nnt_survreg: NNT-KM and NNT-COX calculator

In vancak/NNTcalculator: Calculator of unadjusted, adjusted and marginal NNT

NNT-KM and NNT-COX calculator

Description

Calculates Laupacis' type conditional (adjusted) and harmonic mean (marginal) NNT(y|x) for survival data. Takes a data-set suitable for a survival analysis, a fixed time point y, and an explanatory variables x, and returns the estimated conditional (adjusted) NNT(y|x), and the estimated unadjusted and harmonic mean (marginal) NNT(y). In the Cox-model-based estimators, the baseline hazard is estimated by the Breslow's nonparametric MLE. In the unadjusted estimator of NNT(y), the survival probabilities are estimated by the Kaplan-Meier nonparametric MLE.

Usage

nnt_survreg(response, status, x, group, adj, time.point, data)

Arguments

response	vector of the response variable; times of the events/censoring
status	column that contains 0/1 indicator, where 1 is failure time, and 0 is censoring time.
x	vector of the explanatory variable.
group	allocated arm variable where 1 corresponds to the treatment arm, and 0 to the control arm.
adj	the x value that the NNT(y|x) need to be conditioned on (adjusted for). The default value is the mean of x.
time.point	the fixed time point y for NNT(y|x), and NNT(y)
data	analyzed data frame that contains the required variables for the computations.

Value

The estimated unadjusted, harmonic mean (marginal) and conditinoal (adjusted) NNTs with their corresponding 95 percent confidence intervals.

References

Vancak, V., Goldberg, Y., & Levine, S. Z. (2021). Guidelines to understand and compute the number needed to treat. Evidence-Based Mental Health, 24(4), 131-136.

Therneau, T. M., & Lumley, T. (2014). Package survival. Survival analysis Published on CRAN, 2, 3.

Kaplan, E. L., & Meier, P. (1958). Nonparametric estimation from incomplete observations. Journal of the American statistical association, 53(282), 457-481.

Cox, D. R., & Oakes, D. (1984). Analysis of survival data (Vol. 21). CRC Press.

Cox, D. R. (1972). Regression models and life-tables. Journal of the Royal Statistical Society: Series B (Methodological), 34(2), 187-202.

Examples

data(survreg_data)

nnt_survreg( response = survreg_data$stop,
             status   = survreg_data$status,
                   x  = survreg_data$x.1,
               group  = survreg_data$x,
                  adj = -1,
           time.point = 0.5,
                 data = survreg_data )

vancak/NNTcalculator documentation built on April 7, 2022, 3:48 a.m.