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Convert Between Odds Ratios, Risk Ratios and Other Metrics of Change in Probabilities

Source: R/convert_between_riskchange.R
oddsratio_to_riskratio.Rd

Convert Between Odds Ratios, Risk Ratios and Other Metrics of Change in Probabilities

Usage

oddsratio_to_riskratio(OR, p0, log = FALSE, verbose = TRUE, ...)

oddsratio_to_arr(OR, p0, log = FALSE, verbose = TRUE, ...)

oddsratio_to_nnt(OR, p0, log = FALSE, verbose = TRUE, ...)

logoddsratio_to_riskratio(logOR, p0, log = TRUE, verbose = TRUE, ...)

logoddsratio_to_arr(logOR, p0, log = TRUE, verbose = TRUE, ...)

logoddsratio_to_nnt(logOR, p0, log = TRUE, verbose = TRUE, ...)

riskratio_to_oddsratio(RR, p0, log = FALSE, verbose = TRUE, ...)

riskratio_to_arr(RR, p0, verbose = TRUE, ...)

riskratio_to_logoddsratio(RR, p0, log = TRUE, verbose = TRUE, ...)

riskratio_to_nnt(RR, p0, verbose = TRUE, ...)

arr_to_riskratio(ARR, p0, verbose = TRUE, ...)

arr_to_oddsratio(ARR, p0, log = FALSE, verbose = TRUE, ...)

arr_to_logoddsratio(ARR, p0, log = TRUE, verbose = TRUE, ...)

arr_to_nnt(ARR, ...)

nnt_to_oddsratio(NNT, p0, log = FALSE, verbose = TRUE, ...)

nnt_to_logoddsratio(NNT, p0, log = TRUE, verbose = TRUE, ...)

nnt_to_riskratio(NNT, p0, verbose = TRUE, ...)

nnt_to_arr(NNT, ...)

Arguments

OR, logOR, RR, ARR, NNT

Odds-ratio of odds(p1)/odds(p0), log-Odds-ratio of log(odds(p1)/odds(p0)), Risk ratio of p1/p0, Absolute Risk Reduction of p1 - p0, or Number-needed-to-treat of 1/(p1 - p0). OR and logOR can also be a logistic regression model.

p0

Baseline risk

log

If:

  • TRUE:

    • In oddsratio_to_*(), OR input is treated as log(OR).

    • In *_to_oddsratio(), returned value is log(OR).

  • FALSE:

    • In logoddsratio_to_*(), logOR input is treated as OR.

    • In *_to_logoddsratio(), returned value is OR.

verbose

Toggle warnings and messages on or off.

...

Arguments passed to and from other methods.

Value

Converted index, or if OR/logOR is a logistic regression model, a parameter table with the converted indices.

Details

If an impossible combination of risk ratio RR and baseline risk p0 is provided, such that RR * p0 > 1, then this conversion will produce invalid results where the expected risk is larger than 1. In such cases riskratio_to_*() functions will return NA.

References

Grant, R. L. (2014). Converting an odds ratio to a range of plausible relative risks for better communication of research findings. Bmj, 348, f7450.

See also

oddsratio(), riskratio(), arr(), and nnt().

Other convert between effect sizes: d_to_r(), diff_to_cles, eta2_to_f2(), odds_to_probs(), w_to_fei()

Examples

p0 <- 0.4
p1 <- 0.7

(OR <- probs_to_odds(p1) / probs_to_odds(p0))
#> [1] 3.5
(RR <- p1 / p0)
#> [1] 1.75
(ARR <- p1 - p0)
#> [1] 0.3
(NNT <- arr_to_nnt(ARR))
#> [1] 3.333333

riskratio_to_oddsratio(RR, p0 = p0)
#> [1] 3.5
oddsratio_to_riskratio(OR, p0 = p0)
#> [1] 1.75
riskratio_to_arr(RR, p0 = p0)
#> [1] 0.3
arr_to_oddsratio(nnt_to_arr(NNT), p0 = p0)
#> [1] 3.5

m <- glm(am ~ factor(cyl),
  data = mtcars,
  family = binomial()
)
oddsratio_to_riskratio(m, verbose = FALSE) # RR is relative to the intercept if p0 not provided
#> Parameter | Risk ratio |       95% CI
#> -------------------------------------
#> (p0)      |       0.73 |             
#> cyl [6]   |       0.59 | [0.11, 1.16]
#> cyl [8]   |       0.20 | [0.02, 0.70]
#> 
#> Uncertainty intervals (profile-likelihood) and p-values
#>   (two-tailed) computed using a Wald z-distribution approximation.