Comparative assessment of three common algorithms for estimating the variance of the area under the nonparametric receiver operating characteristic curve

The area under the receiver operating characteristic (ROC) curve is often used to summarize and compare the discriminatory accuracy of a diagnostic test or modality,and to evaluate the predictive power of statistical models for binary outcomes. Parametric maximum likelihood methods for Þtting of the ROC curve provide direct estimates of the area under the ROC curve and its variance. Nonparametric methods, on the other hand, provide estimates of the area under the ROC curve, but do not directly estimate its variance. Three algorithms for computing the variance for the area under the nonparametric ROC curve are commonly used, although ambiguity exists about their behavior under diverse study conditions. Using simulated data, we found similar asymptotic performance between these algorithms when the diagnostic test produces results on a continuous scale, but found notable differences in small samples, and when the diagnostic test yields results on a discrete diagnostic scale. Copyright 2002 by Stata Corporation.receiver operating characteristic (ROC )curve,trapezoidal rule, sensitivity,specificity,discriminatory accuracy,predictive power

From the help desk: Comparing areas under receiver operating characteristic curves from two or more probit or logit models

Occasionally, there is a need to compare the predictive accuracy of several fitted logit (logistic) or probit models by comparing the areas under the corresponding receiver operating characteristic (ROC) curves. Although Stata currently does not have a ready routine for comparing two or more ROC areas generated from these models, this article describes how these comparisons can be performed using Stata's roccomp command. Copyright 2002 by Stata Corporation.Receiving Operating Characteristic (ROC) curve

Propranolol for Treatment of Infantile Hemangioma: Efficacy and Effect on Pediatric Growth and Development

Purpose. Propranolol has been successful in treating problematic infantile hemangiomas (IH) but concerns regarding its effect on normal growth and development have been raised. This study examines physical growth, developmental milestones, and human growth hormone (hGH) levels in infants receiving propranolol for problematic IH. Method. Monthly heights and weights of children undergoing propranolol therapy for IH were prospectively collected and tabulated. Data analysis and comparison to World Health Organization (WHO) weight-for-age and weight-to-length z-scores was performed. Questionnaires regarding milestones, efficacy, and guardian satisfaction were performed, and a combination of both chart results and phone conducted surveys was tabulated. Serum from a small representative cohort of age-matched children with IH treated and not treated with propranolol was collected. Results. A total of 185 children receiving propranolol therapy between 2008 and 2013 for IH were assigned to this study. The children were divided into two cohorts based on the presence of comorbidities or risk factors that may affect growth and development (n = 142 no comorbidities, n = 43 with comorbidities). Neither cohort demonstrated deviation from normal weight in comparison to WHO normative data. There was a significant deviation for BMI-for-age and weight-for-age z-scores in our population, especially in patients on propranolol for more than 7 months. Based on data from participants, via either completed questionnaires or chart results, most children met their developmental milestones at or before target ages, regardless of the presence of comorbidities. Eighty percent of guardians noticed clinical improvement of the IH, with 91% either happy about or neutral to using the medication. hGH levels were higher in patients receiving propranolol therapy, but not significantly different. Conclusion. Propranolol therapy is effective and well tolerated in the treatment of infantile hemangiomas. This study suggests that propranolol does not impair growth and has no impact on normal pediatric development

Prospective Validation of Eight Different Adherence Measures for Use with Administrative Claims Data among Patients with Schizophrenia

ABSTRACTObjectiveThe aim of this study was to compare the predictive validity of eight different adherence measures by studying the variability explained between each measure and hospitalization episodes among Medicaid-eligible persons diagnosed with schizophrenia on antipsychotic monotherapy.MethodsThis study was a retrospective analysis of the Arkansas Medicaid administrative claims data. Continuously eligible adult schizophrenia (ICD-9-CM = 295.**) patients on antipsychotic monotherapy were identified in the recruitment period from July 2000 through April 2004. Adherence rates to antipsychotic therapy in year 1 were calculated using eight different measures identified from the literature. Univariate and multivariable logistic regression models were used to prospectively predict all-cause and mental health-related hospitalizations in the follow-up year.ResultsAdherence rates were computed for 3395 schizophrenic patients with a mean age of 42.9 years, of which 52.5% (n = 1782) were females, and 52.8% (n = 1793) were white. The proportion of days covered (PDC) and continuous measure of medication gaps measures of adherence had equal C-statistics of 0.571 in predicting both all-cause and mental health-related hospitalizations. The medication possession ratio (MPR) continuous multiple interval measure of oversupply were the second best measures with equal C-statistics of 0.568 and 0.567 for any-cause and mental health-related hospitalizations. The multivariate adjusted models had higher C-statistics but provided the same rank order results.ConclusionsMPR and PDC were among the best predictors of any-cause and mental health-related hospitalization, and are recommended as the preferred adherence measures when a single measure is sought for use with administrative claims data for patients not on polypharmacy

Subarachnoid versus General Anesthesia in Penile Prosthetic Implantation: Outcomes Analyses

The leading patient complaint during the perioperative period for penile prosthesis implantation is postoperative pain, while emesis and urticaria also affect the procedure’s perceived success. In analyzing surgical outcomes, assessment of the anesthetic for postoperative pain and side effects should be included. This paper retrospectively reviews 90 consecutive, primary inflatable penile prosthetic operations performed by a single surgeon at one private medical center. Fifty-seven patients were included in final analysis. Patients who had more than one procedure that day or who used chronic pain medication were excluded. The type and amount of each drug used for each respective side effect (within the first 24 hours after procedure) were compared to determine relative benefit. Twenty patients received general anesthesia (denoted herein as “GA”) and 37 received spinal (or also known as subarachnoid) anesthesia (denoted herein as “SA”). Patients receiving GA had significantly greater (P<0.0001) occurrence and amount of intravenous pain treatment than those receiving SA. Patients with SA required less intravenous pain medication and less treatment for nausea/emesis

A Survey of Patients with Inflatable Penile Prostheses: Assessment of Timing and Frequency of Intercourse and Analysis of Implant Durability

Introduction.  This study was conducted to determine how long after inflatable penile prosthesis (IPP) surgery patients attempt sexual intercourse and the frequency of subsequent relations. We also examined survival‐related factors for the AMS 700 CX, Mentor Alpha 1, and Mentor Alpha Narrow Base. Aims.  The aim was to survey men who received IPPs and collect information about their return to sexual function and frequency of use, and to assess the resilience of their devices. Methods.  Phase I involved retrospective chart review of 1,298 virgin IPP surgeries performed by one surgical team from January 1992 to December 1998. Phase II included 330 subjects selected by stratified, systematic, random sampling from phase I patients. Data were collected by computer‐assisted telephone interview, using a 27‐question survey. All patients had been instructed to wait 4 weeks before using the implant and were taught how to inflate/deflate their prostheses at the 4‐week postsurgical visits. Main Outcome Measures.  The survey examines the length of time after surgery for men to resume sexual function. In the same study, information was garnered about mechanical durability of the device. Results.  Among phase I subjects, the 5‐year survival rate was 83% (N = 1,069) for IPP revision for any reason. Of the 330 phase II subjects, 248 (75%) were successfully contacted; 199 (80%) responded to the full survey and 49 (20%) responded to selected parts of the survey. Sexual intercourse was resumed postoperatively at 1–4 weeks for 41% (78/190), at 5–6 weeks for 31% (59/190), at 7–8 weeks for 16% (30/190), and at >8 weeks for 12% (23/190) of the patients. More than 60% of patients reported using their IPP at least once weekly. Conclusion.  The three‐piece IPP has excellent 5‐year survival rates. Most patients return to sexual activity relatively quickly, with high frequency of usage of their prostheses. Henry GD, Brinkman MJ, Mead SF, Delk JR II, Cleves MA, Jennermann C, Wilson SK, and Kramer AC. A survey of patients with inflatable penile prostheses: Assessment of timing and frequency of intercourse and analysis of implant durability. J Sex Med 2012;9:1715–1721.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92055/1/j.1743-6109.2012.02729.x.pd

Acute and Chronic Acetaminophen Use and Renal Disease: A Case-Control Study Using Pharmacy and Medical Claims

Studies have examined the association between acetaminophen (APAP) use and renal disease; however, their interpretation is limited by a number of methodological issues

Prescription-Acquired Acetaminophen Use and the Risk of Asthma in Adults: A Case-Control Study

Studies have examined the association between acetaminophen (APAP) use and asthma; however, their interpretation is limited by a number of methodological issues