Biomedical subjects

Mark Scholz

Publications and source records attributed to Mark Scholz.

3 recordsLinked to original sources

PubMed2006

Perioperative morbidity associated with bariatric surgery: an academic center experience.

HYPOTHESIS: As the demand for bariatric surgery increases, it becomes increasingly important to define predictors of morbidity and mortality. We hypothesize that specific clinical variables predict postoperative morbidity after bariatric surgery. DESIGN, SETTING, AND PATIENTS: This is a retrospective review of 452 patients undergoing inpatient bariatric surgery at an academic tertiary care institution. INTERVENTIONS: Patients underwent open or laparoscopic gastric bypass or biliopancreatic diversion with duodenal switch at Oregon Health & Science University, Portland, from 2000 to 2003. Patient data were prospectively entered into a database. MAIN OUTCOME MEASURES: Postoperative morbidity and mortality were analyzed among all patients, and logistic regression was used to identify clinical predictors of morbidity. RESULTS: Major and minor morbidity rates were 10% and 13%, respectively; mortality was 0.9%. Age was associated with postoperative complications (odds ratio = 1.056 for each additional year). Duodenal switch was also associated with higher morbidity than gastric bypass (odds ratio = 2.149). Body mass index, sex, diabetes, surgical approach, and surgeon experience did not predict complications. CONCLUSIONS: Increased age is a predictor of complications after bariatric surgery. Duodenal switch is also associated with a higher morbidity rate than gastric bypass. Surgeons should caution older patients (>/=60 years) of a higher risk of postoperative complications, and a higher risk associated with duodenal switch. Large multicenter studies will be necessary to accurately define other clinical predictors of morbidity and mortality after bariatric surgery.

Age Factors↗

PubMed2005

Long-term outcome for men with androgen independent prostate cancer treated with ketoconazole and hydrocortisone.

PURPOSE: The combination of high dose ketoconazole and hydrocortisone (HDK) is active against androgen independent prostate cancer (AIPC). Median response times with HDK tend to be brief but a significant minority of AIPC patients benefit with extended responses. Well characterized response and survival information, especially in the cohort of patients who experience these longer, more durable, responses has not been previously reported. Characterization of this subgroup is of particular interest since men with long-term responses derive the greatest benefit from HDK therapy. MATERIALS AND METHODS: The medical records of 78 patients with AIPC treated with HDK between March 1991 and February 1999 were retrospectively reviewed. Baseline clinical and laboratory factors predictive of prolonged response and survival were identified. RESULTS: The median baseline prostate specific antigen (PSA) before the initiation of HDK was 25.1. The number of patients with zero, 1 to 3, and more than 3 lesions on bone scan were 25, 35 and 18, respectively. Median and mean time to PSA progression was 6.7 and 14.5 months. Median and mean survival time was 38.0 and 42.4 months, respectively. Response time and survival were highly correlated (r = 0.799). A total of 34 (44%) men had a greater than 75% decrease in PSA. The median survival times in men with more vs less than a 75% decrease were 60 vs 24 months, respectively. In a Cox proportional hazard regression, prolonged survival was predicted by percent PSA decrease, extent of disease on bone scan and baseline PSA. CONCLUSIONS: Ketoconazole can induce prolonged responses, occasionally lasting for years. Long responses are more likely to occur in men initiating HDK earlier in the course of disease before the cancer burden becomes excessive.

Aged↗

PubMed2003

Using splines to detect changes in PSA doubling times.

BACKGROUND: PSA doubling time (PSADT) can predict the likelihood of clinical progression in patients with biochemical relapse after surgery or radiation for prostate cancer. Changes in PSA doubling time in response to therapy may be of clinical or investigational significance. How does one estimate PSADT before and after the initiation of therapy and determine if any change is statistically significant or simply the result of random variation? These are the type of questions addressed. METHODS: Our technique uses a best-fitting spline (i.e., a broken-line approximation) to a graph of log PSA on time to estimate PSADTs before and after treatment initiation. A linear regression program is used to produce the fit and to evaluate the statistical significance of any change in PSADT. This method differs from previous methods in that it uses all the data, exploits the continuity of PSA at the time of treatment initiation, and allows one to make statistical significance statements about specific individuals. RESULTS: Our technique is illustrated with data from a pilot clinical trial using a nutritional supplement in 12 men with prostate cancer. A detailed analysis of the first patient shows how the data are handled, how two lines of computer code are sufficient to fit the spline model, and how the doubling times and statistical significance of a change are read from the computer output. In the study, 9 of 12 patients had a statistically significant increase in doubling time. Because the study is preliminary and used only to illustrate our method, no medical discussion of the study is included. The last section of the study, in part expository, is devoted to explaining the underlying principles for those who may want to know not only what to do, but why it works. CONCLUSIONS: The method presented here for determining changes in PSADT is both simple and broadly applicable. It allows the evaluation of the size and statistical significance of an observed change or increase in PSADT in response to therapy for prostate cancer. It can be done using essentially any statistical software and widely accepted statistical methods.

Biomarkers, Tumor↗