High dropout rates are a common problem reported in web-based studies. Understanding which risk factors interrelate with dropping out from the studies provides the option to prevent dropout by tailoring effective strategies.
This study aims to contribute an understanding of the predictors of web-based study dropout among psychosomatic rehabilitation patients. We investigated whether sociodemographics, voluntary interventions, physical and mental health, digital use for health and rehabilitation, and COVID-19 pandemic-related variables determine study dropout.
Patients (N=2155) recruited from 4 psychosomatic rehabilitation clinics in Germany filled in a web-based questionnaire at T1, which was before their rehabilitation stay. Approximately half of the patients (1082/2155, 50.21%) dropped out at T2, which was after the rehabilitation stay, before and during which 3 voluntary digital trainings were provided to them. According to the number of trainings that the patients participated in, they were categorized into a comparison group or 1 of 3 intervention groups. Chi-square tests were performed to examine the differences between dropout patients and retained patients in terms of sociodemographic variables and to compare the dropout rate differences between the comparison and intervention groups. Logistic regression analyses were used to assess what factors were related to study dropout.
The comparison group had the highest dropout rate of 68.4% (173/253) compared with the intervention groups\' dropout rates of 47.98% (749/1561), 50% (96/192), and 42.9% (64/149). Patients with a diagnosis of combined anxiety and depressive disorder had the highest dropout rate of 64% (47/74). Younger patients (those aged <50 y) and patients who were less educated were more likely to drop out of the study. Patients who used health-related apps and the internet less were more likely to drop out of the study. Patients who remained in their jobs and patients who were infected by COVID-19 were more likely to drop out of the study.
This study investigated the predictors of dropout in web-based studies. Different factors such as patient sociodemographics, physical and mental health, digital use, COVID-19 pandemic correlates, and study design can correlate with the dropout rate. For web-based studies with a focus on mental health, it is suggested to consider these possible dropout predictors and take appropriate steps to help patients with a high risk of dropping out overcome difficulties in completing the study.

UNASSIGNED: With the COVID-19 vaccination taking stride all across the globe, there are multiple reports of vaccine-induced adverse reactions (cutaneous and systemic).
UNASSIGNED: To study the frequency and characteristics of mucocutaneous reactions to COVID-19 vaccines.
UNASSIGNED: An online questionnaire-based study was performed among the recipients of COVID-19 vaccines.
UNASSIGNED: Majority (73.6%) of the responders had received the Covishield vaccine (AstraZeneca-Oxford), while 26.4% had been vaccinated with Covaxin (Bharat Biotech-ICMR). One or more post-vaccination mucocutaneous effects were experienced in 87 (19.6%) participants. Vaccine-associated mucocutaneous changes were observed in 19.7% and 22.2% of individuals who received Covishield and Covaxin, respectively. Local injection site reaction was the predominant mucocutaneous finding, followed by urticarial rash, exacerbation of preexisting dermatoses, morbilliform rash, apthous ulcers, pityriasis rosea like eruption, telogen effluvium, herpes zoster, purpuric rash, erythema multiforme and others. Anaphylaxis was reported in three individuals. However, fatality was not reported in any of the vaccine recipients. Intergroup assessment of parameters with respect to type of vaccine was found to be insignificant.
UNASSIGNED: Majority reported mild and self-limiting reactions. This outcome should not discourage the common man in getting vaccinated.

BACKGROUND: The cardinal feature of osteoarthritis (OA) is pain. Although heterogeneity in pain and function have been demonstrated in the long-term course of OA, the more proximate determinants of acute flare-ups remain less clear. How short-term intermittent or transient exposures trigger acute flare-ups has important implications for effective and sustainable self-management strategies.
OBJECTIVE: The primary objective of this study is to identify potential triggers of acute flares in knee OA. Secondary objectives are to determine their course and consequences and describe high-risk participant profiles.
METHODS: We carried out a Web-based case-crossover study. This study aims to recruit 620 community-dwelling adults aged ≥40 years, resident in England, and who have knee pain, with or without a recorded diagnosis of knee OA, and no preexisting diagnosis of inflammatory arthropathy. Participants will be recruited via 3 routes: (1) general practice registers, (2) offline community advertisement, and (3) online social media advertisement. By using questionnaires comparing periods before participants\' self-reported flare-up episodes (hazard periods) with periods during the study when their knee OA symptoms are stable (control periods), triggers preceding flare-ups will be identified and examined using conditional logistic regression. Time-to-resolution of flare-up will be examined by monitoring people\'s daily pain, bothersomeness, and medication usage until the participant reports when their flare-up episode ends. Rates of flare-ups will be examined across different participant and flare characteristics using regression models to identify high-risk participant profiles. A study-specific Patient Advisory Group (PAG) is providing suggestion, input, and ongoing support for all stages of the research process.
RESULTS: Participant recruitment opened in July 2018 and is anticipated to continue for 6 months. The study results will be disseminated through a number of channels, including relevant national or international conferences and peer-reviewed publication in a medical journal, via advocacy or charity organizations, such as Versus Arthritis and across social media. Findings will be fed back to members of our PAG, study participants, and clinicians from participating primary care general practices. The PAG will also take an active role in the overall dissemination strategy.
CONCLUSIONS: This study will provide empirical evidence to help patients identify common knee OA flare triggers and provide health care professionals with questions to identify patients at most risk of frequent flare-ups.
UNASSIGNED: DERR1-10.2196/13428.

UNASSIGNED: GP consultation rates for influenza-like illness (ILI) are poorly known in France and there is a paucity of literature on this topic. In the few articles that have been published, the results are heterogeneous.
UNASSIGNED: The aim of the present study was to estimate the proportion of ILI inducing a GP consultation, and to assess its determinants.
UNASSIGNED: Participants of a French web-based cohort study who reported ≥1 ILI episode between 2012 and 2015 were included. Sociodemographic characteristics, access to health care, and health status variables were collected.
UNASSIGNED: Healthcare-seeking behaviour was analysed and factors associated with a GP consultation identified using a conditional logistic regression.
UNASSIGNED: Of the 6023 ILI episodes reported, 1961 (32.6%) led to a GP consultation, with no difference between those at risk of influenza complications and those not (P = 0.42). A GP consultation was more frequent for individuals living in a rural area (odds ratio [OR] = 1.21, 95% confidence interval [CI] = 1.02 to 1.43); those with a lower educational level (OR = 1.43, 95% CI = 1.18 to 1.74); those using the internet to find information about influenza (OR = 1.63, 95% CI = 1.30 to 2.03); patients presenting with worrying symptoms (fever, cough, dyspnoea, sputum, or asthenia); patients having a negative perception of their own health status (OR = 1.51, 95% CI = 1.07 to 2.13; and those having declared a personal doctor (OR = 2.86, 95% CI = 1.72 to 4.76). A GP consultation was less frequent for individuals using alternative medicine (OR = 0.68, 95% CI = 0.58 to 0.78).
UNASSIGNED: This study allows the identification of specific factors associated with GP consultation for an ILI episode. These findings may help to coordinate health information campaigns and to raise awareness, especially among individuals at risk of influenza complications.

The Internet is widely used to conduct research studies on health issues. Many different methods are used to recruit participants for such studies, but little is known about how various recruitment methods compare in terms of efficiency and costs.
The aim of our study was to compare online and offline recruitment methods for Internet-based studies in terms of efficiency (number of recruited participants) and costs per participant.
We employed several online and offline recruitment methods to enroll 18- to 45-year-old women in an Internet-based Danish prospective cohort study on fertility. Offline methods included press releases, posters, and flyers. Online methods comprised advertisements placed on five different websites, including Facebook and Netdoktor.dk. We defined seven categories of mutually exclusive recruitment methods and used electronic tracking via unique Uniform Resource Locator (URL) and self-reported data to identify the recruitment method for each participant. For each method, we calculated the average cost per participant and efficiency, that is, the total number of recruited participants.
We recruited 8252 study participants. Of these, 534 were excluded as they could not be assigned to a specific recruitment method. The final study population included 7724 participants, of whom 803 (10.4%) were recruited by offline methods, 3985 (51.6%) by online methods, 2382 (30.8%) by online methods not initiated by us, and 554 (7.2%) by other methods. Overall, the average cost per participant was €6.22 for online methods initiated by us versus €9.06 for offline methods. Costs per participant ranged from €2.74 to €105.53 for online methods and from €0 to €67.50 for offline methods. Lowest average costs per participant were for those recruited from Netdoktor.dk (€2.99) and from Facebook (€3.44).
In our Internet-based cohort study, online recruitment methods were superior to offline methods in terms of efficiency (total number of participants enrolled). The average cost per recruited participant was also lower for online than for offline methods, although costs varied greatly among both online and offline recruitment methods. We observed a decrease in the efficiency of some online recruitment methods over time, suggesting that it may be optimal to adopt multiple online methods.

BACKGROUND: Cardiovascular diseases remain the leading cause of death worldwide. Metabolic syndrome (MetS) is the clustering of risk factors for developing the disease. Strong evidence exists for the efficacy of screening for MetS. However, the potential of novel web-based studies for MetS and online assessing of the quality of life (QOL) for these high-risk participants have not been explored.
METHODS: This was a web-based, cross-sectional study. Participants were recruited through online registering on the study website. Then, those who met the study criteria (waist circumference [WC] ≥90 and blood pressure [BP] ≥130/85) were contacted and invited for the clinical assessments, if they wish. Baseline measurements were MetS risk factors (weight, WC, body mass index and BP, total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, triglycerides, and fasting blood glucose) and health-related QOL (HRQOL) that was measured using the short form-36 (SF-36).
RESULTS: There were 1436 (male: 928, female: 508) registration data on the study website. Reviewing the data, of 317 eligible participants that were invited to the study, 229 persons were responded to invitation in the screening program. The mean age of participants was 43.8 (standard deviation [SD] = 9.9) years. MetS was more frequent in male and married persons. In addition, participants with MetS had lower mean (SD) scores than participants without MetS for the following subscales of HRQOL as: role-physical (with MetS 51.1±35.2; versus without MetS 65.3 ± SD = 40.1), vitality (with MetS 65± 21; versus without MetS 75.3 ± 21.1), mental health (with MetS 49.5±30.1; versus without MetS 34.1±17.2)(P < 0.05 for all).
CONCLUSIONS: People with MetS experienced lower HRQOL than without MetS. Internet as a powerful medium offers a novel setting for delivery health information. It seems that high BP and abdominal obesity are associated with lower HRQOL in the participants with MetS. A web-based prevention program could make people aware for their vulnerability to MetS and its complications.

OBJECTIVE: We compared participation and compliance with a web-based data collection on infections among population-based samples recruited in different ways.
METHODS: Individuals were recruited from participants in the German National Cohort study (Group A, n = 279) or persons who were invited to this study but did not participate (Group B, n = 53). A third group was invited to the web-based study only (Group C, n = 145).
RESULTS: Response varied among groups between 3 % (B), 11 % (C) and 61 % (A), but compliance was similar (81-85 %). Response did not differ by age and sex. Compliance was lower among the youngest and oldest participants. In addition, participants currently not employed were more likely to have better compliance. Semi-parametric group-based modelling identified three distinct compliance trajectories; \"poor compliance\" (8 %), \"improving compliance\" (14 %) and \"very good compliance\" (78 %).
CONCLUSIONS: Participation differed among modes of recruitment, but compliance was similar among groups and notably high. Different recruitment approaches can be used and collected data can be combined to achieve greater sample sizes for longitudinal web-based studies.

BACKGROUND: Estimates of the prevalence of female urinary incontinence (UI) vary widely.
OBJECTIVE: To estimate UI prevalence among women in France using data from five national surveys and analyse prevalence differences among the surveys according to their design (representative sample or not, survey focused on UI or not) and UI definition (based on symptoms or disease perception).
METHODS: Data came from two representative telephone surveys, Fecond (5017 women aged 15-49 yr) and Barometer (3089 women aged 40-85 yr), general and urinary postal surveys of the GAZEL cohort (3098 women aged 54-69 yr), and the web-based NutriNet survey (85,037 women aged 18-87 yr).
METHODS: Definitions of UI based on the International Conference on Incontinence Questionnaire UI short form (ICIQ-UI-SF) and on a list of health problems were considered. We compared age-adjusted prevalence rates among studies via logistic regression and generalised linear models.
CONCLUSIONS: Overall, 13% of the women in Fecond, 24% in Barometer, 15% in the GAZEL general survey, 39% in the GAZEL urinary survey, and 1.5% in the NutriNet survey reported any UI. Prevalence rates in representative samples with the same UI definition (ICIQ-UI-SF) were concordant. UI prevalence in the representative samples was 17%. The estimated number of women in France with UI was 5.35 million (95% confidence interval [CI] 5.34-5.36 million) for any UI and 1.54 million (95% CI 1.53-1.55 million) for daily UI. For the GAZEL sample, UI prevalence was lower but UI severity was greater for responses to a questionnaire with the list-based UI definition rather than to a questionnaire with the ICIQ-UI-SF-based definition. In all surveys, information about UI was self-reported and was not validated by objective measurements.
CONCLUSIONS: UI definitions and sampling strategies influence estimates of UI prevalence among women. Precise estimates of UI prevalence should be based on non-UI-focused surveys among representative samples and using a validated standardised symptom-based questionnaire.
RESULTS: We looked at estimates of urinary incontinence (UI) prevalence in studies with different designs and different UI definitions in a large population of French women. We found that estimates varied with the definition and the design. We conclude that the most precise estimates of UI prevalence are obtained in studies of representative populations that are not focused on UI and use a validated international standard questionnaire with sufficient details to allow grading of UI severity. Most women reported rare urine leakages involving small amounts of urine with little impact on their quality of life.