Epidemiology of Uncontrolled and Treatment‑Resistant Hypertension: A Registry‑Based Observational Study

This study aimed to describe blood pressure control rates and prevalence of treatment resistant hypertension among diagnosed individuals. Randomly selected adults who had at least one primary or secondary healthcare visit and who were registered residents of Stockholm County, Sweden, on December 31st, 2019, were included. Blood pressure control in diagnosed individuals was assessed using two targets: <140/90 mmHg and <130/80 mmHg. The prevalence of treatment-resistant hypertension defined by three commonly used criteria was calculated and its association with clinical characteristics, drug treatment patterns, and comorbidities were assessed. By the end of 2019, among those with a hypertension diagnosis, 57% (<140/90 mmHg) or 19% (<130/80 mmHg) had controlled blood pressure depending on the threshold used. The point prevalence of treatment-resistant hypertension ranged from <1% to 17% depending on definition and was associated with older age, higher body mass index, and multiple comorbidities including type 2 diabetes, cardiovascular disease, heart failure, and chronic kidney disease. Blood pressure control remains a major clinical challenge, with fewer than one in five patients with a hypertension diagnosis achieving <130/80 mmHg. The prevalence of treatment-resistant hypertension varied widely depending on the definition used and was closely associated with a greater burden of comorbidities, indicating an unmet need for improved strategies for this clinically challenging subgroup. • High blood pressure is one of the important modifiable risk factors for cardiovascular disease and remains a major cause of preventable cardiovascular complications and premature death worldwide. Despite the availability of effective treatments, many patients do not achieve recommended blood pressure targets, highlighting a gap between guideline recommendations and routine clinical practice. • We studied more than 400,000 adults in Stockholm, Sweden, using healthcare records, blood pressure measurements, and pharmacy dispensing data to examine blood pressure control and treatment-resistant hypertension in routine care. Unlike many previous studies, treatment-resistant hypertension was assessed using evidence that medications had been dispensed rather than prescribed alone. • Among patients with diagnosed hypertension, just over half achieved a blood pressure below 140/90 mmHg. Yet fewer than one in five reached 130/80 mmHg, a more intensive treatment target recommended for many patients in contemporary guidelines. • Depending on the definition used, the estimated prevalence of treatment-resistant hypertension ranged from less than 1% to 17%. This wide variation highlights how strongly prevalence estimates depend on the diagnostic criteria applied and may partly explain the wide differences reported across previous studies. • Patients with treatment-resistant hypertension were generally older and had higher rates of diabetes, chronic kidney disease, heart failure, and cardiovascular disease. Many patients also lacked suitable follow-up blood pressure measurements, highlighting potential gaps in routine care. • Together, these findings show that uncontrolled hypertension remains a major challenge in everyday clinical practice and highlight opportunities to improve blood pressure monitoring, treatment optimization, and cardiovascular risk reduction.