Rheumatology function tests: quantitative physical measures to monitor morbidity and predict mortality in patients with rheumatic diseases.

Physical measures of functional status, including grip strength, walking time and button test, had been used in rheumatology clinical trials for many years, but have been supplanted in recent years by patient questionnaires. While patient questionnaire measures involve minimum professional time and have greater predictive value than physical measures for severe long-term outcomes of rheumatoid arthritis (RA), physical measures bypass socio-cultural differences which may be seen in use of patient questionnaires. Inter-observer and intra-observer reliabilities of these physical measures were excellent when administered according to a standard protocol for instructions. Physical measures of function also were significant predictors of mortality in two cohorts of patients with RA, one monitored between 1973 and 1988, and a second between 1985 and 1990.