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Concept: Confidence interval

505

Both social isolation and loneliness are associated with increased mortality, but it is uncertain whether their effects are independent or whether loneliness represents the emotional pathway through which social isolation impairs health. We therefore assessed the extent to which the association between social isolation and mortality is mediated by loneliness. We assessed social isolation in terms of contact with family and friends and participation in civic organizations in 6,500 men and women aged 52 and older who took part in the English Longitudinal Study of Ageing in 2004-2005. A standard questionnaire measure of loneliness was administered also. We monitored all-cause mortality up to March 2012 (mean follow-up 7.25 y) and analyzed results using Cox proportional hazards regression. We found that mortality was higher among more socially isolated and more lonely participants. However, after adjusting statistically for demographic factors and baseline health, social isolation remained significantly associated with mortality (hazard ratio 1.26, 95% confidence interval, 1.08-1.48 for the top quintile of isolation), but loneliness did not (hazard ratio 0.92, 95% confidence interval, 0.78-1.09). The association of social isolation with mortality was unchanged when loneliness was included in the model. Both social isolation and loneliness were associated with increased mortality. However, the effect of loneliness was not independent of demographic characteristics or health problems and did not contribute to the risk associated with social isolation. Although both isolation and loneliness impair quality of life and well-being, efforts to reduce isolation are likely to be more relevant to mortality.

Concepts: Epidemiology, Statistics, Sample size, Proportional hazards models, Sociology, Interval finite element, Demographics, Confidence interval

250

Background Continuous-flow left ventricular assist systems increase the rate of survival among patients with advanced heart failure but are associated with the development of pump thrombosis. We investigated the effects of a new magnetically levitated centrifugal continuous-flow pump that was engineered to avert thrombosis. Methods We randomly assigned patients with advanced heart failure to receive either the new centrifugal continuous-flow pump or a commercially available axial continuous-flow pump. Patients could be enrolled irrespective of the intended goal of pump support (bridge to transplantation or destination therapy). The primary end point was a composite of survival free of disabling stroke (with disabling stroke indicated by a modified Rankin score >3; scores range from 0 to 6, with higher scores indicating more severe disability) or survival free of reoperation to replace or remove the device at 6 months after implantation. The trial was powered for noninferiority testing of the primary end point (noninferiority margin, -10 percentage points). Results Of 294 patients, 152 were assigned to the centrifugal-flow pump group and 142 to the axial-flow pump group. In the intention-to-treat population, the primary end point occurred in 131 patients (86.2%) in the centrifugal-flow pump group and in 109 (76.8%) in the axial-flow pump group (absolute difference, 9.4 percentage points; 95% lower confidence boundary, -2.1 [P<0.001 for noninferiority]; hazard ratio, 0.55; 95% confidence interval [CI], 0.32 to 0.95 [two-tailed P=0.04 for superiority]). There were no significant between-group differences in the rates of death or disabling stroke, but reoperation for pump malfunction was less frequent in the centrifugal-flow pump group than in the axial-flow pump group (1 [0.7%] vs. 11 [7.7%]; hazard ratio, 0.08; 95% CI, 0.01 to 0.60; P=0.002). Suspected or confirmed pump thrombosis occurred in no patients in the centrifugal-flow pump group and in 14 patients (10.1%) in the axial-flow pump group. Conclusions Among patients with advanced heart failure, implantation of a fully magnetically levitated centrifugal-flow pump was associated with better outcomes at 6 months than was implantation of an axial-flow pump, primarily because of the lower rate of reoperation for pump malfunction. (Funded by St. Jude Medical; MOMENTUM 3 ClinicalTrials.gov number, NCT02224755 .).

Concepts: Blood, Hypertension, Cardiology, Heart, Confidence interval, Anticoagulant, Disability, Point

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Background In an early analysis of this trial, use of a magnetically levitated centrifugal continuous-flow circulatory pump was found to improve clinical outcomes, as compared with a mechanical-bearing axial continuous-flow pump, at 6 months in patients with advanced heart failure. Methods In a randomized noninferiority and superiority trial, we compared the centrifugal-flow pump with the axial-flow pump in patients with advanced heart failure, irrespective of the intended goal of support (bridge to transplantation or destination therapy). The composite primary end point was survival at 2 years free of disabling stroke (with disabling stroke indicated by a modified Rankin score of >3; scores range from 0 to 6, with higher scores indicating more severe disability) or survival free of reoperation to replace or remove a malfunctioning device. The noninferiority margin for the risk difference (centrifugal-flow pump group minus axial-flow pump group) was -10 percentage points. Results Of 366 patients, 190 were assigned to the centrifugal-flow pump group and 176 to the axial-flow pump group. In the intention-to-treat population, the primary end point occurred in 151 patients (79.5%) in the centrifugal-flow pump group, as compared with 106 (60.2%) in the axial-flow pump group (absolute difference, 19.2 percentage points; 95% lower confidence boundary, 9.8 percentage points [P<0.001 for noninferiority]; hazard ratio, 0.46; 95% confidence interval [CI], 0.31 to 0.69 [P<0.001 for superiority]). Reoperation for pump malfunction was less frequent in the centrifugal-flow pump group than in the axial-flow pump group (3 patients [1.6%] vs. 30 patients [17.0%]; hazard ratio, 0.08; 95% CI, 0.03 to 0.27; P<0.001). The rates of death and disabling stroke were similar in the two groups, but the overall rate of stroke was lower in the centrifugal-flow pump group than in the axial-flow pump group (10.1% vs. 19.2%; hazard ratio, 0.47; 95% CI, 0.27 to 0.84, P=0.02). Conclusions In patients with advanced heart failure, a fully magnetically levitated centrifugal-flow pump was superior to a mechanical-bearing axial-flow pump with regard to survival free of disabling stroke or reoperation to replace or remove a malfunctioning device. (Funded by Abbott; MOMENTUM 3 ClinicalTrials.gov number, NCT02224755 .).

Concepts: Blood, Heart, Confidence interval, Disability, Percentage point, Malfunction

225

Controversies are common in medicine. Some arise when the conclusions of research publications directly contradict each other, creating uncertainty for frontline clinicians.

Concepts: Confidence interval

194

The global epidemic of obesity and physical inactivity may have detrimental implications for young people’s cognitive function and academic achievement. This prospective study investigated whether childhood motor function predicts later academic achievement via physical activity, fitness, and obesity. The study sample included 8,061 children from the Northern Finland Birth Cohort 1986, which contains data about parent-reported motor function at age 8 y and self-reported physical activity, predicted cardiorespiratory fitness (cycle ergometer test), obesity (body weight and height), and academic achievement (grades) at age 16 y. Structural equation models with unstandardized (B) and standardized (β) coefficients were used to test whether, and to what extent, physical activity, cardiorespiratory fitness, and obesity at age 16 mediated the association between childhood motor function and adolescents' academic achievement. Physical activity was associated with a higher grade-point average, and obesity was associated with a lower grade-point average in adolescence. Furthermore, compromised motor function in childhood had a negative indirect effect on adolescents' academic achievement via physical inactivity (B = -0.023, 95% confidence interval = -0.031, -0.015) and obesity (B = -0.025, 95% confidence interval = -0.039, -0.011), but not via cardiorespiratory fitness. These results suggest that physical activity and obesity may mediate the association between childhood motor function and adolescents' academic achievement. Compromised motor function in childhood may represent an important factor driving the effects of obesity and physical inactivity on academic underachievement.

Concepts: Obesity, Overweight, Interval finite element, Adolescence, Confidence interval, Prediction interval, Physical fitness, Structural equation modeling

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BACKGROUND:Theoretically, communication systems have the potential to increase the productivity of anesthesiologists supervising anesthesia providers. We evaluated the maximal potential of communication systems to increase the productivity of anesthesia care by enhancing anesthesiologists' coordination of care (activities) among operating rooms (ORs).METHODS:At hospital A, data for 13,368 pages were obtained from files recorded in the internal alphanumeric text paging system. Pages from the postanesthesia care unit were processed through a numeric paging system and thus not included. At hospital B, in a different US state, 3 of the authors categorized each of 898 calls received using the internal wireless audio system (Vocera(®)). Lower and upper 95% confidence limits for percentages are the values reported.RESULTS:At least 45% of pages originated from outside the ORs (e.g., 20% from holding area) at hospital A and at least 56% of calls (e.g., 30% administrative) at hospital B. In contrast, requests from ORs for urgent presence of the anesthesiologist were at most 0.2% of pages at hospital A and 1.8% of calls at hospital B.CONCLUSIONS:Approximately half of messages to supervising anesthesiologists are for activity originating outside the ORs being supervised. To use communication tools to increase anesthesia productivity on the day of surgery, their use should include a focus on care coordination outside ORs (e.g., holding area) and among ORs (e.g., at the control desk).

Concepts: Surgery, Anesthesia, Confidence interval, Anesthesiologist, Operating system, Media technology, Post anesthesia care unit, Paging

167

Background:Fibromatous nodules in the sole of the foot are often called Ledderhose disease. It is a benign nodular formation in the plantar aponeurosis, typically at the distal medial border. A lump forms and it can be a few centimeters in diameter. It is frequently seen as an isolated disease, but a relationship to Dupuytren’s has been noted in some patients.Methods:The study was a part of a large cohort study, the Reykjavík study. Men with Dupuytren’s disease (n = 122) were invited to follow-up 18 years after the initial observation. An equal number of controls, matched for age and smoking habits, were also invited. A total of 92 Dupuytren’s patients and 101 control subjects attended for follow-up and were examined for plantar nodules. Statistical evaluation was carried out using chi-square test and presented as odds ratio (OR) and 95% confidence interval (95% CI).Results:Ledderhose disease was identified in 14 of the 92 (15.2%) men with Dupuytren’s disease, while it was only in 4 of the 101 (3.9%) matched controls (OR = 4.35, 95% CI, 1.3-16.7, P < 0.01). Men operated for Dupuytren's disease or with finger contractures were more likely to have plantar nodules than those with only nodules or strings in the palms (OR = 6.1, 95% CI, 1.8-27.1, P < 0.001). The plantar involvement was related to family history of Dupuytren's disease (OR = 3.1, 95% CI, 1.1-8.5, P = 0.02).Conclusion:Men with manifestations of finger contractures or who need surgery for Dupuytren's disease are more likely to also develop plantar fibromas.Level of Evidence: Level III, retrospective comparative series.

Concepts: Medicine, Epidemiology, Confidence interval, Normal distribution, Rare diseases, Contracture, Dupuytren's contracture, Guillaume Dupuytren

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We assess the efficacy and safety of canaloplasty and trabeculectomy for treatment of glaucoma. We searched the China National Knowledge Infrastructure, PubMed, Web of Science, and WanFang databases for potentially eligible studies. Pooled risk ratio (RR) with 95% confidence interval (CI) was calculated using random- or fixed-effect models if appropriate. Eight studies were included for meta-analysis. There was no difference in intraocular pressure at 6 months (WMD = 0.97, 95%CI: -0.48-2.41). Intraocular pressure in canaloplasty group 12 months after operation was higher than in trabeculectomy group (WMD = 1.90, 95%CI: 0.12-3.69), P < 0.05). The canaloplasty group showed higher success rate than trabeculectomy group (RR = 0.86, 95%CI: 0.77-0.97). The canaloplasty group was more likely to have hyphema (RR = 2.96, 95%CI: 1.51-5.83), P < 0.05) than trabeculectomy group (RR = 0.24, 95, CI(0.06-0.89), P < 0.05]. The incidence of and hypotony and postoperative choroid abnormalities in canaloplasty group was significantly lower than that in trabeculectomy group (RR = 0.30, 95%CI: 0.11-0.83; RR = 0.24, 95%CI: 0.09-0.66), P < 0.05). Both trabeculectomy and canaloplasty can significantly reduce the intraocular pressure in glaucoma patients at 12 months after operation, trabeculectomy leads a more marked IOP decrease than canaloplasty at the cost of a higher complication rate and more demanding for postoperative care.

Concepts: Medical statistics, Intraocular pressure, Glaucoma, Ophthalmology, Confidence interval, Trabecular meshwork, Trabeculectomy

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Background Apixaban, an oral factor Xa inhibitor administered in fixed doses, may simplify the treatment of venous thromboembolism. Methods In this randomized, double-blind study, we compared apixaban (at a dose of 10 mg twice daily for 7 days, followed by 5 mg twice daily for 6 months) with conventional therapy (subcutaneous enoxaparin, followed by warfarin) in 5395 patients with acute venous thromboembolism. The primary efficacy outcome was recurrent symptomatic venous thromboembolism or death related to venous thromboembolism. The principal safety outcomes were major bleeding alone and major bleeding plus clinically relevant nonmajor bleeding. Results The primary efficacy outcome occurred in 59 of 2609 patients (2.3%) in the apixaban group, as compared with 71 of 2635 (2.7%) in the conventional-therapy group (relative risk, 0.84; 95% confidence interval [CI], 0.60 to 1.18; difference in risk [apixaban minus conventional therapy], -0.4 percentage points; 95% CI, -1.3 to 0.4). Apixaban was noninferior to conventional therapy (P<0.001) for predefined upper limits of the 95% confidence intervals for both relative risk (<1.80) and difference in risk (<3.5 percentage points). Major bleeding occurred in 0.6% of patients who received apixaban and in 1.8% of those who received conventional therapy (relative risk, 0.31; 95% CI, 0.17 to 0.55; P<0.001 for superiority). The composite outcome of major bleeding and clinically relevant nonmajor bleeding occurred in 4.3% of the patients in the apixaban group, as compared with 9.7% of those in the conventional-therapy group (relative risk, 0.44; 95% CI, 0.36 to 0.55; P<0.001). Rates of other adverse events were similar in the two groups. Conclusions A fixed-dose regimen of apixaban alone was noninferior to conventional therapy for the treatment of acute venous thromboembolism and was associated with significantly less bleeding (Funded by Pfizer and Bristol-Myers Squibb; ClinicalTrials.gov number, NCT00643201 ).

Concepts: Confidence interval, Normal distribution, Bristol-Myers Squibb, Interval estimation

68

Background Replacing sitting with standing is one of several recommendations to decrease sedentary time and increase the daily energy expenditure, but the difference in energy expenditure between standing versus sitting has been controversial. This systematic review and meta-analysis aimed to determine this difference. Designs and methods We searched Ovid MEDLINE, Ovid Embase Scopus, Web of Science and Google Scholar for observational and experimental studies that compared the energy expenditure of standing versus sitting. We calculated mean differences and 95% confidence intervals using a random effects model. We conducted different predefined subgroup analyses based on characteristics of participants and study design. Results We identified 658 studies and included 46 studies with 1184 participants for the final analysis. The mean difference in energy expenditure between sitting and standing was 0.15 kcal/min (95% confidence interval (CI) 0.12-0.17). The difference among women was 0.1 kcal/min (95% CI 0.0-0.21), and was 0.19 kcal/min (95% CI 0.05-0.33) in men. Observational studies had a lower difference in energy expenditure (0.11 kcal/min, 95% CI 0.08-0.14) compared to randomised trials (0.2 kcal/min, 95% CI 0.12-0.28). By substituting sitting with standing for 6 hours/day, a 65 kg person will expend an additional 54 kcal/day. Assuming no increase in energy intake, this difference in energy expenditure would be translated into the energy content of about 2.5 kg of body fat mass in 1 year. Conclusions The substitution of sitting with standing could be a potential solution for a sedentary lifestyle to prevent weight gain in the long term. Future studies should aim to assess the effectiveness and feasibility of this strategy.

Concepts: Statistics, Obesity, Randomized controlled trial, Body fat percentage, Confidence interval, Random effects model