A patient history generally provides the most important information in diagnosis and management of patients with most rheumatic diseases, including osteoarthritis (OA). Patient history components can be expressed as quantitative, structured, "scientific" data, rather than "subjective" narrative descriptions, using patient self-report questionnaires. The Western Ontario McMaster (WOMAC) questionnaire is used in all OA clinical trials, and the health assessment questionnaire (HAQ) in all rheumatoid arthritis (RA) clinical trials, as "disease-specific" questionnaires. However, both questionnaires include scores for physical function function and pain; physical function scores are correlated highly significantly at r=0.78 in both RA and OA patients, while WOMAC pain scores are correlated with HAQ visual analogue scale (VAS) pain scores at r=0.73 in OA and r=0.71 in RA. Therefore, the WOMAC and HAQ may be regarded as largely "generic" questionnaires, at least for people with arthritis. Since it is not feasible to ask patients with different diagnoses to complete different care questionnaires in busy clinical settings, a single multidimensional HAQ (MDHAQ), derived from the HAQ and largely similar and informative in all rheumatic diseases, has been used in all rheumatology patients in several settings. The MDHAQ also has been incorporated into two OA clinical trials, with virtually identical results to the WOMAC. In routine clinical care, MDHAQ scores have documented that the disease burden of OA is comparable to RA in terms of scores for pain, physical function, and RAPID3 (routine assessment of patient index data) an index of pain, function and patient global assessment. Further observations indicate capacity of the MDHAQ to recognise fibromyalgia similarly to formal fibromyalgia criteria, as well as the ineffectiveness of opioids in OA, and similar prevalence of depression and other psychological issues in OA to RA. These findings also illustrate the value of a database of MDHAQ data for retrospective analysis of serendipitous observations from routine clinical care.