The role of clinical uncertainty in treatment decisions for diabetic patients with uncontrolled blood pressure

Background: Factors underlying failure to intensify therapy in response to elevated blood pressure have not been systematically studied. Objective: 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. Design: Prospective cohort study. Setting: 9 Veterans Affairs facilities in 3 midwestern states. Participants: 1169 diabetic patients with scheduled visits to 92 primary care providers from February 2005 to March 2006. Measurements: Proportion of patients who had a change in a blood pressure treatment (medication intensification or planned follow-up within 4 weeks). 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). Results: Overall, 573 (49%) patients had a blood pressure treatment change at the visit. The following factors made treatment change less likely: repeated blood pressure by provider recorded as less than 140/90 mm Hg versus 140/90 mm Hg or greater or no recorded repeated blood pressure (13% vs. 61%; P < 0.001); home blood pressure reported by patients as less than 140/90 mm Hg versus 140/90 mm Hg or greater or no recorded home blood pressure (18% vs. 52%; P < 0.001); provider systolic blood pressure goal greater than 130 mm Hg versus 130 mm Hg or less (33% vs. 52%; P = 0.002); discussion of conditions unrelated to hypertension and diabetes versus no discussion (44% vs. 55%; P = 0.008); and discussion of medication issues versus no discussion (23% vs. 52%; P < 0.001). Limitation: Providers knew that the study pertained to diabetes and hypertension, and treatment change was assessed for 1 visit per patient. Conclusion: Approximately 50% of diabetic patients presenting with a substantially elevated triage blood pressure received treatment change at the visit. Clinical uncertainty about the true blood pressure value was a prominent reason that providers did not intensify therapy.