print: Print objects in the timeROC library

Description Usage Arguments Details Author(s) See Also Examples

Description

Printing of objects created with the timeROC function

Usage

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## S3 method for class 'ipcwsurvivalROC'
print(x, No.lines=5,digits=2, ...)
## S3 method for class 'ipcwcompetingrisksROC'
print(x, No.lines=5,digits=2, ...)
## S3 method for class 'ipcwsurvivalSeSpPPVNPV'
print(x, No.lines=5,digits=2, ...)
## S3 method for class 'ipcwcompetingrisksSeSpPPVNPV'
print(x, No.lines=5,digits=2, ...)

Arguments

x

Object of class "ipcwsurvivalROC", "ipcwcompetingrisksROC", "ipcwsurvivalSeSpPPVNPV" or "ipcwcompetingrisksSeSpPPVNPV".

No.lines

The (maximum) number of lines printed. Each line corresponds to a time point included in the vector times of the object x. For example, if No.lines=5, then the function chooses the five time points corresponding to the quantiles of the vector times of the object x. If No.lines=10, it chooses the deciles, etc...

digits

The number of significant digits. Default value is digits = 2.

...

Not used.

Details

The print function recalls the sample size (after having removed missing data), the AUC estimates, and the estimated standard errors (only if they have been estimated) for at maximum No.lines time points. In addition, it displays the frequencies of :

Furthermore, the function recalls the method used to compute the inverse probability of censoring weights.

Author(s)

Paul Blanche pabl@sund.ku.dk

See Also

timeROC, SeSpPPVNPV

Examples

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##-------------Without competing risks-------------------
library(survival)
data(pbc)
head(pbc)
pbc<-pbc[!is.na(pbc$trt),] # select only randomised subjects
pbc$status<-as.numeric(pbc$status==2) # create event indicator: 1 for death, 0 for censored

ROC.bili.cox<-timeROC(T=pbc$time,
                      delta=pbc$status,marker=pbc$bili,
                      other_markers=as.matrix(pbc[,c("chol","albumin")]),
                      cause=1,weighting="cox",
                      times=quantile(pbc$time,probs=seq(0.2,0.8,0.01)))

# prints descriptive statistics and AUC estimates (5,10 and 20 lines)
print(ROC.bili.cox)
print(ROC.bili.cox,No.lines=10)
print(ROC.bili.cox,No.lines=20,digits=1)

# Se, Sp, PPV and NPV computation for serum bilirunbin at threshold c=0.9(mg/dl) 
res.SeSpPPVNPV.bili <- SeSpPPVNPV(cutpoint=0.9,
                                  T=pbc$time,
                                  delta=pbc$status,marker=pbc$bili,
                                  other_markers=as.matrix(pbc[,c("chol","albumin")]),
                                  cause=1,weighting="cox",
                                  times=quantile(pbc$time,probs=seq(0.2,0.8,0.1)))

# prints descriptive statistics and Se, Sp, PPV and NPV
#  estimates for serum bilirunbin at threshold c=0.9(mg/dl) 
print(res.SeSpPPVNPV.bili,No.lines=20,digits=1)

ROC.bili.marginal<-timeROC(T=pbc$time,
                           delta=pbc$status,marker=pbc$bili,
                           cause=1,weighting="marginal",
                           times=quantile(pbc$time,probs=seq(0.1,0.9,0.2)),
                           iid=TRUE)

# prints descriptive statistics, AUC estimates and also standard errors
# of AUCs because weighting="marginal" and iid=TRUE were used.
print(ROC.bili.marginal)

##-------------With competing risks-------------------
data(Melano)
ROC.thick<-timeROC(T=Melano$time,delta=Melano$status,
                   marker=Melano$thick,cause=1,
                   weighting="marginal",
                   times=c(1500,2000,2500),iid=TRUE)

# prints descriptive statistics, AUC estimates and also standard errors
# of AUCs because weighting="marginal" and iid=TRUE were used.
print(ROC.thick)


# Se, Sp, PPV and NPV computation for tumor thickness at
#threshold c=3 (1/100 mm)
res.SeSpPPVNPV.thick <- SeSpPPVNPV(cutpoint=3,
                                  T=Melano$time,delta=Melano$status,
                                  weighting="marginal",
                                  marker=Melano$thick,cause=1,
                                  times=c(1800,2000,2200),
                                  iid=TRUE)
print(res.SeSpPPVNPV.thick,digits=1)

Example output

  id time status trt      age sex ascites hepato spiders edema bili chol
1  1  400      2   1 58.76523   f       1      1       1   1.0 14.5  261
2  2 4500      0   1 56.44627   f       0      1       1   0.0  1.1  302
3  3 1012      2   1 70.07255   m       0      0       0   0.5  1.4  176
4  4 1925      2   1 54.74059   f       0      1       1   0.5  1.8  244
5  5 1504      1   2 38.10541   f       0      1       1   0.0  3.4  279
6  6 2503      2   2 66.25873   f       0      1       0   0.0  0.8  248
  albumin copper alk.phos    ast trig platelet protime stage
1    2.60    156   1718.0 137.95  172      190    12.2     4
2    4.14     54   7394.8 113.52   88      221    10.6     3
3    3.48    210    516.0  96.10   55      151    12.0     4
4    2.54     64   6121.8  60.63   92      183    10.3     4
5    3.53    143    671.0 113.15   72      136    10.9     3
6    3.98     50    944.0  93.00   63       NA    11.0     3
Time-dependent-Roc curve estimated using IPCW  (n=284, without competing risks). 
          Cases Survivors Censored AUC (%)
t=999.2      48       226       10   83.90
t=1425.95    63       184       37   87.47
t=1839.5     76       139       69   87.57
t=2388.1     87        96      101   83.82
t=3039       98        57      129   80.11

Method used for estimating IPCW:cox 

Total computation time : 1.26  secs.
Time-dependent-Roc curve estimated using IPCW  (n=284, without competing risks). 
          Cases Survivors Censored AUC (%)
t=999.2      48       226       10   83.90
t=1233.88    58       208       18   85.34
t=1386.94    62       190       32   86.67
t=1548.4     68       170       46   87.51
t=1771.02    74       148       62   88.17
t=1964.28    78       130       76   86.92
t=2234.2     83       112       89   82.92
t=2459.7     89        90      105   83.41
t=2615.27    94        76      114   80.78
t=3039       98        57      129   80.11

Method used for estimating IPCW:cox 

Total computation time : 1.26  secs.
Time-dependent-Roc curve estimated using IPCW  (n=284, without competing risks). 
          Cases Survivors Censored AUC (%)
t=999.2      48       226       10    83.9
t=1118.45    52       219       13    84.5
t=1216       58       209       17    85.4
t=1297.57    60       201       23    86.0
t=1386.94    62       190       32    86.7
t=1434       64       180       40    87.8
t=1510.09    67       173       44    87.5
t=1614       69       163       52    87.1
t=1700.45    73       155       56    88.2
t=1785.28    74       145       65    88.0
t=1930.04    78       133       73    87.2
t=2056.3     79       123       82    85.5
t=2176.76    82       117       85    84.3
t=2267.36    84       109       91    83.6
t=2357.24    86        99       99    83.1
t=2459.7     89        90      105    83.4
t=2573.81    92        80      112    83.3
t=2658.26    94        74      116    81.0
t=2814.86    97        65      122    81.2
t=3039       98        57      129    80.1

Method used for estimating IPCW:cox 

Total computation time : 1.26  secs.
Predictive accuracy measures at cutpoint c=0.9 estimated using IPCW (n=284, with competing risks). 
No. of positive (X>c) =191, No. of negative (X<=c) =93. 

         Cases Survivors Censored Se (%) Sp (%) PPV (%) NPV (%)
t=999.2     48       226       10   95.9   39.7    24.7    97.9
t=1307.4    60       198       26   96.8   42.6    31.9    97.9
t=1548.4    68       170       46   97.2   46.3    38.0    98.0
t=1839.5    76       139       69   94.3   49.4    43.6    95.5
t=2234.2    83       112       89   90.1   48.5    46.6    90.7
t=2555.7    92        83      109   86.8   49.0    53.4    84.7
t=3039      98        57      129   86.5   51.4    59.6    82.2

Method used for estimating IPCW:cox 

Total computation time : 1.11  secs.
Time-dependent-Roc curve estimated using IPCW  (n=312, without competing risks). 
         Cases Survivors Censored AUC (%)   se
t=675.1     31       280        1   81.93 3.73
t=1307.4    68       218       26   85.66 2.56
t=1839.5    86       156       70   88.03 2.25
t=2555.7   102        94      116   83.41 3.17
t=3665.9   120        32      160   81.57 3.85

Method used for estimating IPCW:marginal 

Total computation time : 0.21  secs.
Time-dependent-Roc curve estimated using IPCW  (n=205, with competing risks). 
       Cases Survivors Other events Censored AUC_1 (%) se_1 AUC_2 (%) se_2
t=1500    36       159            8        2     80.47 3.87     79.54 3.87
t=2000    46       103           10       46     75.22 4.18     74.04 4.14
t=2500    53        66           11       75     71.14 4.77     70.12 4.63

Method used for estimating IPCW:marginal 

Total computation time : 0.52  secs.
Predictive accuracy measures at cutpoint c=3 estimated using IPCW (n=205, with competing risks). 
No. of positive (X>c) =72, 
No. of negative (X<=c) =133. 
       Cases Survivors Other events Censored   Se se_Se Sp_1 se_Sp1 Sp_2
t=1800    45       124            9       27 66.2   7.1 71.0    4.1 70.1
t=2000    46       103           10       46 64.3   7.1 71.8    4.4 70.3
t=2200    50        83           11       61 59.6   7.1 71.1    5.0 69.9
       se_Sp_2 PPV (%) se_PPV NPV_1 se_NPV_1 NPV_2 se_NPV_2
t=1800     4.0    38.9    5.7  83.8      3.3  87.8      3.0
t=2000     4.3    39.3    5.9  82.9      3.5  86.8      3.1
t=2200     4.8    41.1    6.2  77.9      4.1  83.1      3.7

Method used for estimating IPCW:marginal 

Total computation time : 0.02  secs.

timeROC documentation built on Dec. 25, 2019, 9:06 a.m.

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