Internet Based Vascular Risk Factor Intervention and Self Management Study (IRIS)

The objective of the study is to evaluate the efficacy and cost-effectiveness of an internet based vascular risk factor program on top of usual care compared to usual care alone for treatment of vascular risk factors in patients at high risk for new vascular events.

Study design: randomized non-blinded trial Study population: patients in the Rijnstate Hospital Arnhem and the UMC Utrecht, The Netherlands with a recent diagnosis of cerebral, cardiac or peripheral artery disease that entered the risk factor screening programs in these hospitals revealing 2 or more treatable risk factors.

Intervention: After the screening program patients will be randomized to usual care alone or to the internet program on top of usual care. Usual care for risk factor management will be delivered by the medical specialist and/or the general practitioner. Patients randomized to the internet based intervention program are first seen by the nurse practitioner on a regular clinic visit. The internet dossier is than created and explained to the patient. Subsequent contacts between nurse practitioner and patient about risk factor management is mainly by the internet. The nurse practitioner works according to the national guidelines for cardiovascular risk management ('CardioVascular Risico Management 2006') and is supervised by an internist. The study period is 1 year. All patients in both groups ware asked to return to the clinic for a follow up measurement of risk factors after 1 year.

Outcome measures: Primary outcome is the difference in Framingham heart risk score between baseline and after 1 year. As secondary outcome the percentage of patients achieving treatment goals for each risk factor and the average change in the absolute value of each risk factors after 1 year will be used.

Sample size calculation/data analysis: 380 patients. Changes in risk factors (absolute change and fraction of patients achieving treatment goal of each risk factor) at the start and after 1 year and between the groups are tested with independent sample t-test and Chi-square test.

Economic evaluation: The balance between costs and effects of the internet based vascular risk factor management program will be compared to usual care. Using a previously developed cardiovascular disease model incremental cost-utility analyses will be conducted with remaining life expectancy as the relevant time horizon.