Table 4.

Cost analysis

	Nonstandard		Total among group
	Incremental	Decremental
n	91	14	105
1 dialysis per week
Patient-years of observation	21.4	4.5	25.9
Number of dialysis	1115	234	1349
2 dialysis per week
Patient-years of observation	37.8	14.5	52.2
Number of dialysis	3926	1505	5431
Total among nonstandard dialysis frequency
Patient-years of observation	59.2	19.0	78.2
Number of dialysis	5041	1739	6780

Summary
Patient-years of observation on nonstandard HD	Number of sessions observed on nonstandard HD	Number of sessions expected on thrice-weekly HD	“Saved” HD sessions
78.2	6780	12,199	5419a

HD, hemodialysis.

The hypothetic dialysis sessions were calculated using the following equation: $n_{dialysissession}=Wy\ast Dfreq\ast Pyear$,

where Wy is the number of weeks per year (i.e., 52), Dfreq is the dialysis frequency considered, and Pyear is the patient-years of observation.

With an overall follow-up of 219 patient-years in the total incident population of 158 patients (median follow-up per patient: 1.03 years), 5419 dialysis sessions correspond to 15.86% of the theoretical 34,164 sessions calculated with respect to the standard thrice-weekly HD.

Bold value indicates significant differences.

^aEquivalent to 1,896,850 Euros for dialysis costs (each session calculated at 350 Euros) and 270,950 Euros for transportation (calculated at 50 Euros for each dialysis session).