Telemonitoring shows significant benefits for certain patients with chronic heart failure (CHF), according to two studies presented at the Heart Failure Congress 2011 held in Gothenburg, Sweden.

The studies revealed that telemonitoring showed significant benefits in defined subgroups of patients. The results, which will be used to help in the design of future trials, come after the overall results from both trials demonstrated no statistical benefit for telemonitoring.

Two recent meta-analyses (including a Cochrane Review) showed that telemedical monitoring of CHF patients can improve overall survival by 17 percent to 47 percent during six to 12 months of follow-up. The results, however, are in direct contrast to the studies presented.

"The fact that we showed no benefit when two meta-analyses had previously demonstrated benefit suggested there could be problems with our study design and indicated the importance of undertaking further post hoc analyses," said Friedrich Koehler, the principal investigator of the Telemedicine to Improve Mortality in Heart Failure study (TIM-HF). r, from Charité Universitätsmedizin, Berlin. "There was a real danger that with the wrong trial design we could be writing off life saving therapies."

TIM-HF study

In the Telemedicine to Improve Mortality in Heart Failure study (TIM-HF) Koehler and colleagues found themselves in the unique position of being involved in the development of the telemonitoring platform used in the study. The investigators defined key features for the telemedical system, which included using mobile phone technology to enable monitoring devices to be used anywhere, the ability to get data transmitted within one minute and an easy to use system that could be operated by elderly patients.

"It's vitally important to develop mobile systems because the current improvements we're seeing in the health status of heart failure patients are enabling them to get out and about more than ever before," explained Koehler, adding that the entire equipment (which includes a portable ECG device, scales, blood pressure monitoring equipment, and a pulse oximeter to measure oxygen saturation) can be packed in small box that together with the equipment weighs less than 10 kg.

The technology, which cost €16 million to develop, was funded by a public-private partnership between the German Federal Ministry of Economics &Technology and industry. The system has also been designed to incorporate monitoring of co morbidities such as diabetes, chronic obstructive pulmonary disease, anticoagulants, and implantable cardiac device information. For emergency support, a mode for continuous ECG monitoring and oxygen saturation can be activated.

In the TIM-HF trial - which took place between January 2008 and June 2010 at 165 participating sites - 710 stable patients with NYHA class II or III , left ventricular ejection fractions less than 35 percent and a history of HF decompensation were randomized to remote telemedical management (n=354) or usual care (n=356). Results published in Circulation  showed that at a median follow-up of 26 months remote telemonitoring management delivered no significant beneficial benefits compared to usual care on all-cause mortality (P=0.87), or the composite end point of cardiovascular death and HF hospitalisation (P=0.44).

Reluctant to write off the technology, the investigators decided to undertake a second analysis exploring outcomes in pre specified sub groups according to age, NYHA class, whether patients lived alone or not, median left ventricular ejection fractions, episodes of prior HF decompensation, the presence of implantable cardioverter defibrillators uric acid levels, blood pressure creatinine levels and scores from questionnaires that screened for depression (the PHQ-9 depression scores).

The investigators found that for patients with a prior history of decompensation, no depression on the PH-Q depression score, and who had left ventricular ejection fractions above 25 percent, cardiovascular death was statistically less likely to occur in the group randomised to telemedicine monitoring than those randomised to usual care (P<0.027). There was also a statistically significant benefit for the group randomised to telemedicine for the number of days lost due to hospitalisation for heart failure and death (p<0.005).

The information, said Koehler, forms the basis of a hypothesis, which will be used to define the patient population in the TIM-HF II study which is due to start enrolment in autumn 2011.

The TEHAF study

In the Tailored Telemonitoring in Patients with Heartfailure (TEHAF study) Josiane Boyne and colleagues, from Maastricht University Medical Centre (The Netherlands), undertook a multicentre randomized controlled trial to investigate the effectiveness of incorporating the Health Buddy system into telemonitoring. The system consists of an easy to use device with a liquid crystal display that has four buttons that patients use to answer daily questions about heart failure related symptoms, knowledge of the condition and their behaviour.

The concept is that patients' responses can be automatically triaged into low, medium or high risk levels, enabling care providers to target high risk patients and anticipate problems. No transfer of vital signs was used in the study, with the exception of patients providing information about weight. To meet more specific patients' needs around treatment or education, the investigators created four different sets of dialogues that had variable emphasis on symptoms, knowledge and behaviour.

Of the 382 patients with NYHA II-IV included in the study- which was conducted in three Dutch centres, 197 were allocated to the intervention group and 185 to usual care.

Analysis after one year showed that 9.1 percent (18) in the intervention group were admitted to hospital for heart failure versus 13.5 percent (25) in the usual-care group (HR 0.65, CI 0.35-1.17, p=0.151), a result that was not statistically significant.

However the latest subgroup analysis of the primary endpoint, presented at the Heart Failure Congress 2011, found that patients in the intervention group with a heart failure durations of ≤18 months had a significant decrease in number of admissions for heart failure, (P=0.026, HR 0.26, CI 0.07-0.93). The subgroup analysis showed no such significant effects for patients who had heart failure duration > 18 months. Furthermore, for patients in the intervention group a significant decrease was found their face-to-face contacts with heart failure nurses (p<0.001).

The results, say the authors, suggest that the Health Buddy system offers particular benefits for patients with heart failure duration of less than 18 months. "Our system is based on the hypothesis that more knowledge leads to better compliance and therefore less symptoms. We therefore think that patients diagnosed recently have greater potentially to be influenced by the system than patients with longer histories of the condition who have already adapted their life styles," said Boyne , adding that another possibility is that heart failure deteriorates with time, so that patients with longer duration of heart failure may prove harder to treat. The observed decrease in contact with the heart failure nurse, she said, offers promise from the perspective of reducing future demands on the health care system.