Isolated Diastolic Hypertension and Kidney and Cardiovascular Outcomes in CKD: The Chronic Renal Insufficiency Cohort (CRIC) Study

RATIONALE & OBJECTIVE: The clinical significance of isolated diastolic hypertension in patients with chronic kidney disease (CKD) is unclear. We assessed the prevalence of isolated diastolic hypertension and its association with adverse kidney and cardiovascular outcomes in participants in the Chronic Renal Insufficiency Cohort (CRIC) study. STUDY DESIGN: Prospective cohort study. SETTING & POPULATION: CRIC study participants with complete baseline data on systolic blood pressure (SBP) and diastolic BP (DBP) (N=5,621). EXPOSURE: Isolated diastolic hypertension defined as SBP ≤ 130 mm Hg and DBP >80 mm Hg. REFERENCE GROUP: Normotension, defined as SBP ≤ 130 mm Hg and DBP ≤ 80 mm Hg. OUTCOMES: Composite kidney events (50% decline in estimated glomerular filtration rate or onset of kidney failure), composite cardiovascular events (myocardial infarction, heart failure, stroke, or peripheral arterial disease), and all-cause mortality. ANALYTICAL APPROACH: Cox proportional hazards models adjusted for demographic, health behavior, and clinical covariates. RESULTS: Of the 5,621 participants, 347 (6.2%) had isolated diastolic hypertension. Among the 347 participants with isolated diastolic hypertension, there was no association between isolated diastolic hypertension and the composite kidney outcome (HR, 1.17; 95% CI, 0.93-1.47; P = 0.18), composite cardiovascular events (HR, 0.91; 95% CI, 0.65-1.27; P = 0.58), or all-cause mortality (HR, 0.82; 95% CI, 0.57-1.19; P = 0.30). LIMITATIONS: Older age of cohort and low number of participants of Asian ethnicity limit generalizability of findings. A relatively small sample size is inadequate to detect modest associations with outcomes. CONCLUSIONS: Isolated diastolic hypertension was not associated with the risk of adverse kidney and cardiovascular events in participants with CKD. PLAIN LANGUAGE SUMMARY: Clinicians frequently encounter patients with kidney disease who have controlled systolic blood pressure (BP) but high diastolic BP and do not know whether they should intensify BP treatment in an attempt to control the diastolic BP. We examined whether having controlled systolic BP but uncontrolled diastolic BP leads to worse heart and kidney outcomes in patients with chronic kidney disease. We did not find any such association. However, our study was relatively small and had a number of limitations. Till larger studies confirm or refute this finding, we recommend not increasing blood pressure medications to improve the diastolic BP control if the systolic BP is already well controlled in patients with chronic kidney disease.