Patient Reported Outcomes Measurement Information System (PROMIS): Validity and Reliability in LUPUS
The PROMIS initiative began in 2004. PROMIS provides a set of instruments that measures patient-reported health status.
PROMIS uses the psychometric framework of Item Response Theory (IRT) and it is facilitated by a computer (Computer Adaptive Testing [CAT]) process. The questions in each instrument are selected on the basis of the patient's responses to previous questions. IRT's algorithm allows the selection of questions that are appropriate for each patient and adjusts the length of the test accordingly. More importantly, PROMIS allows the measurement of the construct with a minimum subset of questions compared to the use of the entire set of questions.
Kasturi et al evaluated the validity and the reliability of PROMIS CATs in patients with SLE. In this study, selected patients completed SF-36, LupusQoL and selected PROMIS CATs domains relevant to patients with lupus. PROMIS CATs domains were compared with similar domains in SF-36 and Lupus QoL. PROMIS CATs retest reliability was determined with Intraclass Correlation Coefficients (ICC).
In the 204 patients studied, PROMIS CATs correlated with SF-36 and LupusQoL, confirming the validity of PROMIS CATs.
PROMIS CATs did not correlate with measures of disease activity and damage, confirming that health-related quality of life is an independent domain very important in the management of patients with lupus.
The authors claimed an excellent reliability with an ICC ranging from 0.72 (domain: anger) to 0.88 (domain: sleep disturbance and other domains). In reliability studies, an ICC of 0.80 or greater is recommended. It is crucial to ensure that the instrument being used is reliable otherwise the utility of this instrument in the measurement of responsiveness (change over time) will be jeopardized!
In conclusion, PROMIS CATs is very promising for the assessment of patient-reported health status (health-related quality of life) BUT further work is needed!
Dr. Touma is a clinical epidemiologist and an Assistant Professor of Medicine in the Division of Rheumatology at the University of Toronto, and Staff Physician and Clinician Scientist in the Division of Rheumatology, Toronto Western Hospital and Mount Sinai Hospital. In 2012 he completed his PhD in Clinical Epidemiology and subsequently completed one year of post-doctoral work in Measurement in Clinical Research.View Full Bio