Blood pressure variability, mortality, and cardiovascular outcomes in CKD patients

Background and objectives Short-term BP variability (derived from 24-hourambulatory BP monitoring) and longterm BP variability (from clinic visit to clinic visit) are directly related to risk for cardiovascular events, but these relationshipshave been scarcelyinvestigatedinpatientswithCKD, andtheirprognosticvalue in thispopulationis unknown. Design, setting, participants, & measurements In a cohort of 402 patients with CKD, we assessed associations of short- and long-term systolic BP variability with a composite end point of death or cardiovascular event. Variabilitywas defined as the standard deviation of observed BPmeasurements.Wefurther tested the prognostic value of these parameters for risk discrimination and reclassification. Results Mean±SD short-termsystolic BP variabilitywas 12.±63.3mmHg, and mean ± SDlong-termsystolic BP variability was 12.7±5.1 mm Hg. For short-term BP variability, 125 participants experienced the composite end point over a median follow-up of 4.8 years (interquartile range, 2.3-8.6 years). For long-term BP variability, 110 participants experiencedthe composite endpoint over amedian follow-upof 3.2 years (interquartile range, 1.0-7.5 years). In adjusted analyses, long-term BP variability was significantly associated with the composite end point (hazard ratio, 1.24; 95% confidence interval, 1.01 to 1.51 per 5-mm Hg higher SD of office systolic BP), but shorttermsystolicBPvariabilitywas not (hazard ratio, 0.92; 95%confidence interval, 0.68 to 1.25 per 5-mmHghigher SD of 24-hour ambulatory systolic BP). Neither estimate of BP variability improved risk discrimination or reclassification compared with a simple risk prediction model. Conclusions In patients with CKD, long-termbut not short-term systolic BP variability is related to the risk of death and cardiovascular events. However, BP variability has a limited role for prediction in CKD.