Representativeness of Participants in Heart Failure

To the Editor: E-health is rapidly emerging in heart failure (HF) management. E-health trials evaluate health services and information delivered through internet and related technologies such as telemonitoring systems. Randomized controlled trials (RCTs) provide the strongest evidence on the effects of interventions. However, eligibility criteria and the willingness to participate may result in differences between participants and nonparticipants. As a consequence, the results of the trial may not be generalizable to the whole domain of patients. Selectivity of participants in HF RCTs is well-known, but is not yet investigated in HF e-health trials. Better, insight in representativeness of patients in e-health RCTs is pivotal. HF e-health trials may be even more sensitive to selectivity than HF device and drug trials, as they require more active participation and technical “savviness. ” We aimed to compare the characteristics of participants with nonparticipants in the e-Vita HF study, a 3-arm RCT on the effectiveness of 2 e-health tools in patients with HF: (1) the European Society of Cardiology/Heart Failure Association website heartfailurematters.org and (2) an interactive platform for HF disease management, including telemonitoring facilities, and with a link to heartfailurematters.org were compared with (3) usual care as delivered by 9 HF outpatient clinics in the Netherlands. We additionally compared the characteristics of e-Vita HF participants with the population of previously published randomized HF e-health studies summarized in a recently published Cochrane review. Important eligibility criteria for the e-Vita HF study were (1) confirmed HF for at least 3 months and (2) access to internet, e-mail, and basic user skills. In total, 405 HF patients consented to participate. A random sample of nonparticipants (n = 402) was taken as the comparison group. Demographic and disease-specific characteristics of the participants and nonparticipants were collected at baseline. As a surrogate to the individual’s socio-economic status (SES), we used the area SES by linking the 4 digits of the Dutch postal codes to the SES levels of the Netherlands Institute for Social research database. This SES was categorized as low if <0, middle if 0, and as high if SES was >0. Participants signed an informed consent. Available data of the nonparticipants were analyzed anonymously, as was approved by the Medical Ethical Committee of the University Medical Center Utrecht, the Netherlands. Table 1 shows the characteristics of participants and nonparticipants in the e-Vita HF study. Participants were younger (mean age 66.7 vs 73.4 years, P < .001), more often male (75% vs 58%, P < .001), and had in general fewer comorbidities. After adjustment for age, anemia, and angina pectoris were no longer significantly less prevalent in participants compared with nonparticipants, whereas SES now was significantly higher in participants compared with nonparticipants. In the Cochrane review, we identified 18 telemonitoring studies, published between 2001 and 2014 (data on nonparticipants were not presented). The mean age of participants was 68 years (range 54–78 years), 73% (range 35–85%) were men, 30% (4–43%) had diabetes and 43% (15–67%) was known with hypertension. These characteristics were similar to participants of the e-Vita HF trial.