Apparent Treatment-Resistant Hypertension and Cardiovascular Risk in Hemodialysis Patients: Ten-Year Outcomes of the Q-Cohort Study

Apparent Treatment-Resistant Hypertension in the First Year Associated With Cardiovascular Mortality in Peritoneal Dialysis Patients

BACKGROUND

Few reports have focused on the association between apparent treatment-resistant hypertension (aTRH) and cardiovascular (CV) mortality in peritoneal dialysis (PD) population, thus we conducted this retrospective cohort to explore it.

METHODS

This was a retrospective cohort study conducted from January 2011 to January 2020 with PD patients in 4 Chinese dialysis centers. aTRH was defined according to the American College of Cardiology and American Heart Association guidelines. aTRH duration was calculated as the total number of months when patients met the diagnostic criteria in the first PD year. The primary outcome was CV mortality, and the secondary outcomes were CV events, all-cause mortality, combined endpoint (all-cause mortality and transferred to hemodialysis [HD]), and PD withdrawal (all-cause mortality, transferred to HD, and kidney transplantation). Cox proportional hazards models were used to assess the association.

RESULTS

A total of 1,422 patients were finally included in the analysis. During a median follow-up period of 26 months, 83 (5.8%) PD patients incurred CV mortality. The prevalence of aTRH was 24.1%, 19.9%, and 24.6% at 0, 3, and 12 months after PD initiation, respectively. Overall, aTRH duration in the first PD year positively associated with CV mortality (per 3 months increment, adjusted hazards ratio [HR], 1.29; 95% confidence interval 1.10, 1.53; P = 0.002). After categorized, those with aTRH duration more than 6 months presented the highest adjusted HR of 2.92. Similar results were found for secondary outcomes, except for the CV event.

CONCLUSIONS

Longer aTRH duration in the first PD year is associated with higher CV mortality and worse long-term clinical outcomes. Larger studies are warranted to confirm these findings.

CLINICAL TRIALS REGISTRATION

There is no clinical trial registration for this retrospective study.

Resistant Hypertension in Dialysis: Epidemiology, Diagnosis, and Management

Apparent treatment-resistant hypertension is defined as an elevated BP despite the use of ≥3 antihypertensive medications from different classes or the use of ≥4 antihypertensives regardless of BP levels. Among patients receiving maintenance hemodialysis or peritoneal dialysis, using this definition, the prevalence of apparent treatment-resistant hypertension is estimated to be between 18% and 42%. Owing to the lack of a rigorous assessment of some common causes of pseudoresistance, the burden of true resistant hypertension in the dialysis population remains unknown. What distinguishes apparent treatment-resistance from true resistance is white-coat hypertension and adherence to medications. Accordingly, the diagnostic workup of a dialysis patient with apparent treatment-resistant hypertension on dialysis includes the accurate determination of BP control status with the use of home or ambulatory BP monitoring and exclusion of nonadherence to the prescribed antihypertensive regimen. In a patient on dialysis with inadequately controlled BP, despite adherence to therapy with maximally tolerated doses of a β -blocker, a long-acting dihydropyridine calcium channel blocker, and a renin-angiotensin system inhibitor, volume-mediated hypertension is the most important treatable cause of resistance. In daily clinical practice, such patients are often managed with intensification of antihypertensive therapy. However, this therapeutic strategy is likely to fail if volume overload is not adequately recognized or treated. Instead of increasing the number of prescribed BP-lowering medications, we recommend diet and dialysate restricted in sodium to facilitate achievement of dry weight. The achievement of dry weight is facilitated by an adequate time on dialysis of at least 4 hours for delivering an adequate dialysis dose. In this article, we review the epidemiology, diagnosis, and management of resistant hypertension among patients on dialysis.

Resistant hypertension in dialysis

Hypertension is the most common finding in chronic kidney disease patients, with prevalence ranging from 60% to 90% depending on the stage and etiology of the disease. It is also a significant independent risk factor for cardiovascular disease, progression to end-stage kidney disease and mortality. According to the current guidelines, resistant hypertension is defined in the general population as uncontrolled blood pressure on three or more antihypertensive drugs in adequate doses or when patients are on four or more antihypertensive drug categories irrespective of the blood pressure control, providing that antihypertensive treatment included diuretics. The currently established definitions of resistant hypertension are not directly applicable to the end-stage kidney disease setting. The diagnosis of true resistant hypertension requires confirmation of adherence to therapy and confirmation of uncontrolled blood pressure values by ambulatory blood pressure measurement or home blood pressure measurement. In addition, the term "apparent treatment-resistant hypertension," defined as an uncontrolled blood pressure on three or more antihypertensive medication classes, or use of four or more medications regardless of blood pressure level was introduced. In this comprehensive review we focused on the definitions of hypertension, and therapeutic targets in patients on renal replacement therapy, including the limitations and biases. We discussed the issue of pathophysiology and assessment of blood pressure in the dialyzed population, management of resistant hypertension as well as available data on prevalence of apparent treatment-resistant hypertension in end-stage kidney disease. To conclude, larger sample-size and even higher quality studies about drug adherence should be conducted in the population of patients with the end-stage kidney disease who are on dialysis. It also should be determined how and when blood pressure should be measured in the group of dialysis patients. Additionally, it should be stated what the target blood pressure values in this group of patients really are. The definition of resistant hypertension in this group should be revisited, and its relationship to both subclinical and clinical endpoints should be established.

Apparently Resistant Hypertension in Polish Hemodialyzed Population: Prevalence and Risk Factors

BACKGROUND

The aim of this study was to assess the prevalence, characteristics, and determinants of apparent treatment-resistant hypertension (aTRH) in an unselected large population of patients with end-stage kidney disease (ESKD) treated with hemodialysis (HD) throughout the country.

METHODS

A database of 5879 patients (mean age 65.2 ± 14.2 years, 60% of males receiving hemodialysis) was obtained from the biggest provider of hemodialysis in the country. Hypertension and aTRH were defined using pre- or/and post-dialysis BP values. Patients with and without aTRH (non-aTRH) were compared.

RESULTS

Using pre- and post-dialysis criteria, hypertension was diagnosed in 90.7% and 89.1% of subjects, respectively. According to pre- and post-dialysis blood pressure criteria, aTRH incidences were 40.9% and 38.4%, respectively. The hypertensive patients with aTRH versus non-aTRH were younger, had a higher rate of cardiovascular disease, lower dialysis vintage, shorter time on dialysis, higher eKt/V, higher ultrafiltration, higher pre- and post-dialysis BP and HR, and higher use of antihypertensive drugs. Factors that increase the risk of aTRH according to both pre- and post-dialysis BP criteria were age-OR 0.99 [0.98-0.99] and 0.99 [0.98-0.99], the history of CVD 1.26 [1.08-1.46] and 1.30 [1.12-1.51], and diabetes 1.26 [1.08-1.47] and 1.28 [1.09-1.49], adjusted OR with 95% CI.

CONCLUSIONS

In the real-life world, as much as 40% of HD patients may have aTRH. In ESKD HD patients, aTRH seems to be multifactorial, influenced by patient-related rather than dialysis-related factors. Various definitions of aTRH preclude easy comparisons between studies.

Prevalence of Apparent Treatment-Resistant Hypertension in ESKD Patients Receiving Peritoneal Dialysis

BACKGROUND

Apparent treatment-resistant hypertension (aTRH) is defined as failure to achieve adequate blood pressure (BP) control despite taking ≥3 antihypertensive medications from different categories or when taking ≥4 antihypertensives regardless of BP levels.

METHODS

In this cross-sectional study, we estimated the prevalence of aTRH in 140 patients receiving long-term peritoneal dialysis (PD) in four centers of Northern Greece, using the "gold-standard" method of ambulatory BP monitoring for the assessment of BP control status. The presence of subclinical overhydration was evaluated with the method of bioimpedance spectroscopy (BIS).

RESULTS

Incorporating the diagnostic threshold of 130/80 mmHg for 24-hour ambulatory BP, the prevalence of aTRH in the overall study population was 30%. Compared to patients without aTRH, those with aTRH tended to be older in age, had higher PD vintage, had higher dialysate-to-plasma creatinine ratio, had more commonly history of diabetes mellitus, and were more commonly current smokers. With respect to the volume status, the overhydration index in BIS was higher in those with versus without aTRH (2.0 ± 1.9 L vs. 1.1 ± 2.0 L, P < 0.05). The prevalence of volume overload, defined as an overhydration index in BIS > 2.5 L, was also higher in the subgroup of patients with aTRH (38.1% vs. 18.4, P = 0.01).

CONCLUSION

The present study showed that among patients on PD, the prevalence of aTRH was 30%. However, 38% of PD patients with aTRH had subclinical overhydration in BIS, suggesting that the achievement of adequate volume control may be a therapeutic opportunity to improve the management of hypertension in this high-risk patient population.The present study showed that among patients on PD, the prevalence of aTRH was 30%. However, 38% of PD patients with aTRH had subclinical overhydration in BIS, suggesting that the achievement of adequate volume control may be a therapeutic opportunity to improve the management of hypertension in this high-risk patient population.

CLINICAL TRIALS REGISTRATION

Trial Number NCT03607747.

Current apparent treatment-resistant hypertension in patients undergoing peritoneal dialysis: A multi-center cross-sectional study

Apparent treatment‐resistant hypertension (aTRH) is the most commonly used term to report resistant hypertension (RH) and is considered as a common problem in dialysis population. However, few reports have focused on peritoneal dialysis (PD) hypertensive patients. The authors conducted a multi‐center cross‐sectional study involving 1789 PD patients from nine centers in Guangdong, China. The prevalence of aTRH was estimated by home blood pressure (BP) monitoring. Evaluating drug adherence through Eight‐item Morisky Medication Adherence Scale (MMAS‐8) and pill counting was performed to assess RH in one PD center. Related factors of aTRH were analyzed using logistic regression analysis. The prevalence of aTRH in PD patients was estimated at 42.2% (755 out of 1789 hypertensive patients) based on home BP. Of those, 91.4% patients were classified as uncontrolled RH, 2.0% as controlled RH, and 6.6% as refractory hypertension. The prevalence of RH was 40.6% and 41.9% among those with medium/high adherence based on the MMAS‐8 scores and the pill counting rate, respectively. PD patients who were younger, with higher body mass index, with lower serum albumin and poorer dialysis adequacy were significantly associated with higher aTRH incident. In conclusion, the present study demonstrates a high prevalence of aTRH in PD population, which occurs in about two in five treated hypertensive patients. Nutritional status and dialysis adequacy might tightly associate with aTRH.

Association of the nutritional risk index for Japanese hemodialysis patients with long-term mortality: The Q-Cohort Study

BACKGROUND

Protein-energy wasting (PEW) is a risk factor for mortality in patients undergoing hemodialysis. Recently, a nutritional risk index for Japanese hemodialysis patients (NRI-JH) has been proposed as a surrogate index of PEW. However, no study has determined the association of the NRI-JH with long-term mortality in patients undergoing hemodialysis. Furthermore, the validity of the NRI-JH has not been confirmed.

METHODS

In total, 3046 patients undergoing hemodialysis and registered in the Q-Cohort Study were followed up for 10 years. The NRI-JH was calculated on the basis of body mass index and serum levels of albumin, total cholesterol, and creatinine. The patients were divided into four groups according to the NRI-JH scores: 0-3 (G1, n = 1343), 4-7 (G2, n = 1136), 8-10 (G3, n = 321), and 11-13 (G4, n = 246). We examined the association between the NRI-JH and the 4-year and 10-year risks of all-cause, cardiovascular, and infection-related deaths using the Cox proportional hazards model.

RESULTS

During the follow-up period, 647 patients died during the first 4 years, and 1503 patients died within 10 years. The 4-year prognosis was analyzed and compared with the lowest NRI-JH score group. Multivariable-adjusted hazard ratios (95% confidence intervals) for all-cause death were 1.93 (1.57-2.38), 2.68 (2.05-3.50), and 3.16 (2.40-4.16) in the G2, G3, and G4 groups, respectively. Similarly, a higher NRI-JH score was associated with an increased risk of cardiovascular and infection-related deaths.

CONCLUSION

A higher NRI-JH score was associated with an increased risk of long-term mortality in patients undergoing maintenance hemodialysis.

TRIAL REGISTRATION

The study protocol was registered in the University Hospital Medical Information Network (UMIN) clinical trial registry (UMIN ID: 000000556).

Clinical epidemiological analysis of cohort studies investigating the pathogenesis of kidney disease

In recent years, large cohort studies of patients with chronic kidney disease (CKD) have been established all over the world. These studies have attempted to analyze the pathogenesis of CKD using a large body of published evidence. The design of cohort studies is characterized by the measurement of the exposure prior to the occurrence of the outcome, which has the advantage of clarifying the temporal relationship between predictors and outcomes and estimating the strength of the causal relationship between predictors and multiple outcomes. Recent advances in biostatistical analysis methods, such as propensity scores and risk prediction models, are facilitating causal inference using higher quality evidence with greater precision in observational studies. In this review, we will discuss clinical epidemiological research of kidney disease based on the analysis of observational cohort data sets, with a focus on our previous studies.

Impact of Multivascular Disease on Cardiovascular Mortality and Morbidity in Patients Receiving Hemodialysis: Ten-Year Outcomes of the Q-Cohort Study

AIM

Multivascular disease, indicating concurrent arteriosclerotic lesions in a number of different vascular beds, is an independent risk factor for recurrent ischemic events in the general population. However, the impact of multivascular disease on the risk of developing cardiovascular disease has not been fully evaluated in patients receiving hemodialysis.

METHODS

A total of 3,504 hemodialysis patients were prospectively followed for 10 years. In this study, multivascular disease was defined as the coexistence of coronary artery disease and stroke. We examined the relationship between multivascular disease and the occurrence of composite cardiovascular endpoint, consisting of cardiovascular death, nonfatal coronary artery disease, nonfatal stroke, and peripheral artery disease.

RESULTS

The proportion of participants with multivascular disease was 5.7% (n=200) at baseline. During follow-up (median, 106.6 months; interquartile range, 50.1-121.8 months), 1,311 patients experienced the composite endpoint, which was defined as at least one of the following: cardiovascular death (n=620), nonfatal coronary artery disease (n=318), nonfatal stroke (n=340), and peripheral artery disease (n=257). Compared with the group with no history of cardiovascular disease, the risk of experiencing the composite endpoint increased significantly with higher numbers of injured vascular beds in patients with single vascular disease (hazard ratio, 1.68; 95% confidence interval, 1.49-1.89) and in those with multivascular disease (hazard ratio, 2.11; 95% confidence interval, 1.71-2.60). In a multivariable analysis, multivascular disease was an independent predictor of cardiovascular events, in addition to diabetes, aging, and hypertension.

CONCLUSIONS

This study clearly demonstrated that multivascular disease was a powerful predictor for cardiovascular mortality and morbidity in patients receiving hemodialysis.

Apparent Treatment-Resistant Hypertension Assessed by Office and Ambulatory Blood Pressure in Chronic Kidney Disease-A Report from the Chronic Renal Insufficiency Cohort Study

Background

Apparent treatment-resistant hypertension is common in patients with CKD. Whether measurement of 24-hour ambulatory BP monitoring is valuable for risk-stratifying patients with resistant hypertension and CKD is unclear.

Methods

We analyzed data from the Chronic Renal Insufficiency Cohort study, a prospective study of participants (n=1186) with CKD. Office BP was measured using standardized protocols; ambulatory BP was measured using Spacelabs monitors. Apparent treatment-resistant hypertension was defined on the basis of office BP, ambulatory BP monitoring, and use of more than three antihypertensive medications. Outcomes were composite cardiovascular disease, kidney outcomes, and mortality. Groups were compared using Cox regression analyses with a control group of participants without apparent treatment-resistant hypertension.

Results

Of 475 participants with apparent treatment-resistant hypertension on the basis of office BP, 91.6% had apparent treatment-resistant hypertension confirmed by ambulatory BP monitoring. Unadjusted event rates of composite cardiovascular disease, kidney outcomes, and mortality were higher in participants with ambulatory BP monitoring-defined apparent treatment-resistant hypertension compared with participants without apparent treatment-resistant hypertension. In adjusted analyses, the risks of composite cardiovascular disease (hazard ratio, 1.27; 95% confidence interval [95% CI], 0.59 to 2.7), kidney outcomes (hazard ratio, 1.68; 95% CI, 0.88 to 3.21), and mortality (hazard ratio, 1.27; 95% CI, 0.5 to 3.25) were not statistically significantly higher in participants with ambulatory BP monitoring-defined apparent treatment-resistant hypertension compared with participants without apparent treatment-resistant hypertension.

Conclusions

In our study population with CKD, most patients with apparent treatment-resistant hypertension defined on the basis of office BP have apparent treatment-resistant hypertension confirmed by ambulatory BP monitoring. Although ABPM-defined apparent treatment-resistant hypertension was not independently associated with clinical outcomes, it identified participants at high risk for adverse clinical outcomes.

Higher Cholesterol Level Predicts Cardiovascular Event and Inversely Associates With Mortality in Hemodialysis Patients: 10-Year Outcomes of the Q-Cohort Study

The prevalence of atherosclerotic diseases is higher in hemodialysis patients. The aim of the current study was to investigate associations between cholesterol level and the incidences of cardiovascular disease (CVD) and mortality in hemodialysis patients. A total of 3517 participants undergoing maintenance hemodialysis were followed up for 10 years. Total cholesterol (TC) level was divided into quartile in baseline data. The multivariate analyses were calculated by a Cox proportional hazards model. The incidences of ischemic heart disease (IHD), peripheral artery disease (PAD), and CVD were significantly positively associated with higher cholesterol levels after adjustment for confounding factors (P < 0.01, P = 0.04, and P < 0.01, respectively). Furthermore, the incidences of cancer-associated mortality and all-cause mortality were significantly positively associated with lower cholesterol levels after adjustment for confounding factors (both P < 0.01). The lowest TC level at all-cause mortality risk was 179 mg/dL. From these results, higher TC predicts IHD, PAD, and CVD events, and lower TC predicts cancer-associated mortality and all-cause mortality in patients undergoing maintenance hemodialysis.