Uncertainty about true blood pressure values may underlie many reasons why physicians do not intensify antihypertensive therapy, according to a study published in the May 20 issue of the Annals of Internal Medicine.

Eve A. Kerr, MD, MPH, of the Ann Arbor Veteran Affairs (VA) Health Services Research and Development Service Center of Excellence in Michigan, and colleagues undertook the study to examine the process of care for diabetic patients with elevated triage blood pressure ( 140/90 mm Hg) during routine primary care visits to assess whether a treatment change occurred and to what degree specific patient and provider factors correlated with the likelihood of treatment change.

In the prospective cohort study, the researchers examine d 1,169 diabetic patients with scheduled visits to 92 primary care providers from February 2005 to March 2006 in nine VA facilities in three Midwestern states.

The investigators studied a proportion of patients who had a change in a blood pressure treatment (medication intensification or planned follow-up within four weeks). They predicted probability of treatment change was calculated from a multilevel logistic model that included variables assessing clinical uncertainty, competing demands and prioritization and medication-related factors (controlling for blood pressure).

Overall, the researchers found that 573 (49 percent) patients had a blood pressure treatment change at the visit.

According to the authors, the following factors made treatment change less likely:

• Repeated blood pressure by provider recorded as less than 140/90 mm Hg vs. 140/90 mm Hg or greater or no recorded repeated blood pressure (13 vs. 61 percent);
• Home blood pressure reported by patients as less than 140/90 mm Hg vs. 140/90 mm Hg or greater or no recorded home blood pressure (18 vs. 52 percent);
• Provider systolic blood pressure goal greater than 130 mm Hg versus 130 mm Hg or less (33 vs. 52 percent);
• Discussion of conditions unrelated to hypertension and diabetes versus no discussion (44 vs. 55 percent); and
• Discussion of medication issues versus no discussion (23 vs. 52 percent).

The researchers noted that the providers knew that the study pertained to diabetes and hypertension and treatment change was assessed for one visit per patient, which they acknowledged as a limitation of the study.

Based on the results, Kerr and colleagues concluded that approximately 50 percent of diabetic patients presenting with a substantially elevated triage blood pressure received treatment change at the visit; and clinical uncertainty about the true blood pressure value was a prominent reason that providers did not intensify therapy.