make_table2 and its associated methods are provided to create standard table 2s based on the supplied results from appropriate estimation routines. A typical table 2 consist of one row for each treatment group in each results object. The table contains the number of subjects, total amount of observed person-time during follow-up, number of events, estimates of interest (possibly at a specified time point, when applicable), and confidence interval for the specified coverage level. When there are multiple treatment groups for a given results object then a typical table 2 also adds a column providing the specified effect measure and associated confidence interval comparing a given treatment to the reference group for each row with the exception of the reference group.

Note that the person-time, events, and rates are computed using all of the follow-up time and not with respect to e.g. risk_time or count_time (as appropriate).

make_table2(obj, ...)

# S3 method for cumrisk
make_table2(
  ...,
  effect_measure_type = "RD",
  rate_round = 2,
  pt_round = 0,
  pt_scale = 1,
  risk_round = 1,
  risk_time = NULL,
  alpha = 0.05,
  rate_alpha = 0.05,
  ref = 1,
  boot_method = "normal",
  caption = "",
  table_footer = "",
  calc_rate_ci = FALSE,
  scale_pt_display = TRUE
)

# S3 method for cumcount
make_table2(
  ...,
  effect_measure_type = "CD",
  count_round = 1,
  count_time = NULL,
  alpha = 0.05,
  ref = 1,
  boot_method = "normal",
  caption = "",
  table_footer = ""
)

# S3 method for hr
make_table2(..., hr_round = 2, alpha = 0.05, caption = "", table_footer = "")

Arguments

obj

An object with an associated method for creating table 2s.

...

For the make_table2 generic function, arguments to be passed on to the appropriate method. For a given method, any remaining inputs to ... should be objects with an associated method for creating table 2s supplied as either as seperate arguments or as a list.

effect_measure_type

A string identifying the type of effect measure to be computed from among the following options for a given method.

  • cumrisk: "RD" (risk difference), "RR" (risk ratio), "logRR" (logarithm of the risk ratio), or "AR" (attributable risk)

  • cumcount: "CD" (count difference) or "CR" (count ratio)

Note that when a given input results object was created using bootstrap estimation and boot_method is "log-normal", then only effect measures with support on the positive real line can be used (i.e. "RR" or "CR"). See the Cumulative risk effect measure types and Cumulative count effect measure types sections for the definitions of the various effect measures.

rate_round

The number of significant digits used for rounding the rate

pt_round

The number of significant digits used for rounding person-time

pt_scale

A scaling factor for the person time (default pt_scale = 1).

risk_round

The number of significant digits used for rounding the risk

risk_time

The time at which the cumulative risk estimates should be returned (the default value of NULL returns all times)

alpha

The desired nominal significance level of the confidence intervals

rate_alpha

The desired nominal significance level of the confidence intervals for the rate

ref

The category to use as the reference for effect measure calculations.

boot_method

The specific bootstrap approach used to compute confidence intervals (default method = "normal" for a normal approximation on the risk scale, other choices include "log-normal" for normal approximation on the log scale). When a given input results object was created without using bootstrap estimation then the value of boot_method is ignored. Note that when a given input results object was created using bootstrap estimation and boot_method is "log-normal", then only effect measures specified via effect_measure_type with support on the positive real line can be used.

caption

Text that will be added above the top left of the table, ie a title to the table

table_footer

Additional footer information accepts html formatting

calc_rate_ci

Logical that allows user to output confidence intervals for rates in table 2. Defaults to FALSE.

scale_pt_display

Logical that allows user to turn off pt_scale for person-time but not for rate (default = TRUE)

count_round

The number of significant digits used for rounding the count

count_time

The desired time at which to extract the the cumulative count and count difference. If NULL, uses the median time in the cumcount object.

hr_round

The number of decimal places used for rounding the hazard ratio. Default is 2.

Value

An object of class c("datatables", "htmlwidget") used to display the results.

Methods (by class)

  • make_table2(cumrisk): Creates a formatted table 2 from supplied cumrisk objects

  • make_table2(cumcount): Creates a formatted table 2 from supplied cumcount objects

  • make_table2(hr): Creates a formatted table 2 from supplied hr objects

Cumulative risk effect measure types

Risk difference

Mean: \(\mathrm{E}[Y^{1}] - \mathrm{E}[Y^{0}]\)

Variance with IPW: \( \mathrm{Var}[Y^{1}] + \mathrm{Var}[Y^{0}] + \frac{2}{n} \mathrm{E}[Y^{1}] \, \mathrm{E}[Y^{0}] \)

Variance otherwise: \(\mathrm{Var}[Y^{1}] + \mathrm{Var}[Y^{0}]\)

Risk ratio

Mean: \(\frac{\mathrm{E}[Y^{1}]}{\mathrm{E}[Y^{0}]}\)

Variance with IPW: \( \frac{\mathrm{Var}[Y^{1}]}{(\mathrm{E}[Y^{0}])^{2}} + \frac{\mathrm{Var}[Y^{0}]\,(\mathrm{E}[Y^{1}])^2} {(\mathrm{E}[Y^{0}])^{4}} + \frac{2\,(\mathrm{E}[Y^{1}])^2}{n\,(\mathrm{E}[Y^{0}])^2} \)

Variance otherwise: \( \frac{\mathrm{Var}[Y^{1}]}{(\mathrm{E}[Y^{0}])^{2}} + \frac{\mathrm{Var}[Y^{0}]\,(\mathrm{E}[Y^{1}])^2} {(\mathrm{E}[Y^{0}])^{4}} \)

Logarithm of the risk ratio

Mean: \(\mathrm{log}\frac{\mathrm{E}[Y^{1}]}{\mathrm{E}[Y^{0}]}\)

Variance with IPW: \( \frac{\mathrm{Var}[Y^{1}]}{(\mathrm{E}[Y^{1}])^{2}} + \frac{\mathrm{Var}[Y^{0}]}{(\mathrm{E}[Y^{0}])^{2}} + \frac{2}{n} \)

Variance otherwise: \( \frac{\mathrm{Var}[Y^{1}]}{(\mathrm{E}[Y^{1}])^{2}} + \frac{\mathrm{Var}[Y^{0}]}{(\mathrm{E}[Y^{0}])^{2}} \)

Attributable risk

Mean: \(\frac{\mathrm{E}[Y^{1}] - \mathrm{E}[Y^{0}]}{\mathrm{E}[Y^{1}]}\)

Variance with IPW: \( \frac{\mathrm{Var}[Y^{0}]}{(\mathrm{E}[Y^{1}])^{2}} + \frac{\mathrm{Var}[Y^{1}]\,(\mathrm{E}[Y^{0}])^{2}} {(\mathrm{E}[Y^{1}])^{4}} + \frac{2\,(\mathrm{E}[Y^{0}])^{2}}{n\,(\mathrm{E}[Y^{1}])^{2}} \)

Variance otherwise: \( \frac{\mathrm{Var}[Y^{0}]}{(\mathrm{E}[Y^{1}])^{2}} + \frac{\mathrm{Var}[Y^{1}]\,(\mathrm{E}[Y^{0}])^{2}} {(\mathrm{E}[Y^{1}])^{4}} \)

Cumulative count effect measure types

Count difference

Mean: \(\mathrm{E}[Y^{1}] - \mathrm{E}[Y^{0}]\)

Variance with IPW: \( \mathrm{Var}[Y^{1}] + \mathrm{Var}[Y^{0}] + \frac{2}{n} \mathrm{E}[Y^{1}] \, \mathrm{E}[Y^{0}] \)

Variance otherwise: \(\mathrm{Var}[Y^{1}] + \mathrm{Var}[Y^{0}]\)

Count ratio

Mean: \(\frac{\mathrm{E}[Y^{1}]}{\mathrm{E}[Y^{0}]}\)

Variance with IPW: \( \frac{\mathrm{Var}[Y^{1}]}{(\mathrm{E}[Y^{0}])^{2}} + \frac{\mathrm{Var}[Y^{0}]\,(\mathrm{E}[Y^{1}])^2} {(\mathrm{E}[Y^{0}])^{4}} + \frac{2\,(\mathrm{E}[Y^{1}])^2}{n\,(\mathrm{E}[Y^{0}])^2} \)

Variance otherwise: \( \frac{\mathrm{Var}[Y^{1}]}{(\mathrm{E}[Y^{0}])^{2}} + \frac{\mathrm{Var}[Y^{0}]\,(\mathrm{E}[Y^{1}])^2} {(\mathrm{E}[Y^{0}])^{4}} \)

Author

make_table2: Alexander Breskin

make_table2.cumrisk: M. Alan Brookhart & Robert A. Overman

make_table2.cumcount: M. Alan Brookhart & Robert A. Overman & Alexander Breskin

make_table2.hr: Brendan Brown