Vera Lisovskaja

Time to secondary progression in patients with multiple sclerosis who were treated with first generation immunomodulating drugs

Background: It is currently unknown whether early immunomodulatory treatment in relapsing–remitting MS (RRMS) can delay the transition to secondary progression (SP). Objective: To compare the time interval from onset to SP in patients with RRMS between a contemporary cohort, treated with first generation disease modifying drugs (DMDs), and a historical control cohort. Methods: We included a cohort of contemporary RRMS patients treated with DMDs, obtained from the Swedish National MS Registry (disease onset between 1995–2004, n = 730) and a historical population-based incidence cohort (onset 1950–64, n = 186). We retrospectively analyzed the difference in time to SP, termed the “period effect” within a 12-year survival analysis, using Kaplan-Meier and Cox regression analysis. Results: We found that the “period” affected the entire severity spectrum. After adjusting for onset features, which were weaker in the contemporary material, as well as the therapy initiation time, the DMD-treated patients still exhibited a longer time to SP than the controls (hazard ratios: men, 0.32; women, 0.53). Conclusion: Our results showed there was a longer time to SP in the contemporary subjects given DMD. Our analyses suggested that this effect was not solely driven by the inclusion of benign cases, and it was at least partly due to the long-term immunomodulating therapy given.

Uncertainty in Material Flow Analysis Indicators at Different Spatial Levels

Material flow analysis (MFA) is a tool for research and decision support in environmental policy and management. In order to promote the use of MFA at different spatial scales, a quantification of the uncertainty in nationwide, regional, and urban MFA methodologies is provided. In particular, the impact of the input data quality on the main MFA indicators is analyzed and the sources and extent of uncertainties for different spatial scales are listed. The types, origin, and extent of the errors are described in detail and several imputation methods are explained and evaluated. By introducing a novel approach to account measurement errors in data sets with very few details on the measurement errors, this article aims at contributing to the development of a standardized method to account for the uncertainty in MFA studies. This study uses the time series of MFA data for 1996-2011 at three spatial scalesnationwide (Sweden), regional (the Stockholm Region), and metropolitan (Stockholm, Gothenburg, and Malmo)to determine how propagation of measurement errors affects the MFA results. The following MFA indicators were studied: direct material input; domestic processed output; and domestic material consumption. Generally, availability decreased as the spatial scale was lowered, whereas data errors increased. In the specific case of Sweden, the data on freight transport by rail and on waste produced by economic activities at the regional and metropolitan level should be improved.

Clinically isolated syndromes with no further disease activity suggestive of multiple sclerosis at the age of population life expectancy

The proportion of patients with clinically isolated syndrome (CIS) reported to convert to clinically definite multiple sclerosis varied between 30 and 75%. We studied the lifetime probability of remaining in the “CIS only” condition. The study was based on the longitudinally followed Gothenburg 1950–1964 incidence cohort (n = 306). Survival analysis revealed that 17.8% of 236 attack onset patients remained “CIS only”. Patients with afferent (optic and sensory) symptoms had a better prognosis with approximately 30% of these patients remaining “CIS only”. Patients who had experienced no relapse during the first 25 years remained “CIS only” for the subsequent 25 years of follow-up.

Foot deformities, function in the lower extremities, and plantar pressure in patients with diabetes at high risk to develop foot ulcers

Objective Foot deformities, neuropathy, and dysfunction in the lower extremities are known risk factors that increase plantar peak pressure (PP) and, as a result, the risk of developing foot ulcers in patients with diabetes. However, knowledge about the prevalence of these factors is still limited. The aim of the present study was to describe the prevalence of risk factors observed in patients with diabetes without foot ulcers and to explore possible connections between the risk factors and high plantar pressure. Patients and methods Patients diagnosed with type 1 (n=27) or type 2 (n=47) diabetes (mean age 60.0±15.0 years) were included in this cross-sectional study. Assessments included the registration of foot deformities; test of gross function at the hip, knee, and ankle joints; a stratification of the risk of developing foot ulcers according to the Swedish National Diabetes Register; a walking test; and self-reported questionnaires including the SF-36 health survey. In-shoe PP was measured in seven regions of interests on the sole of the foot using F-Scan®. An exploratory analysis of the association of risk factors with PP was performed. Results Neuropathy was present in 28 (38%), and 39 (53%) had callosities in the heel region. Low forefoot arch was present in 57 (77%). Gait-related parameters, such as the ability to walk on the forefoot or heel, were normal in all patients. Eighty percent had normal function at the hip and ankle joints. Gait velocity was 1.2±0.2 m/s. All patients were stratified to risk group 3. Hallux valgus and hallux rigidus were associated with an increase in the PP in the medial forefoot. A higher body mass index (BMI) was found to increase the PP at metatarsal heads 4 and 5. Pes planus was associated with a decrease in PP at metatarsal head 1. Neuropathy did not have a high association with PP. Conclusions This study identified several potential risk factors for the onset of diabetic foot ulcers (DFU). Hallux valgus and hallux rigidus appeared to increase the PP under the medial forefoot and a high BMI appeared to increase the PP under the lateral forefoot. There is a need to construct a simple, valid, and reliable assessment routine to detect potential risk factors for the onset of DFU.

Comparison of plantar pressure in three types of insole given to patients with diabetes at risk of developing foot ulcers – A two-year, randomized trial

Background Special insoles and shoes designed to prevent foot ulcers caused by repetitive high pressures are recommended for patients with diabetes who have any of the following risk factors: neuropathy; peripheral vascular disease; foot deformities; previous ulcers; amputation; and skin pathologies. However, there is a need for increased knowledge regarding: a) differences in the peak pressure (PP) and pressure time integral (PTI) for different types of insoles; and b) the properties of the pressure distribution for insoles used over a period of several months. We present the results of a randomized trial to compare the plantar pressures of three commonly used insoles. Objectives The primary objective was to compare the PP and PTI between three types of insoles. The secondary objective was to explore the long-term pattern of peak plantar pressure distribution and variations in specific regions of interest (ROI). The tertiary objective was to investigate the impacts of insole adjustments, how much the insoles were used, and the levels of patient satisfaction. Methods In a 2-year trial, 114 patients with type 1 (N = 31) or type 2 (N = 83) diabetes (62 men and 52 women; mean age, 57.7 ± 15.4 years; duration of diabetes, 12.3 ± 11.2 years; neuropathy, 38%), were randomized to be supplied with one of three different insoles. The ethylene vinyl acetate (EVA) insoles were used in outdoor walking shoes. The 35 EVA group (N = 39) received soft custom-made insoles composed of EVA of 35 shore A hardness, the 55 EVA group (N = 37) received custom-made insoles composed of EVA of 55 shore hardness, and the control group (N = 38) received prefabricated insoles composed of a hard core with a top layer of soft 12 shore hardness microfiber. Using F-Scan®, the in-shoe plantar pressures were measured at seven ROI (hallux, metatarsal head 1, metatarsal head 2, metatarsal head 4, metatarsal head 5, lateral aspect of the mid-foot, heel) on five occasions during the study period. The plantar-pressure variables used were PP (main outcome) and PTI. The plantar patterns of load were explored, satisfaction and usage of the insoles were rated by the participants, and insole adjustments were recorded. Results A mixed model analysis estimated lower PP values in the heel regions for the 35 EVA and 55 EVA insoles (171 ± 13 and 161 ± 13 kPa, respectively) than for the prefabricated insoles (234 ± 10 kPa) (p < 0.001). Also for some of the other six ROI indications of difference in PP or PTI could be observed. The redistribution of peak plantar pressure for all of the insoles, was stable at the mid-foot, while the proportion of load on the distal area changed during the study period According to the self-reported answers (scale, 0–100), the average usage of the insoles was rated as 79 and satisfaction was rated as 85 (N = 75). Thirty-two percent of the subjects had not received foot care. Fourteen adjustments to insoles were made during the study period, and 86 pairs of insoles were exchanged due to wear, with 49% being exchanged in the 35 EVA group. Conclusions Custom-made insoles used in combination with stable walking shoes gave lower pressures at the heel region. The variation makes it difficult to detect a systematic difference in plantar pressure for the 6 ROI, if such a difference indeed exists. The levels of satisfaction and usage for all the insoles tested were high. The insoles maintained their pressure redistribution properties over long periods, and few adjustments were needed.

Upper Respiratory Infections and MRI Activity in Relapsing-Remitting Multiple Sclerosis

Background: Although clinical reports have suggested a relationship between systemic infections and multiple sclerosis (MS) relapses, MRI evidence supporting an association is conflicting. Here we evaluated the temporal relationship between upper respiratory infections (URIs) and MRI activity in relapsing-remitting (RR) MS. Methods: We combined individual data on URI with data on active lesions in pre-scheduled MRI examinations performed every 4 weeks for 28 weeks in 69 patients. A 4-week at-risk (AR) period started, by definition, 1 week before the onset of a URI. We recorded the relationship between the number of active lesions in each MRI with (1) the number of days of AR time in the immediately preceding 4-week period and (2) the number of days passed since the onset of a preceding URI. Results: Average MRI lesions/day showed no difference between AR (0.0764) and not-AR (0.0774) periods. The number of lesions in 483 pre-scheduled MRI examinations did not correlate with the AR proportion in the prior 4-week period (rho = -0.03), and time from URI onset did not correlate with lesion number on the next MRI examination (rho = 0.003). Conclusion: The occurrence of a URI did not increase the risk of MRI activity evaluated in an adjacent 4-week window in RRMS.

A novel fibrosis index comprising a non-cholesterol sterol accurately predicts HCV-related liver cirrhosis.

Diagnosis of liver cirrhosis is essential in the management of chronic hepatitis C virus (HCV) infection. Liver biopsy is invasive and thus entails a risk of complications as well as a potential risk of sampling error. Therefore, non-invasive diagnostic tools are preferential. The aim of the present study was to create a model for accurate prediction of liver cirrhosis based on patient characteristics and biomarkers of liver fibrosis, including a panel of non-cholesterol sterols reflecting cholesterol synthesis and absorption and secretion. We evaluated variables with potential predictive significance for liver fibrosis in 278 patients originally included in a multicenter phase III treatment trial for chronic HCV infection. A stepwise multivariate logistic model selection was performed with liver cirrhosis, defined as Ishak fibrosis stage 5–6, as the outcome variable. A new index, referred to as Nordic Liver Index (NoLI) in the paper, was based on the model: Log-odds (predicting cirrhosis) = −12.17+ (age×0.11) + (BMI (kg/m2)×0.23) + (D7-lathosterol (μg/100 mg cholesterol)×(−0.013)) + (Platelet count (x109/L)×(−0.018)) + (Prothrombin-INR×3.69). The area under the ROC curve (AUROC) for prediction of cirrhosis was 0.91 (95% CI 0.86–0.96). The index was validated in a separate cohort of 83 patients and the AUROC for this cohort was similar (0.90; 95% CI: 0.82–0.98). In conclusion, the new index may complement other methods in diagnosing cirrhosis in patients with chronic HCV infection.

On the choice of doses for phase III clinical trials

Many potential new medicines fail in phase III clinical trials, because of either insufficient efficacy or intolerability. Such failures may be caused by the absence of an effect and also if a suboptimal dose is being tested. It is thus important to consider how to optimise the choice of dose or doses that continue into the confirmatory phase. For many indications, it is common to test one single active dose in phase III. However, phase IIB dose-finding trials are relatively small and often lack the ability of precisely estimating the dose-response curves for efficacy and tolerability. Because of this uncertainty in dose response, it is reasonable to consider bringing more than one dose into phase III. Using simple but illustrative models, we find the optimal doses and compare the probability of success, for fixed total sample sizes, when one or two active doses are included in phase III.

Validation of gait analysis with dynamic radiostereometric analysis (RSA) in patients operated with total hip arthroplasty

We simultaneously examined 14 patients with OTS and dynamic radiostereometric analysis (RSA) to evaluate the accuracy of both skin‐ and a cluster‐marker models. The mean differences between the OTS and RSA system in hip flexion, abduction, and rotation varied up to 9.5° for the skin‐marker and up to 11.3° for the cluster‐marker models, respectively. Both models tended to underestimate the amount of flexion and abduction, but a significant systematic difference between the marker and RSA evaluations could only be established for recordings of hip abduction using cluster markers (p = 0.04). The intra‐class correlation coefficient (ICC) was 0.7 or higher during flexion for both models and during abduction using skin markers, but decreased to 0.5–0.6 when abduction motion was studied with cluster markers. During active hip rotation, the two marker models tended to deviate from the RSA recordings in different ways with poor correlations at the end of the motion (ICC ≤0.4). During active hip motions soft tissue displacements occasionally induced considerable differences when compared to skeletal motions. The best correlation between RSA recordings and the skin‐ and cluster‐marker model was found for studies of hip flexion and abduction with the skin‐marker model. Studies of hip abduction with use of cluster markers were associated with a constant underestimation of the motion. Recordings of skeletal motions with use of skin or cluster markers during hip rotation were associated with high mean errors amounting up to about 10° at certain positions.

A decision theoretic approach to optimization of multiple testing procedures

This paper focuses on the concept of optimizing a multiple testing procedure (MTP) with respect to a predefined utility function. The class of Bonferroni-based closed testing procedures, which includes, for example, (weighted) Holm, fallback, gatekeeping, and recycling/graphical procedures, is used in this context. Numerical algorithms for calculating expected utility for some MTPs in this class are given. The obtained optimal procedures, as well as the gain resulting from performing an optimization are then examined in a few, but informative, examples.