The results of a standardized diagnostic care pathway in patients referred for difficult-to-treat hypertension: the IDENTIFY study

Background Current guidelines recommend combining diagnostic and therapeutic modalities for patients with difficult-to-treat hypertension within a dedicated hypertension clinic. Contemporary evidence on the combined diagnostic and therapeutic efficacy of such clinics remains limited. Purpose This study aimed to investigate the diagnostic and therapeutic efficacy of a dedicated care pathway within a specialised hypertension clinic. Methods This single-centre retrospective cohort study included patients referred for difficult-to-treat hypertension without a previous diagnosis of a secondary cause of hypertension. Diagnostic yield, changes in 30-minute unattended office BP and antihypertensive medication were assessed between baseline and the final visit within 12 months. Time to first BP control was analysed using Kaplan–Meier estimates and multivariable Cox proportional hazards regression. Results A total of 204 consecutive patients were included, 54% were female with a median age of 50 years [IQR 37 to 62]. Baseline unattended office BP was 139 mmHg systolic [IQR 126 to 156] and 86 mmHg diastolic [IQR 78 to 95] while taking a median of 3 [IQR 1.2 to 5.0] defined daily doses of antihypertensive drugs. Thirty-minute unattended office BP control <135/85 mmHg was present at baseline in 69 patients (34%) (Figure 1A). At the final visit, unattended office BP decreased by −9 mmHg systolic (95% CI −12 to −6) and −4 mmHg diastolic (95% CI −6 to −2) (both p<0.001) (Figure 1B). BP control was achieved in 87 patients (51%) with a median time to first BP control of 9.7 months [IQR 6.8 to 11.3] (Figure 1A). A higher baseline systolic BP was independently associated with a lower rate of achieving BP control (HR 0.80 per 10 mmHg increase; 95% CI 0.69 to 0.93; p=0.004), whereas female sex was associated with a higher rate of achieving BP control (HR 1.74; 95% CI 1.00 to 3.02; p=0.049). The number of antihypertensive medications remained unchanged, with a median change of 0 classes (95% CI −1 to 0; p=0.49) and a median change of 0.0 defined daily doses (95% CI −0.4 to 0.3; p=0.93) (Figure 1B). The number of patients receiving a fixed-dose combination pill increased significantly from 22 patients (13%) at baseline to 61 patients (36%) at the final visit (p<0.001) (Figure 2). A secondary cause of hypertension was newly diagnosed in 51 patients (25%), with primary hyperaldosteronism being the most frequent aetiology in 31 patients (15%). Conclusion A standardised hypertension care pathway in a specialised academic clinic was associated with significant BP reduction and identification of a secondary cause of hypertension in 25% of patients, without increasing medication burden but with greater use of fixed-dose combination therapy. BP control was achieved in 51% of patients within 12 months after referral.