Publications

Dual Processing Theories (DPT) assume that human cognition is governed by two distinct types of processes typically referred to as type 1 (intuitive) and type 2 (deliberative). Based on DPT we have derived a Dual Processing Model (DPM) to describe and explain therapeutic medical decision-making. The DPM model indicates that doctors decide to treat when treatment benefits outweigh its harms, which occurs when the probability of the disease is greater than the so called "threshold probability" at which treatment benefits are equal to treatment harms. Here we extend our work to include a wider class of decision problems that involve diagnostic testing. We illustrate applicability of the proposed model in a typical clinical scenario considering the management of a patient with prostate cancer. To that end, we calculate and compare two types of decision-thresholds: one that adheres to expected utility theory (EUT) and the second according to DPM. Our results showed that the decisions to administer a diagnostic test could be better explained using the DPM threshold. This is because such decisions depend on objective evidence of test/treatment benefits and harms as well as type 1 cognition of benefits and harms, which are not considered under EUT. Given that type 1 processes are unique to each decision-maker, this means that the DPM threshold will vary among different individuals. We also showed that when type 1 processes exclusively dominate decisions, ordering a diagnostic test does not affect a decision; the decision is based on the assessment of benefits and harms of treatment. These findings could explain variations in the treatment and diagnostic patterns documented in today's clinical practice.

OBJECTIVES: The objective of the study was to assess the association between Grading of Recommendations Assessment, Development and Evaluation (GRADE) factors and the strength of recommendations.

STUDY DESIGN AND SETTING: The study was conducted as part of the development of clinical practice guideline (CPG) by American Association of Blood Banking related to role of prophylactic vs. therapeutic transfusion for the management of thrombocytopenia. The association between GRADE factors and strength of recommendations was assessed using logistic regression and multilevel mixed effect logistic regression model.

RESULTS: Seventeen members of the CPG panel participated in the recommendation process. The quality of evidence was the only statistically significant (odds ratio = 4.5; P < 0.001) GRADE factor associated with the strength of recommendations. The predictive model showed that there is about 90% probability that panelists would issue the same (strong) recommendation when confidence in the effects of intervention is high vs. 10% when the quality of evidence is very low.

CONCLUSION: The results showed that quality of evidence is a key determinant for making a strong vs. a weak recommendation.

BACKGROUND: Most persons with cancer living in the United States are older than 65 years of age; however, in general, elderly persons are under-represented in clinical trials and outcomes data are lacking.

METHODS: Outcomes data were analyzed of elderly participants (≥65 years of age) enrolled in phase 1 clinical trials and the results compared with those of younger patients. All consecutive, single-center, phase 1 oncology trials initiated and completed at the H. Lee Moffitt Cancer Center & Research Institute between 1997 and 2007 were included. Patient data (including survival, response, and toxicity rates) were extracted from a cancer registry database and electronic medical records at Moffitt Cancer Center.

RESULTS: After excluding multi-institution trials, we analyzed 39 trials for a total of 1,162 enrolled study participants, 32.7% of whom were elderly. Among patients who underwent transplantation, median survival rates were worse in those who were elderly compared with those who were younger (44.9 vs 32.9 months; P = .0037). However, in the no-transplantation setting, participants who were elderly had a median survival rate of 10.9 months (95% confidence interval [CI]: 8.9-13.1) compared with 8.8 months (95% CI: 7.9-10.3) in those who were younger (P = .15). Both groups had similar overall response rates (15.2% vs 13.1%) and similar treatment-related mortality rates (1% vs 0.9%, respectively). Adverse events occurring among the elderly and younger participants were not statistically significant.

CONCLUSIONS: Survival, response, toxicity, and treatment-related mortality rates were not significantly different between the elderly and younger phase 1 trial participants in the no-transplantation setting. Regardless of the complex pharmacological profiles and logistical issues involved in treating the elderly population, our data imply that elderly study participants do at least as well as their younger counterparts, contributing to the justification of increasing the phase 1 trial enrollment of elderly patients.

INTRODUCTION: Microsporidial myositis is a rare opportunistic infection that has been reported in HIV-infected and HIV-uninfected immunocompromised patients.

METHODS: In this study we present a retrospective analysis of 5 cases of microsporidial myositis in HIV-infected patients, including the clinical, laboratory, and histologic features, and a review of the literature.

RESULTS: Five young men with HIV infection [median CD4 count of 20 cells (range 14-144)/mm(3) ] who presented with signs and symptoms suggestive of myositis underwent EMG-NCV and muscle biopsy, which revealed signs compatible with microsporidial myositis. Early and aggressive treatment led to improvement in 3 patients. Two of the 5 patients died due to a delay in diagnosis, because the spores were mistaken for Candida without confirmatory stains or a high index of suspicion.

CONCLUSIONS: Myositis in HIV-infected patients with low CD4 counts should be evaluated using muscle biopsy. A high index of suspicion is required for early diagnosis of microsporidial myositis in HIV-infected patients. Early diagnosis and immediate, aggressive treatment are the keys to favorable outcomes in these patients.

BACKGROUND & AIMS: A radiofrequency ablation technique known as Stretta was recommended by the Society of American Gastrointestinal and Endoscopic Surgeons as an alternative treatment for gastroesophageal reflux disease (GERD). However, randomized controlled trials of the efficacy of Stretta have produced conflicting findings, and those from previous systematic reviews were compromised as a result of deficiencies in study conduct and reporting of findings. We performed a systematic review to evaluate all evidence on the efficacy of Stretta for the management of GERD.

METHODS: We searched MEDLINE and the Cochrane Central Register of Controlled Trials (The Cochrane Library) from inception until February 28, 2014, along with other databases, for randomized controlled trials of Stretta in patients with GERD. Primary outcomes were physiologic parameters of GERD, including normalization of esophageal pH values and augmentation of lower esophageal sphincter pressure (LESP). Secondary outcomes were health-related quality of life (HRQOL) and ability to stop the use of proton pump inhibitors (PPIs). For quality assurance purposes, 2 investigators were involved throughout the study. Data were pooled under a random-effects model. The systematic review was performed as per the standards of the Cochrane collaboration.

RESULTS: We collected data from 4 trials and a total of 165 patients (153 patients were analyzed). Three trials compared Stretta vs sham, and 1 trial compared Stretta with PPI therapy. The overall quality of evidence was very low. The pooled results showed no difference between Stretta and sham or management with PPI in patients with GERD for the outcomes of mean (%) time the pH was less than 4 over a 24-hour time course, LESP, ability to stop PPIs, or HRQOL.

CONCLUSIONS: In a meta-analysis of trials, we found that Stretta for patients with GERD does not produce significant changes, compared with sham therapy, in physiologic parameters, including time spent at a pH less than 4, LESP, ability to stop PPIs, or HRQOL.

OBJECTIVES: Published negative studies should have the same rigour of methodological quality as studies with positive findings. However, the methodological quality of negative versus positive studies is not known. The objective was to assess the reported methodological quality of positive versus negative studies published in Indian medical journals.

DESIGN: A systematic review (SR) was performed of all comparative studies published in Indian medical journals with a clinical science focus and impact factor >1 between 2011 and 2013. The methodological quality of randomised controlled trials (RCTs) was assessed using the Cochrane risk of bias tool, and the Newcastle-Ottawa scale for observational studies. The results were considered positive if the primary outcome was statistically significant and negative otherwise. When the primary outcome was not specified, we used data on the first outcome reported in the history followed by the results section. Differences in various methodological quality domains between positive versus negative studies were assessed by Fisher's exact test.

RESULTS: Seven journals with 259 comparative studies were included in this SR. 24% (63/259) were RCTs, 24% (63/259) cohort studies, and 49% (128/259) case-control studies. 53% (137/259) of studies explicitly reported the primary outcome. Five studies did not report sufficient data to enable us to determine if results were positive or negative. Statistical significance was determined by p value in 78.3% (199/254), CI in 2.8% (7/254), both p value and CI in 11.8% (30/254), and only descriptive in 6.3% (16/254) of studies. The overall methodological quality was poor and no statistically significant differences between reporting of methodological quality were detected between studies with positive versus negative findings.

CONCLUSIONS: There was no difference in the reported methodological quality of positive versus negative studies. However, the uneven reporting of positive versus negative studies (72% vs 28%) indicates a publication bias in Indian medical journals with an impact factor of >1.

INTRODUCTION: Double balloon enteroscopy (DBE) and single balloon enteroscopy (SBE) are 2 types of commonly used balloon-assisted enteroscopic techniques for "deep enteroscopy." Although there are several randomized controlled trials assessing the superiority of DBE compared with SBE, the results from individual randomized controlled trials seem conflicting. We performed a systematic review and meta-analysis to assess the efficacy of DBE compared with SBE.

METHODS: Primary outcomes were diagnostic and therapeutic yield. Secondary outcomes were failure rates, adverse events, complete enteroscopy, anterograde/retrograde insertion depths, and procedure times. We searched MEDLINE and the Cochrane Central Register of Controlled Trials (CENTRAL) from inception until February 28, 2014, as well as other databases. For quality assurance purposes throughout the systematic review process, dual extraction was performed. The systematic review was performed as per the standards of Cochrane collaboration.

RESULTS: Four trials enrolling a total of 375 patients were included. DBE did not offer an advantage over SBE in therapeutic yield [risk ratio (RR), 1.11; 95% confidence interval (CI): 0.90, 1.37; P=0.33)] or diagnostic yield (RR=1.08; 95% CI: 0.89, 1.32; P=0.42), failure rates (RR=0.68; 95% CI: 0.23, 2.05; P=0.5), overall adverse events (RR=1.41; 95% CI: 0.32, 6.3; P=0.65), or complete enteroscopy rates (RR=1.73; 95% CI: 0.86, 3.48; P=0.12). No evidence existed for an advantage of anterograde or retrograde procedure time between these 2 modalities [mean difference (MD), 3.78; 95% CI, -30.76, 38.32; P=0.83; and MD, -0.53; 95% CI: -7.66, 6.59; P=0.88, respectively]. Neither anterograde nor retrograde insertion depths appeared to differ between the 2 studies analyzed (MD, -7.36; 95% CI: -40.36, 25.64; P=0.66 and MD, 7.86; 95% CI: -12.68, 28.40; P=0.45, respectively).

CONCLUSIONS: Performance of SBE and DBE appears to be similar in terms of diagnostic/therapeutic yield, insertion depths, procedure time, complete enteroscopy, failure rates, or adverse events.

BACKGROUND: Decision-making relies on both analytical and emotional thinking. Cognitive reasoning styles (e.g. maximizing and satisficing tendencies) heavily influence analytical processes, while affective processes are often dependent on regret. The relationship between regret and cognitive reasoning styles has not been well studied in physicians, and is the focus of this paper.

METHODS: A regret questionnaire and 6 scales measuring individual differences in cognitive styles (maximizing-satisficing tendencies; analytical vs. intuitive reasoning; need for cognition; intolerance toward ambiguity; objectivism; and cognitive reflection) were administered through a web-based survey to physicians of the University of South Florida. Bonferroni's adjustment was applied to the overall correlation analysis. The correlation analysis was also performed without Bonferroni's correction, given the strong theoretical rationale indicating the need for a separate hypothesis. We also conducted a multivariate regression analysis to identify the unique influence of predictors on regret.

RESULTS: 165 trainees and 56 attending physicians (age range 25 to 69) participated in the survey. After bivariate analysis we found that maximizing tendency positively correlated with regret with respect to both decision difficulty (r=0.673; p<0.001) and alternate search strategy (r=0.239; p=0.002). When Bonferroni's correction was not applied, we also found a negative relationship between satisficing tendency and regret (r=-0.156; p=0.021). In trainees, but not faculty, regret negatively correlated with rational-analytical thinking (r=-0.422; p<0.001), need for cognition (r=-0.340; p<0.001), and objectivism (r=-0.309; p=0.003) and positively correlated with ambiguity intolerance (r=0.285; p=0.012). However, after conducting a multivariate regression analysis, we found that regret was positively associated with maximizing only with respect to decision difficulty (r=0.791; p<0.001), while it was negatively associated with satisficing (r=-0.257; p=0.020) and objectivism (r=-0.267; p=0.034). We found no statistically significant relationship between regret and overall accuracy on conditional inferential tasks.

CONCLUSION: Regret in physicians is strongly associated with their tendency to maximize; i.e. the tendency to consider more choices among abundant options leads to more regret. However, physicians who exhibit satisficing tendency - the inclination to accept a "good enough" solution - feel less regret. Our observation that objectivism is a negative predictor of regret indicates that the tendency to seek and use empirical data in decision-making leads to less regret. Therefore, promotion of evidence-based reasoning may lead to lower regret.