RELIABILITY AND VALIDITY OF SELF-REPORT CD4 COUNTS IN PERSONS HOSPITALIZED WITH HIV DISEASE

Studies of health care outcomes and clinical decision making for peopl e with HIV disease depend on CD4 cell count data to accurately assess the stage of disease. The possibility of obtaining reliable and valid data from self-reported CD4 counts is an unexplored source of potentia lly important, cost-effective information for these purposes. We exami ned the extent of agreement of self-reported CD4 counts with medical r ecord CD4 among 120 patients (95% male, 69% white, 5% injection drug u sers) hospitalized with HIV-related illness at seven Los Angeles area hospitals. Average record and report CD4 counts did not differ signifi cantly, and record and report CD4 counts were highly correlated (produ ct moment correlation of 0.84, intraclass correlation of 0.82). Agreem ent between self-reports and medical records varied by CD4 level: at h igher levels of CD4, the differences between self-reports and medical records tended to be larger, with sell-reports yielding upwardly biase d estimates compared to the medical records. These findings suggest th at self report CD4 data may provide clinically adequate estimates of t rue CD4 counts. The study needs to be replicated in other populations, notably those with larger numbers of subjects who are female, of mino rity ethnicity, or injection drug users. (C) 1997 Elsevier Science Inc .