Gout among Patients with Dialysis: Prevalence, Associated Factors, Treatment Patterns, and Outcomes-Population-Based Retrospective Cohort Study

Key Points

Population-based retrospective cohort study to evaluate clinical correlates of gout and its impact on patients undergoing chronic dialysis. 13.5% of US dialysis-dependent patients had gout and were older and male, with a higher prevalence of hypertension and cardiovascular disease. Gout diagnosis was associated with a higher incidence of cardiovascular conditions, levels of anemia, hospitalization, and mortality.

Background

An association between gout and nondialysis chronic renal disease has long been recognized, yet limited research exists regarding prevalence, treatment, anemia management, and outcomes in patients with ESKD undergoing dialysis.

Methods

Using data from United States Renal Data System, we conducted a population-based retrospective cohort study in adult patients covered by Medicare and on dialysis in 2017. Multivariate logistic regression models were used to estimate potential factors and odds of gout diagnosis. Antigout medications and impact on anemia management were assessed and compared between gout and nongout dialysis patients using descriptive and regression analyses. Associations for all-cause mortality and cardiovascular-related hospitalizations during 1 year of study follow-up were compared between gout and nongout patients using multivariate Cox regression models.

Results

Of 231,841 ESKD Medicare patients in 2017 undergoing continuous dialysis, 31,300 (13.5%) had one or more gout diagnostic code(s). Increased odds of having a gout diagnosis were independently associated with older age, male sex, Asian race, obesity, hypertension, and cardiovascular disease. Gout diagnosis was associated with higher prevalence for anemia as indicated by increased erythropoietin-stimulating agent requirements (odds ratio=1.18 for high versus low erythropoietin-stimulating agent dose, 95% confidence interval [95% CI], 1.14 to 1.22) and likelihood of blood transfusions (odds ratio=1.34, 95% CI, 1.30 to 1.38). During the 1-year study follow-up, mortality among gout versus nongout patients was higher by 3% (95% CI, 0 to 6) and a composite association of mortality and cardiovascular disease hospitalization was higher by 6% (95% CI, 3 to 9) after adjusting for comorbid conditions.

Conclusions

A gout diagnosis was found in 13.5% of US dialysis-dependent patients and was associated with a higher burden of comorbid cardiovascular conditions as well as an elevated incidence of hospitalization and mortality. These observations improve our current understanding of gout among the dialysis population and highlight the importance of new and better treatments to improve outcomes.

Reduced fracture risk with early corticosteroid withdrawal after kidney transplant

Corticosteroid use after kidney transplantation results in severe bone loss and high fracture risk. Although corticosteroid withdrawal in the early posttransplant period has been associated with bone mass preservation, there are no published data regarding corticosteroid withdrawal and risk of fracture. We hypothesized lower fracture incidence in patients discharged from the hospital without than with corticosteroids after transplantation. From the United States Renal Data System (USRDS), 77, 430 patients were identified who received their first kidney transplant from 2000 to 2006. Fracture incidence leading to hospitalization was determined from 2000 to 2007; discharge immunosuppression was determined from United Networks for Organ Sharing forms. Time-to-event analyses were used to evaluate fracture risk. Median (interquartile range) follow-up was 1448 (808-2061) days. There were 2395 fractures during follow-up; fracture incidence rates were 0.008 and 0.0058 per patient-year for recipients discharged with and without corticosteroid, respectively. Corticosteroid withdrawal was associated with a 31% fracture risk reduction (HR 0.69; 95% CI 0.59-0.81). Fractures associated with hospitalization are significantly lower with regimens that withdraw corticosteroid. As this study likely underestimates overall fracture incidence, prospective studies are needed to determine differences in overall fracture risk in patients managed with and without corticosteroids after kidney transplantation.

HIVAN and medication use in chronic dialysis patients in the United States: analysis of the USRDS DMMS Wave 2 study

BACKGROUND

The use and possible effects of factors known to improve outcomes in patients with human immunodeficiency virus associated nephropathy (HIVAN), namely of angiotensin converting enzyme inhibitors (ACE) and antiretroviral therapy, has not been reported for a national sample of dialysis patients.

METHODS

We conducted a historical cohort study of the United States Renal Data System (USRDS) Dialysis Morbidity and Mortality Study (DMMS) Wave 2 to identify risk factors associated with increased mortality in these patients. Data were available for 3374 patients who started dialysis and were followed until March 2000. Cox Regression analysis was used to model adjusted hazard ratios (AHR) with HIVAN as a cause of end stage renal disease (ESRD) and its impact on mortality during the study period, adjusted for potential confounders.

RESULTS

Of the 3374 patients who started dialysis, 36 (1.1%) had ESRD as a result of HIVAN. Only 22 (61%) of patients with HIVAN received antiretroviral agents, and only nine patients (25%) received combination antiretroviral therapy, and only 14% received ACE inhibitors. Neither the use of multiple antiretroviral drugs (AHR, 0.62, 95% CI, 0.10, 3.86, p = 0.60), or ACE inhibitors were associated with a survival advantage. Patients with HIVAN had an increased risk of mortality (adjusted hazard ratio, 4.74, 95% Confidence Interval, 3.12, 7.32, p < 0.01) compared to patients with other causes of ESRD.

CONCLUSIONS

Medications known to improve outcomes in HIV infected patients were underutilized in patients with HIVAN. Adjusted for other factors, a primary diagnosis of HIVAN was associated with increased mortality compared with other causes of ESRD.

Diabetic ketoacidosis and hyperglycemic hyperosmolar syndrome after renal transplantation in the United States

BACKGROUND: The incidence and risk factors for diabetic ketoacidosis (diabetic ketoacidosis) and hyperglycemic hyperosmolar syndrome (hyperglycemic hyperosmolar syndrome, previously called non-ketotic hyperosmolar coma) have not been reported in a national population of renal transplant (renal transplantation) recipients. METHODS: We performed a historical cohort study of 39,628 renal transplantation recipients in the United States Renal Data System between 1 July 1994 and 30 June 1998, followed until 31 Dec 1999. Outcomes were hospitalizations for a primary diagnosis of diabetic ketoacidosis (ICD-9 code 250.1x) and hyperglycemic hyperosmolar syndrome (code 250.2x). Cox Regression analysis was used to calculate adjusted hazard ratios for time to hospitalization for diabetic ketoacidosis or hyperglycemic hyperosmolar syndrome. RESULTS: The incidence of diabetic ketoacidosis and hyperglycemic hyperosmolar syndrome were 33.2/1000 person years (PY) and 2.7/1000 PY respectively for recipients with a prior diagnosis of diabetes mellitus (DM), and 2.0/1000 PY and 1.1/1000 PY in patients without DM. In Cox Regression analysis, African Americans (AHR, 2.71, 95 %CI, 1.96-3.75), females, recipients of cadaver kidneys, patients age 33-44 (vs. >55), more recent year of transplant, and patients with maintenance TAC (tacrolimus, vs. cyclosporine) had significantly higher risk of diabetic ketoacidosis. However, the rate of diabetic ketoacidosis decreased more over time in TAC users than overall. Risk factors for hyperglycemic hyperosmolar syndrome were similar except for the significance of positive recipient hepatitis C serology and non-significance of female gender. Both diabetic ketoacidosis (AHR, 2.44, 95% CI, 2.10-2.85, p < 0.0001) and hyperglycemic hyperosmolar syndrome (AHR 1.87, 95% CI, 1.22-2.88, p = 0.004) were independently associated with increased mortality. CONCLUSIONS: We conclude that diabetic ketoacidosis and hyperglycemic hyperosmolar syndrome were associated with increased risk of mortality and were not uncommon after renal transplantation. High-risk groups were identified.

Atrial fibrillation in chronic dialysis patients in the United States: risk factors for hospitalization and mortality

BACKGROUND

The incidence and risk factors for hospitalized atrial fibrillation have not been previously assessed in a national population of dialysis patients.

METHODS

We analyzed the United States Renal Data System (USRDS) Dialysis Morbidity and Mortality Study (DMMS) Wave II in a historical cohort study of hospitalized atrial fibrillation. Data from 3374 patients who started dialysis in 1996 with valid follow-up times were available for analysis, censored at the time of renal transplantation and followed until November 2000. Cox Regression analysis was used to model factors associated with time to first hospitalization for atrial fibrillation (ICD9 code 427.31x) adjusted for comorbidities, demographic factors, baseline laboratory values, blood pressures, dialysis modality, and cardioprotective medications.

RESULTS

The incidence density of atrial fibrillation was 12.5/1000 person years. Factors associated with atrial fibrillation were older age (> or = 71 years vs. <48 years), extremes (both high and low) of pre-dialysis systolic blood pressure, dialysis modality (hemodialysis vs. peritoneal dialysis), and digoxin use. Baseline use of coumadin was associated with reduced mortality in patients later hospitalized for atrial fibrillation.

CONCLUSIONS

Dialysis patients had a high incidence of atrial fibrillation. This risk was largely segregated among those with established risk factors for atrial fibrillation, and hemodialysis patients. Use of coumadin was associated with improved survival among patients later hospitalized for atrial fibrillation.

Hospitalized poisonings after renal transplantation in the United States

BACKGROUND

The national incidence of and risk factors for hospitalized poisonings in renal transplant recipients has not been reported.

METHODS

Historical cohort study of 39,628 renal transplant recipients in the United States Renal Data System between 1 July 1994 and 30 June 1998. Associations with time to hospitalizations for a primary diagnosis of poisonings (ICD-9 codes 960.x-989.x) within three years after renal transplant were assessed by Cox Regression.

RESULTS

The incidence of hospitalized poisonings was 2.3 patients per 1000 person years. The most frequent causes of poisonings were immunosuppressive agents (25.3%), analgesics/antipyretics (14.1%), psychotropic agents (10.0%), and insulin/antidiabetic agents (7.1%). In Cox Regression analysis, low body mass index (BMI, <21.6 vs. >28.3 kg/m2, adjusted hazard ratio (AHR), 3.02, 95% CI, 1.45-6.28, and allograft rejection, AHR 1.83, 95% CI, 1.15-2.89, were the only factors independently associated with hospitalized poisonings. Hospitalized poisonings were independently associated with increased mortality (AHR, 1.54, 95% CI 1.22-1.92, p = 0.002).

CONCLUSIONS

Hospitalized poisonings were associated with increased mortality after renal transplantation. However, almost all reported poisonings in renal transplant recipients were due to the use of prescribed medications. Allograft rejection and low BMI were the only independent risk factors for poisonings identified in this population.

Polycystic kidney disease in patients on the renal transplant waiting list: trends in hematocrit and survival

BACKGROUND

The patient characteristics and mortality associated with autosomal dominant polycystic kidney disease (PKD) have not been characterized for a national sample of end stage renal disease (ESRD) patients on the renal transplant waiting list.

METHODS

40,493 patients in the United States Renal Data System who were initiated on ESRD therapy between 1 April 1995 and 29 June 1999 and later enrolled on the renal transplant waiting list were analyzed in an historical cohort study of the relationship between hematocrit at the time of presentation to ESRD and survival (using Cox Regression) in patients with PKD as a cause of ESRD.

RESULTS

Hematocrit levels at presentation to ESRD increased significantly over more recent years of the study. Hematocrit rose in parallel in patients with and without PKD, but patients with PKD had consistently higher hemoglobin. PKD was independently associated with higher hematocrit in multiple linear regression analysis (p < 0.0001). In logistic regression, higher hematocrit was independently associated with PKD. In Cox Regression analysis, PKD was associated with statistically significant improved survival both in comparison with diabetic (hazard ratio, 0.64, 95% CI 0.53-0.77, p < 0.001) and non-diabetic (HR 0.68, 95% CI 0.56-0.82, p = 0.001) ESRD patients, adjusted for all other factors.

CONCLUSIONS

Hematocrit at presentation to ESRD was significantly higher in patients with PKD compared with patients with other causes of ESRD. The survival advantage of PKD in ESRD persisted even adjusted for differences in hematocrit and in comparison with patients on the renal transplant waiting list.