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Concept: Median


Objective To investigate the association between active commuting and incident cardiovascular disease (CVD), cancer, and all cause mortality.Design Prospective population based study. Setting UK Biobank.Participants 263 450 participants (106 674 (52%) women; mean age 52.6), recruited from 22 sites across the UK. The exposure variable was the mode of transport used (walking, cycling, mixed mode v non-active (car or public transport)) to commute to and from work on a typical day.Main outcome measures Incident (fatal and non-fatal) CVD and cancer, and deaths from CVD, cancer, or any causes.Results 2430 participants died (496 were related to CVD and 1126 to cancer) over a median of 5.0 years (interquartile range 4.3-5.5) follow-up. There were 3748 cancer and 1110 CVD events. In maximally adjusted models, commuting by cycle and by mixed mode including cycling were associated with lower risk of all cause mortality (cycling hazard ratio 0.59, 95% confidence interval 0.42 to 0.83, P=0.002; mixed mode cycling 0.76, 0.58 to 1.00, P<0.05), cancer incidence (cycling 0.55, 0.44 to 0.69, P<0.001; mixed mode cycling 0.64, 0.45 to 0.91, P=0.01), and cancer mortality (cycling 0.60, 0.40 to 0.90, P=0.01; mixed mode cycling 0.68, 0.57 to 0.81, P<0.001). Commuting by cycling and walking were associated with a lower risk of CVD incidence (cycling 0.54, 0.33 to 0.88, P=0.01; walking 0.73, 0.54 to 0.99, P=0.04) and CVD mortality (cycling 0.48, 0.25 to 0.92, P=0.03; walking 0.64, 0.45 to 0.91, P=0.01). No statistically significant associations were observed for walking commuting and all cause mortality or cancer outcomes. Mixed mode commuting including walking was not noticeably associated with any of the measured outcomes.Conclusions Cycle commuting was associated with a lower risk of CVD, cancer, and all cause mortality. Walking commuting was associated with a lower risk of CVD independent of major measured confounding factors. Initiatives to encourage and support active commuting could reduce risk of death and the burden of important chronic conditions.

Concepts: Death, Disease, Statistics, Sustainable transport, Median, Commuting, Bicycle, Epidemiology


“Climate dice,” describing the chance of unusually warm or cool seasons, have become more and more “loaded” in the past 30 y, coincident with rapid global warming. The distribution of seasonal mean temperature anomalies has shifted toward higher temperatures and the range of anomalies has increased. An important change is the emergence of a category of summertime extremely hot outliers, more than three standard deviations (3σ) warmer than the climatology of the 1951-1980 base period. This hot extreme, which covered much less than 1% of Earth’s surface during the base period, now typically covers about 10% of the land area. It follows that we can state, with a high degree of confidence, that extreme anomalies such as those in Texas and Oklahoma in 2011 and Moscow in 2010 were a consequence of global warming because their likelihood in the absence of global warming was exceedingly small. We discuss practical implications of this substantial, growing, climate change.

Concepts: Median, Climate, Climate change, Standard deviation, Normal distribution, Global warming, Weather, Earth


Background Child-parent screening for familial hypercholesterolemia has been proposed to identify persons at high risk for inherited premature cardiovascular disease. We assessed the efficacy and feasibility of such screening in primary care practice. Methods We obtained capillary blood samples to measure cholesterol levels and to test for familial hypercholesterolemia mutations in 10,095 children 1 to 2 years of age during routine immunization visits. Children were considered to have positive screening results for familial hypercholesterolemia if their cholesterol level was elevated and they had either a familial hypercholesterolemia mutation or a repeat elevated cholesterol level 3 months later. A parent of each child with a positive screening result for familial hypercholesterolemia was considered to have a positive screening result for familial hypercholesterolemia if he or she had the same mutation as the child or, if no mutations were identified, had the higher cholesterol level of the two parents. Results The use of a prespecified cholesterol cutoff value of 1.53 multiples of the median (MoM, corresponding to a percentile of 99.2) identified 28 children who had positive screening results for familial hypercholesterolemia (0.3% of the 10,095 children; 95% confidence interval [CI], 0.2 to 0.4), including 20 with a familial hypercholesterolemia mutation and 8 with a repeat cholesterol level of at least 1.53 MoM. A total of 17 children who had a cholesterol level of less than 1.53 MoM also had a familial hypercholesterolemia mutation. The overall mutation prevalence was 1 in 273 children (37 in 10,095; 95% CI, 1 in 198 to 1 in 388). The use of an initial cholesterol cutoff value of 1.35 MoM (95th percentile) plus a mutation, or two cholesterol values of at least 1.50 MoM (99th percentile), identified 40 children who had positive screening results for familial hypercholesterolemia (0.4% of the 10,095 children, including 32 children who had a familial hypercholesterolemia mutation and 8 who did not have the mutation) and 40 parents who had positive screening results for familial hypercholesterolemia. Conclusions Child-parent screening was feasible in primary care practices at routine child immunization visits. For every 1000 children screened, 8 persons (4 children and 4 parents) were identified as having positive screening results for familial hypercholesterolemia and were consequently at high risk for cardiovascular disease. (Funded by the Medical Research Council.).

Concepts: Mother, Genetic disorder, Median, Mutation, Immune system, Cancer, Atherosclerosis, Hypercholesterolemia


BACKGROUND: To evaluate institutional nursing care performance in the context of national comparative statistics (benchmarks), approximately one in every three major healthcare institutions (over 1,800 hospitals) across the United States, have joined the National Database for Nursing Quality Indicators[REGISTERED SIGN] (NDNQI[REGISTERED SIGN]). With over 18,000 hospital units contributing data for nearly 200 quantitative measures at present, a reliable and efficient input data screening for all quantitative measures for data quality control is critical to the integrity, validity, and on-time delivery of NDNQI reports. METHODS: With Monte Carlo simulation and quantitative NDNQI indicator examples, we compared two ad-hoc methods using robust scale estimators, Inter Quartile Range (IQR) and Median Absolute Deviation from the Median (MAD), to the classic, theoretically-based Minimum Covariance Determinant (FAST-MCD) approach, for initial univariate outlier detection. RESULTS: While the theoretically based FAST-MCD used in one dimension can be sensitive and is better suited for identifying groups of outliers because of its high breakdown point, the ad-hoc IQR and MAD approaches are fast, easy to implement, and could be more robust and efficient, depending on the distributional property of the underlying measure of interest. CONCLUSION: With highly skewed distributions for most NDNQI indicators within a short data screen window, the FAST-MCD approach, when used in one dimensional raw data setting, could overestimate the false alarm rates for potential outliers than the IQR and MAD with the same pre-set of critical value, thus, overburden data quality control at both the data entry and administrative ends in our setting.

Concepts: Standard deviation, Absolute deviation, Median absolute deviation, Normal distribution, Dimension, Outlier, Robust statistics, Median


BACKGROUND: The clinical course of Cystic Fibrosis (CF) is usually measured using the percent predicted FEV1 and BMI Z-score referenced against a healthy population, since achieving normality is the ultimate goal of CF care. Referencing against age and sex matched CF peers may provide valuable information for patients and for comparison between CF centers or populations. Here, we used a large database of European CF patients to compute CF specific reference equations for FEV1 and BMI, derived CF-specific percentile charts and compared these European data to their nearest international equivalents. METHODS: 34859 FEV1 and 40947 BMI observations were used to compute European CF specific percentiles. Quantile regression was applied to raw measurements as a function of sex, age and height. Results were compared with the North American equivalent for FEV1 and with the WHO 2007 normative values for BMI. RESULTS: FEV1 and BMI percentiles illustrated the large variability between CF patients receiving the best current care. The European CF specific percentiles for FEV1 were significantly different from those in the USA from an earlier era, with higher lung function in Europe. The CF specific percentiles for BMI declined relative to the WHO standard in older children. Lung function and BMI were similar in the two largest contributing European Countries (France and Germany). CONCLUSION: The CF specific percentile approach applied to FEV1 and BMI allows referencing patients with respect to their peers. These data allow peer to peer and population comparisons in CF patients.

Concepts: Quartile, File sharing, Percentile rank, Quantile, Median, Reference, Cystic fibrosis, Peer-to-peer


BACKGROUND: The management of pregnancy in patients with narcolepsy poses many questions regarding therapy, including the risk to the mother and fetus related to the disease, potential risks at the time of conception, the risk to both the mother and the fetus of the medications used to treat narcolepsy, and the risk to the infant from medications that might be secreted in breast milk. There are no detailed practice parameters on the treatment of narcolepsy patients during pregnancy. We surveyed narcolepsy specialists from around the world to determine their clinical approach to the management of patients with narcolepsy at the time of conception, during pregnancy and while breastfeeding. METHODS: Survey invitations were sent via e-mail to 75 clinicians worldwide between 2/2011 and 3/2011 with 34 responses (USA, n=10; Brazil, n=3; Czech Republic, n=2; France, n=2; Italy; n=2; Netherlands, n=2; Canada, n=1; Denmark, n=1; Finland, n=1; Germany, n=1; Japan, n=1; Spain, n=1; unknown n=7). Responders who completed the survey had 20years (median range, 5-35) of experience in sleep medicine practice with a median number of five narcolepsy patients seen per week. The number of pregnant narcoleptic patients followed per physician was five (median range 1-40). RESULTS: The survey results indicated that the management of patients with narcolepsy varies greatly from clinician to clinician and from country to country. The majority of the clinicians stopped the narcolepsy medications at the time of conception, during pregnancy, and during breastfeeding some reduced the dose and others did not change the dosage, depending on the particular medication. CONCLUSIONS: The findings from our survey and literature review suggest that the perceived risks of narcolepsy medication during pregnancy to the mother and the fetus usually are overestimated, as the risk for teratogenic effects from narcolepsy medications in therapeutic doses is essentially nonexistent. However, the potential for rare complications during pregnancy and congenital abnormalities cannot be excluded. Most narcolepsy patients have vaginal delivery without complications. In rare cases patients had cataplexy that interfered with delivery, but if caesarian is required there appears to be no increased anaesthetic or surgical risks. Further prospective information for the appropriate treatment of narcolepsy patients during pregnancy is needed.

Concepts: Dose, Median, Hospital, Infant, Breastfeeding, Childbirth, Pregnancy, Narcolepsy


BACKGROUND: The ability to drive is important for ensuring quality of life for many older adults. Glaucoma is prevalent in this age group and may affect driving. The purpose of this study is to determine if glaucoma and glaucomatous visual field (VF) loss are associated with driving cessation, limitations, and deference to another driver in older adults. METHODS: Cross-sectional study. Eighty-one glaucoma subjects and 58 glaucoma suspect controls between age 60 and 80 reported if they had ceased driving, limited their driving in various ways, or preferred another to drive. RESULTS: Twenty-three percent of glaucoma subjects and 6.9% of suspects had ceased driving (p = 0.01). Glaucoma subjects also had more driving limitations than suspects (2.0 vs. 1.1, p = 0.007). In multivariable models, driving cessation was more likely for glaucoma subjects as compared to suspects (OR = 4.0; 95% CI = 1.1-14.7; p = 0.03). The odds of driving cessation doubled with each 5 decibel (dB) decrement in the better-eye VF mean deviation (MD) (OR = 2.0; 95% CI = 1.4-2.9; p < 0.001). Glaucoma subjects were also more likely than suspects to report a greater number of driving limitations (OR = 4.7; 95% CI = 1.3-16.8; p = 0.02). The likelihood of reporting more limitations increased with the VF loss severity (OR = 1.6/5 dB decrement in the better-eye VF MD; 95% CI = 1.1-2.4; p = 0.02). Neither glaucoma nor VF MD was associated with other driver preference (p > 0.1 for both). CONCLUSIONS: Glaucoma and glaucomatous VF loss are associated with greater likelihood of driving cessation and greater limitation of driving in the elderly. Further prospective study is merited to assess when and why people with glaucoma change their driving habits, and to determine if their observed self-regulation of driving is adequate to ensure safety.

Concepts: Preference, Absolute deviation, Suspect, Median, Ageing, Gerontology, Middle age, Old age


Background Studies have suggested an association between frequent acetaminophen use and asthma-related complications among children, leading some physicians to recommend that acetaminophen be avoided in children with asthma; however, appropriately designed trials evaluating this association in children are lacking. Methods In a multicenter, prospective, randomized, double-blind, parallel-group trial, we enrolled 300 children (age range, 12 to 59 months) with mild persistent asthma and assigned them to receive either acetaminophen or ibuprofen when needed for the alleviation of fever or pain over the course of 48 weeks. The primary outcome was the number of asthma exacerbations that led to treatment with systemic glucocorticoids. Children in both groups received standardized asthma-controller therapies that were used in a simultaneous, factorially linked trial. Results Participants received a median of 5.5 doses (interquartile range, 1.0 to 15.0) of trial medication; there was no significant between-group difference in the median number of doses received (P=0.47). The number of asthma exacerbations did not differ significantly between the two groups, with a mean of 0.81 per participant with acetaminophen and 0.87 per participant with ibuprofen over 46 weeks of follow-up (relative rate of asthma exacerbations in the acetaminophen group vs. the ibuprofen group, 0.94; 95% confidence interval, 0.69 to 1.28; P=0.67). In the acetaminophen group, 49% of participants had at least one asthma exacerbation and 21% had at least two, as compared with 47% and 24%, respectively, in the ibuprofen group. Similarly, no significant differences were detected between acetaminophen and ibuprofen with respect to the percentage of asthma-control days (85.8% and 86.8%, respectively; P=0.50), use of an albuterol rescue inhaler (2.8 and 3.0 inhalations per week, respectively; P=0.69), unscheduled health care utilization for asthma (0.75 and 0.76 episodes per participant, respectively; P=0.94), or adverse events. Conclusions Among young children with mild persistent asthma, as-needed use of acetaminophen was not shown to be associated with a higher incidence of asthma exacerbations or worse asthma control than was as-needed use of ibuprofen. (Funded by the National Institutes of Health; AVICA number, NCT01606319 .).

Concepts: Nebulizer, Normal distribution, Interquartile range, Paracetamol, Aspirin, Inhaler, Median, Asthma


Background In multicenter studies, tight glycemic control targeting a normal blood glucose level has not been shown to improve outcomes in critically ill adults or children after cardiac surgery. Studies involving critically ill children who have not undergone cardiac surgery are lacking. Methods In a 35-center trial, we randomly assigned critically ill children with confirmed hyperglycemia (excluding patients who had undergone cardiac surgery) to one of two ranges of glycemic control: 80 to 110 mg per deciliter (4.4 to 6.1 mmol per liter; lower-target group) or 150 to 180 mg per deciliter (8.3 to 10.0 mmol per liter; higher-target group). Clinicians were guided by continuous glucose monitoring and explicit methods for insulin adjustment. The primary outcome was the number of intensive care unit (ICU)-free days to day 28. Results The trial was stopped early, on the recommendation of the data and safety monitoring board, owing to a low likelihood of benefit and evidence of the possibility of harm. Of 713 patients, 360 were randomly assigned to the lower-target group and 353 to the higher-target group. In the intention-to-treat analysis, the median number of ICU-free days did not differ significantly between the lower-target group and the higher-target group (19.4 days [interquartile range {IQR}, 0 to 24.2] and 19.4 days [IQR, 6.7 to 23.9], respectively; P=0.58). In per-protocol analyses, the median time-weighted average glucose level was significantly lower in the lower-target group (109 mg per deciliter [IQR, 102 to 118]; 6.1 mmol per liter [IQR, 5.7 to 6.6]) than in the higher-target group (123 mg per deciliter [IQR, 108 to 142]; 6.8 mmol per liter [IQR, 6.0 to 7.9]; P<0.001). Patients in the lower-target group also had higher rates of health care-associated infections than those in the higher-target group (12 of 349 patients [3.4%] vs. 4 of 349 [1.1%], P=0.04), as well as higher rates of severe hypoglycemia, defined as a blood glucose level below 40 mg per deciliter (2.2 mmol per liter) (18 patients [5.2%] vs. 7 [2.0%], P=0.03). No significant differences were observed in mortality, severity of organ dysfunction, or the number of ventilator-free days. Conclusions Critically ill children with hyperglycemia did not benefit from tight glycemic control targeted to a blood glucose level of 80 to 110 mg per deciliter, as compared with a level of 150 to 180 mg per deciliter. (Funded by the National Heart, Lung, and Blood Institute and others; HALF-PINT number, NCT01565941 .).

Concepts: Diabetes, Blood glucose monitoring, Interquartile range, Median, Carbohydrate, Diabetes mellitus, Hyperglycemia, Blood sugar


Background The level of anticoagulation in response to a fixed-dose regimen of warfarin is difficult to predict during the initiation of therapy. We prospectively compared the effect of genotype-guided dosing with that of standard dosing on anticoagulation control in patients starting warfarin therapy. Methods We conducted a multicenter, randomized, controlled trial involving patients with atrial fibrillation or venous thromboembolism. Genotyping for CYP2C9*2, CYP2C9*3, and VKORC1 (-1639G→A) was performed with the use of a point-of-care test. For patients assigned to the genotype-guided group, warfarin doses were prescribed according to pharmacogenetic-based algorithms for the first 5 days. Patients in the control (standard dosing) group received a 3-day loading-dose regimen. After the initiation period, the treatment of all patients was managed according to routine clinical practice. The primary outcome measure was the percentage of time in the therapeutic range of 2.0 to 3.0 for the international normalized ratio (INR) during the first 12 weeks after warfarin initiation. Results A total of 455 patients were recruited, with 227 randomly assigned to the genotype-guided group and 228 assigned to the control group. The mean percentage of time in the therapeutic range was 67.4% in the genotype-guided group as compared with 60.3% in the control group (adjusted difference, 7.0 percentage points; 95% confidence interval, 3.3 to 10.6; P<0.001). There were significantly fewer incidences of excessive anticoagulation (INR ≥4.0) in the genotype-guided group. The median time to reach a therapeutic INR was 21 days in the genotype-guided group as compared with 29 days in the control group (P<0.001). Conclusions Pharmacogenetic-based dosing was associated with a higher percentage of time in the therapeutic INR range than was standard dosing during the initiation of warfarin therapy. (Funded by the European Commission Seventh Framework Programme and others; number, NCT01119300 .).

Concepts: Thrombosis, Median, Clinical trial, European Commission, Seventh Framework Programme, Anticoagulant, Atrial fibrillation, Warfarin