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

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 Despite some recent improvements in blood pressure control, the number of patients with inadequate control remains high and contributes to excess morbidity and mortality, especially among patients at high risk from complications of hypertension (18). Several studies have suggested that clinical inertiathe failure by providers to initiate or intensify therapy (medication intensification) in the face of apparent need to do sois a main contributor to poor control of hypertension (912). Although the failure to intensify treatment medications for patients with elevated blood pressures at visits has been well documented (5, 6, 1218), factors underlying what seems to be clinical inertia have been studied less systematically. When providers are queried after clinic visits about the lack of medication intensification for elevated blood pressure, they variously report that the patient's true blood pressure was lower than the clinic blood pressure reading, that other patient concerns precluded attention on blood pressure management, and that patient adherence should be improved before medication intensification (6, 17). Some studies have examined the role of various clinical and patient factors in intensification decisions (6, 8, 17, 19, 20), but no study has used a detailed conceptual model to comprehensively examine the relative contribution of a broad array of potential patient, provider, organizational, and visit-specific contributors to a medication intensification decision. In addition, although a frequently cited reason for deferring medication changes is that the clinic blood pressure does not reflect the patient's true blood pressure (21, 22), this clinical uncertainty and its effects have not been explored. To better understand factors underlying apparent clinical inertia for hypertension, we designed the ABATe (Addressing Barriers to Treatment for Hypertension) study to examine treatment change decisions for diabetic primary care patients with elevated triage blood pressures before a primary care visit. We defined elevated blood pressure for this population to be 140/90 mm Hg, a value well above guideline targets for diabetic patients and one clearly requiring some type of action (4). Our goals were to assess how often patients presenting with an elevated triage blood pressure received medication intensification or were scheduled for close follow-up and the role that clinical uncertainty about blood pressure, competing demands and prioritization, medication-related factors, and care organization play in treatment change decisions. Methods Conceptual Model On the basis of theories of patient, provider, and organization behavior (2336), we developed a conceptual modelthe hypertension clinical action modelto examine decisions that drive treatment change (medication intensification or prompt blood pressure follow-up) for elevated blood pressure (Figure 1). The model, developed by 2 internists and 3 PhD-level methodologists in conjunction with development of ABATe and before data collection, proposes such treatment change decisions at a visit are based on 4 main conceptual domains: clinical uncertainty (Is the patient's blood pressure truly elevated? Does the clinic blood pressure reflect the true blood pressure?), competing demands and prioritization (What other problems need to be addressed at this visit? Is blood pressure management a priority for this particular patient? Does the provider place priority on blood pressure management in general?), medication-related factors (Should adherence be addressed first? Is the medication regimen too complex? Will the patient accept another medication?), and care organization (Is there sufficient time to address hypertension? Are staff available for follow-up?). In addition, as part of grant development, we hypothesized that the following factors would lead to a lower probability of treatment change: uncertainty about whether the patient's visit blood pressure reflected their true blood pressure (clinical uncertainty), comorbid conditions unrelated to hypertension and diabetes (37), a lower priority placed by the provider on the importance of treating elevated blood pressure, a higher number of baseline medications, perceived medication adherence problems, shorter clinic visit times, and lack of staff to follow up for blood pressure medication adjustment. Figure 1. Hypertension clinical action model. Design Setting We conducted a prospective cohort study of patients with scheduled primary care visits at 9 Veterans Affairs facilities located in 3 midwestern states. These facilities varied in size and structure, with 3 large academic-affiliated medical centers, 1 large nonacademic medical center, and 1 large and 4 small community-based outpatient clinics. From 15 February 2005 to 14 February 2006, approximately 33500 diabetic patients visited primary care providers (including residents) in these facilities (range per facility, 1050 to 9200 diabetic patients). The institutional review boards of all participating facilities approved the study protocol. Both patients and providers gave written informed consent before participating. Providers received a $50 bookstore gift card, and patients received a $10 department store gift card for completing initial surveys. Providers were told that the study was about diabetes and hypertension, with the purpose being to study challenges in treating patients with diabetes and ways to overcome these challenges so that quality of care can be enhanced. Primary Care Providers We invited all nonresident primary care providers with patient care responsibility at least 2 half-days per week to participate in the study. Of the eligible 126 providers approached, 104 consented to participate, for an overall recruitment rate of 83% (median facility-level recruitment rate, 88%). By the time recruitment started, 12 providers had stopped working at their facility or changed their patient care responsibilities, leaving 92 primary care providers still eligible to participate (range per facility, 2 to 28 providers; median, 8). Patients As specified by our institutional review board protocols, potentially eligible patients were referred to study staff by triage personnel. During the enrollment periods at each facility, study staff screened all referred patients who presented for a scheduled visit to participating primary care providers and whose lowest triage systolic blood pressure was 140 mm Hg or greater or whose lowest triage diastolic blood pressure was 90 mm Hg or greater (Figure 2). In each of the facilities, triage staff routinely used an electronic cuff to check the patient's blood pressure before the provider visit. Triage policies specified that a second blood pressure measurement should be obtained if the first blood pressure was elevated. In addition to the triage blood pressure, study staff screened patients for the following inclusion criteria: the participant confirmed a diagnosis of diabetes, the participating provider was the primary provider of diabetes care for the participant, and the participant spoke English. Patients with impaired decision-making ability (for example, dementia and traumatic brain injury) or terminal disease and residents of nursing homes were excluded. Of the 1556 patients approached by study staff, 213 were ineligible (Figure 2) and 1169 provided written informed consent to participate in the study (approached and eligible, 87%; median facility-level recruitment rate, 89%). We enrolled a median of 14 patients per provider (range, 1 to 16 patients) from February 2005 to March 2006. Recruitment time per facility varied from 4 to 12 months. Figure 2. Study flow diagram. PCP = primary care provider. *Diabetic patients presenting for a primary care visit to 1 of 92 participating providers were referred for eligibility assessment if their lowest triage blood pressure was140/90 mm Hg. *Number of responses varied by individual item. Our prespecified sample size calculations stipulated that we needed at least 11 patients from 80 physicians across 8 sites (that is, 880 patients) to detect a moderate difference in treatment change (about 12%) when competing demands were or were not present. Data Sources We included data from 5 sources in our analysis (Table 1). First, a baseline survey completed by all providers provided variables assessing provider prioritization to blood pressure management, general provider characteristics, and availability of ancillary support for blood pressure management. Second, providers completed a brief visit survey for each patient after the same clinic session in which they saw the patient (completion rate, 99%). This survey provided information on which issues were discussed during the visit, the provider's blood pressure goal for the patient, and whether medications were changed during the visit. Third, a patient survey conducted at enrollment provided sociodemographic characteristics, self-reported adherence and difficulty with medications, and self-management practices (completion rate, 91%). Fourth, review of electronic medical records documented free text blood pressure values and notes on actions taken at the enrollment visit. Finally, patient age, prescribed medications and th