A few investigators have now observed a condition in which normal blood pressures in the clinic are accompanied by elevated measures during daily life, a condition termed isolated clinic normotension. A variety of other names have been associated with this condition, including isolated home hypertension (Bobrie et al., 20001), ‘white coat’ normotension (Prattichizzo and Galetta, 1996), reverse ‘white coat’ hypertension (Wing et al., 2002), or masked hypertension (Pickering et al., 2002). For our purposes, let’s refer to the condition as isolated clinic normotension to be consistent with the terminology used to describe isolated clinic hypertensive patients.
Prior to the advent of reliable ambulatory technologies, physicians were unaware that isolated clinic normotension existed. It was simply assumed that patients who had normal blood pressure values in the clinic also maintained these normal values during daily life. This assumption, however, turned out to be incorrect.
Although the existence of isolated clinic normotension was acknowledged in some earlier work with ambulatory instrumentation (Hoegholm et al., 1992), the prevalence of these individuals was unknown until relatively recently. Results now from several studies have confirmed that isolated clinic normotension is very common, with prevalence estimates ranging from 10 to 45 percent among patients with normal clinic blood pressures (Bobrie et al., 2001; Donner-Banzhoff et al., 1998; Larkin, Schauss, and Elnicki, 1998a; Segre et al., 2003; Selenta, Hogan, and Linden, 2000; Wing et al., 2002).
Although the exact prevalence of isolated clinic normotension in the general population is yet unknown, there is clear evidence that it occurs frequently and that hypertension is presumably undetected in these individuals.