Berthold Lausen

eHealth Trends in Europe 2005-2007: A Population-Based Survey

Background In the last decade, the number of Internet users worldwide has dramatically increased. People are using the Internet for various health-related purposes. It is important to monitor such use as it may have an impact on the individual’s health and behavior, patient-practitioner roles, and on general health care provision. Objectives This study investigates trends and patterns of European health-related Internet use over a period of 18 months. The main study objective was to estimate the change in the proportion of the population using the Internet for health purposes, and the importance of the Internet as a source of health information compared to more traditional sources. Methods The survey data were collected through computer-assisted telephone interviews. A representative sample (N = 14,956) from seven European countries has been used: Denmark, Germany, Greece, Latvia, Norway, Poland, and Portugal. The European eHealth Consumer Trends Survey was first conducted in October-November 2005 and repeated in April-May 2007. In addition to providing background information, respondents were asked to rate the importance of various sources of health information. They were also queried as to the frequency of different online activities related to health and illness and the effects of such use on their disposition. Results The percentage of the population that has used the Internet for health purposes increased from an estimated 42.3% (95% CI [Confidence Interval] 41.3 - 43.3) in 2005 to an estimated 52.2% (95% CI 51.3 - 53.2) in 2007. Significant growth in the use of the Internet for health purposes was found in all the seven countries. Young women are the most active Internet health users. The importance of the Internet as a source of health information has increased. In 2007, the Internet was perceived as an important source of health information by an estimated 46.8% (95% CI 45.7 - 47.9) of the population, a significant increase of 6.5 % (95% CI 4.9 - 8.1) from 2005. The importance of all the traditional health information channels has either decreased or remained the same. An estimated 22.7% (95% CI 21.7 - 23.6) are using it for more interactive services than just reading health information. Conclusion The Internet is increasingly being used as a source of health information by the European population, and its perceived importance is rising. Use of the Internet for health purposes is growing in all age groups and for both men and women, with especially strong growth among young women. We see that experienced Internet health users are also using the Internet as an active communication channel, both for reaching health professionals and for communicating with peers.

Maximally selected rank statistics

A common statistical problem is the assessment of the predictive power of a quantitative variable for some dependent variable. A maximally selected rank statistic regarding the quantitative variable provides a test and implicitly an estimate of a cutpoint as a simple classification rule. Restricting the selection to an arbitrary given inner part of the support of the quantitative variable, we show that the asymptotic null distribution of the maximally selected rank statistic is the distribution of the supremum of the absolute value of a standardized Gaussian process on an interval. The asymptotic argument holds also in the case of tied or censored observations. We compare Monte Carlo results with an approximation of the asymptotic distribution under the null hypothesis. In addition, we investigate the behaviour of the test procedure and of the familiar Spearman rank test for independence, under some alternatives. Moreover, we discuss some aspects of the problem of estimating an underlying cutpoint.

Automated segmentation of the optic nerve head for diagnosis of glaucoma

Glaucoma is the second most common cause of blindness worldwide. Low awareness and high costs connected to glaucoma are reasons to improve methods of screening and therapy. A well-established method for diagnosis of glaucoma is the examination of the optic nerve head using scanning-laser-tomography. This system acquires and analyzes the surface topography of the optic nerve head. The analysis that leads to a diagnosis of the disease depends on prior manual outlining of the optic nerve head by an experienced ophthalmologist. Our contribution presents a method for optic nerve head segmentation and its validation. The method is based on morphological operations, Hough transform, and an anchored active contour model. The results were validated by comparing the performance of different classifiers on data from a case-control study with contours of the optic nerve head manually outlined by an experienced ophthalmologist. We achieved the following results with respect to glaucoma diagnosis: linear discriminant analysis with 27.7% estimated error rate for automated segmentation (aut) and 26.8% estimated error rate for manual segmentation (man), classification trees with 25.2% (aut) and 22.0% (man) and bootstrap aggregation with 22.2% (aut) and 13.4% (man). It could thus be shown that our approach is suitable for automated diagnosis and screening of glaucoma.

Energy intake of 1 to 18 year old German children and adolescents.

In a sample of 695 healthy well-nourished German children and adolescents covering the total age range from 1 to 18 years, 3d weighed diet records were collected and measurements of body height and weight were taken. 10% non-plausible records (reported energy intake (EI):estimated basal metabolic rate (BMR) < Cut off 1.06) were excluded from further analysis. The rate of non-plausible records was low in the childhood age groups (2-6%), higher in the male (10%), and highest in the female adolescents (30%). Recalculation of age and sex specific cut offs based on assumed light physical activity levels (PAL) reduced the exclusion rate to 6.5% (total) and 20% (female adolescents). The reported energy intake of the total sample based on plausible records (n = 627, EI:BMR > or = 1.06) was close to the new estimations of energy requirements assuming light physical activity which are proposed for the revision of the current FAO/WHO energy requirements. The sample was of normal height and weight compared to the Netherlands growth references. For a definite interpretation of the low reported energy intake in the context of health promoting physical activity patterns of children and adolescents more scientific evidence should be available.

Homocysteine and risk of open-angle glaucoma.

Summary.Homocysteine levels and the frequency of heterozygous methylenetetrahydrofolate reductase (MTHFR) C677T mutation are increased in open-angle glaucoma. Since homocysteine can induce vascular injury, alterations in extracellular matrix remodelling, and neuronal cell death, these findings may have important implications for understanding glaucomatous optic neuropathy.

Evaluating the effect of optimized cutoff values in the assessment of prognostic factors

In clinical research the assessment of prognostic factors is often based on the division of the patients into two groups: a high risk and a low risk group. A common strategy is to select an optimal cutoff value in the prognostic factor which defines the two groups. The effect is measured as difference between the groups. We provide simple correction formulae for the correct P-value of the selected two-sample statistic. Moreover, we discuss consequences of that optimization on both the estimator of the cutoff point and the estimated effect. An approximate confidence region for both parameters is given. The small sample behaviour is analysed by means of a Monte-Carlo study. The optimization of the cutoff value results in an overestimation of the difference between the prognostic groups. Extensions of our discussion to censored data are given, too. Finally, we apply our approach to an example from oncology.

Double-bagging: combining classifiers by bootstrap aggregation

The combination of classifiers leads to substantial reduction of misclassification error in a wide range of applications and benchmark problems. We suggest using an out-of-bag sample for combining different classifiers. In our setup, a linear discriminant analysis is performed using the observations in the out-of-bag sample, and the corresponding discriminant variables computed for the observations in the bootstrap sample are used as additional predictors for a classification tree. Two classifiers are combined and therefore method and variable selection bias is no problem for the corresponding estimate of misclassification error, the need of an additional test sample disappears. Moreover, the procedure performs comparable to the best classifiers used in a number of artificial examples and applications.

Bundling classifiers by bagging trees

The quest of selecting the best classifier for a discriminant analysis problem is often rather difficult. A combination of different types of classifiers promises to lead to improved predictive models compared to selecting one of the competitors. An additional learning sample, for example the out-of-bag sample, is used for the training of arbitrary classifiers. Classification trees are employed to bundle their predictions for the bootstrap sample. Consequently, a combined classifier is developed. Benchmark experiments show that the combined classifier is superior to any of the single classifiers in many applications.

Online Communication Between Doctors and Patients in Europe: Status and Perspectives

Background Use of the Internet for health purposes is steadily increasing in Europe, while the eHealth market is still a niche. Online communication between doctor and patient is one aspect of eHealth with potentially great impact on the use of health systems, patient-doctor roles and relations and individuals’ health. Monitoring and understanding practices, trends, and expectations in this area is important, as it may bring invaluable knowledge to all stakeholders, in the Health 2.0 era. Objective Our two main goals were: (1) to investigate use of the Internet and changes in expectations about future use for particular aspects of communication with a known doctor (obtaining a prescription, scheduling an appointment, or asking a particular health question), and (2) to investigate how important the provision of email and Web services to communicate with the physician is when choosing a new doctor for a first time face-to-face appointment. The data come from the second survey of the eHealth Trends study, which addressed trends and perspectives of health-related Internet use in Europe. This study builds on previous work that established levels of generic use of the Internet for self-help activities, ordering medicine or other health products, interacting with a Web doctor/unknown health professional, and communicating with a family doctor or other known health professional. Methods A representative sample of citizens from seven European countries was surveyed (n = 7022) in April and May of 2007 through computer-assisted telephone interviews (CATI). Respondents were questioned about their use of the Internet to obtain a prescription, schedule an appointment, or ask a health professional about a particular health question. They were also asked what their expectations were regarding future use of the Internet for health-related matters. In a more pragmatic approach to the subject, they were asked about the perceived importance when choosing a new doctor of the possibility of using email and the Web to communicate with that physician. Logistic regression analysis was used to draw the profiles of users of related eHealth services in Europe among the population in general and in the subgroup of those who use the Internet for health-related matters. Changes from 2005 to 2007 were computed using data from the first eHealth Trends survey (October and November 2005, n = 7934). Results In 2007, an estimated 1.8% (95% confidence interval [CI], 1.5 - 2.1) of the population in these countries had used the Internet to request or renew a prescription; 3.2% (95% CI 2.8 - 3.6) had used the Internet to schedule an appointment; and 2.5% (95% CI 2.2 - 2.9) had used the Internet to ask a particular health question. This represents estimated increases of 0.9% (95% CI 0.5 - 1.3), 1.7% (95% CI 1.2 - 2.2), and 1.4% (95% CI 0.9 - 1.8). An estimated 18.0% (95% CI 17.1 - 18.9) of the populations of these countries expected that in the near future they would have consultations with health professionals online, and 25.4% (95% CI 24.4 - 26.3) expected that in the near future they would be able to schedule an appointment online. Among those using the Internet for health-related purposes, on average more than 4 in 10 people considered the provision of these eHealth services to be important when choosing a new doctor. Conclusions Use of the Internet to communicate with a known health professional is still rare in Europe. Legal context, health policy issues, and technical conditions prevailing in different countries might be playing a major role in the situation. Interest in associated eHealth services is high among citizens and likely to increase.

Stat1 and CD74 overexpression is co-dependent and linked to increased invasion and lymph node metastasis in triple-negative breast cancer.

Triple-negative breast cancer is difficult to treat because of the lack of rationale-based therapies. There are no established markers and targets that can be used for stratification of patients and targeted therapy. Here we report the identification of novel molecular features, which appear to augment metastasis of triple negative breast tumors. We found that triple-negative breast tumors can be segregated into 2 phenotypes based on their genome-wide protein abundance profiles. The first is characterized by high expression of Stat1, Mx1, and CD74. Seven out of 9 tumors from this group had invaded at least 2 lymph nodes while only 1 out of 10 tumors in group 2 was lymph node positive. In vitro experiments showed that the interferon-induced increase in Stat1 abundance correlates with increased migration and invasion in cultured cells. When CD74 was overexpressed, it increased cell adhesion on matrigel. This effect was accompanied with a marked increase in the membrane expression of beta-catenin, MUC18, plexins, integrins, and other proteins involved in cell adhesion and cancer metastasis. Taken together, our results show that Stat1/CD74 positive triple-negative tumors are more aggressive and suggest an approach for development of better diagnostics and more targeted therapies for triple negative breast cancer. This article is part of a Special Issue entitled: Proteomics: The clinical link.