Sequential drug decision problems in long-term medical conditions: a case Study of Primary Hypertension Eunju Kim ba, ma, msc

4.4Conceptual framework of the hypertension sequential drug decision problem

Figure ‎4. graphically represents the sequential drug choice process in primary hypertension. For a patient newly diagnosed with primary hypertension, the initial treatment decision is made depending on the comorbidity, the level of blood pressure and 10-year CVD risk. If the patient has stage 2 or 3 hypertension (i.e., BP ≥ 160/100); or stage 1 hypertension (i.e., 140/90 ≤ BP < 160/100) with a high CVD risk (10-year CVD risk ≥ 20%), pharmacological treatment usually starts with a single drug at low dose; although one of the two drug combinations may be used. For patients with CVD currently or previously, a drug will be selected depending on their medical history and the compelling indications.

As the result of the initial treatment, the patient either achieves the treatment goal or has the same or a worse SBP, CVD, DM or AE due to the drug. In the worst case, the patient may die due to a CVD-related or non-CVD related reason. If the initial drug cannot achieve the treatment goal, then it will be substituted with another single drug or two or three drug combination. In this study, the two or three drug combinations means both adding a second or third-line drug to the current treatment regimen and multiple drugs combined into a single pill. If the patient has a CVD or DM, one of the drugs recommended in clinical guidelines will be given. If the patient achieves the treatment goal, the current treatment regimen usually continues the drug at the same dose or at a lower dose. Depending on the result of second-line treatment, the patient evaluation and treatment decision procedure repeats over the patients’ lifetime.

1) D represents thiazide type diuretics; BB represents beta-blockers; CCB represents calcium channel blockers; ACEI represents angiotensin-converting enzyme inhibitors; and ARB represents angiotensin II receptor blockers.

Figure ‎4.. Graphical display of the sequential drug decision process in primary hypertension

The sequential drug decision process in primary hypertension in Figure 4.5 was conceptualised using the elements of the mathematical description of an SDDP P(T, H, HS, A, SS, DS, Ω, p, r, f) in section 2.4.