Association of smoking with cardiovascular and infection-related morbidity and mortality in chronic hemodialysis

Smoking and risk of fractures requiring hospitalization in hemodialysis patients: a nationwide cohort study in Japan

BACKGROUND

Smoking is a well-established lifestyle risk factor for fractures in the general population, but evidence specific to hemodialysis populations is lacking. This nationwide cohort study used data from the Japanese Society for Dialysis Therapy Renal Data Registry to examine the association between smoking status and fractures.

METHODS

A total of 154,077 patients (64.2% men; mean age, 68 years) aged ≥20 years undergoing maintenance hemodialysis thrice a week at the end of 2016 were followed for 1 year. Among these, 19,004 (12.3%) patients were current smokers. Standardized incidence rate ratios of hospitalization due to any fracture were calculated and analyzed by multivariable logistic regression analysis, controlling for potential confounders. Propensity score matching and subgroup analyses were also performed as sensitivity analyses.

RESULTS

During the 1-year follow-up period, 3,337 fractures requiring hospitalization (1,201 hip, 479 vertebral, and 1,657 other fractures) occurred in 3,291 patients. The age- and sex-standardized incidence ratio for current smokers was 1.24 (95% confidence interval, 1.12-1.39) relative to non-smokers. Standardized incidence ratios were similar after stratification by age group and sex. Multivariable logistic regression analysis revealed a 1.25-fold higher risk of any fracture requiring hospitalization (95% confidence interval, 1.10-1.42) in current smokers relative to non-smokers in a fully adjusted model. Propensity score matching showed similar results (odds ratio, 1.25; 95% confidence interval, 1.05-1.48). Subgroup analyses for baseline covariates revealed no significant interactions.

CONCLUSIONS

Smoking is a significant risk factor for any fracture requiring hospitalization in hemodialysis patients.

Smoking Cessation and Coronary Artery Calcification in CKD

BACKGROUND AND OBJECTIVES

Smoking is associated with vascular calcification and a higher risk of cardiovascular disease. In this study, we investigated the association of smoking dose and cessation with coronary artery calcification (CAC) in patients with CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

From a nationwide, prospective cohort of Korean patients with CKD, 1914 participants were included. Prevalent CAC was defined as an Agatston score >0, using computed tomography. CAC progression was defined as ≥30%/yr increase in Agatston score at the 4-year follow-up examination in patients with baseline CAC.

RESULTS

Prevalent CAC was observed in 952 (50%) patients. Compared with never smokers, former smokers had a similar prevalence ratio for CAC, but current smokers had a 1.25-fold higher prevalence ratio (95% confidence interval [95% CI], 1.10 to 1.42). Among former smokers, a lower smoking load of <10 pack-years (prevalence ratio, 0.77; 95% CI, 0.65 to 0.90) and longer duration of smoking cessation (prevalence ratio for 10 to <20 years, 0.85; 95% CI, 0.73 to 0.98: prevalence ratio for ≥20 years, 0.83; 95% CI, 0.73 to 0.96) were associated with lower risk of prevalent CAC compared with current smoking. The prevalence ratios did not differ between never smoking and long-term cessation. However, short-term cessation with heavy smoking load was associated with a higher risk of prevalent CAC (prevalence ratio, 1.21; 95% CI, 1.03 to 1.40) compared with never smoking. CAC progression was observed in 111 (33%) patients with baseline CAC. Compared with never smokers, former smokers showed a similar risk of CAC progression, but current smokers had a higher risk (relative risk, 1.92; 95% CI, 1.30 to 2.86).

CONCLUSIONS

In CKD, former smoking with a lower smoking load and long-term cessation were associated with a lower risk of prevalent CAC than current smoking. CAC progression was more pronounced in current smokers.

Effect of statin on life prognosis in Japanese patients undergoing hemodialysis

The effect of statin on hemodialysis patients is controversial. Although previous large-scale studies did not clarify its effect in this population, recent studies suggest that statins could be useful in reducing the risk of cardiovascular events and all-cause mortality in specific groups of patients undergoing hemodialysis. The aforementioned large-scale studies included a small percentage of Asians, and few studies have investigated the effects of statins in Asians undergoing hemodialysis. Thus, we investigated the benefits of statins in patients undergoing maintenance hemodialysis at a single center in Japan. We obtained demographic, clinical, and hemodialysis data of all patients who underwent maintenance hemodialysis at the Nagasaki Renal Center between July 2011 and June 2012. Patients were followed-up until June 2018. We studied 339 patients, of which 51 (15.0%) were prescribed pitavastatin. The mean observation period was 4.1±2.3 years, 43% were women, and the median hemodialysis vintage at baseline was 4.7 years. During the follow-up, 198 patients (58%) died, of which 22 (43%) were prescribed pitavastatin and 176 (61%) were not prescribed any statins. After propensity score matching based on age, sex, dialysis vintage, dialysis time, diabetes mellitus, ischemic heart disease, dry weight, left ventricular ejection fraction, and serum albumin, an intergroup comparison between those who received statins and those who did not (44 patients in each group) showed significant differences in survival rate based on the log-rank test (P<0.05). Although the causes of death did not differ significantly between groups, deaths due to cardiovascular events, infections, and cancer were fewer in the group prescribed statins. Our results suggest that statins may reduce mortality in Japanese patients undergoing maintenance hemodialysis. Although potential residual confounders exist, statins may have an influence on the reduction in the incidence of cardiovascular events, infections, and cancer. Nevertheless, further studies are required to prove this hypothesis.

Smoking has no impact on survival and it is not associated with ACE gene I/D polymorphism in hemodialysis patients

INTRODUCTION

The relationship between smoking and mortality in patients on hemodialysis is controversial. Earlier studies showed that the insertion/deletion (I/D) polymorphism of the ACE gene might have an effect on mortality. The aim of this study was to test the impact of smoking on survival and whether this association was influenced by ACE gene I/D polymorphism in patients on maintenance hemodialysis.

PARTICIPANTS AND METHODS

In this prospective, multicenter cohort study we analyzed 709 prevalent patients on maintenance hemodialysis. Patients were allocated into groups based on their smoking habit. Outcome data were collected during the 144-month follow-up period. Outcomes of current smokers and lifelong non-smokers were compared. In order to control for interactions between predictor variables, we also identified 160 matched pairs for further sub-analysis.

RESULTS

The vast majority of patients (67%) were non-smokers, followed by current smokers (22.2%) and ex-smokers (9.8%). Smoking had no impact on survival in the matched pair analysis ( p = 0.99). After adjustment for ACE I/D polymorphism and other co-variates, smoking had no effect on survival.

CONCLUSION

Our data suggest that smoking has no impact on survival; neither is it associated with ACE gene I/D polymorphism in hemodialysis patients.

Cigarette Smoking and Its Hazards in Kidney Transplantation

Cigarette smoking affects many organs. It causes vasoconstriction through activation of sympathetic nervous system which leads to elevation of blood pressure and reduction in glomerular filtration rate and filtration pressure. It also causes thickening of renal arterioles. Cigarette smoking increases the risk of microalbuminuria and accelerates progression of microalbuminuria to macroalbuminuria. Furthermore, it causes rapid loss of glomerular filtration rate in chronic kidney disease patients. After kidney donation, these factors may be injurious to the solitary kidney. Kidney donors with history of cigarette smoking are prone to develop perioperative complications, pneumonia, and wound infection. Postkidney transplantation various stressors including warm and cold ischemia time, delayed graft function, and exposure to calcineurin inhibitors may result in poor graft function. Continuation of cigarette smoking in kidney transplant recipients will add further risk. In this review, we will specifically discuss the effects of cigarette smoking on normal kidneys, live kidney donors, and kidney transplant recipients. This will include adverse effects of cigarette smoking on graft and patient survival, cardiovascular events, rejection, infections, and cancers in kidney transplant recipients. Lastly, the impact of kidney transplantation on behavior and smoking cessation will also be discussed.

Differential impact of smoking on mortality and kidney transplantation among adult Men and Women undergoing dialysis

BACKGROUND

The extent to which smoking contributes to adverse outcomes among men and women of all ages undergoing dialysis is uncertain. The objective of this study was to determine the differential impact of smoking on risks of mortality and kidney transplantation by age and by sex at dialysis initiation.

METHODS

We conducted a population-based cohort of incident U.S dialysis patients (n = 1, 220, 000) from 1995-2010. Age- and sex-specific mortality and kidney transplantation rates were determined for patients with and without a history of cardiovascular disease. Multivariable Cox regression evaluated relative hazard ratios (HR) for death and kidney transplantation at 2 years stratified by atherosclerotic condition, smoking status and age. Analyses were adjusted for demographic characteristics, non-cardiovascular conditions, laboratory variables, socioeconomic and lifestyle factors.

RESULTS

The average age was 62.8 (±15) years old, 54 % were male, and the majority was white. During 2-year follow-up, 40.5 % died and 5.7 % were transplanted. Age- and sex-specific mortality rates were significantly higher while transplantation rates were significantly lower for smokers with atherosclerotic conditions than non-smokers (P < 0.01). The adjusted mortality hazards were significantly higher for smokers with pre-existing coronary disease (HR 1.15, 95 % CI (1.11-1.18), stroke (HR 1.21, 1.16-1.27) and peripheral vascular disease (HR = 1.21, 1.17-1.25) compared to non-smokers without these conditions (HR 1.00, referent group). The magnitude of effect was greatest for younger patients than older patients. Contrastingly, the adjusted risks of kidney transplantation were significantly lower for smokers with coronary disease: (HR 0.60, 0.52-0.69), stroke; (HR 0.47, 0.37-0.60), and peripheral arterial disease (HR 0.55, 0.46-0.66) respectively compared to non-smokers without these conditions.

CONCLUSIONS

We provide compelling evidence that smoking is associated with adverse clinical outcomes and reduced lifespans among dialysis patients of all ages and sexes. The adverse impact is greatest for younger men and women.

Tobacco and the pediatric chronic kidney disease population

Tobacco use and exposure are preventable causes of morbidity and mortality. Whereas the impact of this public health issue is well described in adults with kidney disease, its role in the pediatric chronic kidney disease (CKD) population is largely unknown. This review discusses the prevalence of tobacco use and exposure in children with CKD, updates the reader on how tobacco affects the kidney, and presents intervention strategies relevant to this patient population.

Evidence-based cardiology in hemodialysis patients

Cardiac events are the major cause of death in hemodialysis patients. Because of the paucity of randomized clinical trials (RCTs) in hemodialysis patients, most cardiovascular therapies in this population are based on observational studies or results extrapolated from studies that excluded hemodialysis patients. However, associations discovered in observational studies do not prove causality, and these studies often report surrogate outcomes rather than clinical end points. Furthermore, interventions that show effectiveness in the general population may have drastically different outcomes and side effect profiles in hemodialysis patients. This review discusses the results of RCTs undertaken recently to evaluate cardiovascular therapies in hemodialysis patients and emphasizes clinically relevant outcomes. Although some interventions have produced similar outcomes in hemodialysis patients and the general population, others have not, suggesting that the management of cardiovascular disease in hemodialysis patients may require strategies that differ from the best practice guidelines applied to general population.