Studying psychoactive substance use in injured patients: Does exclusion of late arriving patients bias the results?

BackgroundMost studies of the prevalence of psychoactive substances in injured emergency department patients have excluded those who arrive more than 6 h after injury. This may cause a selection bias. The aim of this study was: (1) to describe the characteristics of patients who arrive more than 6 h after injury, compared to patients who arrive sooner (2) to examine whether self-report can add to the assessment of alcohol use when the patient is assessed more than 6 h after injury.MethodsBlood sample analysis and self-report data were used to assess the prevalence of psychoactive substances in injured patients admitted to an emergency department within 48 h of injury (n = 1611). Discriminant function analysis was used to assess group differences.ResultsThe patients who arrived more than 6 h after injury differed significantly from those who arrived earlier in several respects. They more often screened positive for hypnotics; they were older, they were more likely to have had a fall and they were more often injured at home and at night. Self reported use of alcohol showed good consistency with blood sample screening within 6 h of injury and could therefore be used to assess alcohol use more than 6 h after injury.ConclusionsPatients who arrive more than 6 h after injury differ significantly from those who arrive earlier. Future studies on the prevalence of psychoactive substances in emergency departments could expand the inclusion window.     

Poor patient-reported outcome after shoulder replacement in young patients with cuff-tear arthropathy: a matched-pair analysis from the Danish Shoulder Arthroplasty Registry

Background and purpose — Reverse shoulder arthroplasty (RSA) has become the treatment of choice for cuff-tear arthropathy. There are, however, concerns about the longevity and the outcome of an eventual revision procedure. Thus, resurfacing hemiarthroplasty (RHA) with extended articular surface has been suggested for younger patients. We compared the patient-reported outcome of these arthroplasty designs for cuff-tear arthropathy.

Patients and methods — We included patients operated on because of cuff-tear arthropathy and reported to the Danish Shoulder Arthroplasty Registry (DSR) from January 1, 2006 to December 31, 2013. 117 RHA cases were matched by age and sex with 233 RSA controls. 34 of the RHAs were conventional and 67 were RHAs with extended articular surface. The Western Ontario Osteoarthritis of the Shoulder (WOOS) Index at 1 year was used as primary outcome. The score was converted to a percentage of a maximum score. Revision, defined as removal or exchange of any component or the addition of a glenoid component, was used as secondary outcome.

Results — Median WOOS was 49 (30–81) for RHA and 77 (50–92) for RSA (p < 0.001). For patients younger than 65 years, median WOOS was 58 (44–80) after RHA, similar to the 54 after RSA (37–85). For patients older than 65 years, median WOOS was 48 (28–82) after RHA and 79 (55–92) after RSA (p < 0.001).

Interpretation — In all patients RSA had a clinically and statistically better patient-reported outcome than RHA. However, in patients younger than 65 years the functional outcome was similar and poor for either arthroplasty type. The optimal treatment of CTA in young patients remains a challenge.     

Decreased migration with locally administered bisphosphonate in cemented cup revisions using impaction bone grafting technique

Background and purpose — Impaction bone grafting (IBG) in revision hip surgery is an established method in restoring bone stock deficiencies. We hypothesized that local treatment of the morsellized allograft with a bisphosphonate in cemented revision would, in addition to increased bone density, also reduce the early migration of the cup as measured by radiostereometry (RSA).

Patients and methods — 20 patients with aseptic cup loosening underwent revision using the IBG technique. The patients were randomized to either clodronate (10 patients) or saline (10 patients, control group) as local adjunct to the morsellized bone. The outcome was evaluated by dual-energy X-ray absorptiometry (DXA) during the first year regarding periacetabular bone density and with radiostereometric analysis (RSA) for the first 2 years regarding cup migration.

Results — 2 patients were lost to follow-up: 9 patients remained in the clodronate and 9 in the control group. Less proximal migration was found in the clodronate group compared with the controls, measured both over time (mixed-models analysis, p = 0.02) as well as at the specified time points up to 2 years (0.22?mm and 0.59?mm respectively, p = 0.02). Both groups seemed to have stabilized at 1 year. We found similar bone mineral density measured by DXA, and similar RSA migration in the other directions. No cups were re-revised.

Interpretation — Local treatment of the allograft bone with clodronate reduced early proximal migration of the revised cup but without any measurable difference in periacetabular bone density.     

Accurate determination of blood–brain barrier permeability using dynamic contrast-enhanced T1-weighted MRI: a simulation and in vivo study on healthy subjects and multiple sclerosis patients

Dynamic contrast-enhanced magnetic resonance imaging (DCE–MRI) is increasingly used to estimate permeability in situations with subtle blood–brain barrier (BBB) leakage. However, the method''s ability to differentiate such low values from zero is unknown, and no consensus exists on optimal selection of total measurement duration, temporal resolution, and modeling approach under varying physiologic circumstances. To estimate accuracy and precision of the DCE–MRI method we generated simulated data using a two-compartment model and progressively down-sampled and truncated the data to mimic low temporal resolution and short total measurement duration. Model fit was performed with the Patlak, the extended Tofts, and the Tikhonov two-compartment (Tik-2CM) models. Overall, 17 healthy controls were scanned to obtain in vivo data. Long total measurement duration (15 minutes) and high temporal resolution (1.25 seconds) greatly improved accuracy and precision for all three models, enabling us to differentiate values of permeability as low as 0.1 ml/100 g/min from zero. The Patlak model yielded highest accuracy and precision for permeability values <0.3 ml/100 g/min, but for higher values the Tik-2CM performed best. Our results emphasize the importance of optimal parameter setup and model selection when characterizing low BBB permeability.     

Children younger than 7 years with type 1 diabetes are less physically active than healthy controls

Aim: To examine if children younger than 7 years with type 1 diabetes are less physically active and spend more time sedentary than healthy children. Methods: Using a repeated measures case‐control study design, physical activity (PA) was measured by continuous combined accelerometer and heart rate registration for 7 days at two time points during 1 year (autumn and spring). PA data were expressed as time spent sedentary, in moderate and vigorous intensity PA and total PA. Differences between groups and gender were analysed with mixed linear regression models. In this study there were 24 children (12 girls) with type 1 diabetes mellitus and 26 (14 girls) healthy controls, all younger than 7 years at inclusion. Results: Children with diabetes were less active overall (p = 0.010) and spent 16 min less in moderate‐to‐vigorous PA (p = 0.006). The difference in sedentary time (21 min less) between groups was not significant (p = 0.21). Overall PA (12.1 counts/min per day, p = 0.004) and time in moderate and vigorous PA (16.0 min/day, p = 0.002) was significantly higher in boys than in girls. A significant effect of age was observed. Conclusion: Physical activity is significantly reduced in young children with type 1 diabetes.     

Radiostereometric analysis in hip revision surgery-optimal time for index examination: 6 patients revised with impacted allografts and cement followed weekly for 6 weeks

We revised the hip (6 stems and 5 sockets) with impacted morselized allografts and cement in 6 patients. We followed prosthetic migration by roentgen radiostereometric analysis (RSA) every 7th day for 6 weeks after the first (index) examination performed on the first postoperative day before mobilization. Most of the migration occurred during the first 2 weeks. In most cases more than half of the distal stem migration was seen between the 1st and 14th days. In all cases, the stem and socket migrations slowed down gradually and several prosthetic components had become stable after 5 weeks. We conclude that it is essential to perform the index RSA examination on the 1st or 2nd day after surgery and to state when and how weight bearing should be permitted. Otherwise it will be difficult to compare prosthetic migration in various studies and define normative values for migration predicting survival.     

Severe hypoglycaemia in 1076 adult patients with type 1 diabetes: influence of risk markers and selection

BACKGROUND: Differences between studies in rates of severe hypoglycaemia in type 1 diabetic cohorts are common and poorly understood. The purpose of this study was to assess the frequency of severe hypoglycaemia in unselected patients treated in different secondary care centres and to evaluate the influence of risk markers, clinical setting and selection. METHODS: Cross-sectional Danish-British multicentre survey of 1076 consecutive adult patients with clinical type 1 diabetes who completed a detailed questionnaire on hypoglycaemia and related issues. Key variable was the self-reported rate of severe hypoglycaemia during the preceding year. RESULTS: The overall rate of severe hypoglycaemia in the preceding year was 1.3 episodes/patient-year and episodes were reported by 36.7% of subjects. The distribution was highly skewed with 5% of subjects accounting for 54% of all episodes. There were no significant differences between countries or centres. Reduced hypoglycaemia awareness, peripheral neuropathy and smoking were the only significant risk markers of severe hypoglycaemia in a stepwise multivariate analysis. In a subgroup selected to be similar to the Diabetes Control and Complications Trial (DCCT) cohort, the rate of severe hypoglycaemia was 0.35 episodes/patient-year and only retinopathy was a significant risk marker together with state of awareness. CONCLUSION: Severe hypoglycaemia remains a significant clinical problem in type 1 diabetes. The rate of severe hypoglycaemia and the influence of risk markers are very sensitive to selection and differences in rates between centres or studies seem to disappear after correction for differences in clinical characteristics. Smoking is a novel overall risk marker of severe hypoglycaemia.