Sensitivity, Specificity, Reliability, and Clinical Validity of Provider-Reported Symptoms
A Comparison with Self-Reported Symptoms
Published in: Journal of Acquired Immune Deficiency Syndromes, v. 21, no. 2, June 1, 1999, p. 126-133
BACKGROUND: If symptoms are to be recognized and effectively addressed in clinical research, they must be collected using sensitive, specific, reliable, and clinically meaningful methods. OBJECTIVE: To perform a comparison of self-administered symptom survey data with data from conventional provider-reports. DESIGN/METHODS: Secondary data analysis of AIDS Clinical Trials Group Study 081 (ACTG 081), a randomized trial taking place in 33 sites comparing three approaches to prophylaxis for Pneumocystis carinii-related pneumonia that found no difference among treatment arms. The study was performed on 842 subjects with advanced HIV infection. No intervention was undertaken as a result of this study. ACTG 081 included data on functional status, global quality of life and survival, and two methods of symptom measurement: an open-ended, provider-reported symptom assessment (provider-report) and a self-administered symptom survey (self-report). Agreement was measured using kappa scores. Sensitivity and specificity were calculated using self-report as the standard. Reliability was measured by intersite variation and test-retest reliability (8 weeks later). Clinical validity was evaluated by testing expected associations with functional status, global quality of life, and survival. RESULTS: Symptom data were available for 808 patients (96%). Patient and provider agreement was poor (mean kappa, 0.14; range, 0.07-0.25). Compared with self-report, providers underreported the presence and severity of symptoms (mean symptom count, 5.2 versus 1.3; mean severity score, 1.3 versus 0.74). provider-report demonstrated greater variability by site (R2 associated with site, 0.02 versus 0.16) and poorer test-retest reliability (mean kappa, 0.34 versus 0.25). Provider-report severity scores were less strongly associated than were self-report with functional status (chi2, 252 versus 80), global quality of life (R2 for model, 0.57 versus 0.15), and survival (chi2, 38 versus 24). Self-reported symptom severity was strongly correlated to patient-reported global quality of life (p, 0.75; p < .0001). CONCLUSIONS: Provider-reported symptoms as currently collected within the ACTG are less sensitive and reproducible than a self-administered symptom survey. Provider-reported severity scores are also more weakly associated with functional status, global quality of life, and survival. A self-reported symptom survey may provide a better method of symptom measurement for HIV research.