Use of “spydergrams” to present and interpret SF-36 health-related quality of life data across rheumatic diseases

Abstract

The Medical Outcomes Study Short Form-36 (SF-36) is a generic measure of health-related quality of life (HRQOL), validated and cross-culturally translated, which has been extensively utilised in rheumatology. In randomised controlled trials and observational studies, SF-36 provides rich data regarding HRQOL; but as typically portrayed, patterns of disease and treatment-associated effects can be difficult to discern. "Spydergrams" offer a simplified means to visualise complex results across all domains of SF-36 in a single figure: depicting disease and population-specific patterns of decrements in HRQOL compared with age and gender-matched normative data, as well as providing a tool for interpreting complex treatment-associated or longitudinal changes. Utilising spydergrams as a standard format to illustrate and report changes in SF-36 across different rheumatic diseases can greatly facilitate analyses and interpretations of clinical trial results, as well as providing patients an accessible means to compare baseline scores and treatment-associated improvements with normative data from individuals without arthritis. Furthermore, SF-6D utility scores based on mean changes across all eight domains of SF-36 are suggested as a quantitative means of summarising changes illustrated by spydergrams, offering a universal metric for cost-effectiveness analyses of therapeutic interventions.