OBJECTIVES To estimate the impact of performance status (ECOG), age, concomitant conditions, length of diagnosis, exposure to chemotherapy treatment and caregiver need on health related quality of life (HRQoL) in 800 adult female breast cancer patients in the USA and 5 European countries (France, Germany, Italy, Spain and UK). METHODS Data were drawn from the Adelphi Breast Cancer Disease Specific Programme (DSP), a cross-sectional study of consulting patients, undertaken in 2007. Physicians collected data on the next 7 patients presenting with breast cancer during the study period. Patients were asked to report on their HRQoL (FACT-B). OLS regressions were performed using STATA. Diagnostic tests were performed (joint significance, misspecification and multicolinearity) and White standard errors were applied. RESULTS Eight hundred (Europe, 686; USA, 114) patient records were analysed. FACT-B scores were significantly impacted in line with worsening ECOG performance status (Grade 1: -7.44, overall; -5.94, USA; -13.48, Europe; all p<0.001: Grade 2: -14.92, overall; -13.45, USA; -19.39, Europe; all p<0.001: Grade 3: -22.04, overall; -20.87, USA; -21.94, Europe; all p<0.001, except USA, p<0.05). No Grade 4 patients were present in the sample. FACT-B scores were lower overall and in Europe, in patients currently receiving chemotherapy (-9.13, overall; -9.78, Europe; all p<0.001), those with a caregiver (-5.64, overall; -7.05, Europe; all p<0.001). Longer diagnosis (+0.82, P<0.05) and presence of mental health related concomitant conditions (-7.25, P<0.05) were significant in US patients only. Age and heart related concomitant conditions were not significant. Models showed overall robustness to the diagnostic tests performed. CONCLUSIONS A significant association was seen between the patient-reported FACT-B scores and the physician-reported ECOG performance status. The impact of the various factors identified, including chemotherapy use, mental health related concomitant conditions and time since diagnosis, can provide useful indicators to be taken into account in the management of breast cancer patients.