition and evidence that effects, if missed, must be modest, giving no support to the central tenet of the TTM.