The Role of Clinical Uncertainty in Treatment Decisions for Diabetic Patients with Uncontrolled Blood Pressure

20 May 2008 | Volume 148 Issue 10 | Pages 717-727

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.

Editors' Notes Context Why do clinicians fail to intensify antihypertensive therapy when a patient's blood pressure is elevated? Contribution This study involved 1169 diabetic patients seen by 92 primary care providers at 9 Veterans Affairs facilities. All had elevated triage blood pressures, but only half received antihypertensive treatment intensification by providers. Patient reports of home blood pressures or repeated blood pressures by providers within normal limits and discussion of medication issues decreased the likelihood of antihypertensive intensification at clinic visits. Implication Uncertainty about true blood pressure values may underlie many reasons why physicians do not intensify antihypertensive therapy. —The Editors

 

Author and Article Information

From the Center for Clinical Management Research, Veterans Affairs Ann Arbor Healthcare System, and the University of Michigan Department of Internal Medicine, Ann Arbor, Michigan, and Roudebush Veterans Affairs Medical Center and Indiana University, Indianapolis, Indiana.

Acknowledgment: The authors thank recruitment coordinator Claire Robinson; research assistants Stacey Hirth, Susan Jaeger, Madhavi Diwanji, Janice Thompson, Caroline Lynch, and Diana Newman, who worked tirelessly to recruit patients; data manager Jennifer Davis; site principal investigators Drs. David Aron, Martin Bermann, and Ketan Shah, without whom the study could not have been done; and the many providers and patients who participated. They also thank Drs. Rodney Hayward, Michele Heisler, and John Piette for their suggestions on earlier drafts of this manuscript. The authors are particularly grateful to Drs. Jane Forman and Richard Frankel for their insightful contributions to the overall study design.

Grant Support: By a research grant from the U.S. Department of Veterans Affairs Health Services Research and Development Service (IIR 02-225) and in part by the Michigan Diabetes Research and Training Center Grant (P60DK-20572) from the National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health.

Potential Financial Conflicts of Interest: None disclosed.

Reproducible Research Statement: Study protocol: Available by contacting Dr. Kerr (e-mail, ekerr{at}umich.edu). Statistical code: Available by contacting Dr. Hofer (e-mail, thofer{at}umich.edu). Data set: Not available.

Requests for Single Reprints: Eve A. Kerr, MD, MPH, Ann Arbor Veteran Affairs Health Services Research and Development Service Center of Excellence, PO Box 130170, Ann Arbor, Michigan 48113; e-mail, ekerr{at}umich.edu.

Current Author Addresses: Drs. Kerr, Hogan and Hofer, and Ms. Klamerus: Ann Arbor Veteran Affairs Health Services Research and Development Service Center of Excellence, PO Box 130170, Ann Arbor, MI 48113-0170.

Dr. Zikmund-Fisher: University of Michigan Division of General Medicine, 300 North Ingalls, #7C27, Ann Arbor, MI 48109-5429.

Dr. Subramanian: Roudebush Veterans Affairs Medical Center and Indiana University, Diabetes Translation Research Center, IF-122, 250 University Boulevard, Indianapolis, IN 46202.

Author Contributions: Conception and design: E.A. Kerr, B.J. Zikmund-Fisher, M.M. Hogan, T.P. Hofer.

Analysis and interpretation of the data: E.A. Kerr, B.J. Zikmund-Fisher, M.L. Klamerus, U. Subramanian, M.M. Hogan, T.P. Hofer.

Drafting of the article: E.A. Kerr, M.L. Klamerus, T.P. Hofer.

Critical revision of the article for important intellectual content: B.J. Zikmund-Fisher, U. Subramanian, M.M. Hogan, T.P. Hofer.

Final approval of the article: E.A. Kerr, B.J. Zikmund-Fisher, M.L. Klamerus, U. Subramanian, T.P. Hofer.

Provision of study materials or patients: U. Subramanian.

Statistical expertise: T.P. Hofer.

Obtaining of funding: E.A. Kerr, T.P. Hofer.

Administrative, technical, or logistic support: M.L. Klamerus.

Collection and assembly of data: M.L. Klamerus, U. Subramanian.

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