PREVALENCE OF PATIENT WITH TREATMENT-RESISTANT HYPERTENSION AND SCREENING RATE FOR PRIMARY HYPERALDOSTERONISM IN THAI AMBULATORY CARE SETTING

Abstract

Objective: Patients with treatment-resistant hypertension (TRH) have significantly higher mortality outcomes when compared with controlled hypertension. Primary hyperaldosteronism (PA) is one of the common treatable causes of this condition. Although the practice guidelines recommend testing for PA among those with TRH, the screening rates in Thailand's ambulatory care setting are unknown. Design and method: This is a single-center cross-sectional study. All hypertensive adults followed at ambulatory clinics of a tertiary care hospital between January 2020, and May 2022 were screened. Patients who met one of two following criteria were diagnosed as TRH: 1) uncontrolled blood pressure (BP) despite the use of 3 antihypertensive drug classes, including diuretics 2) concurrent use of greater than or equal to 4 antihypertensive drug classes, regardless of BP control. Patients without data of consecutive office BP records at least one month apart or lack of laboratory results were excluded. Hypokalemia was defined as a low serum potassium level identified on at least 2 visits. Results: Among 2,047 patients diagnosed with hypertension, the prevalence of TRH was 9.4% (192 patients) with a mean (±SD) age of 74 (±10) years, 59% were women, and the mean number of antihypertensive agents was 3.8±0.7. The screening rate for PA in TRH and non-TRH groups were 3.1% and 0.8%, respectively (p = 0.001). Among those with TRH, the screened PA group significantly had more prevalence of hypokalemia than the non-screened group (33.3% vs 2.7%, p<0.001). From subgroup analysis of all patients with hypokalemia and without hypokalemia, the testing rates for PA were 18.2% and 0.6%, respectively (p<0.001). The average duration from first hypokalemia detection to receiving testing for PA was 19 months. Five of the 20 patients received screening were diagnosed with PA and had better BP control after receiving appropriate treatment. Conclusions: This is the first study in Thailand to examine a PA screening rate in a real-life, ambulatory care setting. The low screening rate reflects the unawareness and inertia of physicians to adhere to guideline-recommended practices. Initiatives to encourage PA screening should be more emphasized and barriers that caused low screening rate should be further explored.