Significance of estimating the glomerular filtration rate for the management of hypertension in type 2 diabetes with microalbuminuria

The relationship between day-to-day variability in home blood pressure measurement and multiple organ function

Blood pressure variability (BPV) is associated with the prognosis of cardiovascular diseases. However, it is unclear how BPV is related to various organs. The aim of this study is to investigate the association between BPV and multiple organ functions. A total of three hundred fifteen participants (114 males; mean age: 70 ± 9 years) participated in a community health checkup held in Tarumizu City. Home blood pressure (BP) was measured using a HEM-9700T (OMRON Healthcare, Kyoto, Japan). Day-to-day BPV was evaluated by the coefficient of variation (CV) of home BP measured in the morning for one month. N-terminal pro B-type natriuretic peptide (NT-pro BNP) and high-sensitivity (hs-)troponin T were measured as cardiac biomarkers. Liver stiffness and renal function were evaluated using the Fibrous-4 (Fib4) index and estimated glomerular filtration rate (eGFR), respectively. NT-pro BNP and hs-troponin T were divided by the median value. Fib4 index greater than 2.67 and eGFR less than 60 mL/min/1.73 m² were defined as high Fib4 index and low eGFR, respectively. In a multivariable logistic regression analysis, the CV of systolic BP was significantly associated with high NT-pro BNP, high Fib 4 index, and low eGFR, but not with high hs-troponin T. In contrast, the CV of diastolic BP was not associated with low eGFR, and the other three biomarkers had the same results as systolic BP. In conclusion, day-to-day BPV of systolic BP is independently associated with NT-pro BNP, eGFR, and Fib4 index, but not with hs-troponin T. In contrast, diastolic BPV was not found to be associated with eGFR.

Novel Indices of Home Blood Pressure Variability and Hypertension-Mediated Organ Damage in Treated Hypertensive Patients

INTRODUCTION

Although multiple home blood pressure variability (HBPV) indices have been proposed, the superiority of one over another is not clear in treated hypertensives.

AIM

We evaluated the correlation between different indices of HBPV and hypertension-mediated organ damage (HMOD) in this population and determined predictors of greater HBPV.

METHODS

We included adult treated hypertensives who performed an HBP monitoring (duplicate sitting BP readings in the morning, afternoon, and evening for 4 days, Omron HEM-705CP-II), laboratory measurements, transthoracic echocardiogram and carotid-femoral pulse wave velocity. We selected HBPV indices from three different calculation approaches: coefficient of variation (CoV), difference between maximum and minimum BP (MMD), and morning BP increase (MI), and evaluated their correlation with left ventricular mass index, relative wall thickness (RWT), ejection fraction, arterial stiffness and estimated glomerular filtration rate through a correlation matrix. For those variability indices significantly associated with HMOD, we constructed multiple linear regression models to determine independent predictors of HBPV.

RESULTS

We included 204 patients, mean age 67.2 (± 13.8) years, 64% female. CoV and MMD for systolic BP showed the greatest correlation with HMOD. Factors independently associated both with CoV and MMD were: older age (b = 0.07; 95% CI 0.04-0.07; p < 0.001 and b = 0.4; 95% CI 0.2-0.5; p < 0.001, respectively), history of stroke (b = 3.6; 95% CI 0.9-6.4; p = 0.01 and b = 25.7; 95% CI 10.1-41.2; p = 0.001, respectively), and body mass index [b = - 0.1; 95% CI - 0.2 to (- 0.02); p = 0.01 and b = - 0.5; 95% CI - 0.9 to (- 0.1); p = 0.01, respectively].

CONCLUSION

CoV and MMD showed the greatest association with HMOD in treated hypertensives. Older age, history of stroke and lower body mass index were easy-to-detect predictors.

Associations Between Day-by-Day Home Blood Pressure Variability and Renal Function and Albuminuria in Patients With and Without Diabetes

BACKGROUND

The phenotype of diabetic kidney disease represents a lower estimated glomerular filtration rate (eGFR) and albuminuria. We investigated the association between day-by-day home blood pressure (BP) variability and the eGFR in subjects with diabetes and compared this association with that in subjects without diabetes. We then attempted to determine whether the association is present in albuminuria.

METHODS

We analyzed 4,231 patients with risk factors of cardiovascular disease (24.4% with diabetes) from the J-HOP (Japan Morning Surge-Home Blood Pressure) study. Home BP was measured in the morning and evening for 14 days. We calculated the SD, coefficient of variation, average real variability (ARV), and variation independent of the mean of the subjects' morning and evening home systolic BP (SBP) as the indexes of day-by-day home BP variability.

RESULTS

A multiple linear regression analysis adjusted for covariates showed both average morning and evening SBP were associated with the log-transformed urine albumin-to-creatinine ratio (UACR) with and without diabetes (all P < 0.05), but not with the eGFR except for an association of average evening SBP in the no-diabetes group. None of the indexes of day-by-day morning and evening home SBP variability were associated with the log-transformed UACR except for the association between the ARV of home morning SBP in the diabetes group. All of the indexes of day-by-day morning and evening home SBP variability were associated with the eGFR only in the diabetes group (all P < 0.05).

CONCLUSIONS

The association between increased day-by-day home BP variability and impaired renal function was unique in diabetes.

Longitudinal trends in renal function in chronic hepatitis B patients receiving oral antiviral treatment

BACKGROUND

Long term renal safety of antiviral agents against hepatitis B virus (HBV) has been debated.

AIM

To compare longitudinal trends of renal function among HBV mono-infected patients receiving entecavir (ETV), tenofovir disoproxil fumarate (TDF), and adefovir (ADV) in comparison to untreated subjects.

METHODS

A retrospective cohort consisting of 815 patients with chronic HBV infection was constructed. Serial estimated glomerular filtration rate (eGFR) was compared to the expected rate of age-dependent decline in eGFR, derived from the National Health and Nutrition Examination Survey (NHANES) data. Generalised estimating equations and linear mixed-effects models were used to compare trends in eGFR (in mL/min/1.73m² as a "unit").

RESULTS

In NHANES data (n = 23 051), each year of age was associated with a 0.86 unit decrease in eGFR in subjects without hypertension and 0.96 units with hypertension. The Stanford cohort consisted of patients who received ETV (n = 207), TDF (n = 191), ADV (n = 46) or no therapy (n = 371). After a median follow-up 4.0 (interquartile range: 1.9-6.5) years, there was no significant difference in the expected and observed rates of eGFR decline in untreated HBV patients. Patients receiving antiviral treatment experienced steeper reduction in renal function than expected. In the multivariable model, ETV was associated with eGFR loss at 1.81 units per year (P = 0.06, compared to untreated patients). TDF- and ADV-treated patients experienced significantly higher rate of eGFR loss at 2.21 and 2.63 units per year, respectively (both P < 0.01).

CONCLUSION

In this longitudinal cohort study, HBV patients receiving antiviral therapy, particularly TDF and ADV, experienced more rapid loss in eGFR.

Effect of Home Blood Pressure on Inducing Remission/Regression of Microalbuminuria in Patients With Type 2 Diabetes Mellitus

BACKGROUND

The Home Blood Pressure for Diabetic Nephropathy study is a prospective observational study conducted to determine the effect of home blood pressure (HBP) on remission/regression of microalbuminuria in patients with type 2 diabetes mellitus (DM).

METHODS

Patients with type 2 DM having microalbuminuria were followed-up for 3 years. Remission of microalbuminuria was defined as shift from microalbuminuria to normoalbuminuria. Regression of microalbuminuria was defined as a 50% reduction in urinary albumin-creatinine ratio from baseline. All measurements of morning and evening HBP were averaged every year and defined as all HBP.

RESULTS

In total, 235 patients were followed up. The 3-year cumulative incidences of remission and regression were 32.3% and 44.7%, respectively. Following analysis of all cases, the degree of decline in all home systolic blood pressure (AHSBP), rather than mean AHSBP, influenced the incidence of remission/regression. There was a strong relationship between the decline in AHSBP during the follow-up period and AHSBP at baseline. Therefore, separate analyses of the patients with AHSBP below 140 mm Hg at baseline were performed, which revealed that mean AHSBP during the follow-up period independently affected the incidence of remission/regression. The hazard ratio for inducing remission/regression was significantly lower in patients with AHSBP during the follow-up period above 130 mm Hg than in those with AHSBP below 120 mm Hg.

CONCLUSIONS

Optimal AHSBP for the induction of remission/regression of microalbuminuria might be below 130 mm Hg. It is required to confirm whether keeping AHSBP below 130 mm Hg leads to subsequent renoprotection or not.

CLINICAL TRIALS REGISTRATION

Trial Number UMIN000000804.

SYSTEMIC RISK FACTORS IN BILATERAL PROLIFERATIVE DIABETIC RETINOPATHY REQUIRING VITRECTOMY

PURPOSE

The visual outcome after vitrectomy for proliferative diabetic retinopathy (PDR) is often poor. Bilateral vitrectomy has been especially associated with a poor visual prognosis in patients with PDR. The authors investigated the systemic risk factors for PDR requiring bilateral vitrectomy compared with unilateral vitrectomy.

METHODS

The authors retrospectively reviewed 86 consecutive patients with Type 2 diabetes mellitus with PDR who underwent vitrectomy. These patients were divided into 2 groups: bilateral vitrectomy within 1 year (n = 25) and unilateral vitrectomy (n = 61). The authors compared the systemic risk factors: age, sex, duration of diabetes, hemoglobin A1c, body mass index, estimated glomerular filtration rate, uric albumin, hypertension, dyslipidemia, history of ischemic heart disease, arteriosclerosis obliterans, and smoking.

RESULTS

There were significantly more cases with severe renal dysfunction in the bilateral vitrectomy group compared with the unilateral one (estimated glomerular filtration rate <30 mL/minute/1.73 m; bilateral cases = 5/25; unilateral cases = 2/61; P = 0.02).

CONCLUSION

The authors found that severe renal dysfunction may be a risk factor in PDR requiring bilateral vitrectomy, indicating that careful attention needs to be paid to prevent the progression of diabetic retinopathy to severe PDR in the other eye if patients have severe unilateral PDR and severe renal dysfunction.

Comparison of the Effects of Telbivudine and Entecavir Treatment on Estimated Glomerular Filtration Rate in Patients with Chronic Hepatitis B

Background/Aims

The aim of this study was to evaluate the estimated glomerular filtration rate (eGFR) during telbivudine (LdT) versus entecavir (ETV) treatment in chronic hepatitis B (CHB) patients with underlying comorbidities such as diabetes mellitus (DM), hypertension, and cirrhosis.

Methods

From 2010 to 2012, 116 CHB patients treated with LdT and 578 treated with ETV were compared in this real-practice cohort. The mean changes in eGFR (Modification of Diet in Renal Disease [MDRD] formula) from baseline to months 6, 12, and 18 were analyzed using a linear mixed model.

Results

In LdT-treated patients, the mean eGFR increased by 7.6% at month 18 compared with the eGFR at baseline (MDRD formula in mL/min/1.73 m²). However, in ETV-treated patients, the mean eGFR decreased by 4.1% at month 18 compared with the eGFR at baseline. In the LdT-treated patients with DM, hypertension, cirrhosis or low eGFR <90 mL/min/1.73 m², the mean eGFR showed a steady improvement, whereas the mean eGFR was reduced in the same subgroups of ETV-treated patients.

Conclusions

The eGFR gradually increased over time during LdT treatment, especially in patients with mild abnormal eGFR at baseline, and in those with DM, hypertension, and cirrhosis, whereas a reduction in eGFR was seen with ETV treatment.

Blood pressure variability: assessment, predictive value, and potential as a therapeutic target

A large body of evidence has consistently supported the relationship between blood pressure (BP) levels and the risk of cardiovascular complications. In recent years, several independent studies have also indicated that this risk may not only depend on the magnitude of the blood pressure elevation per se but also on the presence of other associated conditions such as increased blood pressure variability. This concept has been supported by a series of reports, most of which post hoc analyses of clinical trials in hypertension, showing that increasing values of BP variability (BPV) (either in the short term, in the midterm, or in the long term) may predict development, progression, and severity of cardiac, vascular, and renal organ damage, as well as cardiovascular events and mortality. Remarkably, studies conducted in populations at high cardiovascular risk have shown increasing values of BPV in the individual subjects (so-called intra- or within-individual BPV) to be strong predictors of cardiovascular morbidity and mortality, even to a larger extent than average BP values. However, in subjects at low to moderate cardiovascular risk, the contribution of BPV to cardiovascular risk prediction over and beyond average BP values has been shown to be only moderate. The aim of this paper is to critically review the evidence addressing the prognostic relevance of different components of BPV addressing a yet open question, i.e., whether routine assessment of BPV in clinical practice should be regarded as an additional target of antihypertensive treatment to improve cardiovascular protection.

Practical use of home blood pressure monitoring in chronic kidney disease

Despite the availability of blood pressure (BP)-lowering medications and dietary education, hypertension is still poorly controlled in the chronic kidney disease (CKD) population. As glomerular filtration rate declines, the number of medications required to achieve BP targets increases, which may lead to reduced patient adherence and therapeutic inertia by the clinician. Home BP monitoring (HBPM) has emerged as a means of improving diagnostic accuracy, risk stratification, patient adherence, and therapeutic intervention. The definition of hypertension by HBPM is an average BP >135/85 mm Hg. Twelve readings over the course of 3-5 days are sufficient for clinical decision making. Diagnostic accuracy is especially important in the CKD population as approximately half of these patients have either white coat hypertension or masked hypertension. Preliminary data suggest that HBPM outperforms office BP monitoring in predicting progression to end-stage renal disease or death. When combined with additional support such as telemonitoring, medication titration, or behavioral therapy, HBPM results in a sustained improvement in BP control. HBPM must be adapted to provide information on the phenomena of nondipping (absence of nocturnal fall in BP) and reverse dipping (paradoxical increase in BP at night). These diurnal patterns are more prevalent in the CKD population and are important cardiovascular risk factors. Ambulatory BP monitoring provides nocturnal BP readings and unlike HBPM may be reimbursed by Medicare when certain criteria are met. Further studies are needed to determine whether HBPM is cost-effective in the current US healthcare system.

Blood pressure variability assessed by home measurements: a systematic review

Accumulating evidence suggests that day-by-day blood pressure (BP) variability assessed using self-measurements by patients at home (HBPV) provides useful information beyond that of average home BP. This systematic review summarizes the current evidence on day-by-day HBPV. A systematic literature search (PubMed) revealed 22 eligible articles. Independent prognostic value of day-by-day HBPV for cardiovascular events and total mortality was demonstrated in two outcome studies, whereas novel indices of variability had minimal or no independent prognostic ability. Although findings are not consistent among the studies, the evidence suggests that HBPV has an independent role in the progression of preclinical cardiac, arterial and renal damage and is affected by age, gender, average BP and heart rate level, antihypertensive treatment, antihypertensive drug class and other factors. However, there is large diversity among the available studies in the home BP monitoring protocols, the indices used to quantify HBPV and the end points selected for evaluation. Overall, these preliminary data largely based on heterogeneous studies indicate an important and independent role of day-by-day HBPV in the pathogenesis of hypertension-induced cardiovascular damage. Yet, fundamental questions remain unanswered, including the optimal variability index, the optimal home monitoring schedule required, the threshold that defines increased HBPV and the impact of treatment-induced variability change on organ damage and cardiovascular events. Until these questions are adequately addressed in future studies, HBPV should largely remain a research issue with limited practical value for individual patients.