Bosnian cohort will track whether fixed-dose perindopril and amlodipine brings uncontrolled hypertension under control
A prospective observational study in Bosnia and Herzegovina is set to examine how a fixed-dose combination of perindopril and amlodipine performs in adults with essential hypertension whose blood pressure remains above target. The cohort, listed as active and not recruiting, is built around a simple bedside question with real-world consequences: can a once-daily combination tablet improve blood pressure control, maintain adherence, and avoid unacceptable adverse reactions over 12 months?
The study plans to enroll an estimated 600 patients and follow them from baseline through one, three, six, and 12 months. Investigators will document heart rate, blood pressure, laboratory values, treatment adherence, adverse drug reactions, and concomitant therapy at each visit. In practical terms, the protocol is trying to capture what happens outside the clean boundaries of a randomized trial, where uncontrolled hypertension is managed in everyday clinics and patients often take multiple medications at once.
A fixed-dose strategy built around a familiar pharmacologic pairing
The intervention uses a once-daily fixed combination of perindopril + amlodipine, supplied in several dose strengths, including 4 mg/5 mg, 4 mg/10 mg, 8 mg/5 mg, and 8 mg/10 mg tablets. This pairing is clinically intuitive. Perindopril, an angiotensin-converting enzyme inhibitor, reduces angiotensin II–mediated vasoconstriction and blunts aldosterone-driven sodium retention, while amlodipine, a dihydropyridine calcium-channel blocker, relaxes vascular smooth muscle and lowers systemic vascular resistance. When the two are combined, blood pressure can fall through complementary mechanisms rather than a single pharmacologic lever.
In patients with persistent elevation of blood pressure, combination therapy often becomes necessary because monotherapy may not offset the combined effects of vascular stiffness, neurohormonal activation, and salt sensitivity. A fixed-dose tablet can simplify treatment, reduce pill burden, and make daily use more realistic for patients who already face competing cardiovascular risks. The study is designed to see whether those advantages translate into measurable control in routine practice, not just in selected trial populations.
One sentence in the protocol captures the central ambition clearly: blood pressure should move from uncontrolled values into guideline-defined targets, or at minimum fall by 10 to 15 mmHg systolic and 5 to 10 mmHg diastolic.
Guideline targets define the primary endpoint
The primary outcome is therapy effectiveness over 12 months, measured by whether blood pressure is reduced to normal values according to the 2018 ESC/ESH hypertension guidelines or falls by the prespecified systolic and diastolic thresholds. That endpoint matters because uncontrolled hypertension remains one of the most modifiable drivers of stroke, myocardial infarction, heart failure, and chronic kidney disease. Even modest reductions in blood pressure can have meaningful clinical consequences when sustained over time.
The cohort includes adults aged 18 to 75 years with blood pressure values of at least 140/90 mmHg. The age range suggests a broad adult hypertension population rather than a narrowly selected specialty clinic sample. Participants of any sex are eligible, and healthy volunteers are not included, which is appropriate for a treatment-effectiveness study centered on patients who already have the disease.
The design is observational rather than interventional in the randomized sense, so the study will not test whether the combination is superior to another drug strategy head-to-head. Instead, it will describe what happens when clinicians use this fixed-dose regimen in routine care. That approach can be useful when the question is not whether a drug works in principle, but how reliably it works in the messy, variable environment of daily practice.
Adherence will likely determine how much of the pharmacology reaches the patient
Therapy adherence is the first secondary outcome, and in hypertension that is often where outcomes are won or lost. A drug that lowers blood pressure effectively in theory still fails if patients forget doses, stop therapy because they feel well, or abandon treatment after an initial side effect. Fixed-dose combinations can improve persistence by collapsing multiple medications into one pill, especially in chronic asymptomatic disease where patients may not feel an immediate benefit from treatment.
The study will also record concomitant therapy, which is important because blood pressure management rarely happens in isolation. Patients with hypertension may also receive lipid-lowering agents, glucose-lowering therapy, or other cardiovascular medications, and those additional drugs can shape both adherence and adverse-effect interpretation. In real-world cohorts, polypharmacy is often part of the disease burden itself.
A second standout sentence in the protocol is the explicit focus on adverse reactions during the full 12-month period. Safety is not a side note here.
Renal and electrolyte monitoring may be as important as the blood pressure readings
Safety monitoring includes laboratory assessments of neutrophils, platelets, triglycerides, total cholesterol, HDL, LDL, AST, ALT, urea, creatinine, sodium, potassium, and blood glucose. Those measurements reflect more than administrative thoroughness; they mirror the organs and metabolic systems most likely to reveal treatment-related problems or underlying cardiovascular risk. Creatinine and potassium are especially relevant with perindopril, which can alter renal hemodynamics and potassium balance. Liver enzymes, sodium, and glucose add another layer of surveillance when patients are followed across a year of chronic therapy.
The exclusion criteria are consistent with standard clinical caution for this drug class. Patients with a history of angioedema, pregnancy, breastfeeding, planned pregnancy, significant bilateral renal artery stenosis, severe hypotension, outflow tract obstruction of the left ventricle, hemodynamically unstable heart failure after myocardial infarction, severe liver damage, primary hyperaldosteronism, or concurrent use of specific interacting therapies are excluded. The protocol also excludes concurrent aliskiren in patients with diabetes or renal impairment, as well as sacubitril/valsartan, both of which raise safety concerns when combined with renin-angiotensin system blockade.
Withdrawal criteria are equally pragmatic. Participants can leave the study if their clinical state worsens enough to require additional diuretic therapy or hospitalization, if serious adverse events emerge, if pregnancy occurs, or if another disease changes the course of follow-up. Those provisions matter because uncontrolled hypertension rarely exists in a vacuum; patients can deteriorate for reasons that force treatment changes before the 12-month endpoint is reached.
Real-world follow-up in Sarajevo may fill a gap left by controlled trials
The study is being conducted in Sarajevo at the Clinic for diseases of the heart, blood vessels and rheumatism at the Clinical Center University of Sarajevo. For a regional cohort, that setting may provide a useful snapshot of how combination antihypertensive therapy performs in a population seen in routine specialist care. The planned sample size of 600 patients gives the project enough breadth to describe adherence patterns, laboratory trends, and adverse reactions across a sizable clinical cohort, even if it cannot answer all comparative questions.
Because the study is prospective, investigators will be able to observe changes over time rather than relying on a single clinic encounter. That time structure is important in hypertension, where the first blood-pressure check may not predict long-term control and where tolerability often changes after the early weeks of treatment. A patient who tolerates the first month well may still develop cough, edema, dizziness, laboratory abnormalities, or simple disengagement later on.
The record does not include results yet, so no efficacy or safety conclusions can be drawn from the registry entry itself. What it does establish is a clear framework for monitoring a common antihypertensive combination in everyday use, with attention to the issues clinicians actually face: whether blood pressure falls far enough, whether patients keep taking the medicine, and whether the treatment creates renal, electrolyte, hepatic, or hemodynamic problems along the way. The absence of posted results leaves those questions open until the follow-up phase is complete and the cohort is fully observed.