Hypertension and Diabetes
What are the pros to treating early surrogates?
- From the University Hospital Erlangen, Erlangen, Germany.
- Corresponding author: Roland E. Schmieder, roland.schmieder{at}uk-erlangen.de.
In recent years, the British Medical Journal published several papers apropos the “parachute approach evidence-based medicine” (1). In the original profound article, Smith and Pell argued that the parachute use to prevent death and major trauma due to capital challenge is clearly obvious, and there is no need for randomized controlled trials (2). Although this argument may hold true in medicine for only few situations, waiting for the results of randomized end point trials of therapeutic interventions can cost hundred of lives under certain circumstances. If the science is good, we should act before trials are performed using intermediate end points or “surrogates” as therapeutic targets. Indeed, surrogate parameters have emerged as most helpful tools for an evidence-based approach for therapeutic decisions in cardiovascular medicine. The ensuing article outlines the pro arguments that surrogates are most acceptable targets for treating patients with hypertension and diabetes.
ELIGIBILITY OF SURROGATES
According to Merriam Webster's dictionary, the meaning of surrogate is “one appointed to act in place of another” and “one that serves as a substitute.” In the 2007 European Society of Hypertension Guidelines (3), the word “surrogate” is replaced by the wording “intermediate end point,” thereby pointing to the fact that, in hypertensive disease, a surrogate in general reflects early structural or functional changes of the vascular, renal, or cardiac tissue due to the presence of cardiovascular risk factors. More specifically, certain requirements for clinical use of organ damage measures should be fulfilled before a clinical parameter is considered an intermediate end point or surrogate for fatal or nonfatal cardiovascular complications. These eligibility criteria are as follows: the surrogate must be a sensitive and common marker of early damage in cardiovascular disease, should ideally be measured noninvasively, should have a high reproducibility (low between/within-observer variability), the assessment must be (worldwide) standardized, and evidence of prognostic …
