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Concept: Percentage point

239

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

169

BACKGROUND: Validation of administrative data is important to assess potential sources of bias in outcome evaluation and to prevent dissemination of misleading or inaccurate information. The purpose of the study was to determine the completeness and accuracy of endoscopy data in several administrative data sources in the year prior to colorectal cancer diagnosis as part of a larger project focused on evaluating the quality of pre-diagnostic care. Methods: Primary and secondary data sources for endoscopy were collected from the Alberta Cancer Registry, cancer medical charts and three different administrative data sources. 1672 randomly sampled patients diagnosed with invasive colorectal cancer in years 2000-2005 in Alberta, Canada were included. A retrospective validation study of administrative data for endoscopy in the year prior to colorectal cancer diagnosis was conducted. A gold standard dataset was created by combining all the datasets. Number and percent identified, agreement and percent unique to a given data source were calculated and compared across each dataset and to the gold standard with respect to identifying all patients who underwent endoscopy and all endoscopies received by those patients. Results: The combined administrative data and physician billing data identified as high or higher percentage of patients who had one or more endoscopy (84% and 78%, respectively) and total endoscopy procedures (89% and 81%, respectively) than the chart review (78% for both). Conclusions: Endoscopy data has a high level of completeness and accuracy in physician billing data alone. Combined with hospital in/outpatient data it is more complete than chart review alone.

Concepts: Evaluation, Colorectal cancer, Physician, Data, Data set, Endoscopy, Sigmoidoscopy, Percentage point

155

Background Concern persists that inflexible duty-hour rules in medical residency programs may adversely affect the training of physicians. Methods We randomly assigned 63 internal medicine residency programs in the United States to be governed by standard duty-hour policies of the 2011 Accreditation Council for Graduate Medical Education (ACGME) or by more flexible policies that did not specify limits on shift length or mandatory time off between shifts. Measures of educational experience included observations of the activities of interns (first-year residents), surveys of trainees (both interns and residents) and faculty, and intern examination scores. Results There were no significant between-group differences in the mean percentages of time that interns spent in direct patient care and education nor in trainees' perceptions of an appropriate balance between clinical demands and education (primary outcome for trainee satisfaction with education; response rate, 91%) or in the assessments by program directors and faculty of whether trainees' workload exceeded their capacity (primary outcome for faculty satisfaction with education; response rate, 90%). Another survey of interns (response rate, 49%) revealed that those in flexible programs were more likely to report dissatisfaction with multiple aspects of training, including educational quality (odds ratio, 1.67; 95% confidence interval [CI], 1.02 to 2.73) and overall well-being (odds ratio, 2.47; 95% CI, 1.67 to 3.65). In contrast, directors of flexible programs were less likely to report dissatisfaction with multiple educational processes, including time for bedside teaching (response rate, 98%; odds ratio, 0.13; 95% CI, 0.03 to 0.49). Average scores (percent correct answers) on in-training examinations were 68.9% in flexible programs and 69.4% in standard programs; the difference did not meet the noninferiority margin of 2 percentage points (difference, -0.43; 95% CI, -2.38 to 1.52; P=0.06 for noninferiority). Conclusions There was no significant difference in the proportion of time that medical interns spent on direct patient care and education between programs with standard duty-hour policies and programs with more flexible policies. Interns in flexible programs were less satisfied with their educational experience than were their peers in standard programs, but program directors were more satisfied. (Funded by the National Heart, Lung, and Blood Institute and the ACGME; iCOMPARE ClinicalTrials.gov number, NCT02274818 .).

Concepts: Physician, Medical school, Percentage point, Residency, Medical education, Medical education in the United States, Intern, Internship

46

Poor sanitation remains a major public health concern linked to several important health outcomes; emerging evidence indicates a link to childhood stunting. In India over half of the population defecates in the open; the prevalence of stunting remains very high. Recently published data on levels of stunting in 112 districts of India provide an opportunity to explore the relationship between levels of open defecation and stunting within this population. We conducted an ecological regression analysis to assess the association between the prevalence of open defecation and stunting after adjustment for potential confounding factors. Data from the 2011 HUNGaMA survey was used for the outcome of interest, stunting; data from the 2011 Indian Census for the same districts was used for the exposure of interest, open defecation. After adjustment for various potential confounding factors - including socio-economic status, maternal education and calorie availability - a 10 percent increase in open defecation was associated with a 0.7 percentage point increase in both stunting and severe stunting. Differences in open defecation can statistically account for 35 to 55 percent of the average difference in stunting between districts identified as low-performing and high-performing in the HUNGaMA data. In addition, using a Monte Carlo simulation, we explored the effect on statistical power of the common practice of dichotomizing continuous height data into binary stunting indicators. Our simulation showed that dichotomization of height sacrifices statistical power, suggesting that our estimate of the association between open defecation and stunting may be a lower bound. Whilst our analysis is ecological and therefore vulnerable to residual confounding, these findings use the most recently collected large-scale data from India to add to a growing body of suggestive evidence for an effect of poor sanitation on human growth. New intervention studies, currently underway, may shed more light on this important issue.

Concepts: Regression analysis, Public health, Statistics, Statistical significance, Monte Carlo, Analysis of variance, Statistical terminology, Percentage point

33

We tested a voluntary self-control commitment device to help grocery shoppers make healthier food purchases. Participants, who were already enrolled in a large-scale incentive program that discounts the price of eligible groceries by 25%, were offered the chance to put their discount on the line. Agreeing households pledged that they would increase their purchases of healthy food by 5 percentage points above their household baseline for each of 6 months. If they reached that goal, their discount was awarded as usual; otherwise, their discount was forfeited for that month. Thirty-six percent of households that were offered the binding commitment agreed; they subsequently showed an average 3.5-percentage-point increase in healthy grocery items purchased in each of the 6 months; households that declined the commitment and control-group households that were given a hypothetical option to precommit did not show such an increase. These results suggest that self-aware consumers will seize opportunities to create restrictive choice environments for themselves, even at some risk of financial loss.

Concepts: Health, Nutrition, Motivation, Marketing, Percentage point, Supermarket, Interest rate, Grocer

30

The Affordable Care Act mandates that private health insurance plans cover prescription contraceptives with no consumer cost sharing. The positive financial impact of this new provision on consumers who purchase contraceptives could be substantial, but it has not yet been estimated. Using a large administrative claims data set from a national insurer, we estimated out-of-pocket spending before and after the mandate. We found that mean and median per prescription out-of-pocket expenses have decreased for almost all reversible contraceptive methods on the market. The average percentages of out-of-pocket spending for oral contraceptive pill prescriptions and intrauterine device insertions by women using those methods both dropped by 20 percentage points after implementation of the ACA mandate. We estimated average out-of-pocket savings per contraceptive user to be $248 for the intrauterine device and $255 annually for the oral contraceptive pill. Our results suggest that the mandate has led to large reductions in total out-of-pocket spending on contraceptives and that these price changes are likely to be salient for women with private health insurance.

Concepts: Health insurance, Birth control, Mode, Intrauterine device, Combined oral contraceptive pill, Economics, Arithmetic mean, Percentage point

30

BACKGROUND: Previous research has shown that tobacco control funding in California has reduced per capita cigarette consumption and per capita healthcare expenditures. This paper refines our earlier model by estimating the effect of California tobacco control funding on current smoking prevalence and cigarette consumption per smoker and the effect of prevalence and consumption on per capita healthcare expenditures. The results are used to calculate new estimates of the effect of the California Tobacco Program. METHODOLOGY/PRINCIPAL FINDINGS: Using state-specific aggregate data, current smoking prevalence and cigarette consumption per smoker are modeled as functions of cumulative California and control states' per capita tobacco control funding, cigarette price, and per capita income. Per capita healthcare expenditures are modeled as a function of prevalence of current smoking, cigarette consumption per smoker, and per capita income. One additional dollar of cumulative per capita tobacco control funding is associated with reduction in current smoking prevalence of 0.0497 (SE.00347) percentage points and current smoker cigarette consumption of 1.39 (SE.132) packs per smoker per year. Reductions of one percentage point in current smoking prevalence and one pack smoked per smoker are associated with $35.4 (SE $9.85) and $3.14 (SE.786) reductions in per capita healthcare expenditure, respectively (2010 dollars), using the National Income and Product Accounts (NIPA) measure of healthcare spending. CONCLUSIONS/SIGNIFICANCE: Between FY 1989 and 2008 the California Tobacco Program cost $2.4 billion and led to cumulative NIPA healthcare expenditure savings of $134 (SE $30.5) billion.

Concepts: Costs, Cigarette, Economics, Cost, Statistical terminology, Percentage point, Health care in the United States, Per capita income

22

PurposePompe disease results from lysosomal acid α-glucosidase (GAA) deficiency and its associated glycogen accumulation and muscle damage. Alglucosidase alfa (recombinant human GAA (rhGAA)) received approval in 2006 as a treatment for Pompe disease at the 160 L production scale. In 2010, larger-scale rhGAA was approved for patients up to 8 years old without cardiomyopathy. NCT01526785 evaluated 4,000 L rhGAA efficacy/safety in US infantile- or late-onset Pompe disease (IOPD, LOPD) patients up to 1 year old transitioned from 160 L rhGAA.MethodsA total of 113 patients (87 with IOPD; 26 with LOPD) received 4,000 L rhGAA for 52 weeks dosed the same as previous 160 L rhGAA. Efficacy was calculated as the percentage of patients stable/improved at week 52 (without death, new requirement for invasive ventilation, left ventricular mass z-score increase >1 if baseline was >2, upright forced vital capacity decrease ≥15% predicted, or Gross Motor Function Measure-88 decrease ≥8 percentage points). Safety evaluation included an extension ≤20 months.ResultsWeek 52 data was available for 104 patients, 100 of whom entered the extension. At week 52, 87/104 (83.7%) were stable/improved. Overall survival was 98.1% overall, 97.6% IOPD, 100% LOPD; 92.4% remained invasive ventilator-free (93.4% IOPD, 88.7% LOPD). Thirty-five patients had infusion-associated reactions. Eight IOPD patients died of drug-unrelated causes.ConclusionsMost Pompe disease patients were clinically stable/improved after transitioning to 4,000 L rhGAA. Safety profiles of both rhGAA forms were consistent.Genetics in Medicine advance online publication, 22 March 2018; doi:10.1038/gim.2018.2.

Concepts: Death, Respiratory physiology, Left ventricular hypertrophy, Standard deviation, Glycogen storage disease, Percentage point, Glycogen storage disease type II, Vital capacity

21

Background The most effective method for repair of a groin hernia involves the use of a synthetic mesh, but this type of mesh is unaffordable for many patients in low- and middle-income countries. Sterilized mosquito meshes have been used as a lower-cost alternative but have not been rigorously studied. Methods We performed a double-blind, randomized, controlled trial comparing low-cost mesh with commercial mesh (both lightweight) for the repair of a groin hernia in adult men in eastern Uganda who had primary, unilateral, reducible groin hernias. Surgery was performed by four qualified surgeons. The primary outcomes were hernia recurrence at 1 year and postoperative complications. Results A total of 302 patients were included in the study. The follow-up rate was 97.3% after 2 weeks and 95.6% after 1 year. Hernia recurred in 1 patient (0.7%) assigned to the low-cost mesh and in no patients assigned to the commercial mesh (absolute risk difference, 0.7 percentage points; 95% confidence interval [CI], -1.2 to 2.6; P=1.0). Postoperative complications occurred in 44 patients (30.8%) assigned to the low-cost mesh and in 44 patients (29.7%) assigned to the commercial mesh (absolute risk difference, 1.0 percentage point; 95% CI, -9.5 to 11.6; P=1.0). Conclusions Rates of hernia recurrence and postoperative complications did not differ significantly between men undergoing hernia repair with low-cost mesh and those undergoing hernia repair with commercial mesh. (Funded by the Swedish Research Council and others; Current Controlled Trials number, ISRCTN20596933 .).

Concepts: Epidemiology, Clinical trial, Medical statistics, Randomized controlled trial, Surgery, Hernia, Hernias, Percentage point

18

Patient satisfaction surveys are an increasingly common element of efforts to evaluate the quality of healthcare. Many patient satisfaction surveys in low/middle-income countries frame statements positively and invite patients to agree or disagree, so that positive responses may reflect either true satisfaction or bias induced by the positive framing. In an experiment with more than 2200 patients in Nigeria, we distinguish between actual satisfaction and survey biases. Patients randomly assigned to receive negatively framed statements expressed significantly lower levels of satisfaction (87%) than patients receiving the standard positively framed statements (95%-p<0.001). Depending on the question, the effect is as high as a 19 percentage point drop (p<0.001). Thus, high reported patient satisfaction likely overstates the quality of health services. Providers and policymakers wishing to gauge the quality of care will need to avoid framing that induces bias and to complement patient satisfaction measures with more objective measures of quality.

Concepts: Health care, Health care provider, Patient, Illness, Sentence, Percentage point, Frame