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Concept: Observational study


An affordable, user-friendly fertility-monitoring tool remains an unmet need. We examine in this study the correlation between pulse rate (PR) and the menstrual phases using wrist-worn PR sensors. 91 healthy, non-pregnant women, between 22-42 years old, were recruited for a prospective-observational clinical trial. Participants measured PR during sleep using wrist-worn bracelets with photoplethysmographic sensors. Ovulation day was estimated with “Clearblue Digital-Ovulation-urine test”. Potential behavioral and nutritional confounders were collected daily. 274 ovulatory cycles were recorded from 91 eligible women, with a mean cycle length of 27.3 days (±2.7). We observed a significant increase in PR during the fertile window compared to the menstrual phase (2.1 beat-per-minute, p < 0.01). Moreover, PR during the mid-luteal phase was also significantly elevated compared to the fertile window (1.8 beat-per-minute, p < 0.01), and the menstrual phase (3.8 beat-per-minute, p < 0.01). PR increase in the ovulatory and mid-luteal phase was robust to adjustment for the collected confounders. There is a significant increase of the fertile-window PR (collected during sleep) compared to the menstrual phase. The aforementioned association was robust to the inter- and intra-person variability of menstrual-cycle length, behavioral, and nutritional profiles. Hence, PR monitoring using wearable sensors could be used as one parameter within a multi-parameter fertility awareness-based method.

Concepts: Scientific method, Pregnancy, Observational study, Menstrual cycle, Ovulation


What is the association between day of delivery and measures of quality and safety of maternity services, particularly comparing weekend with weekday performance?

Concepts: Scientific method, Childbirth, Observational study, The Association, Sunshine pop


Antimicrobial review is an important part of antimicrobial stewardship. A novel enzyme template generation and amplification technique (ETGA), the Cognitor(®) Minus (Momentum Bioscience, Long Hanborough, UK) test, has a 99.5% negative predictive value for bacteraemia and fungaemia. This observational study asked two questions: (1) Does a negative ETGA, indicating no bacteraemia or fungaemia, aid antimicrobial review within 48 h of admission; (2) In this real-life clinical setting, does a negative ETGA mean no bacteraemia or fungaemia?

Concepts: Scientific method, Molecular biology, Blood, Microbiology, Observational study, Question, Bacteremia, Long Hanborough


Austerity measures and health-system redesign to minimise hospital expenditures risk adversely affecting patient outcomes. The RN4CAST study was designed to inform decision making about nursing, one of the largest components of hospital operating expenses. We aimed to assess whether differences in patient to nurse ratios and nurses' educational qualifications in nine of the 12 RN4CAST countries with similar patient discharge data were associated with variation in hospital mortality after common surgical procedures.

Concepts: Patient, Risk, Observational study, Surgery, Educational psychology, Nursing, Nurse, Expense


To examine how hospitals that volunteered to be under financial incentives for more than a decade as part of the Premier Hospital Quality Incentive Demonstration (early adopters) compared with similar hospitals where these incentives were implemented later under the Hospital Value-Based Purchasing program (late adopters).

Concepts: Hospital, Observational study, Incentive


Observational associations between cannabis and schizophrenia are well documented, but ascertaining causation is more challenging. We used Mendelian randomization (MR), utilizing publicly available data as a method for ascertaining causation from observational data.

Concepts: Scientific method, Genetics, Observational study, Correlation does not imply causation



BACKGROUND Whether hearing loss is independently associated with accelerated cognitive decline in older adults is unknown. METHODS We studied 1984 older adults (mean age, 77.4 years) enrolled in the Health ABC Study, a prospective observational study begun in 1997-1998. Our baseline cohort consisted of participants without prevalent cognitive impairment (Modified Mini-Mental State Examination [3MS] score, ≥80) who underwent audiometric testing in year 5. Participants were followed up for 6 years. Hearing was defined at baseline using a pure-tone average of thresholds at 0.5 to 4 kHz in the better-hearing ear. Cognitive testing was performed in years 5, 8, 10, and 11 and consisted of the 3MS (measuring global function) and the Digit Symbol Substitution test (measuring executive function). Incident cognitive impairment was defined as a 3MS score of less than 80 or a decline in 3MS score of more than 5 points from baseline. Mixed-effects regression and Cox proportional hazards regression models were adjusted for demographic and cardiovascular risk factors. RESULTS In total, 1162 individuals with baseline hearing loss (pure-tone average >25 dB) had annual rates of decline in 3MS and Digit Symbol Substitution test scores that were 41% and 32% greater, respectively, than those among individuals with normal hearing. On the 3MS, the annual score changes were -0.65 (95% CI, -0.73 to -0.56) vs -0.46 (95% CI, -0.55 to -0.36) points per year (P = .004). On the Digit Symbol Substitution test, the annual score changes were -0.83 (95% CI, -0.94 to -0.73) vs -0.63 (95% CI, -0.75 to -0.51) points per year (P = .02). Compared to those with normal hearing, individuals with hearing loss at baseline had a 24% (hazard ratio, 1.24; 95% CI, 1.05-1.48) increased risk for incident cognitive impairment. Rates of cognitive decline and the risk for incident cognitive impairment were linearly associated with the severity of an individual’s baseline hearing loss. CONCLUSIONS Hearing loss is independently associated with accelerated cognitive decline and incident cognitive impairment in community-dwelling older adults. Further studies are needed to investigate what the mechanistic basis of this association is and whether hearing rehabilitative interventions could affect cognitive decline.

Concepts: Psychology, Regression analysis, Proportional hazards models, Observational study, Cognition, Hearing impairment, Audiogram, Numerical digit


There are conflicting findings from observational studies of the arrhythrogenic potential of azithromycin. Our aim was to quantify the association between azithromycin use and the risk of ventricular arrhythmia.

Concepts: Scientific method, Observational study, The Association, Sunshine pop


Unnecessary diagnostic imaging leads to higher costs, longer emergency department stays, and increased patient exposure to ionizing radiation. We sought to prospectively derive and validate two decision instruments (DIs) for selective chest computed tomography (CT) in adult blunt trauma patients.

Concepts: Ionizing radiation, X-ray, Hospital, Observational study, Medical imaging, Radiology