Prediction of occult atrial fibrillation in patients after cryptogenic stroke and transient ischaemic attack: PROACTIA.

AIMS: Studies with implantable cardiac monitors (ICMs) show that one-third of patients with cryptogenic stroke/transient ischaemic attack (TIA) have episodes of subclinical atrial fibrillation (SCAF) and benefit switching from antiplatelet- to anticoagulant therapy. However, ICMs are costly and resource demanding. We aimed to build a score based on participant's baseline characteristics that could assess individual risk of SCAF. METHODS AND RESULTS: In a prospective study, 236 eligible patients with a final diagnosis of cryptogenic stroke/TIA had an ICM implantated during the index hospitalization. Pre-specified evaluated variables were: CHA2DS2-VASc, P-wave duration, P-wave morphology, premature atrial beats (PAC)/24 h, supraventricular tachycardia/24 h, left atrial end-systolic volume index (LAVI), Troponin-T, NT-proBNP, and D-dimer. SCAF was detected in 84 patients (36%). All pre-specified variables were significantly associated with SCAF detection in univariate analysis. P-wave duration, followed by PAC/24 h, NT-proBNP, and LAVI, had the largest ratio of SCAF prevalence between its upper and lower quartiles (3.3, vs. 3.2, vs. 3.1 vs. 2.8, respectively). However, in a multivariate analysis, only PAC/24t, P-wave duration, P-wave morphology, and LAVIs remained significant predictors and were included in the PROACTIA score. Subclinical atrial fibrillation prevalence was 75% in the highest vs. 10% in the lowest quartile of the PROACTIA score with a 10-fold higher number of patients with an atrial fibrillation burden >6 h in the highest vs. the lowest quartile. CONCLUSION: The PROACTIA score can identify patients with cryptogenic stroke/TIA at risk of subsequent SCAF detection. The large difference in SCAF prevalence between groups may provide a basis for future tailored therapy. CLINICAL TRIAL REGISTRATION: Clinical Trial Registration: ClinicalTrials.gov; NCT02725944.

Stroke unit demand in Norway - present and future estimates.

BACKGROUND: All stroke patients should receive timely admission to a stroke unit (SU). Consequently, most patients with suspected strokes - including stroke mimics (SM) are admitted. The aim of this study was to estimate the current total demand for SU bed capacity today and give estimates for future (2020-2040) demand. METHODS: Time trend estimates for stroke incidence and time constant estimates for length of stay (LOS) were estimated from the Norwegian Patient Registry (2010-2015). Incidence and LOS models for SMs were based on data from Haukeland University Hospital (2008-2017) and Akershus University Hospital (2020), respectively. The incidence and LOS models were combined with scenarios from Statistic Norway's population predictions to estimate SU demands for each health region. A telephone survey collected data on the number of currently available SU beds. RESULTS: In 2020, 361 SU beds are available, while demand was estimated to 302. The models predict a reduction in stroke incidence, which offsets projected demographic shifts. Still, the estimated demand for 2040 rose to 316, due to an increase in SMs. A variation of this reference scenario, where stroke incidence was frozen at the 2020-level, gave a 2040-demand of 480 beds. CONCLUSIONS: While the stroke incidence is likely to continue to fall, this appears to be balanced by an increase in SMs. An important uncertainty is how long the trend of decreasing stroke incidence can be expected to continue. Since the most important uncertainty factors point toward a potential increase, which may be as large as 50%, we would recommend that the health authorities plan for a potential increase in the demand for SU bed capacity.

Neural classification of Norwegian radiology reports: using NLP to detect findings in CT-scans of children.

BACKGROUND: With a motivation of quality assurance, machine learning techniques were trained to classify Norwegian radiology reports of paediatric CT examinations according to their description of abnormal findings. METHODS: 13.506 reports from CT-scans of children, 1000 reports from CT scan of adults and 1000 reports from X-ray examination of adults were classified as positive or negative by a radiologist, according to the presence of abnormal findings. Inter-rater reliability was evaluated by comparison with a clinician's classifications of 500 reports. Test-retest reliability of the radiologist was performed on the same 500 reports. A convolutional neural network model (CNN), a bidirectional recurrent neural network model (bi-LSTM) and a support vector machine model (SVM) were trained on a random selection of the children's data set. Models were evaluated on the remaining CT-children reports and the adult data sets. RESULTS: Test-retest reliability: Cohen's Kappa = 0.86 and F1 = 0.919. Inter-rater reliability: Kappa = 0.80 and F1 = 0.885. Model performances on the Children-CT data were as follows. CNN: (AUC = 0.981, F1 = 0.930), bi-LSTM: (AUC = 0.978, F1 = 0.927), SVM: (AUC = 0.975, F1 = 0.912). On the adult data sets, the models had AUC around 0.95 and F1 around 0.91. CONCLUSIONS: The models performed close to perfectly on its defined domain, and also performed convincingly on reports pertaining to a different patient group and a different modality. The models were deemed suitable for classifying radiology reports for future quality assurance purposes, where the fraction of the examinations with abnormal findings for different sub-groups of patients is a parameter of interest.

Long-term prognosis for patients admitted to a medical intermediate care unit. / Langtidsprognose for pasienter innlagt i en medisinsk overvåkningsavdeling.

BACKGROUND: The intermediate care unit at Akershus University Hospital treats patients with incipient or manifest organ failure. Selecting patients who might benefit from treatment in an intermediate care unit is challenging. Few data are available on long-term survival of patients treated in medical intermediate care units and on how assumed favourable and unfavourable prognostic factors predict long-term survival in this population. MATERIAL AND METHOD: Comorbidity, reason for admission and whether an infection was a direct or contributory reason for the admission were prospectively registered for patients in the unit in 2014 and 2016. We registered mortality up to six years after the admission and conducted a logistic regression analysis with three-year survival as the outcome variable. RESULTS: Of the 2 170 included patients, 153 (7 %) died in the intermediate care unit. Of the 2 017 patients who were discharged alive from the intermediate care unit, 55 % were still alive three years later, including 28 % of older patients aged over 80 years and 23 % of patients with cancer. Age, malignancy, other comorbidity and infection were predictors of mortality. INTERPRETATION: Many patient groups in an intermediate care unit have a poor long-term prognosis. However, people older than 80 years, cancer patients or patients with another serious comorbidity may live long after their stay in an intermediate care unit, and the fact of belonging to these groups should not be an independent reason for withholding treatment.

Capacity and patient flow planning in post-term pregnancy outpatient clinics: a computer simulation modelling study.

BACKGROUND: The demand for a large Norwegian hospital's post-term pregnancy outpatient clinic has increased substantially over the last 10 years due to changes in the hospital's catchment area and to clinical guidelines. Planning the clinic is further complicated due to the high did not attend rates as a result of women giving birth. The aim of this study is to determine the maximum number of women specified clinic configurations, combination of specified clinic resources, can feasibly serve within clinic opening times. METHODS: A hybrid agent based discrete event simulation model of the clinic was used to evaluate alternative configurations to gain insight into clinic planning and to support decision making. Clinic configurations consisted of six factors: X0: Arrivals. X1: Arrival pattern. X2: Order of midwife and doctor consultations. X3: Number of midwives. X4: Number of doctors. X5: Number of cardiotocography (CTGs) machines. A full factorial experimental design of the six factors generated 608 configurations. RESULTS: Each configuration was evaluated using the following measures: Y1: Arrivals. Y2: Time last woman checks out. Y3: Women's length of stay (LoS). Y4: Clinic overrun time. Y5: Midwife waiting time (WT). Y6: Doctor WT. Y7: CTG connection WT. Optimisation was used to maximise X0 with respect to the 32 combinations of X1-X5. Configuration 0a, the base case Y1 = 7 women and Y3 = 102.97 [0.21] mins. Changing the arrival pattern (X1) and the order of the midwife and doctor consultations (X2) configuration 0d, where X3, X4, X5 = 0a, Y1 = 8 woman and Y3 86.06 [0.10] mins. CONCLUSIONS: The simulation model identified the availability of CTG machines as a bottleneck in the clinic, indicated by the WT for CTG connection effect on LoS. One additional CTG machine improved clinic performance to the same degree as an extra midwife and an extra doctor. The simulation model demonstrated significant reductions to LoS can be achieved without additional resources, by changing the clinic pathway and scheduling of appointments. A more general finding is that a simulation model can be used to identify bottlenecks, and efficient ways of restructuring an outpatient clinic.

Surgical site infection after hip fracture - mortality and risk factors: an observational cohort study of 1,709 patients.

Background and purpose - Surgical site infection (SSI) is a devastating complication of hip fracture surgery. We studied the contribution of early deep SSI to mortality after hip fracture surgery and the risk factors for deep SSI with emphasis on the duration of surgery.Patients and methods - 1,709 patients (884 hemi-arthroplasties, 825 sliding hip screws), operated from 2012 to 2015 at a single center were included. Data were obtained from the Norwegian Hip Fracture Register, the electronic hospital records, the Norwegian Surveillance System for Antibiotic Use and Hospital-Acquired Infections, and the Central Population Register.Results - The rate of early (≤ 30 days) deep SSI was 2.2% (38/1,709). Additionally, for hemiarthroplasties 7 delayed (> 30 days, ≤ 1 year) deep SSIs were reported. In patients with early deep SSI 90-day mortality tripled (42% vs. 14%, p < 0.001) and 1-year mortality doubled (55% vs. 24%, p < 0.001). In multivariable analysis, early deep SSI was an independent risk factor for mortality (RR 2.4 for 90-day mortality, 1.8 for 1-year mortality, p < 0.001). In univariable analysis, significant risk factors for early and delayed deep SSI were cognitive impairment, an intraoperative complication, and increasing duration of surgery. However, in the multivariable analysis, duration of surgery was no longer a significant risk factor.Interpretation - Early deep SSI is an independent risk factor for 90-day and 1-year mortality after hip fracture surgery. After controlling for observed confounding, the association between duration of surgery and early and delayed deep SSI was not statistically significant.

Identifying menstrual migraine- improving the diagnostic criteria using a statistical method.

OBJECTIVE: To develop a robust statistical tool for the diagnosis of menstrually related migraine. BACKGROUND: The International Classification of Headache Disorders (ICHD) has diagnostic criteria for menstrual migraine within the appendix. These include the requirement for menstrual attacks to occur within a 5-day window in at least [Formula: see text] menstrual cycles ([Formula: see text]-criterion). While this criterion has been shown to be sensitive, it is not specific. Yet in some circumstances, for example to establish the underlying pathophysiology of menstrual attacks, specificity is also important, to ensure that only women in whom the relationship between migraine and menstruation is more than a chance occurrence are recruited. METHODS: Using a simple mathematical model, a Markov chain, to model migraine attacks we developed a statistical criterion to diagnose menstrual migraine (sMM). We then analysed a data set of migraine diaries using both the [Formula: see text]-criterion and the sMM. RESULTS: sMM was superior to the [Formula: see text]-criterion for varying numbers of menstrual cycles and increased in accuracy with more cycle data. In contrast, the [Formula: see text]-criterion showed maximum sensitivity only for three cycles, although specificity increased with more cycle data. CONCLUSIONS: While the ICHD [Formula: see text]-criterion is a simple screening tool for menstrual migraine, the sMM provides a more specific diagnosis and can be applied irrespective of the number of menstrual cycles recorded. It is particularly useful for clinical trials of menstrual migraine where a chance association between migraine and menstruation must be excluded.

The Burden of Stroke Mimics: Present and Future Projections.

BACKGROUND AND PURPOSE: An increasing proportion of patients presenting with suspected stroke prove to have other conditions, often referred to as stroke mimics. The aim of this study was to present a projection of the number of hospitalized strokes, transient ischemic attacks (TIAs), and stroke mimics in Norway up to the year 2050 based on expected demographic changes, to estimate the burden of stroke mimics in the coming decades. MATERIALS AND METHODS: This prospective study included all admissions to the stroke unit of Akershus University Hospital from March 1, 2012, to February 28, 2013. Relevant resource use was recorded. Based on the age- and sex-specific absolute incidences for the study period, the expected numbers of strokes, TIAs, and stroke mimics in the entire Norwegian population were computed for every fifth year for the period 2020-2050. RESULTS: We included 1881 admissions, of which 38.2% were stroke mimics. With constant age- and sex-dependent incidence rates, we estimated that the number of strokes and stroke mimics will respectively increase by 121.3% and 88.7% (men) and 97.6% and 71.7% (women). For hospital admission levels to stay constant at the 2013 level, an annual reduction of 2.1% and 1.7% (men) and 1.8% and 1.5% (women) must take place for strokes and mimics, respectively. CONCLUSIONS: A significant proportion of stroke unit admissions prove to have other conditions than stroke. With constant age- and sex-dependent incidence rates, the number of stroke mimics admissions will increase substantially over the next decades.

Epidemiology and prognoses in a medical intermediate care unit. / Epidemiologi og prognoser i en medisinsk overvåkningsavdeling.

BACKGROUND: The purpose of medical intermediate care units is the observation and treatment of patients with incipient or manifest organ failure. We wished to obtain data on which conditions result in admission to these units and the prognosis for these patients. MATERIAL AND METHOD: All patients admitted to the medical intermediate care unit at Akershus University Hospital in 2014 were registered prospectively with reason for admission, period of hospitalisation, degree of severity, comorbidity, last place of hospitalisation prior to medical intermediate care and treatment limitations (do-not-resuscitate order and/or do-not-intubate order). Mortality in the hospital and one year after hospitalisation were registered retrospectively. Multiple regression analysis was performed with hospital mortality as the outcome variable. RESULTS: Altogether 1369 patient hospitalisations for 1118 unique patients were included. The most frequent reasons for admission were pneumonia, chronic obstructive pulmonary disease, sepsis, poisonings and hyponatraemia. The degree of severity of the condition for which patients were admitted corresponded to that reported by intensive care departments in Norwegian local hospitals. A total of 13 % died during their stay in hospital and a further 14 % in the course of one year. The highest mortality was for patients with severe infection, cardiac failure and restrictive/neuromuscular respiratory disorder. The degree of severity, age, infection, comorbidity and ward as admitting unit were predictors of mortality during the hospitalisation period. Risk-adjusted mortality ratio of 0.64 satisfied the quality objective for intensive care departments (<0.7). A total of 5.6 % of hospitalisations in the medical intermediate care unit entailed transfer to the intensive care ward. INTERPRETATION: The degree of severity of the condition for which patients were admitted was high, and the treatment outcomes judged upon expected mortality were good. Medical intermediate care units can relieve pressure on wards with seriously ill patients without taking up intensive care beds.

Statistical testing of association between menstruation and migraine.

OBJECTIVE: To repair and refine a previously proposed method for statistical analysis of association between migraine and menstruation. BACKGROUND: Menstrually related migraine (MRM) affects about 20% of female migraineurs in the general population. The exact pathophysiological link from menstruation to migraine is hypothesized to be through fluctuations in female reproductive hormones, but the exact mechanisms remain unknown. Therefore, the main diagnostic criterion today is concurrency of migraine attacks with menstruation. Methods aiming to exclude spurious associations are wanted, so that further research into these mechanisms can be performed on a population with a true association. METHODS: The statistical method is based on a simple two-parameter null model of MRM (which allows for simulation modeling), and Fisher's exact test (with mid-p correction) applied to standard 2 × 2 contingency tables derived from the patients' headache diaries. Our method is a corrected version of a previously published flawed framework. To our best knowledge, no other published methods for establishing a menstruation-migraine association by statistical means exist today. RESULTS: The probabilistic methodology shows good performance when subjected to receiver operator characteristic curve analysis. Quick reference cutoff values for the clinical setting were tabulated for assessing association given a patient's headache history. CONCLUSIONS: In this paper, we correct a proposed method for establishing association between menstruation and migraine by statistical methods. We conclude that the proposed standard of 3-cycle observations prior to setting an MRM diagnosis should be extended with at least one perimenstrual window to obtain sufficient information for statistical processing.

Laparoscopic Lavage vs Primary Resection for Acute Perforated Diverticulitis: The SCANDIV Randomized Clinical Trial.

IMPORTANCE: Perforated colonic diverticulitis usually requires surgical resection, which is associated with significant morbidity. Cohort studies have suggested that laparoscopic lavage may treat perforated diverticulitis with less morbidity than resection procedures. OBJECTIVE: To compare the outcomes from laparoscopic lavage with those for colon resection for perforated diverticulitis. DESIGN, SETTING, AND PARTICIPANTS: Multicenter, randomized clinical superiority trial recruiting participants from 21 centers in Sweden and Norway from February 2010 to June 2014. The last patient follow-up was in December 2014 and final review and verification of the medical records was assessed in March 2015. Patients with suspected perforated diverticulitis, a clinical indication for emergency surgery, and free air on an abdominal computed tomography scan were eligible. Of 509 patients screened, 415 were eligible and 199 were enrolled. INTERVENTIONS: Patients were assigned to undergo laparoscopic peritoneal lavage (n = 101) or colon resection (n = 98) based on a computer-generated, center-stratified block randomization. All patients with fecal peritonitis (15 patients in the laparoscopic peritoneal lavage group vs 13 in the colon resection group) underwent colon resection. Patients with a pathology requiring treatment beyond that necessary for perforated diverticulitis (12 in the laparoscopic lavage group vs 13 in the colon resection group) were also excluded from the protocol operations and treated as required for the pathology encountered. MAIN OUTCOMES AND MEASURES: The primary outcome was severe postoperative complications (Clavien-Dindo score >IIIa) within 90 days. Secondary outcomes included other postoperative complications, reoperations, length of operating time, length of postoperative hospital stay, and quality of life. RESULTS: The primary outcome was observed in 31 of 101 patients (30.7%) in the laparoscopic lavage group and 25 of 96 patients (26.0%) in the colon resection group (difference, 4.7% [95% CI, -7.9% to 17.0%]; P = .53). Mortality at 90 days did not significantly differ between the laparoscopic lavage group (14 patients [13.9%]) and the colon resection group (11 patients [11.5%]; difference, 2.4% [95% CI, -7.2% to 11.9%]; P = .67). The reoperation rate was significantly higher in the laparoscopic lavage group (15 of 74 patients [20.3%]) than in the colon resection group (4 of 70 patients [5.7%]; difference, 14.6% [95% CI, 3.5% to 25.6%]; P = .01) for patients who did not have fecal peritonitis. The length of operating time was significantly shorter in the laparoscopic lavage group; whereas, length of postoperative hospital stay and quality of life did not differ significantly between groups. Four sigmoid carcinomas were missed with laparoscopic lavage. CONCLUSIONS AND RELEVANCE: Among patients with likely perforated diverticulitis and undergoing emergency surgery, the use of laparoscopic lavage vs primary resection did not reduce severe postoperative complications and led to worse outcomes in secondary end points. These findings do not support laparoscopic lavage for treatment of perforated diverticulitis. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01047462.

The effect of activity-based financing on hospital length of stay for elderly patients suffering from heart diseases in Norway.

BACKGROUND: Whether activity-based financing of hospitals creates incentives to treat more patients and to reduce the length of each hospital stay is an empirical question that needs investigation. This paper examines how the level of the activity-based component in the financing system of Norwegian hospitals influences the average length of hospital stays for elderly patients suffering from ischemic heart diseases. During the study period, the activity-based component changed several times due to political decisions at the national level. METHODS: The repeated cross-section data were extracted from the Norwegian Patient Register in the period from 2000 to 2007, and included patients with angina pectoris, congestive heart failure, and myocardial infarction. Data were analysed with a log-linear regression model at the individual level. RESULTS: The results show a significant, negative association between the level of activity-based financing and length of hospital stays for elderly patients who were suffering from ischemic heart diseases. The effect is small, but an increase of 10 percentage points in the activity-based component reduced the average length of each hospital stay by 1.28%. CONCLUSIONS: In a combined financing system such as the one prevailing in Norway, hospitals appear to respond to economic incentives, but the effect of their responses on inpatient cost is relatively meagre. Our results indicate that hospitals still need to discuss guidelines for reducing hospitalisation costs and for increasing hospital activity in terms of number of patients and efficiency.

Using stochastic simulation modelling to study occupancy levels of decentralised admission avoidance units in Norway.

Identifying alternatives to acute hospital admission is a priority for many countries. Over 200 decentralised municipal acute units (MAUs) were established in Norway to divert low-acuity patients away from hospitals. MAUs have faced criticism for low mean occupancy and not relieving pressures on hospitals. We developed a discrete time simulation model of admissions and discharges to MAUs to test scenarios for increasing absolute mean occupancy. We also used the model to estimate the number of patients turned away as historical data was unavailable. Our experiments suggest that mergers alone are unlikely to substantially increase MAU absolute mean occupancy as unmet demand is generally low. However, merging MAUs offers scope for up to 20% reduction in bed capacity, without affecting service provision. Our work has relevance for other admissions avoidance units and provides a method for estimating unconstrained demand for beds in the absence of historical data.

A critical re-evaluation of the regression model specification in the US D1 EQ-5D value function.

BACKGROUND: The EQ-5D is a generic health-related quality of life instrument (five dimensions with three levels, 243 health states), used extensively in cost-utility/cost-effectiveness analyses. EQ-5D health states are assigned values on a scale anchored in perfect health (1) and death (0).The dominant procedure for defining values for EQ-5D health states involves regression modeling. These regression models have typically included a constant term, interpreted as the utility loss associated with any movement away from perfect health. The authors of the United States EQ-5D valuation study replaced this constant with a variable, D1, which corresponds to the number of impaired dimensions beyond the first. The aim of this study was to illustrate how the use of the D1 variable in place of a constant is problematic. METHODS: We compared the original D1 regression model with a mathematically equivalent model with a constant term. Comparisons included implications for the magnitude and statistical significance of the coefficients, multicollinearity (variance inflation factors, or VIFs), number of calculation steps needed to determine tariff values, and consequences for tariff interpretation. RESULTS: Using the D1 variable in place of a constant shifted all dummy variable coefficients away from zero by the value of the constant, greatly increased the multicollinearity of the model (maximum VIF of 113.2 vs. 21.2), and increased the mean number of calculation steps required to determine health state values. DISCUSSION: Using the D1 variable in place of a constant constitutes an unnecessary complication of the model, obscures the fact that at least two of the main effect dummy variables are statistically nonsignificant, and complicates and biases interpretation of the tariff algorithm.

Role of high-risk human papillomavirus (HPV) mRNA testing in the prediction of residual disease after conisation for high-grade cervical intraepithelial neoplasia.

OBJECTIVE: To evaluate testing for high-risk human papillomavirus (HR HPV) E6/E7 mRNA transcripts 6 months after conisation for cervical intraepithelial neoplasia grade 2 or worse (CIN2+) to determine the risk of residual CIN2+. METHODS: We prospectively followed 344 women treated for CIN2+ by conisation. HR HPV mRNA testing (PreTect HPV-Proofer, NorChip®), HR HPV DNA testing (AMPLICOR HPV Test, Roche Diagnostics®) and cytology was performed at 6 and 12 months after conisation. Biopsies were taken within 18 months of conisation if indicated by abnormal cytology, abnormal colposcopy, or positive HPV test. The LINEAR ARRAY HPV Genotyping Test (Roche Diagnostics®) was used to genotype cases with histologically confirmed residual disease diagnosed within 18 months after conisation. RESULTS: 6.4% (22/344) of study women had detected residual CIN2+. They were significantly older than those without residual CIN2+ (43.2 and 37.2 years respectively, p<0.001). Among women with detected residual CIN2+, 54.5% (12/22) had positive resection margins, 63.6% (14/22) had abnormal cytology, and 95.5% (21/22) had a positive HR HPV DNA test at 6 months. Sensitivity of HR HPV mRNA testing was 45.5% (95% confidence interval: 26.8-65.5%) at 6 months to predict detected residual CIN2+. Eight of 12 women who were HR HPV mRNA-negative at 6 months were HR HPV DNA-positive for one of the HPV types included in the mRNA test. CONCLUSION: Detection of E6/E7 mRNA transcripts by PreTect HPV Proofer does not seem suitable for short-term follow-up to detect residual CIN2+ after conisation.

No Correlation Between Ethical Judgment in Trolley Dilemmas and Vaccine Scenarios for Nurse Specialist Students.

We tested whether responses to trolley problems by nurse specialist students correlated with their responses to hypothetical vaccine problems, as a follow-up to a similar study on ethics committees. No statistically significant correlation was found between the trolley and vaccination scores. These results confirmed and strengthened the finding of a very weak correlation (possibly zero), and the point estimate was even lower than for the ethics committees. Hence, the nurse specialists' responses to the trolley problems cannot be used to indicate any direction for their responses to the vaccine problems, although there is a common core issue of sacrificing some for many. The respondents reported a relatively high willingness to push one man in front of a trolley to save five. They also reported a high willingness to act in trolley dilemmas compared with vaccination dilemmas, although the dimensions of risk-reward ratios and consent heavily favored the latter.

A Markov chain method for counting and modelling migraine attacks.

To ensure reproducibility in research quantifying episodic migraine attacks, and identifying attack onset, a sound theoretical model of a migraine attack, paired with a uniform standard for counting them, is necessary. Many studies report on migraine frequencies-e.g. the fraction of migraine-days of the observed days-without paying attention to the number of discrete attacks. Furthermore, patients' diaries frequently contain single, migraine-free days between migraine-days, and we argue here that such 'migraine-locked days' should routinely be interpreted as part of a single attack. We tested a simple Markov model of migraine attacks on headache diary data and estimated transition probabilities by mapping each day of each diary to a unique Markov state. We explored the validity of imputing migraine days on migraine-locked entries, and estimated the effect of imputation on observed migraine frequencies. Diaries from our patients demonstrated significant clustering of migraine days. The proposed Markov chain model was shown to approximate the progression of observed migraine attacks satisfactorily, and imputing on migraine-locked days was consistent with the conceptual model for the progression of migraine attacks. Hence, we provide an easy method for quantifying the number and duration of migraine attacks, enabling researchers to procure data of high inter-study validity.

Do clinicians read our reports? Integrating the radiology information system with the electronic patient record: experiences from the first 2 years.

This study aimed to determine how clinicians adapted to and utilized new routines for accessing radiology reports after the integration of an electronic patient record (EPR) with a radiology information system (RIS). Activity-related data describing the availability and receipt of radiology reports were collected from the EPR and the RIS over a period of 2 years. Twelve percent of the final radiology reports had not been opened 4 weeks after they had been entered into the EPR. For opened reports, the median time after a report was available in the EPR until it was first opened by a clinician was less than 1 h for preliminary reports and less than 4 h for final radiology reports. The use of radiology reports was stable during the second observation year. Some reports were not opened for professional as well as technical reasons. The integrated information systems offered a potential for improving routines related to the transmission of radiology reports. Clinicians did not fully take advantage of this potential in the 2 years after its introduction.

Erlang could have told you so-A case study of health policy without maths.

Little consideration is given to the operational reality of implementing national policy at local scale. Using a case study from Norway, we examine how simple mathematical models may offer powerful insights to policy makers when planning policies. Our case study refers to a national initiative requiring Norwegian municipalities to establish acute community beds (municipal acute units or MAUs) to avoid hospital admissions. We use Erlang loss queueing models to estimate the total number of MAU beds required nationally to achieve the original policy aim. We demonstrate the effect of unit size and patient demand on anticipated utilisation. The results of our model imply that both the average demand for beds and the current number of MAU beds would have to be increased by 34% to achieve the original policy goal of transferring 240 000 patient days to MAUs. Increasing average demand or bed capacity alone would be insufficient to reach the policy goal. Day-to-day variation and uncertainty in the numbers of patients arriving or leaving the system can profoundly affect health service delivery at the local level. Health policy makers need to account for these effects when estimating capacity implications of policy. We demonstrate how a simple, easily reproducible, mathematical model could assist policy makers in understanding the impact of national policy implemented at the local level.