Prevalence of potential modifiable factors of hypertension in patients with difficult-to-control hypertension.

Background: A comprehensive diagnostic evaluation of potential modifiable factors of difficult-to-control hypertension would enable clinicians to target-specific amendable causes. Therefore, we assessed the prevalence of underlying medical conditions, lifestyle factors, and concomitant medication use in an integrated diagnostic evaluation in patients with difficult-to-control hypertension, referred to a tertiary center. Methods: The study population consisted of 653 patients referred between 2006 and 2016 for difficult-to-control hypertension to the University Medical Center Utrecht. Difficult-to-control hypertension was defined by not reaching blood pressure (BP) goals despite BP-lowering drug use, or high office BP (>160/100 mmHg) without BP-lowering drug use. Patients were evaluated according to a highly standardized protocol including 24-h ambulatory blood measurements after cessation of BP-lowering drugs, 24-h urine sample, and a isotonic (0.9%) saline infusion test. Results: In 621 patients (95%) one or more modifiable factors related to hypertension were identified (mean 2.1, SD 1.1). Obesity-related insulin resistance was the most common underlying medical condition which was diagnosed in 130 patients (20%). Primary aldosteronism was diagnosed in 40 patients (6%) and obstructive sleep apnea in 17 patients (3%). Sodium intake was deemed to high (urinary excretion of >6 g/day) in 433 patients (66%). In total, 283 patients (43%) were physical inactive (<30 min/day, during 5 days/week). Oral contraceptive-related hypertension was diagnosed in 10 women (3% of women). Conclusion: In patients with difficult-to-control hypertension there is a high prevalence of potential modifiable factors related to hypertension, highlighting the importance for an integrated diagnostic evaluation.