Assessing reproducibility for interval data in health-related quality of life questionnaires: Which coefficient should be used?

In contrast to other reliability estimates, test-retest reliability (or reproducibility) captures not only the measurement error of an assessment instrument, but also the stability of the construct measured. Consequently, one would expect any departure from identity (Y = X) of measurement pairs (X first, and Y second measurement) to be treated as 'error' by the respective reproducibility statistic, even if 'true' changes happened, e.g. worsening of a disease due to its natural course. The Pearson correlation, still often advocated for continuous measures in test-retest reliability studies, however captures the degree of linearity (Y = bX + a): perfect relationship can be computed, even if the measurement pairs differ not only by a additive constant 'a', but also because of a multiplication of the X-values with the slope 'b'. Therefore, intraclass correlation coefficients (ICCs) have been proposed as alternative statistics for reproducibility. However, only ICCs with absolute agreement definition of concordance capture the degree of identity. ICCs with a consistency definition of concordance measure the degree of additivity (Y = X + a). ICCs are calculated from repeated measures analyses of variance (ANOVAs), and a common population variance must be is assumed for the different measurements. Given this assumption, an ICC computed from a one-way ANOVA seems to be the best choice for this purpose. Otherwise, Lin's concordance correlation coefficient is recommended as identity measure.     

Dosimetric comparison of intensity-modulated radiation therapy for early-stage glottic cancers with and without the air cavity in the planning target volume

For early-stage glottic cancers, intensity-modulated radiation therapy (IMRT) has been shown to have comparable local control to 3D-conformal radiotherapy with the advantage of decreased dose to the carotid arteries. The planning target volume (PTV) for early glottic cancers typically includes the entire larynx, plus a 3 to 5 mm uniform margin. The air cavity within the larynx creates a challenge for the inverse optimization process as the software attempts to “build up” dose within the air. This unnecessary attempt at dose build-up in air can lead to hot spots within the rest of the PTV and surrounding soft tissue. We hypothesized that removal of the air from the PTV would decrease hot spots and allow for a more homogeneous plan while still maintaining adequate coverage of the PTV.We analyzed 20 consecutive patients with early-stage glottic cancer, T1-2N0, who received IMRT at our institution from April 2015 to December 2016. Each patient received 63 to 65.25 Gy in 2.25 Gy per fraction. Two plans were created for each case: one in which the PTV included the laryngeal air cavity and one in which the air cavity was subtracted from the PTV to create a new PTV-air structure. Dosimetric variables were collected for PTV-air structure from both IMRT plans, including V100%, D98% D2%, and D0.2%. Dosimetric variables for spinal cord and the carotid arteries were also recorded. Homogeneity index (HI) defined as D98/D2 was calculated. Two-sided t-tests were used to compare dosimetric variables.The median PTV volume was 69.9 cc (standard deviation [SD] ± 28.7 cc) and the median air cavity volume removed was 11.0 cc (SD ± 3.4 cc). A 2-sided t-test revealed a statistically significant decrease in max dose (112.7% vs 108.8%, p value = 0.0002) and improvement of HI (0.93 vs 0.91, p value = 0.0023) for the PTV air in the IMRT plan optimized for PTV air, which had air excluded, compared to the IMRT plan optimized for PTV with air included. There was no significant worsening of PTV-air coverage or significant increase in doses to the organs at risk (OARs).The removal of the air cavity from the PTV for early-stage glottic cancers does not compromise PTV coverage or sparing of OARs and can result in a more homogeneous IMRT plan. A more homogeneous plan has the potential to reduce treatment morbidity, although further study is warranted to investigate the clinical impact of air cavity removal from the PTV.     

白色白内障超声乳化手术撕囊技巧

目的：探讨白色白内障超声乳化手术的撕囊方法。方法：对76例76只眼,应用一种手法撕囊。向前房内注入黏弹剂,在上方用截囊针截开晶状体前囊约2 mm,用囊膜剪在晶状体前囊截囊口两端呈钝角剪开前囊膜约2-3 mm,再用撕囊镊夹持前囊右侧角逆时针完成撕囊。结果：76只眼白色白内障应用此方法环形撕囊均获成功,成功率为100%,超声乳化手术顺利完成。结论：在白色白内障超声乳化手术中,应用截囊联合剪切撕囊简便、安全、有效,其可显著提高白色白内障连续环形撕囊的成功率,便于掌握和应用。     

El polimorfismo de un solo nucleótido PLAU P141L se asocia con el grado de circulación colateral en pacientes con enfermedad arterial coronaria

Introduction and objectives

Urokinase-type plasminogen activator, which is encoded by the PLAU gene, plays a prominent role during collateral arterial growth. We investigated whether the PLAU P141L (C > T) polymorphism, which causes a mutation in the kringle domain of the protein, is associated with coronary collateral circulation in a cohort of 676 patients with coronary artery disease.

Methods

The polymorphism was genotyped in blood samples using a TaqMan-based genotyping assay, and collateral circulation was assessed by the Rentrop method. Multivariate logistic regression models adjusted by clinically relevant variables to estimate odds ratios were used to examine associations of PLAU P141L allelic variants and genotypes with collateral circulation.

Results

Patients with poor collateral circulation (Rentrop 0-1; n = 547) showed a higher frequency of the TT genotype than those with good collateral circulation (Rentrop 2-3; n = 129; P = .020). The T allele variant was also more common in patients with poor collateral circulation (P = .006). The odds ratio of having poorly developed collaterals in patients bearing the T allele (adjusted for clinically relevant variables) was statistically significant under the dominant model (odds ratio =1.83 [95% confidence interval, 1.16-2.90]; P = .010) and the additive model (odds ratio =1.73 [95% confidence interval, 1.14-2.62]; P = .009).

Conclusions

An association was found between coronary collateral circulation and the PLAU P141L polymorphism. Patients with the 141L variant are at greater risk of developing poor coronary collateral circulation.Full English text available from: www.revespcardiol.org/en     

Economic evaluation of meningococcal serogroup B childhood vaccination in Ontario,Canada

Objective

Invasive Neisseria meningitidis serogroup B (MenB) disease is a low incidence but severe infection (mean annual incidence 0.19/100,000/year, case fatality 11%, major long-term sequelae 10%) in Ontario, Canada. This study assesses the cost-effectiveness of a novel MenB vaccine from the Ontario healthcare payer perspective.

Methods

A Markov cohort model of invasive MenB disease based on high quality local data and data from the literature was developed. A 4-dose vaccination schedule, 97% coverage, 90% effectiveness, 66% strain coverage, 10-year duration of protection, and vaccine cost of C$75/dose were assumed. A hypothetical Ontario birth cohort (n = 150,000) was simulated to estimate expected lifetime health outcomes, quality-adjusted life years (QALYs), and costs, discounted at 5%.

Results

A MenB infant vaccination program is expected to prevent 4.6 invasive MenB disease cases over the lifetime of an Ontario birth cohort, equivalent to 10 QALYs gained. The estimated program cost of C$46.6 million per cohort (including C$318,383 for treatment of vaccine-associated adverse events) were not offset by healthcare cost savings of C$150,522 from preventing MenB cases, resulting in an incremental cost of C$4.76 million per QALY gained. Sensitivity analyses showed the findings to be robust.

Conclusions

An infant MenB vaccination program significantly exceeds commonly used cost-effectiveness thresholds and thus is unlikely to be considered economically attractive in Ontario and comparable jurisdictions.     

囊肿切除胆道重建治疗小儿先天性胆总管囊肿

目的总结72例囊肿切除、胆道重建手术治疗小儿先天性胆总管囊肿的经验,探讨有关的治疗问题.方法回顾1984年至今72例囊肿切除、胆道重建手术治疗的先天性胆总管囊肿患者,其中行囊肿切除、间置空肠十二指肠吻合15例;囊肿切除、肝总管空肠Roux-y吻合57例,所有病例均行紧贴囊壁剥离法切除胆总管囊肿.对手术方式,手术后近、远期并发症进行分析.结果除1例因严重肝硬化死亡外,余71例均痊愈出院,在57例肝总管Roux-y型吻合术中,随访6个月～5年,1例出现腹痛、黄疸、发热,余56例,经B超检查,未见胆管狭窄及扩张.X线钡餐检查,未见有钡剂反流人胆道.结论紧贴囊壁剥离法切除胆总管囊肿,肝总管Roux-y型吻合术是治疗先天性胆总管囊肿的较好方法.     

Exploring the relationship between genetic and environmental influences on initiation and progression of substance use

AIMS: To examine the genetic and environmental contributions to the initiation of use and progression to more serious use of alcohol, cigarettes and marijuana during adolescence, and to examine the relationship between initiation and progression of substance use. DESIGN: The study used a twin-based design and a new theoretical model, the causal-common-contingent (CCC) model. This allows modelling of the relationship between initiation of use and progression to heavier use as a two-stage model and the examination of genetic and environmental influences on both stages, while taking into account their relationship. PARTICIPANTS: The participants consisted of 1214 twin pairs (69% response rate) aged 11-19 years sampled from the UK population-based Cardiff Study of All Wales and North-west of England Twins (CaStANET). MEASUREMENTS: Data on adolescent initiation and progression to more serious use of alcohol, cigarettes and marijuana were obtained using self-report questionnaires. FINDINGS: Initiation of alcohol and progression to heavier alcohol use had separate but related underlying aetiologies. For cigarette and marijuana use the relation between initiation and progression to heavier use was stronger, suggesting greater overlap in aetiologies. For all three substances, environmental influences that make twins more similar (common environment) tended to be greater for initiation, while genetic influences were stronger for heavier use. CONCLUSIONS: These findings have implications for policy decisions aimed at an adolescent and early adult age group. Specifically, these findings suggest that it may be more efficacious to focus alcohol interventions on risk factors for the development of heavier use rather than initiation of use. In contrast, interventions aimed at reducing the initiation of cigarettes and marijuana use may be more appropriate.