Ultrafiltration Rates and the Quality Incentive Program: Proposed Measure Definitions and Their Potential Dialysis Facility Implications

Abstract

Background and objectives: Rapid ultrafiltration rates are associated with adverse outcomes among patients on hemodialysis. The Centers for Medicare and Medicaid Services is considering an ultrafiltration rate quality measure for the ESRD Quality Incentive Program. Two measure developers proposed ultrafiltration rate measures with different selection criteria and specifications. We aimed to compare the proposed ultrafiltration rate measures and quantify dialysis facility operational burden if treatment times were extended to lower ultrafiltration rates.

Design, setting, participants, & measurements: Data were taken from the 2012 database of a large dialysis organization. Analyses of the Centers for Medicare and Medicaid Services measure considered 148,950 patients on hemodialysis, and analyses of the Kidney Care Quality Alliance measure considered 151,937 patients. We described monthly patient and facility ultrafiltration rates and examined differences in patient characteristics across ultrafiltration rate thresholds and differences in facilities across ultrafiltration rate measure scores. We computed the additional treatment time required to lower ultrafiltration rates <13 ml/h per kilogram.

Results: Ultrafiltration rates peaked in winter and nadired in summer. Patients with higher ultrafiltration rates were younger; more likely to be women, nonblack, Hispanic, and lighter in weight; and more likely to have histories of heart failure compared with patients with lower ultrafiltration rates. Facilities had, on average, 20.8%±10.3% (July) to 22.8%±10.6% (February) of patients with ultrafiltration rates >13 ml/h per kilogram by the Centers for Medicare and Medicaid Services monthly measure. Facilities had, on average, 15.8%±8.2% of patients with ultrafiltration rates ≥13 ml/h per kilogram by the Kidney Care Quality Alliance annual measure. Larger facilities (>100 patients) would require, on average, 33 additional treatment hours per week to lower all facility ultrafiltration rates <13 ml/h per kilogram when total treatment time is capped at 4 hours.

Conclusions: Ultrafiltration rates vary seasonally and across clinical subgroups. Extension of treatment time as a strategy to lower ultrafiltration rates may pose facility operational challenges. Prospective studies of ultrafiltration rate threshold implementation are needed.

Keywords: Epidemiology and outcomes; Humans; Kidney Failure, Chronic; Medicaid; Medicare; Prospective Studies; heart failure; hemodialysis; renal dialysis; ultrafiltration.

Figure 1.

The Centers for Medicare and Medicaid Services (CMS) and the Kidney Care Quality Alliance (KCQA) ultrafiltration (UF) rate measure specifications and selection criteria. ^aFor both measures, the UF rate is calculated as UF rate (milliliters per hour per kilogram) = (predialysis weight − postdialysis weight [milliliters])/delivered TT (hours)/postdialysis weight (kilograms). The CMS UF rate measure numerator details are as follows. For the hemodialysis (HD) treatment that meets selection criteria, (1) calculate the UF rate (milliliters per hour per kilogram), and (2) sum the number of patients in each facility with a UF rate >13 ml/h per kilogram. The KCQA UF rate measure numerator details are as follows. For the HD treatments that meet selection criteria, (1) calculate the UF rate (milliliters per hour per kilogram), (2) calculate each patient’s average UF rate for all HD treatments during the week that the monthly Kt/V is drawn, (3) calculate each patient’s average treatment time (TT) for all HD treatments during the week that monthly Kt/V is drawn, and (4) sum the number of patients in each facility with an average UF rate ≥13 ml/h per kilogram and an average TT<240 minutes. ^bThe National Quality Forum reported an exclusion of more than four HD treatments during the calculation period in their documentation of the KCQA measure (6); however, the KCQA measure developers tested an exclusion of four or more HD treatments during the calculation period (21). Because an exclusion of four or more HD treatments represents developer intent and is congruent with the standard practice of three weekly treatments, we evaluated the measure using an exclusion of four or more HD treatments. PD, peritoneal dialysis.

Figure 2.

The flow diagram shows selection of unique patient Centers for Medicare and Medicaid (CMS) and the Kidney Care Quaility Alliance (KCQA) cohorts by application of selection criteria on a rolling monthly basis, and the map illustrates the diverse locations of dialysis facilities included in the analytic cohorts classified by census region. (A) Flow diagram of patient and facility selection on the basis of the CMS and KCQA ultrafiltration (UF) rate measure specifications and (B) census regions of facilities included in the analytical cohort. HD, hemodialysis; LDO, large dialysis organization; PD, peritoneal dialysis; TT, treatment time; wt, weight.

Figure 3.

Illustration of treatment time (TT) extension calculation for a single patient with varying prescribed ultrafiltration (UF) rates over 1 month (13 treatments). The black circles represent the prescribed UF rates on the basis of observed interdialytic weight gains and prescribed TTs without application of a UF rate threshold. The white circles represent the updated UF rates after the application of a UF rate threshold of 13 ml/h per kilogram under the constraint of a 4-hour TT maximum. The striped bars represent the prescribed TT (180 minutes) during the month assessed. The black bars represent the calculated amount of additional TT needed to reduce UF rates to <13 ml/h per kilogram without extending total TT beyond 4 hours. For treatments with a prescribed UF rate of <13 ml/h per kilogram, no additional TT was assigned, and no change to the UF rate was made. For treatments with a prescribed UF rate of ≥13 ml/h per kilogram, the additional TT (in minutes) needed to achieve the UF rate <13 ml/h per kilogram was calculated as follows: ([predialysis weight from current treatment − postdialysis weight from previous treatment (milliliters)]/[postdialysis weight from previous treatment (kilograms) ×12.9])×60− prescribed TT (minutes). Total TT was capped at 4 hours per treatment, such that the UF rate remained ≥13 ml/h per kilogram for treatments in which UF rate reduction to rates <13 ml/h per kilogram would result in TT extension beyond 4 hours. Additional patient TTs were then summed for the month. Detailed methods for estimation of TT extension are described in Supplemental Table 2. HD, hemodialysis.

Figure 4.

Weekly required additional facility treatment time (TT) for a maximum run time of 4 hours with the application of a 13-ml/h per kilogram ultrafiltration (UF) rate threshold stratified by facility size. The additional TT required to lower prescribed UF rates to <13 ml/h per kilogram was computed at the facility level and stratified by facility size. Total TT was capped at 4 hours per the Kidney Care Quality Alliance (KCQA) specifications. For these analyses, prescribed UF rate (milliliters per hour per kilogram) was calculated using the formula (predialysis weight from current treatment − postdialysis weight from previous treatment [milliliters])/prescribed TT (hours)/postdialysis weight from previous treatment (kilograms). For treatments with a prescribed UF rate of <13 ml/h per kilogram, no additional TT was assigned. For treatments with a prescribed UF rate of ≥13 ml/h per kilogram, the additional TT (minutes) needed to achieve the UF rate <13 ml/h per kilogram was calculated as follows: ([predialysis weight from current treatment − postdialysis weight from previous treatment (milliliters)]/[postdialysis weight from previous treatment (kilograms) ×12.9])×60− prescribed TT (minutes). Total TT was capped at 4 hours per treatment, such that the UF rate remained at ≥13 ml/h per kilogram for treatments in which UF rate reduction to rates <13 ml/h per kilogram would result in TT extension beyond 4 hours. Additional patient TTs were then summed for the month at the patient and then facility levels. Detailed methods for estimation of TT extension are described in Supplemental Table 2. CMS, Centers for Medicare and Medicaid Services.