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Calculate the prevalence proportion of injured athletes and the proportion of non-injured (available) athletes in the cohort, on a monthly or season basis. Further information on the type of injury may be specified so that the injury-specific prevalences are reported according to this variable.

Usage

calc_prevalence(injd, time_period = c("monthly", "season"), by = NULL)

Arguments

injd

Prepared data. An injd object.

time_period

Character. One of "monthly" or "season", specifying the periodicity according to which to calculate the proportions of available and injured athletes.

by

Character specifying the name of the column on the basis of which to classify the injuries and calculate proportions of the injured athletes. Defaults to NULL.

Value

A data frame containing one row for each combination of season, month (optionally) and injury type (if by not specified, then this variable has two categories: Available and Injured). Plus, three more columns, specifying the proportion of athletes (prop) satisfying the corresponding row's combination of values, i.e. prevalence, how many athletes were injured at that moment with the type of injury of the corresponding row (n), over how many athletes were at that time in the cohort (n_athlete). See Note section.

Note

If by is specified (and not NULL), it may happen that an athlete in one month suffers two different types of injuries. For example, a muscle and a ligament injury. In this case, this two injuries contribute to the proportions of muscle and ligament injuries for that month, resulting in an overall proportion that exceeds 100%. Besides, the athletes in Available category are those that did not suffer any injury in that moment (season-month), that is, they were healthy all the time that the period lasted.

References

Bahr R, Clarsen B, Derman W, et al. International Olympic Committee consensus statement: methods for recording and reporting of epidemiological data on injury and illness in sport 2020 (including STROBE Extension for Sport Injury and Illness Surveillance (STROBE-SIIS)) British Journal of Sports Medicine 2020; 54:372-389.

Nielsen RO, Debes-Kristensen K, Hulme A, et al. Are prevalence measures better than incidence measures in sports injury research? British Journal of Sports Medicine 2019; 54:396-397.

Examples

# \donttest{
df_exposures <- prepare_exp(raw_df_exposures, person_id = "player_name",
                            date = "year", time_expo = "minutes_played")
df_injuries  <- prepare_inj(raw_df_injuries, person_id = "player_name",
                            date_injured = "from", date_recovered = "until")
injd         <- prepare_all(data_exposures = df_exposures,
                            data_injuries  = df_injuries,
                            exp_unit = "matches_minutes")
# }

calc_prevalence(injd, time_period = "monthly", by = "injury_type")
#> # A tibble: 98 × 6
#>    season           month status         n n_athlete  prop
#>    <fct>            <fct> <fct>      <int>     <int> <dbl>
#>  1 season 2017/2018 Jul   Available     21        23  91.3
#>  2 season 2017/2018 Jul   Muscle         2        23   8.7
#>  3 season 2017/2018 Aug   Available     18        23  78.3
#>  4 season 2017/2018 Aug   Muscle         3        23  13  
#>  5 season 2017/2018 Aug   Unknown        2        23   8.7
#>  6 season 2017/2018 Sep   Available     22        23  95.7
#>  7 season 2017/2018 Sep   Muscle         1        23   4.3
#>  8 season 2017/2018 Oct   Available     19        23  82.6
#>  9 season 2017/2018 Oct   Concussion     1        23   4.3
#> 10 season 2017/2018 Oct   Muscle         2        23   8.7
#> # ℹ 88 more rows
calc_prevalence(injd, time_period = "monthly")
#> # A tibble: 48 × 6
#>    season           month status        n n_athlete  prop
#>    <fct>            <fct> <fct>     <int>     <int> <dbl>
#>  1 season 2017/2018 Jul   Available    21        23  91.3
#>  2 season 2017/2018 Jul   Injured       2        23   8.7
#>  3 season 2017/2018 Aug   Available    18        23  78.3
#>  4 season 2017/2018 Aug   Injured       5        23  21.7
#>  5 season 2017/2018 Sep   Available    22        23  95.7
#>  6 season 2017/2018 Sep   Injured       1        23   4.3
#>  7 season 2017/2018 Oct   Available    19        23  82.6
#>  8 season 2017/2018 Oct   Injured       4        23  17.4
#>  9 season 2017/2018 Nov   Available    18        23  78.3
#> 10 season 2017/2018 Nov   Injured       5        23  21.7
#> # ℹ 38 more rows
calc_prevalence(injd, time_period = "season", by = "injury_type")
#> # A tibble: 11 × 5
#>    season           status         n n_athlete  prop
#>    <fct>            <fct>      <int>     <int> <dbl>
#>  1 season 2017/2018 Available      7        23  30.4
#>  2 season 2017/2018 Concussion     3        23  13  
#>  3 season 2017/2018 Ligament       4        23  17.4
#>  4 season 2017/2018 Muscle        11        23  47.8
#>  5 season 2017/2018 Unknown        8        23  34.8
#>  6 season 2018/2019 Available      2        19  10.5
#>  7 season 2018/2019 Bone          11        19  57.9
#>  8 season 2018/2019 Concussion    13        19  68.4
#>  9 season 2018/2019 Ligament       6        19  31.6
#> 10 season 2018/2019 Muscle        15        19  78.9
#> 11 season 2018/2019 Unknown       13        19  68.4
calc_prevalence(injd, time_period = "season")
#> # A tibble: 4 × 5
#>   season           status        n n_athlete  prop
#>   <fct>            <fct>     <int>     <int> <dbl>
#> 1 season 2017/2018 Available     7        23  30.4
#> 2 season 2017/2018 Injured      16        23  69.6
#> 3 season 2018/2019 Available     2        19  10.5
#> 4 season 2018/2019 Injured      17        19  89.5