Trends in Patient Characteristics and First-Year Medical Costs of Older Incident Hemodialysis Patients, 1995-2005

Background: Characteristics of patients with chronic kidney disease who survive to end-stage renal disease may change over time, affecting subsequent outcomes and costs. We examined trends in older incident hemodialysis patient characteristics and analyzed first-year post-dialysis therapy initiation medical costs. Study Design: Retrospective cohort study. Setting & Participants: All US incident hemodialysis patients aged ≥67 years at dialysis therapy initiation from January 1, 1995, to December 31, 2005, with Medicare Part A and Part B in the prior 2 years. Predictor: Year of dialysis therapy initiation. Outcomes: Changes in patient characteristics and first-year costs. Measurements: Mean and median values for continuous variables and percentages of categorical variables; first-year total medical costs measured per person per year. Observed costs were adjusted using Medicare Price Indices and patient case-mix. Results: Median age at dialysis therapy initiation increased from 74.9 to 77.0 years from 1995 (n = 19,044) to 2005 (n = 31,796; P < 0.001). Diabetes prevalence increased from 54.2% to 64.1% (P < 0.001). Median estimated glomerular filtration rate increased from 8.0 to 11.2 mL/min/1.73 m², and median hemoglobin level increased from 9.4 to 10.2 g/dL. Obesity increased from 8.9% to 22.9% (P < 0.001). First-year observed costs increased by 37.9%; however, inflation-adjusted and case-mix-inflation-adjusted costs were stable. Important adjusters for costs are inability to ambulate/transfer, baseline serum albumin level, primary end-stage renal disease cause, comorbid peripheral vascular disease, and baseline hospital days. Limitations: Population aged ≥67 years at dialysis therapy initiation and results may not generalize to the overall hemodialysis population. Conclusions: From 1995 to 2005, incident hemodialysis patients aged ≥67 years became older, sicker, and more obese with significantly increased estimated glomerular filtration rates and hemoglobin levels at dialysis therapy initiation. Increased first-year post-dialysis therapy initiation costs became stable over time after adjustment for price inflation; case-mix-inflation-adjusted costs remained constant, possibly because of mixed changes in patient characteristics.