Systolic Blood Pressure Control After Participation in a Hypertension Intervention Study

Study Questions:

Is control of systolic blood pressure (SBP) maintained after participation in a hypertension intervention study ends?


The authors performed a retrospective cohort study of patients who completed the Improving Blood Pressure in Colorado study, a randomized, multimodal intervention for hypertension using interactive voice response (IVR) technology combined with instruction and home BP monitoring, conducted between 2006 and 2009, in three health care systems across metropolitan Denver. In the initial study, home BPs recorded via the IVR system were reviewed by clinical pharmacists, and BP management via telephone contact was performed using physician-approved treatment protocols. Control subjects in the original study received usual primary care. For the current study, a retrospective chart review was performed to assess the first SBP recorded during routine care after the original study ended. The proportion of subjects with controlled SBP at the final study visit who had uncontrolled SBP during follow-up was compared for the intervention and usual care groups. Time to uncontrolled SBP was assessed by Kaplan-Meier estimates.


At the conclusion of the Improving Blood Pressure in Colorado study, SBP was controlled in 51.5% versus 46.9% for the intervention versus usual care groups. Of those subjects with controlled SBP, 37.0% and 46.4% of subjects in the intervention and usual care group, respectively, had uncontrolled SBP at first follow-up visit (p = 0.32). Median time to development of uncontrolled SBP was no different between the groups (126 vs. 114 days, respectively; p = 0.47).


The authors concluded that SBP control was not maintained in a significant proportion of subjects following hypertension study participation. The authors opined that these findings suggest the need for interventions to focus on longer-term BP control.


Most clinicians are aware that the intensity of clinical care provided and the close attention paid to subjects during clinical trials can’t be replicated in clinical practice. One expects lower rates of treatment adherence in the real world than what is seen in clinical trials. This always poses a dilemma for the clinician as to whether results obtained in clinical trial reports necessarily translate to their clinical practice. The current study highlights the added difficulty in this regard when the clinical trial is a study of a method of care delivery, rather than a therapeutic agent. The current report serves to highlight that methods to improve BP control based on changes in care delivery are practically unsustainable if those changes in care delivery are not sustained. In the current report, nearly one half of subjects whose BP was controlled with the care delivery intervention studied had lost control of BP by their very next follow-up visit. In fact, only about 4 months’ time was required for control of BP to be lost. This begs the question: ‘Should we study an intervention that isn’t practically or financially sustainable?’

Clinical Topics: Prevention, Hypertension

Keywords: Follow-Up Studies, Colorado, Blood Pressure Determination, Hypertension, Primary Health Care

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