Therapeutic Drug Monitoring of Cardiac Medications

The investigators will begin by conducting interviews with patients who have uncontrolled
hypertension, defined as SBP>130 or DBP>80 mmHg despite treatment with > 2 antihypertensive
drugs, from the Primary Care internal Medicine (PCiM) clinic and the cardiology clinic in the
Parkland Health and Hospital System (Parkland). after obtaining informed consent for
participation, we will explain therapeutic drug monitoring (TDM) as one method for accurately
assessing the amount of prescribed antihypertensive medication in a patient's system and how
that can be helpful to their physicians to effectively treat them. in these interviews, the
investigators will assess reasons why patients may be nonadherent, why they may be reluctant
to acknowledge this to their provider, explore how TDM could contradict patient self-report
about adherence, how this contradiction could affect the patient-provider relationship, and
how TDM could be used in a way that is acceptable to patients that enhances both the
patient-provider relationship and improves patient health outcomes. The investigators
anticipate conducting 10 interviews, after completing the patient interviews, the
investigators will use what we have learned to guide the cognitive interviews with the
hypertension clinicians. Provider participants will be recruited among physicians and nurses
working in the PCiM and cardiology clinics at Parkland. The investigators will explore their
responses to patient concerns, explore concerns about discussing and using TDM, especially
how they might communicate the results of TDM testing that contradict patient self-reported
medication adherence. After completing both patient and provider interviews, the
investigators will create a TDM intervention discussion tool for providers to use and pilot
this tool with a small group of TDM intervention pilot participants. This is an outline of
the steps but the investigators will submit the surveys and discussion tools to the IRB for
evaluation once they are developed. This will be done by a separate modification after the
initial approval of the study once we have conducted the initial interviews. This group of
participants will not be the same as the ones who were interviewed earlier. The discussion
tool will include guidance to providers about explaining TDM and how it's useful for
measuring adherence as well as prompts for addressing concerns patients identified in our
interviews with them. The investigators will conduct this pilot intervention with 20 patients
recruited from the PCiM and cardiology clinics who are being seen for their first follow-up
visit post hospitalization, usually one month after discharge. Patients will be consented to
participate in this TDM intervention, which will include measuring blood pressure, obtaining
blood specimens for TDM, and eliciting patient self-report about medication adherence.
Patients will be given their test results when they return for their next visit, usually 1-2
months later. although the blood assays for drug levels are not certified by CLIA nor
approved by the FDA, the investigators are not using drug level information to change dosing
or titrate the medications the patient are taking. During this second visit, the provider
will then review the patient's TDM results and use the TDM discussion tool to guide
conversation about discrepancies and potential barriers to adherence. The investigators will
assess patients' reactions to and satisfaction with the discussion about TDM and its
implications, and measure their blood pressure. Participants' reactions will be assessed by a
survey tool.

The investigators will also assess perspectives about the patient's response to TDM and the
effectiveness of using the TDM intervention discussion tool for facilitating the conversation
with the patient. There are commercial assays that are FDA approved for used already.
although the investigators do not use those assays, the Vanderbilt assays have been validated
and published (though not approved by FDA).

Inclusion Criteria:

Subjects age ≥ 18 to 80 years with uncontrolled hypertension (average clinic blood pressure
of at least 130/80 mmHg despite treatment with 2 or more antihypertensive drugs).

Exclusion Criteria:

1. Presence of hypertensive emergency BP > 180/110 mmHg plus one of the following
features: acute coronary syndrome, acute stroke, hypertensive encephalopathy, aortic
dissection, or acute kidney injury,

2. History of active substance abuse such as alcohol, cocaine, or narcotics

3. Uncontrolled psychiatric disorder such as schizophrenia or major depression

4. Pregnancy

5. Homeless

6. Stage V CKD or end stage renal disease (glomerular filtration rate < 15 ml/min/1.73
m2),

7. Self-report of nonadherence or unwillingness to follow medication regimen prescribed
by the primary care physicians for any reasons,

8. Presence of white coat hypertension (defined as normal 24-h ambulatory systolic BP or
home BP of < 130 and diastolic BP of < 80 mmHg and clinic systolic BP of at least 140
mmHg or diastolic BP of at least 90 mmHg according to the AHA guidelines)

9. Inability to read or write English, because participants may not be able to follow all
study procedures or complete study questionnaires and surveys correctly which may lead
to inaccurate data collection.