Modelling the Clinical and Economic Outcomes of Variations in Intensity of Valsartan-Centric Regimens for Hypertension
AuthorAl Shayban, Dhfer Mahdi D.
AdvisorBootman, J. Lyle
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractPurposes: The purpose of this study was threefold. First, to examine how both the effectiveness of valsartan centric regimens and the patient-related factors affect the control rates of the Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP) and combined SBP/DBP; specifically for Belgian patients with a history of failed or intolerant anti-hypertensive treatment. Secondly, to assess the effectiveness of valsartan treatment groups and the related factors concerning a patients' total cardiovascular risk (TCVR) residuals. Lastly, to attempt to estimate the cost avoidance factor associated with taking varying levels of valsartan treatment doses. Methodology: This research took the form of a secondary-data analysis study, focusing on the analysis of data collected primarily from seven prospective studies conducted between 2004 and 2009, covering different regimens of valsartan. The variants of valsartan doses given to patients included: valsartan monotherapy (80mg or 160 mg); a combination of valsartan with hydrochlorothiazide (HCTZ) (80 mg and 12.5mg, 160mg and 12.5 mg, or 160mg and 25mg); and a combination of valsartan with amlodipine (80mg and 5mg, 160mg and 5mg, or 160mg and 10mg). We applied Bailey's approach, using Kaplan-Meier curves to estimate the distribution of treatment intensity at which the target rates of SBP, DBP and SBP/DBP were achieved. The treatment intensity was calculated by dividing the daily dose prescribed to a patient by the maximum daily recommended dose of that particular drug variant. The outcomes provided by Bailey's approach included the control rates of SBP, DBP and combined SBP/DBP, in addition to the reduction in TCVR residuals. Another aspect of our methodology was the use of a simulation method to estimate the cost avoidance by using valsartan treatment groups. We used OCED data to compare health indicators between the US and Belgium in order to estimate the ratio enabling us to calculate the cost of hypertension per patient per year. This cost was then used in the simulation method to calculate the cost avoidance of using varying levels of the treatment intensity of valsartan regimens. Results: A total of 17,683 patients were included in this study, contributed to by 3,434 physician-investigators. The mean age of the population was 63.63 + 11.83 years, with a mean BMI of 28.45 + 3.13 kg/m^2 and 47.7% of the population was male and the vast majority of the total population was Caucasian (98%). As a baseline the total population who had controlled SBP, DBP and combined SBP/DBP were 1358, 5301 and 1091 respectively. The total population who were categorized as low added risk TCVR, moderate added risk TCVR, high added risk TCVR, and very high added risk TCVR were 192; 3,721; 3,888 and 9,362 respectively. Overall, there was a statistically significant increase in the proportion of patients with controlled SBP, DBP and combined SBP/DBP after 90 days of starting on valsartan-centric regimens (p<0.001). Both older age and the presence of diabetes were associated with a lower control rate of SBP, DBP and combined SBP/DBP (P<0.05). High adherence to valsartan-centric regimens was associated with an increase in the control rates of blood pressure. Substantial reductions in total cardiovascular risk, particularly in the very high added-risk category was observed 5,852 times (33.1%) (P<0.001) and an increase in the low added risk TCVR 3,331 times (18.9%) (p<0.001). The associated cost avoidance with varying levels of treatment intensity were dose related. The cost avoidance associated with the treatment intensity levels of 0.25, 0.5, 0.75, 1.0 and 1.5 were $261,164; $2,403,188; $6,384,142; $8,702,272 and $10,230,321, respectively. Conclusion: The different levels of the treatment intensity of valsartan-centric regimens were effective in increasing the control rates of SBP, DBP and combined SBP/DBP in the real practice for patients whose prior treatment failed. Not only did valsartan regimens improve the BP control rate, they also reduced the TCVR residuals. Additionally, substantial cost avoidance was found to be associated with the use of higher levels of treatment intensity. These results may support the idea that intensive anti-hypertensive treatment may be associated with higher clinical and economic benefits for both patients and payers. However, more research might be needed to validate our results and to address the questions of adverse effects that may be associated with intensive anti-hypertensive therapy and the economic consequences of treating any such effects.
Degree ProgramGraduate College