fixedWindow {daySupply}

Fixed window

Description

Computes the daily dose and days' supply for prescriptions by assuming a fixed number of days of exposure (usually 90 days) for all patients, reflecting the medication supply policies of most medication insurance plans.

Usage

fixedWindow(
  data,
  window_length = 90,
  dspd_qty,
  strength,
  id,
  serv_date,
  tot_dose_disp = NULL,
  Pt_level = FALSE
)

Arguments

data

Sample simulated data. Data may have multiple rows per person (one row per prescription fill). Required columns include: 1. ID: Patient's unique identification number 2. ServDate: Date on which each prescription was filled. 3. DSPD_QTY: Dispensed quantity: Number of tablets dispensed to patient at each prescription fill. 4. strength: Strength of the tablets dispensed.

window_length

The number of days that patients' supply of medication is assumed to last after each prescription refill. Default= 90 days.

dspd_qty

Dispensed quantity: Number of the dispensed tablets to the patient at each prescription fill.

strength

Strength of the tablet dispensed in milligrams.

id

Unique patient identification number.

serv_date

Date of the prescription fill.

tot_dose_disp

Total dose dispensed: dispensed quantity x strength of the tablets dispensed for each prescription fill.

Pt_level

When TRUE, the estimated daily dose and days' supply are averaged for the patient.

Value

fixedWindow returns a dataset called "fixedWindow_result". This data set includes all the variables originally in the data, plus the following:

tot_dose_disp: Total dose dispensed at prescription fill: dispensed quantity x strength of the tablet dispensed.

fixed_window_90_wind_Rx_dose: Daily dose for prescription.

fixed_90_wind_Rx_DS: Days' supply for prescription.

fixed_90_wind_Pt_dose: Average daily dose for patient.

fixed_90_wind_Pt_DS: Average days' supply for patient.

Examples

#Patient collects 100 tablets of 5 mg warfarin  on January 3rd,
#and 100 tablets of 7 mg warfarin on February 1st.

#' #Generate a simulated dataset

library(dplyr)
n_patients <- 10
n_records <- 80
data <- data.frame(ID = rep(c(1 : n_patients), each = n_records))
data %>%
  group_by(ID) %>%
  mutate(ServDate = as.Date('2020/01/01') + abs(round(rnorm(n = 80, 700, 330))),
         DSPD_QTY = abs(round(rnorm(n = 80, 43, 28))),
         strength = abs(round(rnorm(n = 80, 4, 1))))  -> data
data <- as.data.frame(data)

#Assuming window length of 90 days
data_new <- fixedWindow(data, window_length = 90, id = "ID",
                        dspd_qty = "DSPD_QTY", strength = "strength",
                        serv_date = "ServDate", tot_dose_disp =  NULL,
                        Pt_level = TRUE)

#tot_dose_disp = 500mg on January 3rd and 700 mg for February 1st.
#fixed_90_wind_Rx_dose : 500/90 = 5.55 mg  for prescription filled on Jan 3rd;
#                        700/90=7.77 mg for prescription filled on Feb 1st.
#fixed_90_wind_Rx_DS: 90 days for all prescriptions

#pt_level can be set as TRUE to get mean values for each patient
#fixed_90_wind_Pt_dose : (5.55 + 7.77)/2 = 6.66 mg
#fixed_90_wind_Pt_DS: (90 + 90)/2 = 90