CRISTOPH – A cluster-randomised intervention study to optimise the treatment of patients with hypertension in General Practice

Abstract

Background: Recent guidelines for the management of hypertension focus on treating patients according to their global cardiovascular risk (CVR), rather than strictly keeping blood pressure, or other risk factors, below set limit values. The objective of this study is to compare the effect of a simple versus a complex educational intervention implementing this new concept among General Practitioners (GPs). Methods/design:A prospective longitudinal cluster-randomised intervention trial with 94 German GPs consecutively enroling 40 patients each with known hypertension. All GPs then received a written manual specifically developed to transfer the global concept of CVR into daily General Practice. After cluster-randomisation, half of the GPs additionally received a clinical outreach visit, with a trained peer discussing with them the concept of global CVR referring to example study patients from the respective GP. Main outcome measure is the improvement of calculated CVR six months after intervention in the subgroup of patients with high CVR (but no history of cardiovascular disease), defined as 10-year-mortality ≥ 5% employing the European SCORE formula. Secondary outcome measures include the intervention's effect on single risk factors, and on prescription rates of drugs targeting CVR. All outcome measures are separately studied in the three subgroups of patients with 1. high CVR (defined as above), 2. low CVR (SCORE < 5%), and 3. a history of cardiovascular disease. The influence of age, sex, social status, and the perceived quality of the respective doctor-patient-relation on the effects will be examined.Discussion: To our knowledge, no other published intervention study has yet evaluated the impact of educating GPs with the goal to treat patients with hypertension according to their global cardiovascular risk. However, recent guidelines on hypertension [4][5][6], and on both primary and secondary cardiovascular prevention [7] emphasise that rather than to focus on single risk factors, intensity of care should focus on the global cardiovascular risk (CVR) of an individual patient. Global cardiovascular risk is an arithmetical compound of age, sex, and the known cardiovascular risk factors, and can be approximated by means of various risk calculators. If pharmacological risk factor treatment promises a relative risk reduction of some 25% [8,9], or possibly up to 80% in combination therapy [10], then a relevant absolute risk reduction is only possible where there is a relevant absolute risk to begin with. According to the concept of global cardiovascular risk, therefore, pharmacological treatment is only recommended for patients with a cardiovascular 10-year-mortality at or above 5%. The essence of this paradigmatic change is that treatment efforts and resources should be concentrated on where the (high) cardiovascular risk is: "treat risk, not risk factors" [11]. For general practitioners (GPs), this concept is of particular interest because it firstly focuses efforts and resources on high-risk patients, s...

Effectiveness of a medical education intervention to treat hypertension in primary care

“…First, information about overall cardiovascular risk of the patients was not available; this means that among all participants, some of them were at a higher risk for a cardiovascular event than others. Stratifying the patients with this criterion could help to target subsets of patients for intensive interventions according the level of risk [26,27], to make possible a more precise evaluation of the outcomes.…”

From hypertension control to global cardiovascular risk management: an educational intervention in a cluster-randomised controlled trial

“…The detailed protocol of CRISTOPH (cluster-randomised intervention study to optimise the treatment of patients with hypertension) has already been published [ 22 ], as has a secondary analysis of the baseline data [ 23 ]. The trial was registered at ISRCTN44478543.…”

Risk-adjusted versus overall blood pressure control rate for identifying the need for intensified cardiovascular risk reduction: lessons from a cross-sectional study

“…Primary outcome measure was an improvement of calculated CVR in a subset of patients with high CVR but no manifest CVD. Details of the study design have been described elsewhere, 22 publication of the results is pending. 22…”

“…Details of the study design have been described elsewhere, 22 publication of the results is pending. 22…”

“…A total of 89 family practitioners took part in the CRISTOPH study. 22 The majority of the participating medical centres operated with one practitioner (88%); the others were partnerships of two (12%) or three or more (4%). In total, 3523 patients took part in the study.…”