Pantelis Andreou

The Case for Using the Repeatability Coefficient When Calculating Test-Retest Reliability

The use of standardised tools is an essential component of evidence-based practice. Reliance on standardised tools places demands on clinicians to understand their properties, strengths, and weaknesses, in order to interpret results and make clinical decisions. This paper makes a case for clinicians to consider measurement error (ME) indices Coefficient of Repeatability (CR) or the Smallest Real Difference (SRD) over relative reliability coefficients like the Pearson’s (r) and the Intraclass Correlation Coefficient (ICC), while selecting tools to measure change and inferring change as true. The authors present statistical methods that are part of the current approach to evaluate test–retest reliability of assessment tools and outcome measurements. Selected examples from a previous test–retest study are used to elucidate the added advantages of knowledge of the ME of an assessment tool in clinical decision making. The CR is computed in the same units as the assessment tool and sets the boundary of the minimal detectable true change that can be measured by the tool.

Frailty in NHANES: Comparing the frailty index and phenotype

The two most commonly employed frailty measures are the frailty phenotype and the frailty index. We compared them to examine whether they demonstrated common characteristics of frailty scales, and to examine their association with adverse health measures including disability, self-reported health, and healthcare utilization. The study examined adults aged 50+ (n=4096) from a sequential, cross-sectional sample (2003-2004; 2005-2006), National Health and Nutrition Examination Survey. The frailty phenotype was modified from a previously adapted version and a 46-item frailty index was created following a standard protocol. Both measures demonstrated a right-skewed distribution, higher levels of frailty in women, exponential increase with age and associations with high healthcare utilization and poor self-reported health. More people classified as frail by the modified phenotype had ADL disability (97.8%) compared with the frailty index (56.6%) and similarly for IADL disability (95% vs. 85.6%). The prevalence of frailty was 3.6% using the modified frailty phenotype and 34% using the frailty index. Frailty index scores in those who were classified as robust by the modified phenotype were still significantly associated with poor self-reported health and high healthcare utilization. The frailty index and the modified frailty phenotype each confirmed previously established characteristics of frailty scales. The agreement between frailty and disability was high with each measure, suggesting that frailty is not simply a pre-disability stage. Overall, the frailty index classified more people as frail, and suggested that it may have the ability to discriminate better at the lower to middle end of the frailty continuum.

The effect of two configuration factors, time, and thermal cycling on resin to dentin bond strengths

Most in vitro testing of bonding systems is performed using specimens made in a mold with a low configuration (C) factor (ratio of bonded/unbonded surfaces) whereas clinically the C-factor is usually much greater. This study compared the effect of thermal cycling on the measured shear bond strength of 3M Single Bond dental adhesive bonded to dentin using molds with two different C-factors. The hypothesis was that neither C-factor nor thermal cycling would affect measured bond strengths. Resin composite was bonded to human dentin in cylindrical molds with an internal diameter of 3.2mm and either 1mm or 2.5mm deep. The 1mm deep molds had a C-factor of 2.2 and the 2.5mm deep molds had a C-factor of 4.1. Specimens were debonded either 10min after they had been bonded to dentin, or after they had been stored for 7 days in water at 37+/-1 degrees C, or after thermal cycling 5000 times for 7 days. Two-way ANOVA showed that overall both the C-factor and the storage condition had a significant effect on bond strength (p<0.001). There was a significant interaction (p<0.001) between the C-factor and how the specimens had been stored. The GLM/LSMEANS procedure with Sidaks adjustment for multiple comparisons showed that overall the specimens made in the mold with a high C-factor (4.1) had a lower bond strength than those that had been made in the mold with a lower (2.2) C-factor (p<0.001). Thermal cycling had a negative effect on the bond strength only for specimens made in molds with a C-factor of 4.1 (p<0.001).

The association between sedentary behaviour, moderate–vigorous physical activity and frailty in NHANES cohorts

OBJECTIVES (1) To examine how sedentary behaviour and moderate-vigorous (MVPA) are each experienced during the day across different levels of frailty; (2) estimate and compare the extent to which high levels of sedentary behaviour and low levels of MVPA are associated with increased frailty and self-reported health, disability and healthcare utilization. METHODS Community dwelling adults aged 50+ from the National Health and Nutrition Examination Survey (2003-2004; 2005-2006). Frailty was measured with the frailty index and physical activity was measured using ActiGraph accelerometers. RESULTS On average, people engaged in about 8.5h of sedentary behaviour each day. The most frail individuals were more sedentary and less likely to meet weekly MVPA guidelines (9.57 h/day; 8.3%) than non-frail individuals (8.18 h/day; 1.1%; p<0.001). Frail individuals failed to demonstrate the patterns of the healthier individuals-higher levels of sedentary behaviour on Sundays and in the evenings and decreasing MVPA throughout the week. High sedentary behaviour and low MVPA were independently associated with higher levels of frailty, poor self-reported health, high ADL disability and higher healthcare usage. CONCLUSIONS Many people over the age of 50, and most of those who are frail, were highly sedentary with very few meeting the recommended weekly levels of MVPA. Sedentary behaviour and MVPA were independently associated with frailty and adverse health outcomes in middle to older aged adults. Future research should focus on a longitudinal study to determine the temporal relationship between sedentary behaviour and frailty.

Achievement of non-cognitive goals of undergraduate medical education: perceptions of medical students, residents, faculty and other health professionals

Background  Professionalism is increasingly emphasised in medical education. Non‐cognitive goals, including values, attitudes and skills, remain challenging to define and measure. The purpose of this study was to better understand these goals and their achievement in the MD programme.

The utilization of antidepressants and benzodiazepines among people with major depression in Canada

Objective: Although clinical guidelines recommend monotherapy with antidepressants (ADs) for major depression, polypharmacy with benzodiazepines (BDZs) remains an issue. Risks associated with such treatments include tolerance and dependence, among others. We assessed the prevalence and determinants of AD and BDZ utilization among Canadians who experienced a major depressive episode (MDE) in the previous 12 months, and determined the association of seeing a psychiatrist on the utilization of ADs and BDZs. Method: Data were drawn from the 2002 Canadian Community Health Survey: Health and Well-Being, a nationally representative sample of Canadians aged 15 years and older. Descriptive statistics quantified utilization, while logistic regression identified factors associated with utilization, such as sociodemographic characteristics or type of physician seen. Sampling weights and bootstrap variance estimations were used for all analysis. Results: The overall prevalence of AD and BDZ utilization was 49.3% of respondents who experienced an MDE in the past 12 months and reported AD use. Key determinants of utilization were younger age and unemployment in the past week (OR 2.6; P < 0.001). Being seen by a psychiatrist increased utilization (OR 2.5; P < 0.001), possibly because psychiatrists were seeing patients with severe depression. Conclusion: A large proportion of people with past-year MDEs utilized ADs and BDZs. It is unclear how much of this is appropriate given that evidence-based clinical guidelines recommend monotherapy with ADs in the treatment of major depression.

The Effect of Comorbidity on the Competing Risk of Sudden and Nonsudden Death in an Ambulatory Heart Failure Population

BACKGROUND Sudden death (SD) and non-sudden cardiac death are responsible for the majority of deaths in patients with heart failure. We sought to identify the influence of comorbid illness (Charlson Comorbidity Index [CCI]) on competing modes of death in heart failure. METHODS A retrospective analysis of 824 patients followed in a tertiary care heart failure clinic was performed. We analyzed the cumulative incidence of sudden and nonsudden death. Competing risk regression was used to examine the association between medical comorbidities and mode of death. The outcomes of interest were overall mortality, SD, SD and/or appropriate implantable cardioverter-defibrillator therapy (ICD), and non-SD. RESULTS Mean age of the study population was 64.1 ± 14.7 years, 68.6% were male, and mean ejection fraction was 32.8% ± 13.5%. Over a mean follow-up of 4.4 years, 229 patients (27.8%) died. SD accounted for 33 deaths (14.4%), whereas SD/appropriate ICD therapy occurred in 56 patients (24.5%). The risk of non-SD and total mortality increased (P < .0001) as the CCI increased, whereas the risk of SD decreased (P = .03). The cumulative incidence of SD, SD and/or ventricular tachycardia/fibrillation, and non-SD at 5 years was 5.6%, 9.1%, and 27.8%, respectively. In multivariate competing risk analysis, advancing age, New York Heart Association class, and a CCI >4 were significantly associated with non-SD. CONCLUSION Patients with heart failure with significant comorbidities are much more likely to sustain non-SD. These findings may have implications in optimal selection of patients with heart failure for interventions such as prophylactic ICD therapy.

A comparison of factors used by physicians and patients in the selection of antidepressant agents

OBJECTIVES Involving patients in treatment decisions may reduce premature antidepressant treatment terminations and improve clinical and health economic outcomes. However, a first step is to determine what information to provide to patients to facilitate their decision making. The authors therefore identified, valued, and ranked factors of antidepressant treatment selection that are relevant to patients and compared them with the opinions of general practitioners. METHODS Matching surveys were developed for patients and physicians with feedback from focus groups. In the patient group, participation was requested from consecutive patients at four family practice sites in Nova Scotia, Canada. Surveys were mailed to 247 randomly selected general practitioners. RESULTS Surveys were completed by 127 patients and 110 physicians, representing return rates of 70% and 46%, respectively. The most valued of the 12 differentiating factors when selecting an antidepressant, ranked first by both patients and physicians, was common side effects. Also ranked highly by both groups were precautions with antidepressant use, physician antidepressant experience, and discontinuation problems. Groups differed in their ranking of uncommon serious side effects, time since antidepressants were marketed, cost, and dosing schedule. The ranking distributions were significantly different for six of 12 factors between patients and general practitioners (Wilcoxon ranked-sum test). Patient experience with antidepressants did not influence factor value. CONCLUSIONS The data demonstrate moderate disagreement between patients and general practitioners regarding the relative value of antidepressant selection factors. The effect of this disagreement on treatment adherence and other outcomes requires further investigation, as improving patient-physician concordance regarding antidepressant choices may lead to improved treatment acceptance.

Chronic disease risk factors associated with health service use in the elderly

BackgroundTo examine the association between number and combination of chronic disease risk factors on health service use.MethodsData from the 1995 Nova Scotia Health Survey (n = 2,653) was linked to provincial health services administrative databases. Multivariate regression models were developed that included important interactions between risk factors and were stratified by sex and at age 50. Negative-binomial regression models were estimated using generalized estimating equations assuming an autoregressive covariance structure.ResultsAs the number of chronic disease risk factors increased so did the number of annual general practitioner visits, specialist visits and days spent in hospital in people aged 50 and older. This was not seen among individuals under age 50. Comparison of smokers, people with high blood pressure and people with high cholesterol showed no significantly different impact on health service use.ConclusionAs the number of chronic disease risk factors increased so did health service use among individuals over age 50 but risk factor combination had no impact.

Role of the fractalkine receptor CX3CR1 polymorphisms V249I and T280M as risk factors for early‐onset coronary artery disease in patients with no classic risk factors

Objectives. CX3CR1 is a monocyte chemokine receptor and adhesion molecule. Two CX3CR1 mutations, V249I and T280M, reportedly decrease coronary artery disease (CAD) risk independent of established risk factors. An I249 protective effect is attributed to reducing CX3CR1 binding to fractalkine, its ligand. Material and methods. We examined the frequencies of V249I and T280M among early‐onset CAD patients (G1; n = 149; <50 years), late‐onset CAD patients (G2; n = 150; >65 years) and healthy controls (HC; n = 149, 47–93 years) without known CAD risk factors. We compared plasma total cholesterol (TC)/high density lipoprotein‐C (HDL‐C) and apolipoprotein B (APOB)/apolipoprotein AI (APOAI) ratios among the groups and mutation carriers and non‐carriers, and the prevalence of the mutations in G1 and G2 patients with multiple coronary vessel disease (MVD) and myocardial infarction (MI). Results. G1 patients had non‐significantly lower frequencies of I249 versus (vs.) G2 or controls (G1; 51 %, G2: 61 %, controls: 58 %, p = 0.19), with no difference in T280M (p = 0.8). TC/HDL‐C and APOB/APOAI ratios were significantly higher in G1 patients vs. G2 and controls (p<0.0001) independently of either mutation. More G2 patients had MVD than younger ones (p<0.0001); however, more G1 patients were homozygous for V249 compared to G2 patients, who more often had the I249 allele (p<0.02). There was no such association with T280M (p = 0.38). Although more G1 patients had MI, this was not mutation related. Conclusions. There were significantly higher lipid ratios in G1 compared to G2 and HC (G1>G2>HC), but not in mutation prevalence. I249 mutation was associated with MVD in older patients, while V249 homozygosity was associated with the early‐onset CAD. Neither allele affected MI or lipid levels.