# lyl_diff_ref

##### Summarize differences in Life Years Lost.

`lyl_diff`

summarizes differences in estimated Life Years Lost
in two different populations: `lyl_estimation1`

compared to a life table provided in `data_ref`

.

##### Usage

```
lyl_diff_ref(lyl_population1, data_ref, age, surv, rates, decimals = 2,
level = 0.95, weights = NA, lyl_population0)
```

##### Arguments

- lyl_population1
Population of interest: An object of class

`lyl`

or`lyl_range`

(obtained with functions`lyl`

or`lyl_range`

). Alternatively, an object of class`lyl_ci`

can be provided for bootstrapped confidence intervals.- data_ref
A dataframe, where each raw represents an age, for the population of reference The dataframe will contain information on age-specific mortality rates or survivial probability (if both parameters are provided, rates will be used).

- age
Variable in

`data_ref`

containing information on age.- surv
Variable in

`data_ref`

containing information on age-specific survival probability.- rates
Variable in

`data_ref`

containing information on age-specific mortality rates.- decimals
Number of decimals to be reported (default is 2).

- level
Confidence level if

`lyl_population1`

or`lyl_population0`

is obtained with the`lyl_ci`

function (default is 0.95 for 95% confidence intervals)- weights
Vector with age distribution of disease/condition onset to be used when Life Years Lost are estimated over a range of ages (with

`lyl_range`

function). If weights are not provided (dafault is`weights = NA`

), then the differences in Life Years Lost at each age is provided. If weights are provided, then a weighted average is provided.- lyl_population0
Parameter automatically created.

##### Value

A table with the summary of the differences between two populations.

##### References

Plana-Ripoll et al. lillies <U+2013> An R package for the estimation of excess Life Years Lost among patients with a given disease or condition.

*PLoS ONE*. 2020;15(3):e0228073.

##### See Also

##### Examples

```
# NOT RUN {
# Load simulated data as example
data(simu_data)
data(pop_ref)
# Estimate remaining life expectancy and Life Years
# Lost due to specific causes of death after age 45
# years and before age 95 years for those with a disease
diseased <- simu_data[!is.na(simu_data$age_disease), ]
lyl_estimation1 <- lyl(data = diseased, t0 = age_disease,
t = age_death, status = cause_death,
age_specific = 45, tau = 95)
lyl_diff_ref(lyl_estimation1, pop_ref, age = age, surv = survival)
lyl_diff_ref(lyl_estimation1, pop_ref, age = age, rates = mortality_rates)
# Calculate bootstrapped confidence interval (3 iterations to test; more are necessary)
lyl_estimation1_ci <- lyl_ci(lyl_estimation1, niter = 3)
lyl_diff_ref(lyl_estimation1_ci, pop_ref, age = age, surv = survival)
# }
# NOT RUN {
# Estimate remaining life expectancy and Life Years
# Lost due to specific causes of death after each age
# from 0 to 94 years and before age 95 years
lyl_estimation2 <- lyl_range(data = diseased, t0 = age_disease,
t = age_death, status = cause_death,
age_begin = 0, age_end = 94, tau = 95)
lyl_diff_ref(lyl_estimation2, pop_ref, age = age, surv = survival)
lyl_diff_ref(lyl_estimation2, pop_ref, age = age, surv = survival, weights = diseased$age_disease)
# }
# NOT RUN {
# }
```

*Documentation reproduced from package lillies, version 0.2.7, License: MIT + file LICENSE*