Early renal insufficiency and late venous thromboembolism after renal transplantation in the United States.

BACKGROUND: Pulmonary embolism (PE) is the most common preventable cause of death in hospitalized patients. Patients with severe chronic kidney disease (CKD) may be at increased risk for PE in comparison to the general population. Whether severe CKD is associated with increased risk for late venous thromboembolism (VTE) in a population of renal transplant recipients has not been determined. METHODS: Using the US Renal Data System database, we studied 28,924 patients receiving a kidney transplant from January 1, 1996, to July 31, 2000, with Medicare as primary payer, followed up until December 31, 2000. Cox proportional hazards regression models were used to calculate the association of transplant recipient estimated glomerular filtration rate (eGFR; by the Modification of Diet in Renal Disease formula) less than 30 mL/min/1.73 m2 (versus >30 mL/min/1.73 m2) 1 year after renal transplantation with Medicare claims for VTE (either deep-venous thrombosis or PE/infarction) 1.5 to 3 years after renal transplantation. RESULTS: The rate of VTE occurring 1.5 to 3 years after transplantation was 2.9 episodes/1,000 person-years. eGFR less than 30 mL/min/1.73 m2 versus higher at the end of the first year after renal transplantation was associated with significantly increased risk for later VTE (adjusted hazard ratio, 2.05; 95% confidence interval, 1.08 to 3.89). CONCLUSION: Patients with severe CKD after renal transplantation should be regarded as high risk for late VTE, which is a potentially preventable cause of death in this population.

Risk factors for pulmonary embolism in chronic dialysis patients.

BACKGROUND: Risk factors for pulmonary embolism (PE) in end stage renal disease (ESRD) patients have not been studied in a large population. METHODS: 375,152 patients in the United States Renal Data System initiated on dialysis between 1 January 1992 and 30 June 1997 were analyzed in an historical cohort study of hospitalized PE (ICD9 Code 415.1x) occurring prior to receipt of renal transplant. Cox regression models were used to analyze risk factors for PE in dialysis. Dialysis modality was analyzed in an intention to treat fashion, thus patients who changed modalities later were considered to have remained on the same modality. RESULTS: The incidence of pulmonary embolism did not increase over time. Independent risk factors for hospitalizations for PE were similar to those in the general population (older age, females, systemic lupus erythematosus, lower risk for Asians) with the addition of peritoneal dialysis (vs. hemodialysis, adjusted odds ratio 1.56, 95% CI 1.15-2.13), polycystic kidney disease, and congestive heart failure. Notably, in Cox regression analysis, no relation was seen with baseline laboratory results (hematocrit, serum albumin, serum creatinine) or comorbidity (except congestive heart failure) and PE risk. Dialysis patients with PE had increased mortality (hazard ratio 1.20, 95% confidence interval 1.08-1.33). CONCLUSIONS: The incidence of PE did not increase significantly in ESRD patients from 1992-1997. PE were associated with increased mortality. Peritoneal dialysis patients may have higher risk of PE than hemodialysis patients, and other high-risk groups were identified.

Chronic dialysis patients have high risk for pulmonary embolism.

Pulmonary embolism has been considered uncommon in chronic dialysis patients, but has not been adequately studied in a large population. In the US Renal Data System (USRDS), 76,718 patients presenting with end-stage renal disease (ESRD) between January 1, 1996, and December 31, 1996, were analyzed in an historical cohort study. The outcome was hospitalizations with a primary discharge diagnosis of pulmonary embolism (International Classification of Diseases, Ninth Revision code 415.1x) occurring within 1 year of the first ESRD treatment and excluding those occurring after renal transplantation. For dialysis patients, hospitalization rates for pulmonary embolism were obtained from the hospitalization section of the 1999 USRDS. For the general population, hospitalization rates for pulmonary embolism were obtained from the National Hospital Discharge Survey for 1996. Comorbidities from the Medical Evidence Form (Centers for Medicare and Medicaid Services, previously known as the Health Care Financing Administration; form 2728) were used to generate approximated stratified models of adjusted incidence ratios for pulmonary embolism (comorbidities could not be stratified for the general population). In 1996, the overall incidence rate of pulmonary embolism was 149.90/100,000 dialysis patients compared with 24.62/100,000 persons in the US population, with an age-adjusted incidence ratio of 2.34 in dialysis patients. Younger dialysis patients had the greatest relative risk for pulmonary embolism. The age-adjusted incidence ratio of pulmonary embolism after excluding dialysis patients with known risk factors for pulmonary embolism was 2.11. Ninety-five percent confidence intervals for all age categories in both models were statistically significant. Chronic dialysis patients have high risk for pulmonary embolism, independent of comorbidity.