Every 10mmHg reduction in blood pressure results in a 35% reduction in stroke. Veterans Health Administration (VHA) has achieved substantial improvement in hypertension control over the past decade, far exceeding national rates. While this improvement coincides with a broad, national VHA redesign and quality improvement effort, it is unknown how VHA achieved these superior results in hypertension control. We hypothesized that these results were influenced by VHA system redesign and a potential improvement in either patient medication adherence or clinician "treatment intensification" for hypertension.
We evaluated improvement in hypertension control at a large Veterans Affairs Medical Center (VAMC) between 2000 and 2008 by observing rates of patient adherence to antihypertensive treatment and clinician treatment intensification for each study year. These data were combined with information from chart reviews and focus groups. The objective was to understand why hypertension control improved during this time period by analyzing changes in physician and patient behavior (e.g. adherence vs. clinician treatment intensification).
We used a mixed methods approach to evaluate hypertension medication adherence and treatment intensification rates from 2000-2008 and provider beliefs regarding improved blood pressure control.
To evaluate hypertension control rates over time, we accessed VA electronic and administrative data on all Veterans at VA Connecticut Healthcare System (VACHS) with a diagnosis of hypertension, as indicated by an ICD-9 code of 401.X in their medical record. We included only patients who had at least one primary care visit. At each visit, hypertension control was defined as a blood pressure of < 140/90 or < 130/80 among Veterans with both hypertension and diabetes (ICD-9 250.xx). If a Veteran had two or more blood pressure readings on the same day, the lower reading was taken.
We used VA pharmacy data to measure adherence by calculating the total number of days medication was dispensed from a VA pharmacy during the year.
Treatment intensification (a binary "yes/no" variable) was defined as an increase in the dose of an existing anti-hypertensive medication or the addition of a new anti-hypertensive medication after a clinic visit with an above goal blood pressure reading.
To model changes in Veterans' medication adherence over time, we used generalized estimating equations. For the analysis of treatment intensification, we modeled the proportion of intensifications by each provider, out of all visits by Veterans in which intensification was indicated. This measure ranged from 0% (no Veterans received intensification even when indicated) to 100%. Subsequent subgroup analyses investigated the yearly change in intensification in diabetic and non-diabetic patients separately. All analyses were performed using SAS V9.2 (Cary, NC) with a significance level of p<0.05. (269)
Between 2000 and 2008, 52,215 Veterans at VACHS had a hypertension diagnosis and > one primary care visit (97.0% male, 31.4% diabetes). The mean age was 74 years. 39% of Veterans were seen at the main medical center and 61% at one of seven CBOC's in VACHS. Hypertension control rates increased from 50% (2000) to 78% (2008). Patients with diabetes had similar rates of improvement but lower rates of control, (28%-2000; 54%--2008).
Average adherence rates improved significantly from 60% (2000) to 68% (2007), with a decrease to 66% in 2008. Adherence was significantly higher for older, male, and diabetic Veterans and for those with more visits.
During the study period (2000-2008), 37,712 Veterans with hypertension had 150,812 visits with an above goal blood pressure reading. Of these, 77,780 (51.5 %) events had subsequent treatment intensification. Provider-specific intensification rates increased, from an average low of 55% (2000) to a high of 61% (2003). However, intensification rates declined after 2003. Diabetics were less likely than non-diabetics to receive intensification.
We conducted a random sample chart review (N=100) of patients with a diagnosis of hypertension and collected data on blood pressure, medication dosages and classes, as well as clinician decision-making and documentation. Of this group, 57% of patients were not at goal blood pressure, treatment intensification occurred in 38% of this group. Within the group without intensification, 25% were non-adherent, and 15% had follow-up with an outside MD. Approximately 40% did not have a specified reason for lack of treatment intensification.
Of patients receiving pharmacotherapy, approximately 70% were on > 1 anti-hypertensive medications while one third were on monotherapy. Medication classes included diuretics (54%), beta blockers (49%), and ACEI (43%). Patients were generally on appropriate classes of medications given comorbidities and 60% received "optimal" doses. 29% of patients were on thiazide diuretics. Adherence was approximately 86% (as per the medication record or MD note). However, female patients were more likely to be non-adherent.
The following observations were noted:
-Repeat normal BP readings were often not recorded within the vital signs package
-Providers were more likely to overlook elevated BP readings for urgent visits
-Treatment intensification was more likely for patients already on BP medications
We conducted four focus groups of physicians, pharmacists, and other members of the health care team. The data collection protocol was semi-structured and all sessions were digitally recorded and transcribed verbatim. Transcripts were topic-analyzed and iteratively coded using open coding methods.
Providers are involved in improving Veterans' blood pressure through the use of enhanced VHA computer systems and interprofessional support. However, several barriers to adherence were identified. Many patients struggle with polypharmacy challenges and low health literacy. Failure to refill prescriptions regularly, stopping due to side effects, and reluctance to take multiple pills were also documented. Non- adherence was especially problematic among female Veterans. Access to a supportive spouse or family caregiver attenuated some of the challenges for men
Results suggest that rates of Veteran medication adherence to anti-hypertensive medications have improved from 2000-2008. This adherence may be secondary to improved systems implemented in the VHA to remind providers of the importance of patient adherence. Our analysis also suggests that provider treatment intensification initially increased and then was attenuated in the second half of the decade. We suspect that implementation of systems directed at providers may have had an early impact on treatment intensification, improving control and decreasing the need for further intervention. Measures utilized in this study could be applied to other chronic diseases such as diabetes, obstructive lung disease, or pain management where both adherence and treatment intensification are also critically related to clinical outcomes. The results have broad applicability for other VHA and non-VHA practice settings.
External Links for this Project
- Anderson DR, Christison-Lagay J, Villagra V, Liu H, Dziura J. Managing the space between visits: a randomized trial of disease management for diabetes in a community health center. Journal of general internal medicine. 2010 Oct 1; 25(10):1116-22. [view]
- Anderson DR. Self-Management Goal Setting in a Community Health Center: The Impact of Goal Attainment on Diabetes Outcomes. Diabetes Spectrum. 2010 Mar 20; 23(2):97-105. [view]
- Brienza R, Anderson DR, Goulet JL, Meyer E, Peixoto A. Effect of Transformation of the Veterans Affairs Health Care System on the Quality of Hypertension Care. Poster session presented at: Society of General Internal Medicine Annual Meeting; 2012 May 11; Orlando, FL. [view]
- Brienza R, Meyer EM, Anderson DR, Peixoto A. Factors Contributing to Improved Hypertension Management at the VA. Poster session presented at: Society of General Internal Medicine Annual Meeting; 2012 May 11; Orlando, FL. [view]