qlq_cr38 {PROscorer}

Score the EORTC QLQ-CR38 Quality of Life Questionnaire

Description

Scores the European Organization for Research and Treatment of Cancer (EORTC) QLQ-CR38 Colorectal Cancer Module. (Experimental: This function was written quickly... please hand score 1 or 2 patients and check for accuracy)

Usage

qlq_cr38(df, items = NULL, keepNvalid = FALSE)

Arguments

df

A data frame containing responses to the 38 QLQ-CR38 items, and possibly other variables.

items

A character vector with the QLQ-CR38 item names, or a numeric vector indicating the column numbers of the QLQ-CR38 items in df. If items is omitted, then qlq_CR38 will assume that df contains ONLY the QLQ-CR38 items and no other variables. See Details for more information.

keepNvalid

Logical, whether to return variables containing the number of valid, non-missing items on each scale for each respondent should be returned in the data frame with the scale scores. The default is FALSE. Set to TRUE to return these variables, which will be named "scalename_N" (e.g., QL_N). Most users should omit this argument entirely. This argument might be removed from future versions of the package, so please let me know if you think this argument useful and would rather it remain a part of the function.

Details

This function returns a total of 12 different scores from the EORTC QLQ-CR38. The scoring instructions for the QLQ-CR38 are no longer available from the EORTC, and the QLQ-CR38 seems to have been superseded by the QLQ-CR29. This function calculates the QLQ-CR38 scores based on an old SPSS syntax file from the EORTC, and from Sprangers et al. (1999).

In addition to the name of your data frame containing the QLQ-CR38 item responses (df), you need to tell the function how to find the variables that correspond to the QLQ-CR38 items in df. You can do this in 1 of 2 ways:

1. The first way is to manually provide the item names or locations using the items argument. For example, if your first 10 variables in df contain demographics, followed by the 38 QLQ-CR38 items in order starting with the 11th variable, then you could use items = 11:48.

2. The second way only applies if your data frame (df) contains ONLY the 38 variables corresponding to the 38 QLQ-CR38 items, in order, with no other non-QLQ-CR38 variables. In this case, you can just use the df argument and omit items.

Value

A data frame with all 12 of the QLQ-CR38 scores is returned. Of the 12 scores, 4 are Functional Scales and 8 are Symptom Scales (see below). Of the 8 Symptom Scales, 1 is based on a single item and 7 are multi-item scales. Of the 4 Functional Scales, 2 are multi-item and 2 are based on single items. All scores are scaled to range from 0-100, even scores based on single items. Be aware that these single-item scales still have only 4 possible values, even though they are transformed to range from 0-100. The scale names and numbers of items are listed below.

How Missing Data is Handled

The qlq_cr38 function will calculate the scale scores as long as at least half of the items on the given scale have valid, non-missing item responses. Scores calculated in the presence of missing items are pro-rated so that their theoretical minimum and maximum values are identical to those from scores calculated from complete data.

Note

Some of the QLQ-CR38 items/scales are not applicable to all patients. There are 2 questions for men only, 2 questions for women only, 7 questions only for patients WITHOUT a stoma (colostomy bag), and 7 questions only for patients WITH a stoma. Patients will therefore have missing values for some of the scale scores.

Functional Scales (higher is better functioning)

• CR_BI - Body Image (3 items)

• CR_SX - Sexual Functioning (2 items)

• CR_SE - Sexual Enjoyment (1 item)

• CR_FU - Future Perspective (1 item)

Symptom Scales (higher is more symptoms, worse functioning)

• CR_MI - Micturition Problems (3 items)

• CR_GI - Gastrointestinal Tract Symptoms (5 items)

• CR_CT - Chemotherapy Side-Effects (3 items)

• CR_DF - Problems with Defacation (Only for Pts WITHOUT a stoma) (7 items)

• CR_STO - Stoma-Related Problems (Only for Pts w/stoma) (7 items)

• CR_MSX - Male Sexual Problems (2 items)

• CR_FSX - Female Sexual Problems (2 items)

• CR_WL - Weight Loss (1 item)

Optionally, the data frame can additionally have variables containing the number of valid item responses on each scale for each respondent (if keepNvalid = TRUE, but this option might be removed in future package updates).

References

Sprangers, M. A. G., te Velde, A., & Aaronson, N. K. (1999). The construction and testing of the EORTC colorectal cancer-specific quality of life questionnaire module (QLQ-CR38). European Journal of Cancer, 35(2), 238–247. https://doi.org/10.1016/S0959-8049(98)00357-8

Examples

## Not run: 
dat <- PROscorerTools::makeFakeData(n = 10, nitems = 38, prefix = "cr", values = 1:4)
qlq_cr38(dat, items = 1:38)

## End(Not run)