Insulin resistance: syndrome or tendency?

A common strategy in the investigation, diagnosis, and treatment of disease is to identify a potential aetiological factor, measure it, relate the measurement to the severity of disease, and treat the disease by modifying the measurement. "Treating a measurement" is a phrase used disparagingly, and justifiably so when the numbers that represent the disease are given more weight than the patients themselves. But if we can define at what level the measure may be judged dangerous, and modify its value accordingly, we may be able to prevent the disease or its consequences emerging. Examples of this strategy in action include reduction of blood pressure to prevent stroke, and reduction of blood glucose or serum cholesterol concentrations to treat diabetes or prevent coronary heart disease (CHD). However, one has to reach a critical stage in many related areas before such interventions can be contemplated. Thus, potential risk factors must be identified, with feasible pathogenic mechanisms through which they might act; effective methods of measurement and thresholds for clinical intervention need to be established; and effective treatments must be made available. Where are we in this process with insulin resistance? For the aetiology of diabetes we are quite well advanced; with the introduction of new drugs capable of inducing profound and specific reductions in insulin resistance,1 prevention might even be entertained in some cases. However, in its role as a CHD risk factor, major uncertainties remain over the importance of insulin resistance.