ABSTRACT
BACKGROUND: Increasingly, social media is being recognized as a potential resource for patient-generated health data, for example, for pharmacovigilance. Although the representativeness of the web-based patient population is often noted as a concern, studies in this field are limited. OBJECTIVE: This study aimed to investigate the sample bias of patient-centered social media in Dutch patients with gastrointestinal stromal tumor (GIST). METHODS: A population-based survey was conducted in the Netherlands among 328 patients with GIST diagnosed 2-13 years ago to investigate their digital communication use with fellow patients. A logistic regression analysis was used to analyze clinical and demographic differences between forum users and nonusers. RESULTS: Overall, 17.9% (59/328) of survey respondents reported having contact with fellow patients via social media. Moreover, 78% (46/59) of forum users made use of GIST patient forums. We found no statistically significant differences for age, sex, socioeconomic status, and time since diagnosis between forum users (n=46) and nonusers (n=273). Patient forum users did differ significantly in (self-reported) treatment phase from nonusers (P=.001). Of the 46 forum users, only 2 (4%) were cured and not being monitored; 3 (7%) were on adjuvant, curative treatment; 19 (41%) were being monitored after adjuvant treatment; and 22 (48%) were on palliative treatment. In contrast, of the 273 patients who did not use disease-specific forums to communicate with fellow patients, 56 (20.5%) were cured and not being monitored, 31 (11.3%) were on curative treatment, 139 (50.9%) were being monitored after treatment, and 42 (15.3%) were on palliative treatment. The odds of being on a patient forum were 2.8 times as high for a patient who is being monitored compared with a patient that is considered cured. The odds of being on a patient forum were 1.9 times as high for patients who were on curative (adjuvant) treatment and 10 times as high for patients who were in the palliative phase compared with patients who were considered cured. Forum users also reported a lower level of social functioning (84.8 out of 100) than nonusers (93.8 out of 100; P=.008). CONCLUSIONS: Forum users showed no particular bias on the most important demographic variables of age, sex, socioeconomic status, and time since diagnosis. This may reflect the narrowing digital divide. Overrepresentation and underrepresentation of patients with GIST in different treatment phases on social media should be taken into account when sourcing patient forums for patient-generated health data. A further investigation of the sample bias in other web-based patient populations is warranted.
ABSTRACT
Multi-view data refers to a setting where features are divided into feature sets, for example because they correspond to different sources. Stacked penalized logistic regression (StaPLR) is a recently introduced method that can be used for classification and automatically selecting the views that are most important for prediction. We introduce an extension of this method to a setting where the data has a hierarchical multi-view structure. We also introduce a new view importance measure for StaPLR, which allows us to compare the importance of views at any level of the hierarchy. We apply our extended StaPLR algorithm to Alzheimer's disease classification where different MRI measures have been calculated from three scan types: structural MRI, diffusion-weighted MRI, and resting-state fMRI. StaPLR can identify which scan types and which derived MRI measures are most important for classification, and it outperforms elastic net regression in classification performance.
ABSTRACT
OBJECTIVE: To systematically review the literature for studies on cognitive functioning in patients with low-grade glioma to evaluate assessment methods and prevalence of cognitive dysfunction. DATA SOURCES: A search was made in PubMed, Embase, and PsycINFO for articles published between January 2002 and June 2012 using cognition, memory, attention, executive functioning, and low-grade glioma as search terms. STUDY SELECTION: Two reviewers independently performed the study selection and data extraction. Inclusion criteria were: studies including at least 10 adult patients, with suspected or confirmed low-grade glioma and cognitive functioning as outcome measure. DATA EXTRACTION: A standard data extraction form was used, with items regarding study quality, patient characteristics, type of measurement instruments, cognitive domain, definition of cognitive dysfunction, and reported prevalence. DATA SYNTHESIS: Of the 312 articles screened on title/abstract, 69 were screened on full-text and, finally, 17 were included. A total of 46 different measurement instruments were found for the assessment of cognitive functioning; 5 of these were used 5 or more times. There was variability in the definition of cognitive dysfunction. The reported prevalence of cognitive dysfunction ranged from 19% to 83%. CONCLUSION: Many patients with low-grade glioma experience cognitive dysfunction. However, there is no consensus on how to assess cognitive functioning in these patients.
