prLogistic (version 1.2)

Toenail: Toenail Data

Description

Data are from a multicenter study comparing two oral treatments for toe-nail infection, including information for 294 patients measured at 7 weeks, comprising a total of 1908 measurements. The outcome binary variable "onycholysis" indicates the degree of separation of the nail plate from the nail-bed (none or mild versus moderate or severe). Patients were evaluated at baseline (week 0) and at weeks 4, 8, 12, 24, 36, and 48 thereafter.

Usage

data(Toenail)

Format

A data frame with 1,908 observations on the following 5 variables:

ID

Subject's identification.

Response

Degree of onycholysis (0 if none or mild, 1 if moderate or severe).

Treatment

Oral treatment indicator (1=Treatment A, 0= Treatment B).

Month

Exact timing of measurements, in months.

Visit

Visit number (visit numbers 1-7 correspond to scheduled visits at 0, 4, 8, 12, 24, 36, and 48 weeks).

Source

The data come from Data courtesy of Novoartis, Belgium (http://www.blackwellpublishing.com/rss/datasets/C4827r.txt)

References

De Backer, M., De Vroey, C., Lesaffre, E., Scheys, I., and De Keyser, P. (1998). Twelve weeks of continuous oral therapy for toenail onychomycosis caused by dermatophytes: A double-blind comparative trial of terbinafine 250 mg/day versus itraconazole 200 mg/day. Journal of the American Academy of Dermatology, 38, 57-63.

Lesaffre, E. and Spiessens, B. (2001). On the effect of the number of quadrature points in a logistic random-effects model: An example. Journal of the Royal Statistical Society, Series C, 50, 325-335.

Rabe-Hesketh S, Skrondal A (2008). Multilevel and Longitudinal Modeling Using Stata. Mahwah, NJ: Lawrence Erlbaum Associates. Second Edition.

Examples

data("Toenail", package = "prLogistic")
attach(Toenail)
summary(Toenail)