Rheumatoid Arthritis: Ortendahl M

Ortendahl M. · Department for Security Research, Royal Institute of Technology, Stockholm, Sweden. · J Eval Clin Pract. · Pubmed #19018900 No free full text.

Abstract: RATIONALE, AIMS AND OBJECTIVES: Diagnostic reasoning and treatment decisions are a key competence of doctors. A model based on values and probability provides a conceptual framework for clinical judgments and decisions, and also facilitates the integration of clinical and biomedical knowledge into a diagnostic decision. METHOD: Both value and probability are usually estimated values in clinical decision making. Therefore, model assumptions and parameter estimates should be continually assessed against data, and models should be revised accordingly. Introducing parameter estimates for both value and probability, which usually pertain in clinical work, gives the model labelled subjective expected utility. Estimated values and probabilities are involved sequentially for every step in the decision-making process. RESULTS: Introducing decision-analytic modelling gives a more complete picture of variables that influence the decisions carried out by the doctor and the patient. CONCLUSION: A model revised for perceived values and probabilities by both the doctor and the patient could be used as a tool for engaging in a mutual and shared decision-making process in clinical work.

Ortendahl M. · Royal Institute of Technology Stockholm, Sweden. · Ther Clin Risk Manag. · Pubmed #18516269 links to  free full text

Abstract: There is an increased awareness about patients' involvement in the clinical decision process where uncertainty is an unavoidable condition. The impact of psychological factors like risk aversion, risk aversion and time, asymmetry in risk aversion, and risk and control on shared decision-making is discussed. In addition to differences in risk estimates, doctors and patients may exhibit a difference in perception of time perspectives, and losses versus gains.A summary of valuation factors in shared decision-making is presented: (a) the doctors tend to follow expected value combinations more closely, while the patient is more risk aversive; (b) unwillingness to take risks increases for rare outcomes; (c) there is an increased tendency to take risks with delayed outcomes of the decisions; (d) the doctor is generally well informed about risk and time aspects for different diseases, whereas this might not always be the case with the patient; (e) rheumatoid arthritis and diabetes mellitus are chronic diseases, and both create a vulnerability to a variety of complications over time; (f) rheumatoid arthritis demands different combinations of treatments sequentially over time, whereas diabetes mellitus is treated with insulin; (g) many diseases, like rheumatoid arthritis and diabetes mellitus, are not completely affected by control, as the disease may constantly progress.

Ortendahl M, Holmes T, Schettler JD, Fries JF. · Department of Medicine, Stanford University School of Medicine, Palo Alto, California, USA. · J Rheumatol. · Pubmed #12375316 No free full text.

Abstract: OBJECTIVE: Methotrexate (MTX) is used frequently as a disease modifying antirheumatic drug (DMARD) for rheumatoid arthritis (RA), and patients tend to continue taking this drug for longer periods than alternative single agents. The shape of the therapeutic response beyond one or 2 years, however, has not been fully studied. We examined the properties of the pure MTX "therapeutic segment," that period that begins with start of MTX and terminates when MTX is discontinued or another DMARD is added, by observational study. METHODS: We studied new MTX starts for the period 1988 through 1996 for 437 patients from a parent cohort of 4253 patients. Patients were drawn from 8 Arthritis, Rheumatism, and Aging Medical Information System (ARAMIS) data centers: 2 community based populations; 2 private rheumatological practices; 2 university referral practices; and 2 university clinics for underserved minority urban populations. Health Assessment Questionnaire (HAQ) Disability Index scores (0-3) were obtained prospectively each 6 months. RESULTS: At MTX start, patients had relatively long average disease duration of 16.7 years, and had moderately severe disability, with an initial HAQ mean disability score of 1.48. Over the 10 year period examined in the parent cohort of 4253 patients (and thus irrespective of therapy), the prevalence of MTX use rose from 19% to 45%, while mean HAQ disability declined from 1.34 to 1.11. This correspondence is consistent with an accrual of benefits from more frequent use of MTX and other DMARD over this period. The MTX therapeutic segment revealed a distinct shape. HAQ-Disability Index values began at 1.48 at baseline and declined to a maximal improvement of 1.23 at 30 months. This long period to maximum benefit may have been partly driven by a slow titration upward to an optimal dosage. After 42 months, disability for this population began to re-progress and reached 1.39 at 84 months, still below the pretreatment baseline. Re-progression to baseline was about 8 or more years. Cumulative disability averted with MTX treatment for this population was roughly 1.30 disability-unit-years. CONCLUSION: MTX treatment of RA in practice differs substantially from common perception and appears suboptimal by being too little, too late, and too long to treatment change. A modification of the "sawtooth strategy" in which the disease is "ratcheted down" by change of MTX therapy at 3 years or when re-progression has proceeded halfway to baseline, rather than waiting for return to baseline, is suggested by these data. Also suggested is the need for more rapid upward dosage titration and longer maintenance of an optimal or highest tolerated dosage. "Therapeutic segment" data provide insights into strategic approaches to management of RA since they allow estimation of population aggregate properties such as time to maximum benefit and the time to return to baseline.

Ortendahl M, Schettler JD, Fries JF. · Department of Medicine, Stanford University School of Medicine, California, USA. · J Rheumatol. · Pubmed #10813279 No free full text.

Abstract: OBJECTIVE: Duration of therapy has been suggested to represent a measure of effectiveness. Life table analyses of therapy with methotrexate (MTX) in rheumatoid arthritis (RA) have indicated a longer duration than with other drugs. However, individual patients continue taking MTX for different periods of time. We assessed the influence of patient variables at treatment onset upon subsequent duration of MTX therapy. METHODS: Patients with RA (n = 437) from 8 North American databank centers beginning MTX therapy after January 1, 1988, were followed prospectively. Age at onset of MTX treatment, sex, years of education, age at onset of disease, years with disease, number of comorbid conditions, number of disease modifying antirheumatic drugs (DMARD) and nonsteroidal antiinflammatory drugs (NSAID) taken just prior to MTX. disability level, pain, and global assessment prior to starting MTX were used in univariate Kaplan-Meier analyses to predict number of months taking MTX alone. An index that divided the patients into risk strata for predicting duration of therapy was constructed to be clinically useful. RESULTS: The median number of months continuing MTX without addition of other DMARD was 41 months and the median for the total course taking MTX was 52 months. The retention rate was lowest for patients with the most negative initial health state. High level of initial pain, long duration of disease, and not using a DMARD just prior to MTX were associated with low retention rate and can be used to predict expected durations of MTX treatment ranging from 17 to 52 months. For practical guidance in clinical decisions an index was computed based on the predictor variables: level of initial pain, duration of disease, and number of DMARD; this index identifies subgroups with very different durations taking MTX alone. Disease duration at baseline was strongly related to time taking MTX alone and could therefore also be used as a simplified rule in clinical work. CONCLUSION: Expected duration of MTX treatment is influenced by clinical variables, and these may suggest those patients likely to have more or less satisfactory experiences with MTX. The time taking drug alone (therapeutic segment) may be a more logical and sensitive indicator of effectiveness than the total course on the medication.