Many people experience what has been termed, “white-coat” syndrome or hypertension (high blood pressure). It has been dubbed “white-coat” syndrome due to the anxiety that is experienced by patients when visiting their healthcare providers (who often wear white lab coats). This phenomenon is correctly termed “isolated clinic hypertension, “ where their blood pressure in the clinic or office setting is consistently ≥140 mmHg systolic or 90 mmHg diastolic. For people with diabetes (PWD), a blood pressure goal of <130/80 mmHg is desired, and for the general population, a blood pressure of < 120/80 mmHg is the goal.
Data from the PAMELA (Pressioni Arteriose Monitorate E Loro Associazioni) population study showed that “isolated clinic hypertension” is not a clinically innocent and benign condition. On the contrary, “isolated clinic hypertension” was associated with a prevalence of organ damage and a risk of cardiovascular morbidity (risk of disease) and mortality (death). Although this risk is lower than in those people with sustained hypertension (both in- and out-of the clinical office), the risk is still higher than in people with normal blood pressure. In addition, subjects in the PAMELA study with “isolated clinic hypertension” also had higher total serum cholesterol, serum triglycerides, and Body Mass Index (BMI) and lower HDL cholesterol, than in subjects with normal blood pressure–often no different from those values of subjects with “sustained” hypertension. Subjects with “isolated clinic hypertension” also had a greater prevalence of left ventricular hypertrophy*, and greater prevalence of the metabolic syndrome, overt diabetes or impaired fasting blood glucose. Finally, subjects with “isolated clinic hypertension” had higher home blood pressure readings than what would normally be for a person who “truly” had normal blood pressure.
Admittedly, the PAMELA study was observational (with a population representative of a town in the northeast outskirts of Milan), but it cannot be ignored due to the limited amount of data available on “isolated clinic hypertension” and diabetes. More importantly, it cannot be ignored because of what we do know about blood pressure and diabetes. It is well-known and documented through a large body of evidence that cardiovascular and renal (kidney) protection are greatly improved in PWD when clinic blood pressure is aggressively treated to the goal of <130/80 mmHg, and even if the initial clinic blood pressure value is within the normal blood pressure range of 130-139 mmHg. In addition, we know that low blood pressure is protective against diabetes-related microvascular** complications, and that in PWD, because of an early loss of small artery autoregulation, their microcirculation is exposed to a higher blood pressure than that of a person who does not have diabetes.
Therefore, “isolated clinic hypertension” (white-coat syndrome) in PWD, should not be ignored, and treatment should occur as with any other PWD and hypertension.
* Left Ventricular Hypertrophy (LVH) is a thickening of the heart muscle, specifically, the left ventricle. It is a pathological reaction to cardiovascular disease or high blood pressure. It is not a disease itself, but a marker for diseases of the heart.
** Complications of diabetes can be broadly classified as:
- Microvascular: neuropathy (nerve damage), nephropathy (kidney disease) and vision disorders (retinopathy, glaucoma, cataract and corneal disease)
- Macrovascular: heart disease, stroke and peripheral vascular disease (which can lead to ulcers, gangrene and amputation)
- Other complications include: infections, metabolic disorders, impotence, autonomic neuropathy and poor pregnancy outcomes
Source: Diabetes Care, Volume 32, Supplement 2, November 2009.
* Note: Having blood pressure readings that you can trust is important. Only blood pressure monitors that have been validated, or tested for accuracy, should be used. A list of validated blood pressure monitors is available here. If you have a monitor that is not on this list, it does not mean that it is inaccurate, but only that it hasn’t been formally tested. It’s a good idea to bring your monitor to your provider’s office before the first use and then at least once a year to compare readings with an office device.