steno2: Clinical trial: Steno2 baseline and follow-up.
In Epi: Statistical Analysis in Epidemiology

steno2

R Documentation

Clinical trial: Steno2 baseline and follow-up.

Description

Steno-2 was a clinical trial conducted at Steno Diabetes Center 1993-2001. The intervention was intensified treatment versus conventional treatment of diabetes patients with micro-albuminuria. The datsets here concern the extended follow-up of the trial population till 2015. Three files are provided: steno2 with one record per person, st2clin with one record per clinical visit and st2alb with one record per transition between states of albuminuria.

These dataset are entirely simulated, but designed to give approximately the same results as the original.

Usage

data("steno2")
       data("st2clin")
       data("st2alb")

Format

steno2 is a data frame with 160 observations on the following 14 variables:

id: person id, numeric
allo: Original trial allocation, a factor with levels Int Conv
sex: Sex, a factor with levels F M
baseCVD: 0/1 indicator of preexisting CVD at baseline
deathCVD: 0/1 indicator whether cause of death was CVD
doBth: Date of birth, a Date
doDM: Date of diabetes diagnosis, a Date
doBase: Date of entry to study, a Date
doCVD1: Date of 1st CVD event, a Date
doCVD2: Date of 2nd CVD event, a Date
doCVD3: Date of 3rd CVD event, a Date
doESRD: Date of end stage renal disease, a Date
doEnd: Date of exit from follow-up, a Date
doDth: Date of death, a Date

st2clin is data frame with 750 observations on clinical measurements at different clinical visits:

id: person id, numeric
doV: Date of clinical visit, a Date
a1c: Glycosylated hemoglobin, mmol/mol
chol: Total cholesterol, mg/mol
crea: Creatinine, mg/mol

st2alb is data frame with 307 observations of changes in complication (albuminuria) state

id: person id, numeric
doTr: Date of transition, a Date
state: State of albuminuria, factor with levels Norm, Mic, Mac. All persons begin in the state Micro-albuminuria.

Details

The data are not the original; all values of measurements and dates have been randomly perturbed, to prevent identifiability of individuals. Analysis of these data will give only (very) approximately the same results as in the published article, and only some of the aspects of data are included.

References

P. Gaede, J. Oellgaard, B. Carstensen, P. Rossing, H. Lund-Andersen, H. H. Parving & O. Pedersen: Years of life gained by multifactorial intervention in patients with type 2 diabetes mellitus and microalbuminuria: 21 years follow-up on the Steno-2 randomised trial. Diabetologia (2016), 59, pp 2298-2307

Examples

data(steno2)
data(st2alb)
L2 <- Lexis( entry = list(per = doBase,
                          age = doBase - doBth),
              exit = list(per = doEnd),
       exit.status = factor(deathCVD + !is.na(doDth),
                            labels=c("Mic","D(oth)","D(CVD)")),
                id = id,
              data = cal.yr(steno2) )
summary(L2)
#
# Cut at intermediate transitions
cut2 <- data.frame(lex.id = st2alb$id,
                      cut = cal.yr(st2alb$do),
                new.state = st2alb$state)
L3 <- rcutLexis(L2, cut2)
summary(L3)
#
# no direct transitions Mic <-> Mac allowed, so put a cut in between:
dd <- subset(L3, (lex.Cst == "Mac" & lex.Xst =="Norm") |
                 (lex.Cst =="Norm" & lex.Xst == "Mac"))
# artificial visits to the middle state Mic: 
cut3 <- data.frame( lex.id = dd$lex.id,
                       cut = dd$per + dd$lex.dur/2,
                 new.state = "Mic")
L4 <- rcutLexis(L3, cut3)
summary(L4)
#
# Show all transitions
boxes(L4, boxpos = list(x = c(15,15,15,85,85),
                        y = c(50,15,85,25,75)),
          show.BE = TRUE, scale.R = 1000,
          cex=0.8, pos.arr=0.7, font=1, font.arr=1)

Epi documentation built on Oct. 1, 2024, 5:07 p.m.