R: Psoriatic arthritis data

psor {msm} | R Documentation

## Psoriatic arthritis data

### Description

A series of observations of grades of psoriatic arthritis, as indicated by numbers of damaged joints.

### Usage

    psor

### Format

A data frame containing 806 observations, representing visits to a psoriatic arthritis (PsA) clinic from 305 patients. The rows are grouped by patient number and ordered by examination time. Each row represents an examination and contains additional covariates.

`ptnum` | (numeric) | Patient identification number
`months` | (numeric) | Examination time in months
`state` | (numeric) | Clinical state of PsA. Patients in states 1, 2, 3 and 4
|  | have 0, 1 to 4, 5 to 9 and 10 or more damaged joints,
|  | respectively.
`hieffusn` | (numeric) | Presence of five or more effusions
`ollwsdrt` | (character) | Erythrocyte sedimentation rate of less than 15 mm/h

### References

Gladman, D. D. and Farewell, V.T. (1999) Progression in psoriatic arthritis: role of time-varying clinical indicators. J. Rheumatol. 26(11):2409-13

### Examples

    ## Four-state progression-only model with high effusion and low
    ## sedimentation rate as covariates on the progression rates.  High
    ## effusion is assumed to have the same effect on the 1-2, 2-3, and 3-4
    ## progression rates, while low sedimentation rate has the same effect
    ## on the 1-2 and 2-3 intensities, but a different effect on the 3-4.

    data(psor)
    psor.q <- rbind(c(0,0.1,0,0),c(0,0,0.1,0),c(0,0,0,0.1),c(0,0,0,0))
    psor.msm <- msm(state ~ months, subject=ptnum, data=psor,
                    qmatrix = psor.q, covariates = ~ollwsdrt+hieffusn,
                    constraint = list(hieffusn=c(1,1,1),ollwsdrt=c(1,1,2)),
                    fixedpars=FALSE, control = list(REPORT=1,trace=2), method="BFGS")
    qmatrix.msm(psor.msm)
    sojourn.msm(psor.msm)
    hazard.msm(psor.msm)

[Package msm version 1.6.7 Index]