Subtracting Dates, Getting Whole Months

I found the following code on this site in a search for a method to subtract two dates ie [Startdate] and [EndDate] and display the result as a whole number. ie 2, 6 etc. This code finds the difference but displays the results as 1 year 5 months 2 days, where I need the equivalent as 17.
Can this code be modified to produce the desired result and if so how would I go about it. Thanks for the help.

Option Compare Database
Option Explicit

Public Function getTimeElapsed(StartDate, Optional EndDate As Date) As String
On Error GoTo Err_Handler

If IsNull(StartDate) Then
getTimeElapsed = "No startdate"
Exit Function
End If

Dim YY As Integer
Dim MM As Integer
Dim DD As Long

' use current day if EndDate is not supplied,
' + 1 makes both days inclusive.
EndDate = IIf(EndDate = 0, Date, EndDate) + 1

MM = DateDiff("m", StartDate, EndDate)
DD = DateDiff("d", DateAdd("m", MM, StartDate), EndDate)

' recalculate if DD is negative.
If DD < 0 Then
MM = MM - 1
DD = DateDiff("d", DateAdd("m", MM, StartDate), EndDate)
End If

YY = MM 12 ' integer division.
MM = MM Mod 12 ' remainder.

getTimeElapsed = YY & IIf(YY < 2, " year ", " years ") & _
MM & IIf(MM < 2, " month ", " months ") & _
DD & IIf(DD < 2, " day", " days")
Exit Function

Err_Handler:
MsgBox Err.Description
Exit Function

End Function