Sex difference in ambulatory blood pressure control associates with risk of ESKD and death in CKD patients receiving stable nephrology care

Epidemiology and referral patterns of patients living with chronic kidney disease in Johannesburg, South Africa: A single centre experience

Chronic kidney disease (CKD) is a significant contributor to the global burden of non-communicable disease. Early intervention may facilitate slowing down of progression of CKD; recognition of at-risk patient groups may improve detection through screening. We retrospectively reviewed the clinical records of 960 patients attending a specialist nephrology outpatient clinic during the period 1 January 2011-31 December 2021. A significant proportion (47.8%) of patients were referred with established CKD stage G4 or G5. Non-national immigration status, previous diagnosis with diabetes, and advancing age were associated with late referral; antecedent diagnosis with HIV reduced the odds of late referral. Black African patients comprised most of the sample cohort and were younger at referral and more frequently female than other ethnicities; non-nationals were younger at referral than South Africans. Hypertension-associated kidney disease was the leading ascribed aetiological factor for CKD (40.7% of cases), followed by diabetic kidney disease (DKD) (19%), glomerular disease (12.5%), and HIV-associated kidney disease (11.8%). Hypertension-related (25.9%) and diabetic (10.7%) kidney diseases were not uncommon in people living with HIV. Advancing age and male sex increased the likelihood of diagnosis with hypertensive nephropathy, DKD and obstructive uropathy; males were additionally at increased risk of HIV-associated kidney disease and nephrotoxin exposure, as were patients of Black African ethnicity. In summary, this data shows that hypertension, diabetes, and HIV remain important aetiological factors in CKD in the South African context. Despite the well-described risk of CKD in these disorders, referral to nephrology services occurs late. Interventions and policy actions targeting at-risk populations are required to improve referral practices.

Sex disparities in mortality and cardiovascular outcomes in chronic kidney disease

Sex (biologically determined) and gender (socially constructed) modulate manifestations and prognosis of a vast number of diseases, including cardiovascular disease (CVD) and chronic kidney disease (CKD). CVD remains the leading cause of death in CKD patients. Population-based studies indicate that women present a higher prevalence of CKD and experience less CVD than men in all CKD stages, although this is not as clear in patients on dialysis or transplantation. When compared to the general population of the same sex, CKD has a more negative impact on women on kidney replacement therapy. European women on dialysis or recipients of kidney transplants have life expectancy up to 44.8 and 19.8 years lower, respectively, than their counterparts of similar age in the general population. For men, these figures stand at 37.1 and 16.5 years, representing a 21% to 20% difference, respectively. Hormonal, genetic, societal, and cultural influences may contribute to these sex-based disparities. To gain a more comprehensive understanding of these differences and their implications for patient care, well-designed clinical trials that involve a larger representation of women and focus on sex-related variables are urgently needed. This narrative review emphasizes the importance of acknowledging the epidemiology and prognosis of sex disparities in CVD among CKD patients. Such insights can guide research into the underlying pathophysiological mechanisms, leading to optimized treatment strategies and ultimately, improved clinical outcomes.

Effects of Nondipping Blood Pressure Changes: A Nephrologist Prospect

Blood pressure (BP) variations depend on various internal, environmental, and behavioral factors. BP fluctuations occur both in normotensive and hypertensive people. Although it fluctuates over the 24-hr day and night, the morning BP increases after waking up and declines throughout sleep. It is typical for BP to decrease by 10% to 20%, while sleeping, known as dipping BP. However, if there is no decrease in nighttime mean systolic BP or a drop of less than 10 mmHg, it is called nondipping BP. Conversely, reverse dipping BP means an increase in mean systolic BP instead of a drop during the night. Reverse dipping is observed in hypertension (HTN), diabetes mellitus (DM), chronic kidney disease (CKD), and obstructive sleep apnea (OSA) syndrome. The introduction of ambulatory BP monitoring (ABPM) led to the emergence of identifying normal and elevated BP patterns. Non-dipping BP increases the risk of cardiovascular system (CVS) complications such as left ventricular hypertrophy, proteinuria, glomerular filtration rate (GFR) reduction, and CKD progression. A loss or blunting of the normal BP profile is recognized as a deleterious variant, and restoring abnormal BP patterns has been reported to significantly impact end-organ damage, morbidity, and mortality. In this non-systematic clinically-oriented, comprehensive review, we aim to update the BP variables and the pathophysiology of nondipping BP and point out the areas which need more investigation from a nephrology perspective because the nondipping BP increases the risk of proteinuria, GFR reduction, and CKD progression. A literature search of PubMed, Google, EMBASE, and Google Scholar was conducted. Checks of selected papers and relevant reviews complemented the electronic search. With improved BP measurement methods, the physiology of BP profile variations is readily detectable during the day and night. A nondipping BP profile is a distinct BP pattern that may have significant end-organ damage effects and therapeutic importance for nephrologists. The pathophysiology of the nondipping BP variant must be clarified to prevent complications, and further investigations are required. Furthermore, there is debate about the best BP index to utilize: systolic BP, diastolic BP, mean arterial pressure, or a mixture of all. All these areas are important and need new research projects.

Gender-Related Differences in the Levels of Ambulatory BP and Intensity of Antihypertensive Treatment in Patients Undergoing Peritoneal Dialysis

Prior studies have shown that among patients with chronic kidney disease not yet on dialysis, the faster progression of kidney injury in men than in women is, at least partly, explained by sex differences in ambulatory blood pressure (BP) control. The present study aimed to investigate potential differences in the levels of ambulatory BP and intensity of antihypertensive treatment between men and women with end-stage kidney disease undergoing long-term peritoneal dialysis (PD). In a case-control design, 48 male PD patients were matched for age and heart failure status with 48 female patients in a 1:1 ratio. Ambulatory BP monitoring was performed with an oscillometric device, the Mobil-O-Graph (IEM, Stolberg, Germany). The BP-lowering medications actually taken by the patients were prospectively recorded. No gender-related differences were observed in 24 h systolic BP (129.0 ± 17.9 vs. 128.5 ± 17.6 mmHg, p = 0.890). In contrast, 24 h diastolic BP was higher in men than in women (81.5 ± 12.1 vs. 76.8 ± 10.3 mmHg, p = 0.042). As compared with women, men were being treated with a higher average number of antihypertensive medications daily (2.4 ± 1.1 vs. 1.9 ± 1.1, p = 0.019) and were more commonly receiving calcium-channel-blockers (70.8% vs. 43.8%, p = 0.007) and β-blockers (85.4% vs. 66.7%, p = 0.031). In conclusion, the present study shows that among PD patients, the levels of ambulatory BP and intensity of antihypertensive treatment are higher in men than in women. Longitudinal studies are needed to explore whether these gender-related differences in the severity of hypertension are associated with worse cardiovascular outcomes for male patients undergoing PD.

Hypertension as Cardiovascular Risk Factor in Chronic Kidney Disease

Hypertension is the leading modifiable cause of premature death and hence one of the global targets of World Health Organization for prevention. Hypertension also affects the great majority of patients with chronic kidney disease (CKD). Both hypertension and CKD are intrinsically related, as hypertension is a strong determinant of worse renal and cardiovascular outcomes and renal function decline aggravates hypertension. This bidirectional relationship is well documented by the high prevalence of hypertension across CKD stages and the dual benefits of effective antihypertensive treatments on renal and cardiovascular risk reduction. Achieving an optimal blood pressure (BP) target is mandatory and requires several pharmacological and lifestyle measures. However, it also requires a correct diagnosis based on reliable BP measurements (eg, 24-hour ambulatory BP monitoring, home BP), especially for populations like patients with CKD where reduced or reverse dipping patterns or masked and resistant hypertension are frequent and associated with a poor cardiovascular and renal prognosis. Even after achieving BP targets, which remain debated in CKD, the residual cardiovascular risk remains high. Current antihypertensive options have been enriched with novel agents that enable to lower the existing renal and cardiovascular risks, such as SGLT2 (sodium-glucose cotransporter-2) inhibitors and novel nonsteroidal mineralocorticoid receptor antagonists. Although their beneficial effects may be driven mostly from actions beyond BP control, recent evidence underline potential improvements on abnormal 24-hour BP phenotypes such as nondipping. Other promising novelties are still to come for the management of hypertension in CKD. In the present review, we shall discuss the existing evidence of hypertension as a cardiovascular risk factor in CKD, the importance of identifying hypertension phenotypes among patients with CKD, and the traditional and novel aspects of the management of hypertensives with CKD.

Dipping Status, Ambulatory Blood Pressure Control, Cardiovascular Disease, and Kidney Disease Progression: A Multicenter Cohort Study of CKD

RATIONALE & OBJECTIVE

Ambulatory blood pressure (BP) monitoring allows concurrent evaluation of BP control and nocturnal BP dipping status, both related to adverse outcomes. However, few studies have assessed the prognostic role of combining information on dipping status and achieved ambulatory BP in patients with chronic kidney disease (CKD).

STUDY DESIGN

Prospective observational cohort study.

SETTING & PARTICIPANTS

906 patients with hypertension and CKD attending 1 of 3 Italian nephrology clinics.

EXPOSURE

Four groups were defined by simultaneously classifying systolic ambulatory BP levels as being at goal (daytime SBP <135 and nighttime SBP <120 mm Hg) or above goal, and the presence or absence of nocturnal dipping (nighttime to daytime SBP ratio of <0.9 versus ≥0.9).

OUTCOME

The composite of time to initiation of maintenance dialysis or estimated glomerular filtration rate (eGFR) decline ≥50%, and the composite of fatal and nonfatal cardiovascular events.

ANALYTICAL APPROACH

Multivariable Cox proportional hazards models were used to estimate risks of kidney disease progression and cardiovascular disease in the 4 exposure groups where nocturnal dipping with systolic ambulatory BP at goal was the reference group.

RESULTS

The mean patient age was 63.8 years, 61% were male, and 26.4% had diabetes; eGFR was 41.1 ± 20.8 mL/min/1.73 m². The dipping prevalence in each of the 4 groups was as follows: nocturnal dipping with ambulatory BP at goal, 18.6%; no nocturnal dipping with ambulatory BP at goal, 20.5%; nocturnal dipping with ambulatory BP above goal, 11.8%; and no nocturnal dipping with ambulatory BP above goal, 49.1%. Among patients with ambulatory BP above goal, the risk of cardiovascular events was greater in the absence (HR, 2.79 [95% CI, 1.64-4.75]) and presence (HR, 2.05 [95% CI, 1.10-3.84]) of nocturnal dipping. The same held true for risk of kidney disease progression (HRs of 2.40 [95% CI, 1.58-3.65] and 2.11 [95% CI, 1.28-3.48] in the absence and presence of nocturnal dipping, respectively). Patients at the ambulatory BP goal but who did not experience nocturnal dipping had an increased risk of the cardiovascular end point (HR, 2.06 [95% CI, 1.15-3.68]) and the kidney disease progression outcome (HR, 1.82 [95% CI, 1.17-2.82]).

LIMITATIONS

Lack of a diverse cohort (all those enrolled were White). Residual uncontrolled confounding.

CONCLUSIONS

Systolic ambulatory BP above goal or the absence of nocturnal dipping, regardless of ambulatory BP, is associated with higher risks of cardiovascular disease and kidney disease progression among patients with CKD.

PLAIN-LANGUAGE SUMMARY

Among patients with chronic kidney disease (CKD), ambulatory blood pressure (BP) monitoring improves the identification of individuals at high risk of clinical disease outcomes. Those with uncontrolled ambulatory BP are known to have a higher risk of developing cardiovascular disease and kidney disease progression, particularly when their ambulatory BP does not decline by at least 10% at night. Whether this is also true for patients with presence of optimal ambulatory BP levels but a BP pattern of no nighttime decline is largely unknown. We measured ambulatory BP in 900 Italian patients with CKD and followed them for several years. We found that, independent of ambulatory BP level, the absence of nighttime reductions in BP was associated with worsening of CKD and more frequent cardiovascular events. The absence of nighttime declines in BP is an independent risk factor for adverse events among patients with CKD. Future studies are needed to examine whether treating the absence of nighttime declines in BP improves clinical outcomes.

Thiazide diuretics are back in CKD: the case of chlorthalidone

Sodium and volume excess is the fundamental risk factor underlying hypertension in chronic kidney disease (CKD) patients, who represent the prototypical population characterized by salt-sensitive hypertension. Low salt diets and diuretics constitute the centrepiece for blood pressure control in CKD. In patients with CKD stage 4, loop diuretics are generally preferred to thiazides. Furthermore, thiazide diuretics have long been held as being of limited efficacy in this population. In this review, by systematically appraising published randomized trials of thiazides in CKD, we show that this class of drugs may be useful even among people with advanced CKD. Thiazides cause a negative sodium balance and reduce body fluids by 1-2 l within the first 2-4 weeks and these effects go along with improvement in hypertension control. The recent CLICK trial has documented the antihypertensive efficacy of chlorthalidone, a long-acting thiazide-like diuretic, in stage 4 CKD patients with poorly controlled hypertension. Overall, chlorthalidone use could be considered in patients with treatment-resistant hypertension when spironolactone cannot be administered or must be withdrawn due to side effects. Hyponatremia, hypokalaemia, volume depletion and acute kidney injury are side effects that demand a vigilant attitude by physicians prescribing these drugs. Well-powered randomized trials assessing hard outcomes are still necessary to more confidently recommend the use of these drugs in advanced CKD.

Sex differences in ambulatory blood pressure levels, control and phenotypes of hypertension in hemodialysis patients

BACKGROUND AND AIMS

Ambulatory blood pressure (BP) control is worse in men than women with chronic kidney disease or kidney transplantation. So far, no study investigated possible sex differences in the prevalence, control, and phenotypes of BP according to predialysis and 48-h ambulatory blood pressure monitoring (ABPM) in hemodialysis patients. Further, no study has evaluated the diagnostic accuracy of predialysis BP in male and female hemodialysis patients.

METHOD

One hundred and twenty-nine male and 91 female hemodialysis patients that underwent 48-h ABPM were included in this analysis. Hypertension was defined as: (1) predialysis SBP ≥140 or DBP ≥90 mmHg or use of antihypertensive agents, (2) 48-h SBP ≥130 or DBP ≥80 mmHg or use of antihypertensive agents.

RESULTS

Predialysis SBP did not differ between groups, while DBP was marginally higher in men. 48-h SBP (137.2 ± 17.4 vs. 132.2 ± 19.2 mmHg, P  = 0.045), DBP (81.9 ± 12.1 vs. 75.9 ± 11.7 mmHg, P  < 0.001) and daytime SBP/DBP were higher in men. The prevalence of hypertension was not different between groups with the use of predialysis BP or 48-h ABPM (92.2% vs. 89%, P  = 0.411). However, concordant lack of control was more frequent in men than women (65.3% vs. 49.4%, P  = 0.023). The prevalence of white-coat and masked hypertension did not differ between groups; the misclassification rate with the use of predialysis BP was marginally higher in women. In both sexes, predialysis BP showed low accuracy and poor agreement with ABPM for diagnosing ambulatory hypertension [area-under-the-curve in receiver-operating-curve analyses (SBP/DBP): men, 0.681/0.802, women: 0.586/0.707].

CONCLUSION

Ambulatory BP levels are higher in male than female hemodialysis patients. Although hypertension prevalence is similar between sexes, men have worse rates of control. The diagnostic accuracy of predialysis BP was equally poor in men and women.

Sex Differences in Cardiovascular Consequences of Hypertension, Obesity, and Diabetes: JACC Focus Seminar 4/7

It has long been recognized that there are significant differences between the sexes affecting prevalence, incidence, and severity over a broad range of diseases. Until the early 1990s, the limited research conducted on women's health focused primarily on diseases affecting fertility and reproduction, and women were excluded from most clinical trials. For these reasons, the prevention, diagnosis, and treatment of serious chronic diseases such as cardiovascular disease in women continue to be based primarily on findings in men, and sex-specific clinical guidelines are mostly lacking. Hypertension, obesity, and diabetes, interrelated risk factors for cardiovascular disease, differ by sex in terms of prevalence and adverse effects as well as by genetics and biology. Research is needed to understand sex differences in hypertension, obesity, and diabetes to optimally inform sex-specific prevention, diagnosis, and treatment strategies for women and men. In this way, sex-specific clinical guidelines can be developed where warranted.

The Other Way Around: Living With Chronic Kidney Disease From the Perspective of Men

A wealth of evidence has suggested sex (biological) and gender (sociocultural) differences in the prevalence, progression, and outcomes of persons with chronic kidney disease. Much of this evidence tends to emphasize differences in which women are disadvantaged, and less attention is paid to findings in which women are better off or similar to men. However, gender medicine recognizes that men and women have different disease determinants, presentation, and attitudes, and it pertains to both sexes. In this review, we revisit chronic kidney disease through the perspective of men, and illustrate a population segment at need of stringent preventative and management strategies.

Sex differences in ambulatory blood pressure levels, control, and phenotypes of hypertension in kidney transplant recipients

OBJECTIVES

Ambulatory blood pressure (BP) control is worse in men compared with women with chronic kidney disease (CKD) and this may partially explain the faster CKD progression in men. This is the first study investigating possible sex differences in prevalence, control and phenotypes of hypertension in kidney transplant recipients (KTRs) with office-BP and 24-h ambulatory BP monitoring (ABPM).

METHODS

This cross-sectional study included 136 male and 69 female stable KTRs who underwent office-BP measurements and 24-h ABPM. Hypertension thresholds for office and ambulatory BP were defined according to the 2017 ACC/AHA and 2021 KDIGO guidelines for KTRs.

RESULTS

Age, time from transplantation, eGFR and history of major comorbidities did not differ between groups. Office SBP/DBP levels were insignificantly higher in men than women (130.3 ± 16.3/77.3 ± 9.4 vs. 126.4 ± 17.8/74.9 ± 11.5 mmHg; P = 0.118/0.104) but daytime SBP/DBP was significantly higher in men (128.5 ± 12.1/83.0 ± 8.2 vs. 124.6 ± 11.9/80.3 ± 9.3 mmHg; P = 0.032/P = 0.044). No significant between-group differences were detected for night-time BP. The prevalence of hypertension was similar by office-BP criteria (93.4 vs. 91.3%; P = 0.589), but higher in men than women with ABPM (100 vs. 95.7%; P = 0.014). The use of ACEIs/ARBs and CCBs was more common in men. Office-BP control was similar (43.3 vs. 44.4%, P = 0.882), but 24-h control was significantly lower in men than women (16.9 vs. 30.3%; P = 0.029). White-coat hypertension was similar (5.1 vs. 7.6%; P = 0.493), whereas masked hypertension was insignificantly more prevalent in men than women (35.3 vs. 24.2%; P = 0.113).

CONCLUSION

BP levels, hypertension prevalence and control are similar by office criteria but significantly different by ABPM criteria between male and female KTRs. Worse ambulatory BP control in male compared with female KTRs may interfere with renal and cardiovascular outcomes.