The common practice of comparing the survival of responders and nonresponders when reporting the results of cancer chemotherapy treatment is investigated. The usual method of comparing responders and nonresponders is biased in favor of responders, and these results are frequently misinterpreted as providing evidence that response prolongs survival, or that the treatment under study is effective. Two valid methods for comparing responders and nonresponders are discussed and recommendations are made concerning the analysis of survival by response. A comparison of survival by response category may be useful descriptively, but such a comparison should not be used for inference concerning treatment effectiveness.

Background There is a clear need to develop biomarkers for Parkinson disease (PD) diagnosis, differential diagnosis of parkinsonian disorders, and monitoring disease progression. We and others have demonstrated that a decrease in DJ-1 and/or α-synuclein in the cerebrospinal fluid (CSF) is a potential index for PD diagnosis, but not for PD severity. Methods Using highly sensitive and quantitative Luminex assays, we measured total tau, phosphorylated tau, amyloid beta peptide 1-42 (Aβ1-42), Flt3 ligand and fractalkine levels in CSF in a large cohort of PD patients at different stages as well as healthy and diseased controls. The utility of these five markers was evaluated for disease diagnosis and severity/progression correlation alone, as well as in combination with DJ-1 and α-synuclein. The major results were further validated in an independent cohort of cross-sectional PD patients as well as in PD cases with CSF samples collected longitudinally. Findings The results demonstrated that combinations of these biomarkers could differentiate PD patients not only from normal controls but also from patients with Alzheimer disease and multiple system atrophy. Particularly, with CSF Flt3 ligand, PD could be clearly differentiated from multiple system atrophy, a disease that overlaps with PD clinically, with excellent sensitivity (99%) and specificity (95%). In addition, we identified CSF fractalkine/Aβ1-42 that positively correlated with PD severity in cross-sectional samples as well as with PD progression in longitudinal samples. Interpretation We have demonstrated that this panel of seven CSF proteins could aid in PD diagnosis, differential diagnosis, and correlation with disease severity and progression.

Phosphorylated α-synuclein (PS-129), a protein implicated in the pathogenesis of Parkinson’s disease (PD), was identified by mass spectrometry in human cerebrospinal fluid (CSF). A highly sensitive and specific assay was established and used to measure PS-129, along withtotal α-synuclein, in the CSF of patients with PD, other parkinsonian disorders such as multiple system atrophy (MSA) and progressive supranuclear palsy (PSP), and healthy individuals (a total of ~600 samples). PS-129 CSF concentrations correlated weakly with PD severity and, when combined with total α-synuclein CSF concentrations, contributed to distinguishing PD from MSA and PSP. Further rigorous validation in independent cohorts of patients, especially those where samples have been collected longitudinally, will determine whether PS-129 CSF concentrations will be useful for diagnosing PD and for monitoring PD severity and progression.

No abstract

No abstract

Twenty-seven newly diagnosed patients with idiopathic pulmonary fibrosis (IPF) who were previously untreated for IPF were enrolled in a prospective, double-blind, randomized, placebo-controlled study to compare the therapeutic effect of combined prednisone/azathioprine (n = 14) with prednisone plus placebo (n = 13). Prednisone was started at 1.5 mg/kg/day (not to exceed 100 mg/day) for the first 2 wk followed by a biweekly taper to a maintenance dose of 20 mg/day. Azathioprine was administered at a daily dose of 3 mg/kg (not to exceed 200 mg/day). The patients tolerated the use of azathioprine well with few associated side effects. Changes in lung function at 1 yr, as measured by resting alveolar-arterial oxygen difference P[A-a]O2, FVC, and single breath diffusing capacity for carbon monoxide (DLCOSB), were all somewhat better in the azathioprine/prednisone group compared with the prednisone alone group, although none of these comparisons were statistically significant. Six of 14 (43%) patients randomized to prednisone plus azathioprine died during the 9-yr follow-up period, compared with 10 of 13 (77%) patients randomized to prednisone plus placebo. A Cox model survival analysis shows a nonsignificant but potentially large survival advantage for azathioprine/prednisone (hazard ratio 0.48, with 95% confidence interval increasing from 0.17 to 1.38). When adjusted for age, the survival advantage of azathioprine/prednisone becomes marginally significant (hazard ratio 0.26, with 95% confidence interval increasing from 0.08 to 0.88; p = 0.02 by large sample approximation, p = 0.05 by randomization test). We conclude that combined prednisone and azathioprine is a safe and possibly effective regimen for the treatment of IPF.(ABSTRACT TRUNCATED AT 250 WORDS)

"Substituted judgment," in which surrogate decisionmakers approximate patients' wishes, has been recommended for decision making for mentally incapacitated patients. To test understanding of patients' preferences by potential surrogate decisionmakers, we studied primary care physicians' (n = 105) and spouses' (n = 90) predictions of elderly outpatients' (n = 258) preferences for cardiopulmonary resuscitation (CPR) and CPR plus ventilator (CPR + V), assuming three baseline health states: current health, stroke, and chronic lung disease. Although more than three-quarters of physicians and spouses surveyed believed their predictions of patients' preferences were accurate, the accuracy of physicians' and spouses' predictions did not exceed that expected due to chance alone in 5 of 6, and 3 of 6 decisions, respectively. Physicians significantly underestimated patients' preferences for resuscitation in the stroke and chronic lung disease scenarios (p less than .01), and significantly overestimated them in the current health/CPR decision (p less than .05). Spouses overestimated patients' preferences for resuscitation in all decisions, significantly so in the three CPR + V decisions (p less than .05). These results suggest physicians and spouses often do not understand elderly outpatients' resuscitation preferences. Under these circumstances they are unlikely to provide accurate substituted judgments.

Previous research indicates that persons assigning values to ranges of health states consider some states to be worse than death. In a study of decisions regarding life-sustaining treatments, the authors adapted and assessed existing methods for their ability to identify and quantify preferences for health states near to or worse than death in a population of well adults and nursing home residents. The cognitive burdens involved in these decisions were also evaluated. Hypothetical health states based on six attributes of functional status were constructed to describe severe constant pain, dementia, and coma. The methods of rank order, category scaling, time tradeoff, and standard gamble were adapted to quantify states worse than death. Cognitive burden was assessed using completion rates, interviewer assessments, respondents' self-reporting, and investigators' evaluations. For both respondent groups, all methods showed similar degrees of cognitive burden for those able to complete the tasks and were similar in their ability to identify and quantify preferences. The majority of nursing home residents, however, were unable to complete or comprehend the measurement tasks. Most respondents evaluated their current health and severe constant pain as better than death; dementia and coma were more often considered equal to or worse than death. These results indicate that respondents can and do evaluate some health states as worse than death. The authors recommend systematic inclusion of states worse than death to describe a more complete range of preference values and routine assessment of the cognitive burdens of assessment techniques to evaluate methodologies.