More advanced stages of CKD associated with higher prevalence of refractory hypertension

California: Research published in the Clinical Journal of the American Society of Nephrology estimated that half of the patients with Chronic Kidney Disease (CKD) meet the criteria of apparent treatment-resistant hypertension, depending on the clinical guidelines and CKD staging.

Patients not reaching Blood Pressure (BP) goals despite multidrug therapy is common in CKD patients. With the decline in kidney function, Resistant Hypertension (RH) becomes more prevalent, increases the risk of kidney disease progression, and impairs prognosis. This necessitates a thorough understanding of the guidelines and treatment modalities for nephrologists.

The true prevalence rate of RH is unknown but is estimated to range from 2% to 40% in treated hypertensive populations. Studies evaluating RH often lack a uniform definition. Several factors, including failure to assess medication dose, medication adherence, out-of-office BP measurements, and lack of data, have led to an overestimation of the true prevalence of RH.

Against the above background, Jaejin An et al. and the team of the Department of Research and Evaluation from Kaiser Permanente Southern California, Division of Nephrology, Department of Epidemiology and Population Health from the Stanford University School of Medicine estimated the prevalence of apparent treatment-resistant hypertension in patients with CKD.

The prevalence was estimated based on guidelines in two US healthcare systems, namely, American College of Cardiology/American Heart Association, 2017 (ACC/AHA; BP goal < 130/80 mm Hg) and Kidney Disease Improving Global Outcomes, 2021 (KDIGO; systolic BP <120 mm Hg).

Resistant hypertension is blood pressure above goal despite adherence to a combination of at least three antihypertensive medications (optimally dosed), with one diuretic included. The components of diagnostic criteria for treatment-resistant hypertension are based on BP (that remains elevated) above goal despite using≥ 3 classes of antihypertensive medications, patient's individualized target of prescribed ≥ 4 classes of antihypertensive medications regardless of blood pressure, and use of diuretic in sensitivity analyses. These were included in classifying apparent treatment-resistant hypertension.

The researcher's team studied 44543 adult patients from Kaiser Permanente Southern California (KPSC) and 241,465 from Veterans Health Administration (VHA) who had a history of CKD with an estimated glomerular filtration rate <60 ml/min per 1.73 m2 and treated hypertension.

The key points of the study are:

• In KPSC (patient with CKD and treatment hypertension) and VHA cohort, as per ACC/AHA 2017 BP guideline (BP > 130/80 mmHg), the prevalence rate of apparent treatment-resistant was 39 % and 35 %, respectively.

• As per KDIGO 2021 guidelines and systolic BP > 120 mmHg, the prevalence rate was 48 % for the KPSC cohort and 55 % for the VHA cohort.

• The prevalence of apparent treatment-resistant hypertension with diuretic use based on the 2017 ACC/AHA guideline was 31 % in the KPSC cohort and 23 % in VHA cohort.

• As per eGFR on the basis of 2017 ACC/AHA guideline, the prevalence rate in patients with eGFR 45-59, 30-44, 15-29 and < 15 ml/min per 1.73 m2 was 34 %, 42%, 52%,60 % in KPSC cohort and 33 %, 36 %, 41%, 37% in VHA cohort respectively.

The author said, "Apparent treatment-resistant hypertension had a higher prevalence rate at more advanced stages of CKD."

Dr. An and co-author Kurella Tamura et al. concluded that up to half of patients with CKD met the apparent treatment-resistant hypertension criteria depending on the stage of CKD.

Most of the patients with CKD and apparent treatment-resistant hypertension had uncontrolled resistant hypertension or refractory hypertension. The researchers mentioned their study as the most diverse in estimating the link and said that their study data provides an opportunity to improve the treatment and the outcome for those patients who are at risk of adverse effects of high blood pressure.

References:

• An J, Tamura MK, Odden MC, et al. prevalence of apparent treatment-resistant hypertension in chronic kidney disease in two large US health care systems. Clin J Am Soc Nephrol. Published online September 9, 2022

• Resistant Hypertension in People With CKD: A Review Kevin S. Fay and Debbie L. Cohen Am J Kidney Dis. 77(1):110-121. Published online July 23, 2020.