Post-menopausal hormone use and albuminuria

Sex hormones and the risk of cardiovascular disease and mortality in male and female patients with chronic kidney disease: A systematic review and meta-analysis

Patients with chronic kidney disease (CKD) commonly experience sex hormone disturbances, which may be associated with the risk of cardiovascular disease (CVD) and mortality. This review aimed to systematically evaluate current findings on the association of sex hormone levels with the risk of CVD events and mortality (CVD and all-cause) in the CKD population. Articles were systematically searched in CINAHL, Cochrane, and PubMed. A total of 1739 articles were independently screened by two reviewers and 17 prospective cohort studies were included. The clinical conditions of the patients were those with non-dialysis CKD [mean/median estimated glomerular filtration rate (eGFR) between 15-51 ml/min/1.73 m2 ] and those on chronic dialysis (mean/median vintage between 6-125 months). The sample size ranged from 111 to 2419 and the mean/median age of subjects ranged from 52 to 72 years. The sex hormones studied were testosterone, estradiol, prolactin, dehydroepiandrosterone sulfate, and relaxin. A random-effects model was used to generate a pooled hazard ratio (HR) to evaluate the association of total testosterone levels with the risk of CVD and all-cause mortality. Most studies examined total testosterone levels (11 out of 17 studies) and studied only male patients (12 out of 17 studies). A lower total testosterone level was associated with a higher risk of CVD mortality [HR 4.37 (95% CI 1.40-13.65)] and all-cause mortality [1.96 (1.35-2.83)] in males with CKD. To conclude, there is a strong need for additional studies examining the association of sex hormones with cardiovascular and mortality risk in female patients with CKD.

Occupational sedentary behavior and prediction of proteinuria in young to middle-aged adults: a retrospective cohort study

BACKGROUND

Although sedentary behavior is a risk factor of cardiometabolic diseases and mortality, little information is available about a clinical impact of occupational sedentary behavior on chronic kidney disease (CKD).

METHODS

The present retrospective cohort study included 10,212 workers of a national university in Japan who underwent annual health checkups between April 2006 and March 2013. Main exposure of interest was self-reported occupational sedentary behavior at the baseline visit. The outcome was the incidence of proteinuria defined as dipstick urinary protein of 1 + or more. The association between sedentary workers and the incidence of proteinuria was assessed using Cox proportional hazards models adjusting for clinically relevant factors, including television viewing time, the major home sedentary behavior.

RESULTS

During median 4.8 years (interquartile range 2.1-7.9) of the observational period, the incidence of proteinuria was observed in 597 (12.0%) males and 697 (13.3%) females. In males, sedentary workers were identified as a significant predictor of proteinuria (multivariable-adjusted hazard ratio of non-sedentary and sedentary workers: 1.00 [reference] and 1.35 [1.11-1.63]), along with longer television viewing time (< 30 min, 30-60 min, 1-2 h, 2-3 h, and > 3 h/day: 1.15 [0.93-1.42], 1.00 [reference], 1.24 [1.00-1.53], 1.41 [1.03-1.93], and 1.77 [1.13-2.76]), whereas not daily exercise time. In females, neither sedentary workers nor television viewing time was associated with the incidence of proteinuria.

CONCLUSIONS

In conclusion, male sedentary workers were at high risk of proteinuria. Occupational sedentary behavior may be a potentially modifiable target for the prevention of CKD.

Hormone therapy and urine protein excretion: a multiracial cohort study, systematic review, and meta-analysis

OBJECTIVE

Experimental models suggest estrogen has a renoprotective effect, but human studies show variable results. Our objective was to study the association of hormone therapy (HT) and albuminuria in postmenopausal women and to synthesize the results with outcomes from prior studies.

METHODS

We analyzed data from postmenopausal women who participated in the second study visit (2000-2004) of the Genetic Epidemiology Network of Arteriopathy (GENOA) study. The exposure was self-reported HT use and the outcome was albuminuria (urine albumin-to-creatinine ratio >25 mg/g creatinine). We also conducted a systematic review and meta-analysis on the association of HT and urine protein in postmenopausal women. Continuous and dichotomous measures of protein excretion were converted to a standardized mean difference (SMD) for each study.

RESULTS

In the GENOA cohort (n = 2,217), there were fewer women with albuminuria among HT users than nonusers (9% vs 19%, P < 0.001). HT use was associated with decreased odds of albuminuria (odds ratio 0.65, 95% confidence interval (CI), 0.45-0.95), after adjusting for significant differences in age, race, education, comorbidities, and the age at and cause of menopause. The SMD of the effect of HT on urine proteinuria/albuminuria in the randomized control trials (n = 3) was 0.02 (95% CI, -0.29 to 0.33) and -0.13 (95% CI, -0.31 to 0.05) in the observational studies (n = 9). There was significantly less albuminuria among HT users (SMD -0.15, 95% CI, -0.27 to -0.04) in the 9 studies that only reported albuminuria as an outcome and in the 10 studies with a comparator arm (SMD -0.15, 95% CI, -0.26 to -0.04).

CONCLUSIONS

HT is associated with decreased odds of albuminuria, but some of the observed benefits may be related to reported outcomes, the presence of a comparator arm, and the type of study design.

Sex Hormones and Measures of Kidney Function in the Diabetes Prevention Program Outcomes Study

CONTEXT

Despite sex differences in chronic kidney disease (CKD) onset and progression, it is unclear whether endogenous sex hormones are associated with kidney function in persons without CKD.

DESIGN AND METHODS

We conducted a secondary analysis of the Diabetes Prevention Program (DPP) and its follow-up observational study, the DPP Outcomes Study, over 11 years. Participants included overweight and glucose-intolerant men (n = 889) and pre- and postmenopausal women (n = 1281) not using exogenous sex hormones and whose urine albumin-to-creatinine ratio (ACR) was <30 mg/g and normal estimated glomerular filtration ratio (eGFR) was ≥60 mL/min/1.73 m2 at randomization. We examined the association between sex hormone levels and incidence of low eGFR and/or ACR ≥30 mg/g on at least one measurement.

RESULTS

At randomization, the mean (SD) eGFR was 94 (15) mL/min/1.73 m2; the median ACR (interquartile range) was 4.5 (3.3 to 7.6) mg/g. During follow-up, 187 men (24.6%) and 263 women (24.2%) had incident albuminuria and 136 men (17.9%) and 123 women (11.3%) had incident low eGFR. Among men, higher baseline sex hormone-binding globulin (SHBG) level was associated with reduced low eGFR risk (hazard ratio per SD, 0.80; 95% CI, 0.57 to 0.90) in adjusted analyses. No significant associations were observed among women. There were significant interactions between sex steroid levels and low eGFR by randomization arm.

CONCLUSION

Sex steroids were not associated with development of low eGFR or albuminuria. Among men, higher SHBG level was associated with reduced risk of low eGFR on at least one measurement.

CKD in Patients with Bilateral Oophorectomy

BACKGROUND AND OBJECTIVES

Premenopausal women who undergo bilateral oophorectomy are at a higher risk of morbidity and mortality. Given the potential benefits of estrogen on kidney function, we hypothesized that women who undergo bilateral oophorectomy are at higher risk of CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We performed a population-based cohort study of 1653 women residing in Olmsted County, Minnesota who underwent bilateral oophorectomy before age 50 years old and before the onset of menopause from 1988 to 2007. These women were matched by age (±1 year) to 1653 referent women who did not undergo oophorectomy. Women were followed over a median of 14 years to assess the incidence of CKD. CKD was primarily defined using eGFR (eGFR<60 ml/min per 1.73 m2 on two occasions >90 days apart). Hazard ratios were derived using Cox proportional hazards models, and absolute risk increases were derived using Kaplan-Meier curves at 20 years. All analyses were adjusted for 17 chronic conditions present at index date, race, education, body mass index, smoking, age, and calendar year.

RESULTS

Women who underwent bilateral oophorectomy had a higher risk of eGFR-based CKD (211 events for oophorectomy and 131 for referent women; adjusted hazard ratio, 1.42; 95% confidence interval, 1.14 to 1.77; absolute risk increase, 6.6%). The risk was higher in women who underwent oophorectomy at age ≤45 years old (110 events for oophorectomy and 60 for referent women; adjusted hazard ratio, 1.59; 95% confidence interval, 1.15 to 2.19; absolute risk increase, 7.5%).

CONCLUSIONS

Premenopausal women who undergo bilateral oophorectomy, particularly those ≤45 years old, are at higher risk of developing CKD, even after adjusting for multiple chronic conditions and other possible confounders present at index date.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2018_10_11_CJASNPodcast_18_1.

Klotho and Postmenopausal Hormone Replacement Therapy in Women with Chronic Kidney Disease

Kidney function is highly susceptible to age-related changes, with chronic kidney disease (CKD) serving as an important cause of morbidity and mortality in older patients. The prevalence of CKD in Korea is higher among the elderly, relative to the general population, with the most significant increases seen following the onset of menopause. Under normal conditions, estrogen attenuates renal superoxide production and protects the kidney from oxidative damage. As estrogen levels are known to decrease by as much as 80% during menopause, this represents a significant risk for older women. Postmenopausal hormone replacement therapy (HRT) modulates the renin-angiotensin system, thereby reducing the progressive deterioration of renal function. Use of estrogen-based HRT has been shown to ameliorate renal function in postmenopausal women, and delay CKD progression. Renal expression of klotho, an important suppressor of aging, is markedly decreased in CKD patients, making it a promising candidate for use as a prognostic biomarker in CKD. Here, we review the key links between renal function, sex, age, and estrogen levels during menopause, and discuss the use of postmenopausal HRT in CKD attenuation.

Sex Hormone Status in Women With Chronic Kidney Disease: Survey of Nephrologists' and Renal Allied Health Care Providers' Perceptions

Background

Chronic kidney disease (CKD) in reproductive-age women is accompanied by menstrual and fertility disorders and premature menopause.

Objective

We sought to determine nephrologists' and allied health care providers' perceptions on management of sex hormone status in women with CKD.

Methods

An anonymous, Internet-based survey was sent to nephrology society members from Canada, Australia, New Zealand, and the United Kingdom, and the Canadian Association of Nephrology Nurses and Technologists (February-November 2015). We assessed reported perceptions and management of sex hormone status in women with CKD.

Results

One hundred seventy-five nephrologists (21% response rate) and 121 allied health care providers (30%; 116 nurses, 5 pharmacists) responded. Sixty-eight percent of nephrologists and 46% of allied providers were between the ages of 30 and 50 years, and 38% of nephrologists and 89% of allied workers were female. Ninety-five percent of nephrologists agreed that kidney function impacts sex hormone status, although only a minority of nephrologists reported often discussing fertility (35%, female vs male nephrologists, P = .06) and menstrual irregularities with their patients (15%, female vs male nephrologists,P = .02). Transplant nephrologists reported discussing fertility more often than did nontransplant nephrologists (53% vs 30%, P = .03). Physicians were more likely to report discussing fertility (33% vs 7.5%, P < .001) and menstrual irregularities (15% vs 9%, P = .04) with patients than allied health care providers. Forty-three percent of physicians reported uncertainty about the role for postmenopausal hormone therapy in women with CKD.

Conclusion

Nephrologists and allied health care providers recognize an impact of CKD on sex hormones in women but report not frequently discussing sex hormone-related issues with patients. Our international survey highlights an important knowledge gap in nephrology.

Sex and gender differences in chronic kidney disease: progression to end-stage renal disease and haemodialysis

Sex and gender differences are of fundamental importance in most diseases, including chronic kidney disease (CKD). Men and women with CKD differ with regard to the underlying pathophysiology of the disease and its complications, present different symptoms and signs, respond differently to therapy and tolerate/cope with the disease differently. Yet an approach using gender in the prevention and treatment of CKD, implementation of clinical practice guidelines and in research has been largely neglected. The present review highlights some sex- and gender-specific evidence in the field of CKD, starting with a critical appraisal of the lack of inclusion of women in randomized clinical trials in nephrology, and thereafter revisits sex/gender differences in kidney pathophysiology, kidney disease progression, outcomes and management of haemodialysis care. In each case we critically consider whether apparent discrepancies are likely to be explained by biological or psycho-socioeconomic factors. In some cases (a few), these findings have resulted in the discovery of disease pathways and/or therapeutic opportunities for improvement. In most cases, they have been reported as merely anecdotal findings. The aim of the present review is to expose some of the stimulating hypotheses arising from these observations as a preamble for stricter approaches using gender for the prevention and treatment of CKD and its complications.

Long- but not short-term estradiol treatment induces renal damage in midlife ovariectomized Long-Evans rats

Clinical recommendations limit menopausal hormone therapy to a few years, yet the impact of a shorter treatment duration on cardiovascular health is unknown. We hypothesized that both short- and long-term estradiol (E2) treatment exerts positive and lasting effects on blood pressure, vascular reactivity, and renal health. This study was designed to mimic midlife menopause, followed by E2 treatment, that either followed or exceeded the current clinical recommendations. Female Long-Evans retired breeders were ovariectomized (OVX) at 11 mo of age and randomized into three groups: 80-day (80d) vehicle (Veh>Veh), 40-day (40d) E2 + 40d vehicle (E2>Veh), and 80d E2 (E2>E2). In comparison to Veh>Veh, both the E2>Veh and E2>E2 groups had lower systolic blood pressure and enhanced mesenteric relaxation in response to estrogen receptor-α stimulation. Despite the reduced blood pressure, E2>E2 induced renal and cardiac hypertrophy, reduced glomerular filtration, and increased proteinuria. Interestingly, kidneys from E2>Veh rats had significantly fewer tubular casts than both of the other groups. In conclusion, long-term E2 lowered blood pressure but exerted detrimental effects on kidney health in midlife OVX Long-Evans rats, whereas short-term E2 lowered blood pressure and reduced renal damage. These findings highlight that the duration of hormone therapy may be an important factor for renal health in aging postmenopausal women.

Association between Urine Albumin-to-Creatinine Ratio within the Normal Range and Incident Hypertension in Men and Women

PURPOSE

There have been few studies on gender difference in the impact of a urine albumin-to-creatinine ratio (UACR) within the normal range on the risk of hypertension. We evaluated whether the association between the UACR below the microalbuminuria range and the incident risk of hypertension is different between men and women.

MATERIALS AND METHODS

A total of 1173 individuals (442 men and 731 women) aged 40 to 70 years without hypertension was examined at baseline (2005-2008) and followed (2008-2011). We defined the UACR as the amount of albumin (mg/dL) divided by creatinine (g/dL) in randomly voided urine. The subjects were classified according to UACR tertile.

RESULTS

During an average of 2.6 years of follow-up, 57 men (12.9%) and 66 women (9.0%) developed hypertension. In multivariable-adjusted models, the odds ratio for new-onset hypertension comparing the highest and lowest tertiles of UACR was 1.83 [95% confidence interval (CI) 0.85-3.94] in men and 2.69 (95% CI 1.27-5.73) in women. In stratified analyses by menopausal status, higher tertiles of UACR were associated with an increased risk of incident hypertension in postmenopausal women.

CONCLUSION

Higher normal UACR levels were associated with an increased risk of incident hypertension in women. The UACR could have a clinical role in predicting the development of hypertension.

The influence of gender and sexual hormones on incidence and outcome of chronic kidney disease

It has long been known that the female sex is associated with a better clinical outcome in chronic renal diseases. Although many experimental, clinical, and epidemiological studies in adults have attempted to explain the difference in disease progression between females and males, a definitive understanding of the underlying mechanisms is still lacking. Hormone-modulating therapies are being increasingly used for various indications (such as post-menopausal hormone replacement, estrogen- or androgen-receptor antagonists for cancer therapy). Therefore, a deeper knowledge of the interaction between sexual hormones and progression of kidney disease is important, as hormone-modulating therapy for non-renal indication may influence both kidney structure and function. In addition, specific modulation of the sexual hormone system, such as the use of selective estrogen receptor modulators, may represent a therapeutic option for patients with renal diseases. Although conclusive data on this topic in the pediatric population are still lacking, the aim of this review is to familiarize pediatric nephrologists with gender-specific differences in renal physiology, pathophysiology, and the progression of kidney diseases. Experimental models that analyze the effects of sexual hormones on renal structure and function are discussed. It is hoped that this review will stimulate researchers to focus on pediatric studies that will provide a deeper insight into the interaction of gender hormones and the kidney both before and during puberty.

Estrogen receptor alpha expression in podocytes mediates protection against apoptosis in-vitro and in-vivo

CONTEXT/OBJECTIVE

Epidemiological studies have demonstrated that women have a significantly better prognosis in chronic renal diseases compared to men. This suggests critical influences of gender hormones on glomerular structure and function. We examined potential direct protective effects of estradiol on podocytes.

METHODS

Expression of estrogen receptor alpha (ERα) was examined in podocytes in vitro and in vivo. Receptor localization was shown using Western blot of separated nuclear and cytoplasmatic protein fractions. Podocytes were treated with Puromycin aminonucleoside (PAN, apoptosis induction), estradiol, or both in combination. Apoptotic cells were detected with Hoechst nuclear staining and Annexin-FITC flow cytometry. To visualize mitochondrial membrane potential depolarization as an indicator for apoptosis, cells were stained with tetramethyl rhodamine methylester (TMRM). Estradiol-induced phosphorylation of ERK1/2 and p38 MAPK was examined by Western blot. Glomeruli of ERα knock-out mice and wild-type controls were analysed by histomorphometry and immunohistochemistry.

RESULTS

ERα was consistently expressed in human and murine podocytes. Estradiol stimulated ERα protein expression, reduced PAN-induced apoptosis in vitro by 26.5±24.6% or 56.6±5.9% (flow cytometry or Hoechst-staining, respectively; both p<0.05), and restored PAN-induced mitochondrial membrane potential depolarization. Estradiol enhanced ERK1/2 phosphorylation. In ERα knockout mice, podocyte number was reduced compared to controls (female/male: 80/86 vs. 132/135 podocytes per glomerulus, p<0.05). Podocyte volume was enhanced in ERα knockout mice (female/male: 429/371 µm(3) vs. 264/223 µm(3) in controls, p<0.05). Tgfβ1 and collagen type IV expression were increased in knockout mice, indicating glomerular damage.

CONCLUSIONS

Podocytes express ERα, whose activation leads to a significant protection against experimentally induced apoptosis. Possible underlying mechanisms include stabilization of mitochondrial membrane potential and activation of MAPK signalling. Characteristic morphological changes indicating glomerulopathy in ERα knock-out mice support the in vivo relevance of the ERα for podocyte viability and function. Thus, our findings provide a novel model for the protective influence of female gender on chronic glomerular diseases.

A cross-sectional and 10-year prospective study of postmenopausal estrogen therapy and blood pressure, renal function, and albuminuria: the Rancho Bernardo Study

OBJECTIVE

Blood pressure, urine albumin-to-creatinine ratio, and estimated glomerular filtration rate (GFR) are highly correlated conditions. The longitudinal effect of exposure to postmenopausal estrogen therapy on these traits studied together has not been reported.

METHODS

This was a cross-sectional study of 1,044 older postmenopausal community-dwelling women from the Rancho Bernardo Study (1992-1996); 443 women were reevaluated ∼ 10 years later (2002-2005). We determined the cross-sectional and prospective association of baseline postmenopausal estrogen therapy and blood pressure, urine albumin-to-creatinine ratio, GFR, and the odds of categorical hypertension (physician diagnosis, medication, or blood pressure ≥ 140/≥ 90 mm Hg), chronic kidney disease (GFR ≤ 60 mL/min per 1.73 m2), and albuminuria (urine albumin-to-creatinine ratio ≥ 25 mg/g).

RESULTS

At baseline, the mean age was 68.3 years for current estrogen users, 75.4 years for past users, and 74.3 years for never users. In the cross-sectional analyses, current users had lower diastolic blood pressure and lower odds of having chronic kidney disease, independent of covariates. In the ∼ 10-year follow-up, comparisons between never, past, and current estrogen use (91% continuous use since baseline), the mean diastolic blood pressure declined over time in current users, whereas systolic blood pressure increased among never users. Urine albumin-to-creatinine ratio also increased in never users and decreased in current users; GFR did not differ by estrogen use.

CONCLUSIONS

In cross-sectional analyses, estrogen users had better GFR and blood pressure than nonusers did, but the 10-year follow-up showed improved blood pressure and decreased urine albumin-to-creatinine ratio among mostly long-term current users, without differences in GFR by estrogen use. This study suggests no association of GFR with 10 years of continuous estrogen use and an inverse association with albuminuria.

Raloxifene, a selective estrogen receptor modulator, is renoprotective: a post-hoc analysis

Estrogens have a protective effect on kidney fibrosis in several animal models. Here, we tested the effect of raloxifene, an estrogen receptor modulator, on the change in serum creatinine or estimated glomerular filtration rate (eGFR) and incident kidney-related adverse events. We performed a post-hoc analysis of the multiple outcomes of raloxifene evaluation trial, a double-masked, placebo-controlled randomized clinical trial encompassing 7705 post-menopausal women (aged 31-80 years) with osteoporosis. Participants were randomized to either of two doses of raloxifene, 60 or 120 mg/day, or placebo. Serum creatinine was measured at a central laboratory at baseline and annually. Adverse events were assessed every 6 months and uniformly categorized. Compared with those in the placebo group, participants on raloxifene had a slower yearly rate of increase in creatinine (significant at the low dose) and a significantly slower yearly rate of decrease in eGFR for both doses over 3 years of follow-up. Raloxifene was associated with significantly fewer kidney-related adverse events compared with placebo. Thus, treatment with raloxifene was safe and renoprotective. Clinical trials of raloxifene in post-menopausal women with kidney disease designed to look at kidney outcomes are needed to confirm these findings.

Physical activity and albuminuria

Higher urinary albumin excretion predicts future cardiovascular disease, hypertension, and chronic kidney disease. Physical activity improves endothelial function so activity may reduce albuminuria. Among diabetics, physical activity decreases albuminuria. In nondiabetics, prior studies have shown no association. The authors explored the cross-sectional association between physical activity and albuminuria in 3,587 nondiabetic women in 2 US cohorts, the Nurses' Health Study I in 2000 and the Nurses' Health Study II in 1997. Physical activity was expressed as metabolic equivalents per week. The outcome was the top albumin/creatinine ratio (ACR) decile. Multivariate logistic regression was used. Secondary analyses explored the ACR association with strenuous activity and walking. The mean age was 58.6 years. Compared with women in the lowest physical activity quintile, those in the highest quintile had a multivariate-adjusted odds ratio for the top ACR decile of 0.65 (95% confidence interval (CI): 0.46, 0.93). The multivariate-adjusted odds ratio for the top ACR decile for those with greater than 210 minutes per week of strenuous activity compared with no strenuous activity was 0.61 (95% CI: 0.37, 0.99), and for those in the highest quintile of walking compared with the lowest quintile, it was 0.69 (95% CI: 0.47, 1.02). Greater physical activity is associated with a lower ACR in nondiabetic women.