#' Markov model
#'
#' \code{markov_model} implements the main model function.
#'
#' @param l_params_all List with all parameters
#' @param err_stop Logical variable to stop model run if transition array is invalid, if TRUE. Default = FALSE.
#' @param verbose Logical variable to indicate print out of messages. Default = FALSE
#' @return
#' a_TDP: Transition probability array
#' m_M_trace: Full markov cohort trace
#' m_M_agg_trace: Aggregated trace over base health states
#' @export
markov_model_CA <- function(l_params_all, err_stop = FALSE, verbose = FALSE){
### Definition:
## Markov model implementation function
### Arguments:
## l_params_all: List with all parameters
## verbose: Logical variable to indicate print out of messages
### Returns:
## a_TDP: Transition probability array.
## m_M_trace: Matrix cohort trace.
## m_M_agg_trace: Aggregated trace over base health states.
##
with(as.list(l_params_all), {
#### Set up model states ####
n_t <- (n_age_max - n_age_init) * 12 # modeling time horizon in months
l_dim_s <- list() # list of base states
# Base health states
BASE <- l_dim_s[[1]] <- c("MET", "ABS", "REL1", "REL", "OD")
# Injection/non-injection stratification
INJECT <- l_dim_s[[2]] <- c("NI", "INJ")
# Episodes (1-3)
EP <- l_dim_s[[3]] <- c("1", "2", "3")
# HIV status
HIV <- l_dim_s[[4]] <- c("POS", "NEG")
n_t <- (n_age_max - n_age_init) * 12
df_flat <- expand.grid(l_dim_s) #combine all elements together into vector of health states
df_flat <- rename(df_flat, BASE = Var1,
INJECT = Var2,
EP = Var3,
HIV = Var4)
# Create index of states to populate transition matrices
# All treatment
TX <- df_flat$BASE == "MET"
# All out-of-treatment (incl ABS)
OOT <- df_flat$BASE == "REL1" | df_flat$BASE == "REL" | df_flat$BASE == "OD" | df_flat$BASE == "ABS"
# Methadone
all_MET <- df_flat$BASE == "MET"
MET <- df_flat$BASE == "MET"
# Relapse
all_REL <- df_flat$BASE == "REL" | df_flat$BASE == "REL1"
REL <- df_flat$BASE == "REL"
REL1 <- df_flat$BASE == "REL1"
# Overdose
OD <- df_flat$BASE == "OD"
# Abstinence
ABS <- df_flat$BASE == "ABS"
# HIV status
NEG <- df_flat$HIV == "NEG"
POS <- df_flat$HIV == "POS"
# Injection
INJ <- df_flat$INJECT == "INJ"
NI <- df_flat$INJECT == "NI"
# Episodes
EP1 <- df_flat$EP == "1"
EP2 <- df_flat$EP == "2"
EP3 <- df_flat$EP == "3"
df_n <- unite(df_flat, newCol) # combine columns into one data frame of all health states (8 states * 2 inj * 2 HIV * 3 Episodes)
v_n_states <- df_n[,1] # convert df into vector
n_states <- length(v_n_states) # total number of health states
l_index_s <- list(TX = TX, OOT = OOT,
all_MET = all_MET, MET = MET,
all_REL = all_REL, REL = REL, REL1 = REL1,
OD = OD, ABS = ABS,
NEG = NEG, POS = POS,
INJ = INJ, NI = NI,
EP1 = EP1, EP2 = EP2, EP3 = EP3)
#### Time-dependent survival probabilities ####
# Empty 2-D matrix
m_TDP <- array(0, dim = c(n_states, n_t),
dimnames = list(v_n_states, 1:n_t))
# Probability of remaining in health state
# For REL1: p_remain = 0
for(i in 1:n_t){
t <- i+1 # Shift REL ahead 1 month to adjust for REL1
# Non-injection
#m_TDP[REL1 & NI, i] <- 0
# Episode 1
m_TDP[EP1 & MET & NI, i] <- as.vector(exp(p_weibull_scale_MET_NI * (((i - 1)^p_weibull_shape_MET_NI) - (i^p_weibull_shape_MET_NI))))
m_TDP[EP1 & ABS & NI, i] <- as.vector(exp(p_weibull_scale_ABS_NI * (((i - 1)^p_weibull_shape_ABS_NI) - (i^p_weibull_shape_ABS_NI))))
m_TDP[EP1 & REL & NI, i] <- as.vector(exp(p_weibull_scale_REL_NI * (((t - 1)^p_weibull_shape_REL_NI) - (t^p_weibull_shape_REL_NI))))
m_TDP[EP1 & OD & NI, i] <- as.vector(exp(p_weibull_scale_OD_NI * (((i - 1)^p_weibull_shape_OD_NI) - (i^p_weibull_shape_OD_NI))))
# Episode 2
m_TDP[EP2 & MET & NI, i] <- as.vector(exp(p_frailty_MET_NI_2 * p_weibull_scale_MET_NI * (((i - 1)^p_weibull_shape_MET_NI) - (i^p_weibull_shape_MET_NI))))
m_TDP[EP2 & ABS & NI, i] <- as.vector(exp(p_frailty_ABS_NI_2 * p_weibull_scale_ABS_NI * (((i - 1)^p_weibull_shape_ABS_NI) - (i^p_weibull_shape_ABS_NI))))
m_TDP[EP2 & REL & NI, i] <- as.vector(exp(p_frailty_REL_NI_2 * p_weibull_scale_REL_NI * (((t - 1)^p_weibull_shape_REL_NI) - (t^p_weibull_shape_REL_NI))))
m_TDP[EP2 & OD & NI, i] <- as.vector(exp(p_frailty_OD_NI_2 * p_weibull_scale_OD_NI * (((i - 1)^p_weibull_shape_OD_NI) - (i^p_weibull_shape_OD_NI))))
# Episode 3
m_TDP[EP3 & MET & NI, i] <- as.vector(exp(p_frailty_MET_NI_3 * p_weibull_scale_MET_NI * (((i - 1)^p_weibull_shape_MET_NI) - (i^p_weibull_shape_MET_NI))))
m_TDP[EP3 & ABS & NI, i] <- as.vector(exp(p_frailty_ABS_NI_3 * p_weibull_scale_ABS_NI * (((i - 1)^p_weibull_shape_ABS_NI) - (i^p_weibull_shape_ABS_NI))))
m_TDP[EP3 & REL & NI, i] <- as.vector(exp(p_frailty_REL_NI_3 * p_weibull_scale_REL_NI * (((t - 1)^p_weibull_shape_REL_NI) - (t^p_weibull_shape_REL_NI))))
m_TDP[EP3 & OD & NI, i] <- as.vector(exp(p_frailty_OD_NI_3 * p_weibull_scale_OD_NI * (((i - 1)^p_weibull_shape_OD_NI) - (i^p_weibull_shape_OD_NI))))
# Injection
#m_TDP[REL1 & INJ, i] <- 0
# Episode 1
m_TDP[EP1 & MET & INJ, i] <- as.vector(exp(p_weibull_scale_MET_INJ * (((i - 1)^p_weibull_shape_MET_INJ) - (i^p_weibull_shape_MET_INJ))))
m_TDP[EP1 & ABS & INJ, i] <- as.vector(exp(p_weibull_scale_ABS_INJ * (((i - 1)^p_weibull_shape_ABS_INJ) - (i^p_weibull_shape_ABS_INJ))))
m_TDP[EP1 & REL & INJ, i] <- as.vector(exp(p_weibull_scale_REL_INJ * (((t - 1)^p_weibull_shape_REL_INJ) - (t^p_weibull_shape_REL_INJ))))
m_TDP[EP1 & OD & INJ, i] <- as.vector(exp(p_weibull_scale_OD_INJ * (((i - 1)^p_weibull_shape_OD_INJ) - (i^p_weibull_shape_OD_INJ))))
# Episode 2
m_TDP[EP2 & MET & INJ, i] <- as.vector(exp(p_frailty_MET_INJ_2 * p_weibull_scale_MET_INJ * (((i - 1)^p_weibull_shape_MET_INJ) - (i^p_weibull_shape_MET_INJ))))
m_TDP[EP2 & ABS & INJ, i] <- as.vector(exp(p_frailty_ABS_INJ_2 * p_weibull_scale_ABS_INJ * (((i - 1)^p_weibull_shape_ABS_INJ) - (i^p_weibull_shape_ABS_INJ))))
m_TDP[EP2 & REL & INJ, i] <- as.vector(exp(p_frailty_REL_INJ_2 * p_weibull_scale_REL_INJ * (((t - 1)^p_weibull_shape_REL_INJ) - (t^p_weibull_shape_REL_INJ))))
m_TDP[EP2 & OD & INJ, i] <- as.vector(exp(p_frailty_OD_INJ_2 * p_weibull_scale_OD_INJ * (((i - 1)^p_weibull_shape_OD_INJ) - (i^p_weibull_shape_OD_INJ))))
# Episode 3
m_TDP[EP3 & MET & INJ, i] <- as.vector(exp(p_frailty_MET_INJ_3 * p_weibull_scale_MET_INJ * (((i - 1)^p_weibull_shape_MET_INJ) - (i^p_weibull_shape_MET_INJ))))
m_TDP[EP3 & ABS & INJ, i] <- as.vector(exp(p_frailty_ABS_INJ_3 * p_weibull_scale_ABS_INJ * (((i - 1)^p_weibull_shape_ABS_INJ) - (i^p_weibull_shape_ABS_INJ))))
m_TDP[EP3 & REL & INJ, i] <- as.vector(exp(p_frailty_REL_INJ_3 * p_weibull_scale_REL_INJ * (((t - 1)^p_weibull_shape_REL_INJ) - (t^p_weibull_shape_REL_INJ))))
m_TDP[EP3 & OD & INJ, i] <- as.vector(exp(p_frailty_OD_INJ_3 * p_weibull_scale_OD_INJ * (((i - 1)^p_weibull_shape_OD_INJ) - (i^p_weibull_shape_OD_INJ))))
}
# Probability of state-exit
m_leave <- 1 - m_TDP
write.csv(m_TDP,"C:/Users/Benjamin/Desktop/m_TDP.csv", row.names = TRUE)
write.csv(m_leave,"C:/Users/Benjamin/Desktop/m_leave.csv", row.names = TRUE)
#### Mortality ####
# Monthly mortality for each age applied to 12 months, includes state-specific hr
v_mort_NI <- function(hr = hr){
#v_mort <- rep((1 - exp(-v_r_mort_by_age[n_age_init:(n_age_max - 1), ] * (1/12) * hr)), each = 12) # all three functions produce identical results
#v_mort <- rep(1 - (1 - (1 - exp(-v_r_mort_by_age[n_age_init:(n_age_max - 1), ] * hr)))^(1/12), each = 12)
v_mort_NI <- rep((1 - (1 - (1 - exp(-v_r_mort_by_age_NI[n_age_init:(n_age_max - 1), ])))^(1/12)) * hr, each = 12) # test
return(v_mort_NI)
}
v_mort_INJ <- function(hr = hr){
v_mort_INJ <- rep((1 - (1 - (1 - exp(-v_r_mort_by_age_INJ[n_age_init:(n_age_max - 1), ])))^(1/12)) * hr, each = 12) # test
return(v_mort_INJ)
}
# Non-injection
v_mort_MET_NI <- v_mort_NI(hr = hr_MET_NI)
v_mort_REL1_NI <- v_mort_NI(hr = hr_REL1_NI)
v_mort_REL_NI <- v_mort_NI(hr = hr_REL_NI)
v_mort_OD_NEG_NI <- v_mort_NI(hr = hr_OD_NI)
v_mort_OD_POS_NI <- v_mort_NI(hr = hr_HIV_OD_NI) # REMOVE THIS AFTER CA REP
v_mort_ABS_NEG_NI <- v_mort_NI(hr = hr_ABS_NI)
v_mort_ABS_POS_NI <- v_mort_NI(hr = hr_HIV_NI)
# Injection
v_mort_MET_INJ <- v_mort_INJ(hr = hr_MET_INJ)
v_mort_REL1_INJ <- v_mort_INJ(hr = hr_REL1_INJ)
v_mort_REL_INJ <- v_mort_INJ(hr = hr_REL_INJ)
v_mort_OD_NEG_INJ <- v_mort_INJ(hr = hr_OD_INJ)
v_mort_OD_POS_INJ <- v_mort_INJ(hr = hr_HIV_OD_INJ) # REMOVE THIS AFTER CA REP
v_mort_ABS_NEG_INJ <- v_mort_INJ(hr = hr_ABS_INJ)
v_mort_ABS_POS_INJ <- v_mort_INJ(hr = hr_HIV_INJ)
# Create empty mortality matrix
m_mort <- array(0, dim = c(n_states, n_t),
dimnames = list(v_n_states, 1:n_t))
# Populate mortality matrix (monthly death probability from each state)
for (i in 1:n_t){
# Non-injection
m_mort[MET & NI, i] <- v_mort_MET_NI[i]
m_mort[REL1 & NI, i] <- v_mort_REL1_NI[i]
m_mort[REL & NI, i] <- v_mort_REL_NI[i]
m_mort[OD & NI & NEG, i] <- v_mort_OD_NEG_NI[i]
m_mort[OD & NI & POS, i] <- v_mort_OD_POS_NI[i]
m_mort[ABS & NI & NEG, i] <- v_mort_ABS_NEG_NI[i]
m_mort[ABS & NI & POS, i] <- v_mort_ABS_POS_NI[i]
# Injection
m_mort[MET & INJ, i] <- v_mort_MET_INJ[i]
m_mort[REL1 & INJ, i] <- v_mort_REL1_INJ[i]
m_mort[REL & INJ, i] <- v_mort_REL_INJ[i]
m_mort[OD & INJ & NEG, i] <- v_mort_OD_NEG_INJ[i]
m_mort[OD & INJ & POS, i] <- v_mort_OD_POS_INJ[i]
m_mort[ABS & INJ & NEG, i] <- v_mort_ABS_NEG_INJ[i]
m_mort[ABS & INJ & POS, i] <- v_mort_ABS_POS_INJ[i]
}
# Checks
write.csv(m_mort,"C:/Users/Benjamin/Desktop/m_mort.csv", row.names = TRUE)
# Alive probability in each period
m_alive <- 1 - m_mort
#### Unconditional transition probabilities ####
# Empty 2-D unconditional transition matrix (from states, to states)
m_UP <- array(0, dim = c(n_states, n_states),
dimnames = list(v_n_states, v_n_states))
# Populate unconditional transition matrix
# Non-Injection
# From MET
m_UP[MET & NI, ABS & NI] <- p_MET_ABS_NI
m_UP[MET & NI, REL1 & NI] <- p_MET_REL1_NI
m_UP[MET & NI, OD & NI] <- p_MET_OD_NI
# From ABS
m_UP[ABS & NI, REL1 & NI] <- p_ABS_REL1_NI
m_UP[ABS & NI, OD & NI] <- p_ABS_OD_NI
# From REL1
m_UP[REL1 & NI, REL & NI] <- p_REL1_REL_NI
m_UP[REL1 & NI, MET & NI] <- p_REL1_MET_NI
m_UP[REL1 & NI, ABS & NI] <- p_REL1_ABS_NI
m_UP[REL1 & NI, OD & NI] <- p_REL1_OD_NI
# From REL
m_UP[REL & NI, MET & NI] <- p_REL_MET_NI
m_UP[REL & NI, ABS & NI] <- p_REL_ABS_NI
m_UP[REL & NI, OD & NI] <- p_REL_OD_NI
# From OD
m_UP[OD & NI, MET & NI] <- p_OD_MET_NI
m_UP[OD & NI, ABS & NI] <- p_OD_ABS_NI
m_UP[OD & NI, REL1 & NI] <- p_OD_REL1_NI
# Injection
# From MET
m_UP[MET & INJ, ABS & INJ] <- p_MET_ABS_INJ
m_UP[MET & INJ, REL1 & INJ] <- p_MET_REL1_INJ
m_UP[MET & INJ, OD & INJ] <- p_MET_OD_INJ
# From ABS
m_UP[ABS & INJ, REL1 & INJ] <- p_ABS_REL1_INJ
m_UP[ABS & INJ, OD & INJ] <- p_ABS_OD_INJ
# From REL1
m_UP[REL1 & INJ, REL & INJ] <- p_REL1_REL_INJ
m_UP[REL1 & INJ, MET & INJ] <- p_REL1_MET_INJ
m_UP[REL1 & INJ, ABS & INJ] <- p_REL1_ABS_INJ
m_UP[REL1 & INJ, OD & INJ] <- p_REL1_OD_INJ
# From REL
m_UP[REL & INJ, MET & INJ] <- p_REL_MET_INJ
m_UP[REL & INJ, ABS & INJ] <- p_REL_ABS_INJ
m_UP[REL & INJ, OD & INJ] <- p_REL_OD_INJ
# From OD
m_UP[OD & INJ, MET & INJ] <- p_OD_MET_INJ
m_UP[OD & INJ, ABS & INJ] <- p_OD_ABS_INJ
m_UP[OD & INJ, REL1 & INJ] <- p_OD_REL1_INJ
# Apply transition rules
# Episode rules
# Disallowed transitions
m_UP[EP1, EP3] = 0
m_UP[EP2, EP1] = 0
m_UP[EP3, EP1] = 0
m_UP[EP3, EP2] = 0
m_UP[POS, NEG] = 0
m_UP[ABS, TX] = 0
m_UP[REL1, REL1] = 0
# Conditional transitions
# Maintain cycles (initiate episode i+1 with OOT -> TX)
m_UP[TX & EP1, TX & EP2] = 0
m_UP[TX & EP2, TX & EP3] = 0
m_UP[TX & EP1, OOT & EP2] = 0
m_UP[TX & EP2, OOT & EP3] = 0
m_UP[OOT & EP1, OOT & EP2] = 0
m_UP[OOT & EP2, OOT & EP3] = 0
m_UP[OOT & EP1, TX & EP1] = 0
m_UP[OOT & EP2, TX & EP2] = 0
# Checks
write.csv(m_UP,"C:/Users/Benjamin/Desktop/m_UP.csv", row.names = TRUE)
#### Create full time-dependent transition array ####
# Empty 3-D array
a_TDP <- array(0, dim = c(n_states, n_states, n_t),
dimnames = list(v_n_states, v_n_states, 1:n_t))
# Add transitions conditional on state-exit (m_leave = 1 - remain)
for (i in 1:n_t){
a_TDP[, , i] <- m_UP * m_leave[, i]
}
# Add time-dependent remain probabilities
for (i in 1:n_t){
for (j in 1:n_states){
a_TDP[j, j, i] <- m_TDP[j, i]
}
}
# Add NEG -> POS remain probabilities
# To-do: See if there is a better way to do this
for (i in 1:n_t){
# Non-injection
a_TDP[MET & NI & EP1 & NEG, MET & NI & EP1 & POS, i] <- m_TDP[MET & NI & EP1 & NEG, i]
a_TDP[MET & NI & EP2 & NEG, MET & NI & EP2 & POS, i] <- m_TDP[MET & NI & EP2 & NEG, i]
a_TDP[MET & NI & EP3 & NEG, MET & NI & EP3 & POS, i] <- m_TDP[MET & NI & EP3 & NEG, i]
a_TDP[REL & NI & EP1 & NEG, REL & NI & EP1 & POS, i] <- m_TDP[REL & NI & EP1 & NEG, i]
a_TDP[REL & NI & EP2 & NEG, REL & NI & EP2 & POS, i] <- m_TDP[REL & NI & EP2 & NEG, i]
a_TDP[REL & NI & EP3 & NEG, REL & NI & EP3 & POS, i] <- m_TDP[REL & NI & EP3 & NEG, i]
a_TDP[OD & NI & EP1 & NEG, OD & NI & EP1 & POS, i] <- m_TDP[OD & NI & EP1 & NEG, i]
a_TDP[OD & NI & EP2 & NEG, OD & NI & EP2 & POS, i] <- m_TDP[OD & NI & EP2 & NEG, i]
a_TDP[OD & NI & EP3 & NEG, OD & NI & EP3 & POS, i] <- m_TDP[OD & NI & EP3 & NEG, i]
a_TDP[ABS & NI & EP1 & NEG, ABS & NI & EP1 & POS, i] <- m_TDP[ABS & NI & EP1 & NEG, i]
a_TDP[ABS & NI & EP2 & NEG, ABS & NI & EP2 & POS, i] <- m_TDP[ABS & NI & EP2 & NEG, i]
a_TDP[ABS & NI & EP3 & NEG, ABS & NI & EP3 & POS, i] <- m_TDP[ABS & NI & EP3 & NEG, i]
# Injection
a_TDP[MET & INJ & EP1 & NEG, MET & INJ & EP1 & POS, i] <- m_TDP[MET & INJ & EP1 & NEG, i]
a_TDP[MET & INJ & EP2 & NEG, MET & INJ & EP2 & POS, i] <- m_TDP[MET & INJ & EP2 & NEG, i]
a_TDP[MET & INJ & EP3 & NEG, MET & INJ & EP3 & POS, i] <- m_TDP[MET & INJ & EP3 & NEG, i]
a_TDP[REL & INJ & EP1 & NEG, REL & INJ & EP1 & POS, i] <- m_TDP[REL & INJ & EP1 & NEG, i]
a_TDP[REL & INJ & EP2 & NEG, REL & INJ & EP2 & POS, i] <- m_TDP[REL & INJ & EP2 & NEG, i]
a_TDP[REL & INJ & EP3 & NEG, REL & INJ & EP3 & POS, i] <- m_TDP[REL & INJ & EP3 & NEG, i]
a_TDP[OD & INJ & EP1 & NEG, OD & INJ & EP1 & POS, i] <- m_TDP[OD & INJ & EP1 & NEG, i]
a_TDP[OD & INJ & EP2 & NEG, OD & INJ & EP2 & POS, i] <- m_TDP[OD & INJ & EP2 & NEG, i]
a_TDP[OD & INJ & EP3 & NEG, OD & INJ & EP3 & POS, i] <- m_TDP[OD & INJ & EP3 & NEG, i]
a_TDP[ABS & INJ & EP1 & NEG, ABS & INJ & EP1 & POS, i] <- m_TDP[ABS & INJ & EP1 & NEG, i]
a_TDP[ABS & INJ & EP2 & NEG, ABS & INJ & EP2 & POS, i] <- m_TDP[ABS & INJ & EP2 & NEG, i]
a_TDP[ABS & INJ & EP3 & NEG, ABS & INJ & EP3 & POS, i] <- m_TDP[ABS & INJ & EP3 & NEG, i]
}
write.csv(a_TDP[, ,50],"C:/Users/Benjamin/Desktop/a_TDP.csv", row.names = TRUE)
#### Seroconversion ####
# Apply seroconversion probability to re-weight NEG -> POS for to-states each time period
# Probabilities applied equally across POS/NEG initially, re-weight by sero prob
# Non-injection
a_TDP[NEG & NI, MET & NI & NEG, ] <- a_TDP[NEG & NI, MET & NI & NEG, ] * (1 - p_sero_MET_NI)
a_TDP[NEG & NI, MET & NI & POS, ] <- a_TDP[NEG & NI, MET & NI & POS, ] * p_sero_MET_NI
a_TDP[NEG & NI, REL1 & NI & NEG, ] <- a_TDP[NEG & NI, REL1 & NI & NEG, ] * (1 - p_sero_REL1_NI)
a_TDP[NEG & NI, REL1 & NI & POS, ] <- a_TDP[NEG & NI, REL1 & NI & POS, ] * p_sero_REL1_NI
a_TDP[NEG & NI, REL & NI & NEG, ] <- a_TDP[NEG & NI, REL & NI & NEG, ] * (1 - p_sero_REL_NI)
a_TDP[NEG & NI, REL & NI & POS, ] <- a_TDP[NEG & NI, REL & NI & POS, ] * p_sero_REL_NI
a_TDP[NEG & NI, OD & NI & NEG, ] <- a_TDP[NEG & NI, OD & NI & NEG, ] * (1 - p_sero_OD_NI)
a_TDP[NEG & NI, OD & NI & POS, ] <- a_TDP[NEG & NI, OD & NI & POS, ] * p_sero_OD_NI
a_TDP[NEG & NI, ABS & NI & NEG, ] <- a_TDP[NEG & NI, ABS & NI & NEG, ] * (1 - p_sero_ABS_NI)
a_TDP[NEG & NI, ABS & NI & POS, ] <- a_TDP[NEG & NI, ABS & NI & POS, ] * p_sero_ABS_NI
# Injection
a_TDP[NEG & INJ, MET & INJ & NEG, ] <- a_TDP[NEG & INJ, MET & INJ & NEG, ] * (1 - p_sero_MET_INJ)
a_TDP[NEG & INJ, MET & INJ & POS, ] <- a_TDP[NEG & INJ, MET & INJ & POS, ] * p_sero_MET_INJ
a_TDP[NEG & INJ, REL1 & INJ & NEG, ] <- a_TDP[NEG & INJ, REL1 & INJ & NEG, ] * (1 - p_sero_REL1_INJ)
a_TDP[NEG & INJ, REL1 & INJ & POS, ] <- a_TDP[NEG & INJ, REL1 & INJ & POS, ] * p_sero_REL1_INJ
a_TDP[NEG & INJ, REL & INJ & NEG, ] <- a_TDP[NEG & INJ, REL & INJ & NEG, ] * (1 - p_sero_REL_INJ)
a_TDP[NEG & INJ, REL & INJ & POS, ] <- a_TDP[NEG & INJ, REL & INJ & POS, ] * p_sero_REL_INJ
a_TDP[NEG & INJ, OD & INJ & NEG, ] <- a_TDP[NEG & INJ, OD & INJ & NEG, ] * (1 - p_sero_OD_INJ)
a_TDP[NEG & INJ, OD & INJ & POS, ] <- a_TDP[NEG & INJ, OD & INJ & POS, ] * p_sero_OD_INJ
a_TDP[NEG & INJ, ABS & INJ & NEG, ] <- a_TDP[NEG & INJ, ABS & INJ & NEG, ] * (1 - p_sero_ABS_INJ)
a_TDP[NEG & INJ, ABS & INJ & POS, ] <- a_TDP[NEG & INJ, ABS & INJ & POS, ] * p_sero_ABS_INJ
# Episode rules
# Disallowed transitions
a_TDP[EP1, EP3, ] = 0
a_TDP[EP2, EP1, ] = 0
a_TDP[EP3, EP1, ] = 0
a_TDP[EP3, EP2, ] = 0
a_TDP[POS, NEG, ] = 0
a_TDP[ABS, TX, ] = 0
a_TDP[REL1, REL1, ] = 0
# Conditional transitions
# Next episode with out-of-treatment(OOT) EPi -> treatment(TX) EP(i+1)
a_TDP[TX & EP1, OOT & EP2, ] = 0
a_TDP[TX & EP2, OOT & EP3, ] = 0
a_TDP[OOT & EP1, TX & EP1, ] = 0
a_TDP[OOT & EP2, TX & EP2, ] = 0
#### Check transition array ####
check_transition_probability(a_P = a_TDP, err_stop = err_stop, verbose = verbose) # check all probs [0, 1]
check_sum_of_transition_array(a_P = a_TDP, n_states = n_states, n_t = n_t, err_stop = err_stop, verbose = verbose) # check prob sums = 1
#### Run Markov model ####
# Create empty initial state vectors
v_s_init <- rep(0, n_states)
names(v_s_init) <- v_n_states
#### Set initial state vector ####
# Baseline
# Populate first episode in base states
v_s_init[MET & EP1] <- v_init_dist["pe", "MET"]
v_s_init[REL1 & EP1] <- v_init_dist["pe", "REL1"]
v_s_init[REL & EP1] <- v_init_dist["pe", "REL"]
v_s_init[OD & EP1] <- v_init_dist["pe", "OD"]
v_s_init[ABS & EP1] <- v_init_dist["pe", "ABS"]
# Distribute by injection/non-injection
v_s_init[NI] <- v_s_init[NI] * (1 - p_INJ)
v_s_init[INJ] <- v_s_init[INJ] * p_INJ
# Distribute HIV+/-
v_s_init[NEG] <- v_s_init[NEG] * (1 - p_HIV_POS)
v_s_init[POS] <- v_s_init[POS] * p_HIV_POS
write.csv(v_s_init[],"C:/Users/Benjamin/Desktop/v_s_init.csv", row.names = TRUE)
# Create Markov Trace
# Initialize population
a_M_trace <- array(0, dim = c((n_t + 1), n_states, (n_t + 1)),
dimnames = list(0:n_t, v_n_states, 0:n_t))
a_M_trace[1, , 1] <- v_s_init
# All model time periods
for(i in 2:(n_t)){
# Time spent in given health state
for(j in 1:(i - 1)){
#state-time-dependent transition probability (j) * age (model-time)-specific mortality (i)
m_sojourn <- a_TDP[, , j] * m_alive[, i - 1]
v_current_state <- as.vector(a_M_trace[i - 1, , j])
v_same_state <- as.vector(v_current_state * diag(m_sojourn)) # diag returns probability of remaining
a_M_trace[i, ,j + 1] <- v_same_state # add remain to trace
diag(m_sojourn) <- 0
v_new_state <- as.vector(v_current_state %*% m_sojourn) # individuals transitioning to new state
a_M_trace[i, ,1] <- v_new_state + a_M_trace[i, ,1]
}
}
# Collect trace for time-periods across all model states
m_M_trace <- array(0, dim = c((n_t + 1), n_states),
dimnames = list(0:n_t, v_n_states))
for (i in 1:n_t){
m_M_trace[i, ] <- rowSums(a_M_trace[i, ,])
}
# Count cumulative state-specific deaths
m_M_trace_death <- array(0, dim = c((n_t + 1), n_states),
dimnames = list(0:n_t, v_n_states))
for (i in 2:n_t){
m_M_trace_death[i, ] <- m_M_trace[i - 1, ] * m_mort[, i - 1] # State-specific deaths at each time point as function of alive in t-1
}
m_M_trace_cumsum_death <- apply(m_M_trace_death, 2, cumsum) # Cumulative deaths at each time point (use m_M_trace_death for individual period deaths)
#### Create aggregated trace matrices ####
v_agg_trace_states <- c("Alive", "Death", "OD", "REL1", "REL", "MET", "ABS") # states to aggregate
v_agg_trace_death_states <- c("Total", "OD", "REL1", "REL", "MET", "ABS") # states to aggregate
v_agg_trace_sero_states <- c("HIV - Alive", "HIV - Dead") # states to aggregate
n_agg_trace_states <- length(v_agg_trace_states)
n_agg_trace_death_states <- length(v_agg_trace_death_states)
n_agg_trace_sero_states <- length(v_agg_trace_sero_states)
m_M_agg_trace <- array(0, dim = c((n_t + 1), n_agg_trace_states),
dimnames = list(0:n_t, v_agg_trace_states))
m_M_agg_trace_death <- array(0, dim = c((n_t + 1), n_agg_trace_death_states),
dimnames = list(0:n_t, v_agg_trace_death_states))
m_M_agg_trace_sero <- array(0, dim = c((n_t + 1), n_agg_trace_sero_states),
dimnames = list(0:n_t, v_agg_trace_sero_states))
for (i in 1:n_t){
m_M_agg_trace[i, "Alive"] <- sum(m_M_trace[i, ])
m_M_agg_trace[i, "MET"] <- sum(m_M_trace[i, MET])
m_M_agg_trace[i, "REL1"] <- sum(m_M_trace[i, REL1])
m_M_agg_trace[i, "REL"] <- sum(m_M_trace[i, REL])
m_M_agg_trace[i, "ABS"] <- sum(m_M_trace[i, ABS])
m_M_agg_trace[i, "OD"] <- sum(m_M_trace[i, OD])
m_M_agg_trace[i, "Death"] <- 1 - sum(m_M_trace[i, ])
}
for (i in 1:n_t){
m_M_agg_trace_death[i, "Total"] <- sum(m_M_trace_cumsum_death[i, ])
m_M_agg_trace_death[i, "OD"] <- sum(m_M_trace_cumsum_death[i, OD])
m_M_agg_trace_death[i, "REL1"] <- sum(m_M_trace_cumsum_death[i, REL1])
m_M_agg_trace_death[i, "REL"] <- sum(m_M_trace_cumsum_death[i, REL])
m_M_agg_trace_death[i, "MET"] <- sum(m_M_trace_cumsum_death[i, MET])
m_M_agg_trace_death[i, "ABS"] <- sum(m_M_trace_cumsum_death[i, ABS])
}
for (i in 1:n_t){
m_M_agg_trace_sero[i, "HIV - Alive"] <- sum(m_M_trace[i, POS])
m_M_agg_trace_sero[i, "HIV - Dead"] <- sum(m_M_trace_cumsum_death[i, POS])
}
return(list(l_index_s = l_index_s,
a_TDP = a_TDP,
m_M_trace = m_M_trace,
m_M_agg_trace = m_M_agg_trace,
m_M_agg_trace_death = m_M_agg_trace_death,
m_M_agg_trace_sero = m_M_agg_trace_sero))
}
)
}
#' Check if transition array is valid
#'
#' \code{check_transition_probability} checks if individual transition probabilities are in \[0, 1\].
#'
#' @param a_P A transition probability array.
#' @param err_stop Logical variable to stop model run if set up as TRUE. Default = FALSE.
#' @param verbose Logical variable to indicate print out of messages.
#' Default = FALSE
#'
#' @return
#' This function stops if transition probability array is not valid and shows which entries are invalid
#' @import utils
#' @export
check_transition_probability <- function(a_P,
err_stop = FALSE,
verbose = FALSE) {
m_indices_notvalid <- arrayInd(which(a_P < 0 | a_P > 1),
dim(a_P))
if(dim(m_indices_notvalid)[1] != 0){
v_rows_notval <- rownames(a_P)[m_indices_notvalid[, 1]]
v_cols_notval <- colnames(a_P)[m_indices_notvalid[, 2]]
v_cycles_notval <- dimnames(a_P)[[3]][m_indices_notvalid[, 3]]
df_notvalid <- data.frame(`Transition probabilities not valid:` =
matrix(paste0(paste(v_rows_notval, v_cols_notval, sep = "->"),
"; at cycle ",
v_cycles_notval), ncol = 1),
check.names = FALSE)
if(err_stop) {
stop("Not valid transition probabilities\n",
paste(capture.output(df_notvalid), collapse = "\n"))
}
if(verbose){
warning("Not valid transition probabilities\n",
paste(capture.output(df_notvalid), collapse = "\n"))
}
}
}
#' Check if the sum of transition probabilities equal to one.
#'
#' \code{check_sum_of_transition_array} checks if each of the rows of the
#' transition matrices sum to one.
#'
#' @param a_P Transition probability array.
#' @param n_states Number of health states.
#' @param n_t Number of time periods.
#' @param err_stop Logical variable to stop model run if set up as TRUE. Default = FALSE.
#' @param verbose Logical variable to indicate print out of messages. Default = FALSE.
#' @return
#' The transition probability array and the cohort trace matrix.
#' @import dplyr
#' @export
check_sum_of_transition_array <- function(a_P,
n_states,
n_t,
err_stop = FALSE,
verbose = FALSE) {
valid <- (apply(a_P, 3, function(x) sum(rowSums(x))) == n_states)
if (!isTRUE(all_equal(as.numeric(sum(valid)), as.numeric(n_t)))) {
if(err_stop) {
stop("This is not a valid transition Matrix")
}
if(verbose){
warning("This is not a valid transition Matrix")
}
}
}
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