Examining the Association between Non-Adherence and Composite Rate Costs for Hemodialysis Facilities

Background. The substantial body of studies that explored the relationship of non-adherence in hemodialysis (HD) sessions to the patients’ outcome and quality of life has rarely investigated the economic consequences within the end-stage renal disease (ESRD) community. While a few existing studies have examined the relationship between non-adherence with ESRD medical expenditure, none has investigated this relationship at the dialysis facility level. Objectives. This study investigates whether there is an association between non-adherence, as measured by the average HD sessions missed per patient per month, and composite rate (CR) costs for dialysis facilities, using a nationally representative sample. Methods. The study population includes 11,600 facility-years from the years 2004 to 2006. The sources of the CR cost data are the Medicare Independent Renal Dialysis Facility Cost Reports (Form CMS 265-94) and the Medicare Hospital Cost Reports (Form CMS 2552-96). Patient characteristics, comorbidities, and factors associated with an interrupted dialysis month such as missed sessions, transfer between facility, hospitalization, and transplantation, were measured using CMS Form 2728 and/or Medicare claims. Since CR costs were right-skewed, we examined the association using both OLS and log-linear models and compared the coefficient estimates derived from each. In addition, this study investigates whether the inclusion of facility control variables significantly changes the effect. Results. Descriptive statistics show that the average CR cost per month was $2,089.50 between 2004 and 2006. The average dialysis sessions missed per patient per month at the facility level is 0.11. Without facility control variables, the coefficient estimate of non-adherence was not statistically significant in the OLS model, with an R-square of 1.59 percent. The coefficient estimate from the log-linear model was 0.066 (p=0.0059; multiplier=1.07), with an R-square of 15.48 percent. After the inclusion of facility control variables, the OLS coefficient estimate of non-adherence remained insignificant. The R-square increased to 3.37 percent. In the log-linear model with facility control variables, coefficient estimate of non-adherence was also insignificant, although the R-square increased dramatically to 39.44 percent. Conclusion. This study did not find an association between non-adherence and CR costs at the dialysis facility level, except for the log-linear model without facility control variables. Using a log-linear model to predict CR costs seems to be a better approach in examining this association, since the standard deviations derived from log-linear models consistently show a tighter distribution than those derived from OLS models. Given the results from the log-linear model, CR costs were higher with higher non-adherence. Dialysis facilities could consider using various approaches, e.g., reminder phone calls, text messages, and e-mails, to target patients who are more likely to skip to improve adherence. Since the association between non-adherence and CR costs is small, a policy intervention from the CMS may not be necessary at this time.