What is the relationship between renal function and visit-to-visit blood pressure variability in primary care? Retrospective cohort study from routinely collected healthcare data

Long-Term Blood Pressure Variability and Kidney Function in Participants of the ASPREE Trial

BACKGROUND

Whether long-term blood pressure variability (BPV) predicts kidney function decline in generally healthy older adults is unknown. We investigated this association in ASPirin in Reducing Events in the Elderly (ASPREE) trial participants.

METHODS

Between 2010 and 2014, Australian and US individuals aged ≥70 years (≥65 if US minority) were recruited and followed with annual study visits for a median of 4.7 years. Time-to-event analyses and linear mixed effects models were used to examine associations between incident chronic kidney disease (CKD), and trajectories of estimated glomerular filtration rate (eGFR) and log albumin-creatinine ratio (log ACR) with systolic BPV as a continuous measure, and, by tertile of SD of systolic blood pressure (BP). BPV was estimated using systolic BP measures from baseline through the second annual visit, and kidney outcomes were assessed following this period.

RESULTS

Incident CKD occurred in 1,829 of 6,759 participants (27.2%), and more commonly in BPV tertiles 2 (27.4%) and 3 (28.3%) than tertile 1 (25.5%); however, the risk was not significantly increased after covariate adjustment (tertile 3 hazard ratio = 1.02; 95% confidence interval: 0.91-1.14). Analysis of eGFR (n = 16,193) and log ACR trajectories (n = 15,213) showed individuals in the highest BPV tertile having the lowest eGFR and highest log ACR, cross-sectionally. However, the trajectories of eGFR and log ACR did not differ across BPV tertiles.

CONCLUSIONS

CKD and markers of reduced kidney function occur more commonly in individuals with higher BPV; however, BPV does not influence trajectory of decline in kidney function over time in older adults who are in generally good health.

CLINICAL TRIALS REGISTRATION

Trial Number NCT01038583 and ISRCTN83772183.

Change in GFR over time in the Oxford Renal Cohort Study

Background

Decline in kidney function can result in adverse health outcomes. The Oxford Renal Cohort Study has detailed baseline assessments from 884 participants ≥60 years of age.

Aim

To determine the proportion of participants with a decline in estimated glomerular filtration rate (eGFR), identify determinants of decline, and determine proportions with chronic kidney disease (CKD) remission.

Design and setting

Observational cohort study in UK primary care.

Method

Data were used from baseline and annual follow-up assessments to monitor change in kidney function. Rapid eGFR decline was defined as eGFR decrease >5 ml/min/1.73 m²/year, improvement as eGFR increase >5 ml/min/1.73 m²/year, and remission in those with CKD at baseline and eGFR >60 ml/min/1.73 m² during follow-up. Cox proportional hazard models were used to identify factors associated with eGFR decline.

Results

There was a net decline in eGFR in the 884 participants over 5 years of follow-up. In 686 participants with >2 eGFR tests with a median follow-up of 2.1 years, 164 (24%) evidenced rapid GFR decline, 185 (27%) experienced eGFR improvement, and 82 of 394 (21%) meeting CKD stage 1–4 at baseline experienced remission. In the multivariable analysis, smoking status, higher systolic blood pressure, and being known to have CKD at cohort entry were associated with rapid GFR decline. Those with CKD stage 3 at baseline were less likely to exhibit GFR decline compared with normal kidney function.

Conclusion

This study established that 24% of people evidenced rapid GFR decline whereas 21% evidenced remission of CKD. People at risk of rapid GFR decline may benefit from closer monitoring and appropriate treatment to minimise risks of adverse outcomes, although only a small proportion meet the National Institute for Health and Care Excellence criteria for referral to secondary care.

Visit-to-visit blood pressure variability and renal outcomes: results from ONTARGET and TRANSCEND trials

AIMS

There is conflicting evidence on whether in treated hypertensive patients the risk of renal outcomes is associated with visit-to-visit SBP variability. Furthermore, limited evidence is available on how important is SBP variability for prediction of renal outcomes compared with on-treatment mean SBP. We addressed these issues in 28 790 participants of the Ongoing Treatment Alone and in combination with Ramipril Global End point Trial and Telmisartan Randomized AssessmeNt Study in ACE iNtolerant Subjects with Cardiovascular Disease trials.

METHODS AND RESULTS

SBP variability was expressed as the coefficient of variation of the mean with which it showed no relationship. SBP variability and mean values were obtained from five visits during the first 2 years of treatment after the end of the titration phase. Incidence of several renal outcomes (end-stage renal disease, doubling of serum creatinine, new microalbuminuria, new macroalbuminuria and their composite) was calculated from the third year of treatment onward. Patients were divided in quintiles of SBP-coefficient of variation (SBP-CV) or mean SBP, which exhibited superimposable mean blood pressure and SBP-CV values, respectively. A progressive increase of SBP-CV was not accompanied by a parallel increase in a widely adjusted (baseline and on-treatment confounders) risk of most renal outcomes (end-stage renal disease, new macroalbuminuria, new microalbuminuria and their composite) in the subsequent on-treatment years. In contrast, the adjusted risk of most renal outcomes increased progressively from the lowest to the highest quintile of on-treatment mean SBP. Progression from lowest to highest mean on-treatment SBP, but not SBP-CV, was also associated with a less frequent return to normoalbuminuria in patients with initial micro or macroalbuminuria. Renal outcome prediction was slightly improved by the combined use of SBP-CV and mean SBP quintiles.

CONCLUSION

Visit-to-visit SBP variability had no major predictive value for the risk of renal outcomes, which, in contrast, was sensitively predicted by mean on-treatment SBP. A further slight increase in prediction of renal outcomes was seen by combining on-treatment mean SBP and variability.

Long-term blood pressure variability and development of chronic kidney disease in type 2 diabetes

OBJECTIVE

Long-term visit-to-visit SBP variability (VVV) has been shown to predict cerebro-cardiovascular events and end-stage renal disease in chronic kidney disease (CKD) patients. Whether SBP VVV is also a predictor of CKD development in diabetes is currently uncertain. We assessed the role of SBP VVV on the development of CKD in patients with type 2 diabetes (T2D) and hypertension in real life.

METHODS

Clinical records from 30 851 patients with T2D and hypertension, with normal estimated glomerular filtration rate (eGFR) and regular visits during a 4-year follow-up were analyzed. SBP variability was measured by three metrics: coefficient of variation; SD of the mean SBP and average absolute difference of successive values in each individual. CKD was defined as eGFR less than 60 and/or a reduction in eGFR at least 30% from baseline.

RESULTS

Over the 4-year follow-up, 9.7% developed eGFR less than 60 and 4.5% an eGFR reduction at least 30% from baseline. Several clinical characteristics (older age, male sex, SBP, DBP, albuminuria, glycated hemoglobin, insulin treatment) were related to intraindividual SBP variability. Patients with VVV in the upper quintile showed an increased risk of developing both components of CKD [adjusted odds ratio (OR) 1.21, P < 0.001 and 1.32, P < 0.001, respectively]. The multivariable adjusted ORs of SBP coefficient of variation quintiles 2-5 for the incidence of CKD were incrementally higher (OR 1.04, P = 0.601, OR 1.05, P = 0.520, OR 1.21, P < 0.017 and OR 1.42, P < 0.001 as compared with the first quintile).

CONCLUSION

Increased long-term BP variability predicts CKD in patients with T2D and hypertension.

[Follow-up of patients with Ixodes tick-borne borrelioses caused by Borrelia miyamotoi or Borrelia burgdorferi sensu lato]

Ixodes tick-borne borrelioses (ITBB) are caused by two different spirochetes: Borrelia from the group of Borrelia burgdorferi sensu lato, the agents of the classic Lyme borreliosis (LB), and Borrelia miyamotoi that belongs to the group of Borrelia causing tick-borne relapsing fevers. ITBB caused by B. miyamotoi (BM-ITBB) is a previously unknown infectious disease discovered in Russia. It is known that the LB sequelae may reduce the long-term life guality of convalescents.

AIM

To study the follow-up of those who have recovered from new BM-ITBB infection in comparison with persons who have had LB.

SUBJECTS AND METHODS

The investigation enrolled 41 patients with BM-ITBB and 41 patients with LB who were treated at the Republican Infectious Diseases Hospital of Udmurtia. Within a year after the disease, they were followed up through clinical and instrumental examination of cardiac performance, expanded biochemical analysis of blood and urine, which could; estimate kidney and liver functions, and psychological questioning.

RESULTS

Asthenic syndrome and complaints about and objective signs of cardiac dysfunctions persisted supraventricular extrasystoles, left ventricular diastolic dysfunction, and elevated and/or unstable systolic blood pressure were detected in 20-30% of the convalescents for a long time. Kidney dysfunctions were manifested in albuminuria and the decrease of glomerular filtration rate. A year following the disease, 10-20% patients had persistently elevated concentrations of alanine aminotransferase, aspartate aminotransferase, and C-reactive protein and had higher levels of total cholesterol and low-density lipoproteins. The pathological consequences of ITBB were polymorphic and varied in different patients; in general, only 68% of them showed health improvement.

CONCLUSION

We assume that a significant role in the pathogenesis of BM-ITBB and LB is played by vascular endothelial damage possibly associated with the inflammatory and autoimmune aspects of an immune response in Borrelia infection. The consequences of this damage may persist and even intensify during a year, which provokes chronic dysfunction of the heart, kidney, or liver in a number of convalescents.

Visit-to-visit blood pressure variability in children and adolescents with renal disease

BACKGROUND

Increase in blood pressure (BP) variability (BPV) is associated with cardiovascular events, target organ damage, and arterial stiffness in adults. We previously reported that 24-h BPV may be associated with arterial stiffness and underlie white-coat hypertension (WCH). In this study, we examined whether visit-to-visit variability (VVV) could predict WCH and whether VVV correlated with eGFR, eGFR slope, and albuminuria/proteinuria in children and adolescents with renal diseases.

METHODS

VVV was determined as average real variability of office BP measurements between visits, and 24-h BPV as the standard deviation of 24-h ambulatory BP. In 35 renal patients (25 boys and 10 girls, 7-18 years of age), divided into normotension (NT), WCH, and hypertension (HTN), the relationships between VVV and 24-h BPV and VVV in each BP category were studied. In separate 48 renal patients (24 boys and 24 girls, 2-18 years of age), the correlation between VVV and eGFR, eGFR slope, urine albumin or protein excretion was examined.

RESULTS

Systolic VVV was significantly correlated with systolic office BP index. There was no correlation between VVV and 24-h BPV or 24-h pulse pressure. In addition, VVV was not different among NT, WCH, and HTN. Systolic VVV was significantly negatively correlated with eGFR but not with eGFR slope, albuminuria, or proteinuria. A cut-off value of systolic VVV for detecting eGFR < 60 ml/min per 1.73 m² was 8.5.

CONCLUSION

VVV could not predict WCH. Systolic VVV correlated with eGFR but not with eGFR slope, albuminuria/proteinuria. Increased VVV could be a marker of decreased eGFR.

Ambulatory blood pressure variability: a conceptual review

Ambulatory blood pressure (ABP) has long been recognized by researchers as the gold standard of blood pressure (BP) measurement. Researchers and clinicians typically rely on the mean measure of ABP; however, there is considerable variability in the beat-to-beat BP. Although often ignored, this variability has been found to be an independent predictor of cardiovascular disease and mortality. The aim of this paper is to provide a conceptual review of ABP variability (ABPV) focusing on the following: associations between ABPV and health, whether ABPV is reliable, how to calculate ABPV, predictors of ABPV, and treatments for ABPV. Two future directions are discussed involving better understanding ABPV by momentary assessments and improving knowledge of the underlying physiology that explains ABPV. The results of this review suggest that the unique characteristics of ABPV provide insight into the role of BP variability in hypertension and subsequent cardiovascular illness.