New international guidance means more intensive blood pressure-lowering treatment is indicated for more than 10% of patients with chronic kidney disease (CKD), who are otherwise at high risk of cardiovascular events, according to a new South Korean database study.
The study was published Monday online ahead of the May 3 issue of the Journal of the American College of Cardiology, led by Hyeok-Hee Lee, MD, and Hokyou Lee, MD, PhD, from the Yonsei University College of Medicine, Seoul, South Korea.
The 2021 Kidney Disease: Improving Global Outcomes (KDIGO) guideline came with a revised systolic blood pressure target below 120 mm Hg for nondialysis CKD patients, largely based on subgroup results from the SPRINT trial, said the researchers.
Previously, the KDIGO target was ≤130/80 mm Hg for those with albuminuria and ≤140/90 mm Hg for those without.
The researchers noted that the new guidance means initiation or intensification of antihypertensive treatments for some patients.
However, with no diastolic blood pressure target in the new guidance, other patients are no longer candidates for blood pressure-lowering therapy, where they had previously been under 2012 KDIGO guidance.
Blood pressure targets under the new guidance can also differ from the 2017 American College of Cardiology (ACC)/ American Heart Association (AHA) guidelines, which recommend a universal target of less than 130/80 mm Hg for people with or without CKD.
The current study was established to evaluate the potential implications of the new KDIGO target by examining concordance/discordance with the 2021, 2012 and 2017 guidelines among 1,939 adults with nondialysis CKD in the cross-sectional Korea National Health and Nutrition Examination Survey (KNHANES) database. Their median age was 59 years, and 50.6% were men.
The patients were categorized into groups based on the concordance/discordance between guidelines: above 2021 KDIGO only, above 2012 KDIGO only, above both 2021 and 2012 targets, and controlled within both 2021 and 2012 targets. Similar categorization was done for 2021 KDIGO vs. 2017 ACC/AHA guideline.
The association with cardiovascular outcomes for each group was then assessed in 412,167 participants in the longitudinal Korean National Health Insurance Service (NHIS) database, with a median follow-up of 10 years. Their median age was 65 years, and 43.5% were men.
Of the KNHANES patients, 50.2% had blood pressure above the 2021 and 2012 KDIGO targets, 15.9% had blood pressure above the 2021 target only, 3.5% were above the 2012 target only, and 30.4% were controlled within both targets.
Results were similar for comparison between 2021 KDIGO and 2017 ACC/AHA blood pressure targets, the researchers added, with 55.3% of participants with blood pressure above both targets, 10.8% above the 2021 KDIGO target only, 5.1% above the 2017 AHA/ACC target only and 28.8% with blood pressure controlled within both targets.
“In general, those requiring BP [blood pressure] reduction were older, were more likely to be male, had a higher Charlson Comorbidity Index, used BP-, lipid-, and glucose-lowering drugs and renin-angiotensin system blocker more frequently, were more frequent drinkers, and had higher body mass index and fasting glucose levels compared with those not requiring BP reduction,” the researchers added.
Significantly higher risk for those above 2021 target
The participants with blood pressure above the 2021 KDIGO target (≥120 mm Hg) had a significantly higher cardiovascular disease risk, “regardless of whether the other (2012 KDIGO or 2017 ACC/AHA) target was met or not,” said the researchers.
“In contrast, those who had BP within the 2021 KDIGO target (ie, [systolic blood pressure] <120 mm Hg) showed a reduced risk for CVD [cardiovascular disease] events regardless of whether the other target was met or not.”
In NHIS, during follow-up, a total of 37,912 new cardiovascular disease events occurred.
Multivariable-adjusted hazard ratios for cardiovascular disease events were 1.52 in participants with blood pressure above both 2021 and 2012 targets (95% confidence interval [CI]: 1.47-1.58), 1.28 for those above 2021 KDIGO only (95% CI: 1.24-1.32) and 1.07 in those above the 2012 target only (95% CI: 0.61-1.89), compared to those with blood pressure controlled within both targets.
The findings support other recent studies demonstrating the cardiovascular benefits of intensive blood pressure control in patients with nondialysis CKD, the researchers said.
Importance of diastolic blood pressure
The patients who would have been candidates for initiation or intensification of antihypertensive therapy in the 2012 guidance who are no longer covered in 2021 guidance – given the lack of diastolic blood pressure target – “appears to account for only a small proportion (3% - 5%) of the total CKD population […] whose CVD risk also seems equivocal,” the researchers added.
“Taken together with the paucity of evidence regarding cardiovascular risk from isolated [diastolic blood pressure] elevation in CKD, this suggests that a tailored approach may be needed for such patients at this stage,” the researchers concluded.
They called for further studies to determine the benefits of intensive control of diastolic blood pressure when systolic blood pressure is controlled within the 2021 KDIGO target.
In an accompanying editorial, Alexander G. Logan, MD, of Mount Sinai Hospital, University Health Network and the University of Toronto, said the new study provides “valuable new information” on patients with elevated diastolic blood pressure and normal systolic blood pressure who are not indicated for blood pressure-lowering treatment under 2021 KDIGO recommendations.
“The group was small, accounting for 3%-5% of the total CKD population, and the risk of a CVD event was not significantly higher than in the reference group (controlled within both targets),” he said. “In concert with SPRINT findings, these results assign little importance to diastolic [blood pressure] in managing hypertension of older CKD patients.”
Nevertheless, with a paucity of evidence examining the relationship between diastolic hypertension and outcomes independently from systolic blood pressure in CKD patients, Logan stressed that diastolic hypertension cannot be dismissed as an independent risk factor.
Lee H-H, Lee H, Townsend RR, et al. Cardiovascular Implications of the 2021 KDIGO Blood Pressure Guideline for Adults With Chronic Kidney Disease. J Am Coll Cardiol 2022;79:1675-1686.
Logan AG. Implications of Implementing the 2021 KDIGO Blood Pressure Guideline. J Am Coll Cardiol 2022;79:1687-1689.
Image Credit: Kateryna_Kon – stock.adobe.com