The purpose of this historical case series study was to evaluate the association of age on delivered dose intensity of initial CHOP (cyclophosphamide/doxorubicin/ vincristine/prednisone) chemotherapy and the occurrence of hospitalizations for febrile neutropenia for patients with intermediate-grade non-Hodgkin's lymphoma (NHL). Findings are reported for 12 managed community and academic practices. Medical records of 930 NHL patients not enrolled on clinical trial protocols were reviewed. We reported on 577 of the study patients (62%) who received initial CHOP chemotherapy. Median age of the patients was 65.1 years. Older patients (age > or = 65 years) had more hospitalizations for febrile neutropenia (28% vs. 16%; P < 0.05) than younger patients (age, 18-64 years). In patients with advanced-stage NHL (stage III/IV), older patients received fewer cycles of CHOP (< 6 cycles, 35% vs. 22%; P < 0.05) than younger patients. Older patients were planned for lower average relative dose intensity (ARDI < or = 80%; P < 0.05) and had more heart disease and comorbid conditions (P < 0.05) than younger patients. Multiple logistic regression models showed that older patients were more likely to receive a lower dose intensity (ARDI < or = 80%; odds ratio = 2.46, 95% confidence interval [CI]: 1.62-3.72) during their first 3 cycles of therapy and to experience more hospitalizations for febrile neutropenia (odds ratio = 2.17, 95% CI: 1.43-3.30). We found the dose intensity of delivered CHOP chemotherapy for elderly patients to be less than standard CHOP therapy and the risk of hospitalizations for febrile neutropenia to be greater than in younger patients. Prospective clinical trials examining supportive care measures, such as colony-stimulating factor, for elderly NHL patients are recommended.