Classification of patterns of delirium severity scores over time in an elderly population.

OBJECTIVES: To describe and classify individual trajectories of 15-day changes in delirium severity. METHODS: A longitudinal hospital-based study was carried out with 230 medical inpatients aged 65 and over admitted to St Mary's Hospital in Montreal, Canada, between 1996 and 1999, diagnosed with delirium at enrollment, and who had at least four measurements of delirium severity during the next 15 days. Delirium severity was assessed using the Delirium Index (DI). To classify patients' individual trajectories, we applied a new method that relies on principal factor analysis and cluster analysis. We used multiple linear regression to investigate if clusters were associated with DI scores measured at an 8-week follow-up. Multivariable Cox's proportional hazards regression was used to assess whether the clusters were associated with survival over the next 12 months. RESULTS: Individual patterns were classified into five clusters: Steady (n = 89, 38.9%), Fluctuating (n = 36, 15.7%), Worsening (n = 15, 6.6%), Fast Improve-ment (n = 26, 11.3%), and Slow Improvement (n = 63, 27.5%). The Fast Improvement cluster had much lower prevalence of dementia (38.5% vs. 55.6% to 77.8% in other clusters, p = 0.003). Subjects whose 2-week patterns were classified as Fast or Slow Improvement had a significantly lower DI at 8 weeks than those in the Steady or Fluctuating clusters. The Worsening cluster had the largest percentage of deaths. The Fast Improvement and Worsening clusters initially had a high risk of death in the first 2 weeks (adjusted relative risks of approximately 3 and 6, respectively) but that risk decreased rapidly thereafter. CONCLUSION: Two-week trajectories of delirium severity were associated with short-term mortality and delirium severity at 8-week follow-up.

Statistical measures were proposed for identifying longitudinal patterns of change in quantitative health indicators.

OBJECTIVE: To propose statistical measures to identify different longitudinal patterns of change in quantitative health indicators. METHODS: The authors propose several simple measures to discriminate between stable-unstable, increasing-decreasing, linear-nonlinear, monotonic-nonmonotonic patterns of change. They then suggest using factor analysis to select the subset of nonredundant measures, and cluster analysis, based on the selected measures, to identify subgroups of patients with similar longitudinal trajectories. The proposed approach is illustrated using data on osteoarthritis disability from a longitudinal study undertaken in Toronto, Ontario, in 1996-2001. Disability was measured at four points in time for 835 patients, using the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index. RESULTS: The proposed measures allowed the detection of individual patients with specific patterns of change and identification of four different groups of patients with WOMAC scores that are (1) regularly increasing, (2) regularly decreasing, (3) stable over time, or (4) highly unstable, with abrupt changes or short-term fluctuations. CONCLUSION: The proposed approach may be used to (1) screen even large databases to identify particular patterns of change; or (2) summarize different patterns of change by classifying patients into groups with similar trajectories. Once identified, the groups can be investigated to determine whether there are differences in patient characteristics or outcomes.

Efficiency of [(18)F]FDG PET in characterising renal cancer and detecting distant metastases: a comparison with CT.

The purpose of this study was to assess the efficiency of fluorine-18 fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) in the characterisation and primary staging of suspicious renal masses, in comparison with computed tomography, the current standard imaging modality. Fifty-three FDG PET studies were performed within the framework of a prospective study: 35 for both characterisation and staging of a suspicious mass, and 18 for staging early after surgical removal of a renal cancer. In the characterisation of renal masses, a high rate of false negative results was observed, leading to a sensitivity, specificity and accuracy of 47%, 80% and 51% respectively, versus 97%, 0/5 and 83% respectively for CT. FDG PET detected all the sites of distant metastasis revealed by CT, as well as eight additional metastatic sites, leading to an accuracy of 94% versus 89% for CT. However, 36/53 patients (68%) did not have any distant metastasis on either CT or on PET. All but one of these patients had a low Fuhrman histological grade and a limited local stage (< or =pT2). We conclude that FDG PET does not offer any advantage over CT for the characterisation of renal masses but that it appears to be an efficient tool for the detection of distant metastasis in renal cancer. However, our data suggest that a selection process could be implemented to determine which patients should undergo PET. FDG PET could be performed in the event of a solitary metastasis or doubtful images on CT. Selection could also be based on adverse histological findings from nephrectomy specimens in order to perform staging early after nephrectomy.

Early response to chemotherapy in hypopharyngeal cancer: assessment with (11)C-methionine PET, correlation with morphologic response, and clinical outcome.

UNLABELLED: Neoadjuvant chemotherapy in hypopharyngeal cancer globally improves survival, but some patients do not respond to chemotherapy and adjuvant therapy is delayed. Prediction of response to chemotherapy may allow physicians to optimize planned treatment. The aim of this study was to compare treatment response assessed early with (11)C-methionine PET and morphologic response assessed after treatment completion with MRI. METHODS: Thirteen patients with previously untreated squamous cell carcinoma of the hypopharynx, T3 or T4, were included. All patients received 3 courses of chemotherapy comprising cisplatin and 5-fluorouracil. (11)C-Methionine PET was performed before and after the first course of chemotherapy. PET estimation of response was expressed in relative variation of mean standardized uptake value (SUVmean), maximal standardized uptake value (SUVmax), volume of (11)C-methionine tumor uptake, and total tumor uptake. Posttreatment response was assessed with MRI, which was performed before the first course and after treatment completion, and expressed in relative variation of tumor volume. Patients were considered responders if their tumor volume was reduced by more than 50%. RESULTS: The relative decrease in all PET parameters correlated significantly with the relative decrease in MRI volume. The larger area under the receiver operating characteristic curve was obtained for SUVmean (0.883), but that area was close to the area of SUVmax (0.857). For methodologic considerations, SUVmax was more reproducible. The optimal threshold of response for SUVmax was -25%, leading to a mean of 83% (range, 36%-93%) sensitivity and 86% (range, 42%-100%) specificity. Using this threshold, survival at 2 y was improved for responders (83%), compared with nonresponders (57%), but the difference was not statistically significant. CONCLUSION: (11)C-Methionine PET provides early useful information about changes in tumor metabolism induced by chemotherapy in hypopharynx cancer. (11)C-Methionine PET measurements correlate with end-of-treatment response evaluated with MRI and may thus be helpful to physicians in treatment planning by avoiding unnecessary chemotherapy courses for nonresponding patients.