Correlates of 1-Year Change in Quality of Life in Patients with Urologic Chronic Pelvic Pain Syndrome: Findings from the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Research Network.

PURPOSE: We evaluated and identified baseline factors associated with change in health related quality of life among patients with interstitial cystitis/bladder pain syndrome and chronic prostatitis/chronic pelvic pain syndrome. MATERIALS AND METHODS: A total of 191 men and 233 women with interstitial cystitis/bladder pain syndrome or chronic prostatitis/chronic pelvic pain syndrome (collectively referred to as urologic chronic pelvic pain syndrome) were followed for 12 months with bimonthly completion of the Short Form 12 to assess general mental and physical health related quality of life, and with biweekly assessment of condition specific health related quality of life using the Genitourinary Pain Index. A functional clustering algorithm was used to classify participants as improved, stable or worsened for each health related quality of life measure. Ordinal logistic regression was used to determine baseline factors associated with change. RESULTS: Physical health related quality of life improved in 22% of the participants, mental health related quality of life improved in 25% and condition specific health related quality of life improved in 47%. Better baseline physical health related quality of life, older age and the presence of nonurological symptoms were associated with lower likelihood of improvement in physical health related quality of life. Better baseline mental health related quality of life, female sex, and greater baseline depression and stress were associated with a lower likelihood of improvement in mental health related quality of life. Better baseline condition specific health related quality of life and more severe baseline urologic chronic pelvic pain syndrome pain symptoms were associated with a lower likelihood of improvement in condition specific health related quality of life. CONCLUSIONS: While several nonurologic chronic pelvic pain syndrome factors influenced the trajectory of general health related quality of life over time, only condition specific baseline health related quality of life and urologic chronic pelvic pain syndrome symptoms were associated with urologic chronic pelvic pain syndrome specific health related quality of life change. Significant differences in how urologic chronic pelvic pain syndrome impacts various aspects of health related quality of life suggest a multidisciplinary approach to assessment and treatment of these patients.

Urinalysis in patients with neuromyelitis optica spectrum disorder.

BACKGROUND AND PURPOSE: Increasing evidence has demonstrated that aquaporin-4 (AQP4) immunoglobulin G causes damage to the kidney in neuromyelitis optica spectrum disorder (NMOSD). However, changes in urinalysis in NMOSD have not been investigated thus far. Our objective was to evaluate the changes in urinalysis in NMOSD patients. METHODS: Case data were collected from 44 patients with AQP4 antibody-positive NMOSD, 53 patients with multiple sclerosis (MS) and 79 age- and sex-matched healthy controls. Analyses of early morning urine and 24-h urine samples comparing NMOSD with MS patients were conducted. RESULTS: In the acute phase, urine pH levels (P < 0.001) and urine specific gravity levels (P < 0.001) from NMOSD patients were significantly higher and lower, respectively, than for MS patients. 24-h urine sodium and 24-h urine volume from NMOSD patients were significantly higher than for MS patients (both P = 0.001). A 24-h urine volume higher than 2500 ml (odds ratio 11.7, 95% confidence interval 1.863-73.066) and a 24-h urine sodium higher than 200 mmol (odds ratio 16.0, 95% confidence interval 2.122-120.648) are more likely to occur in NMOSD patients in the acute phase than in MS patients. CONCLUSIONS: The urinalysis results were significantly different between NMOSD patients and MS patients. The pathophysiological changes in AQP4 antibody-positive NMOSD patients were not limited to the central nervous system.

Randomized multicenter clinical trial of myofascial physical therapy in women with interstitial cystitis/painful bladder syndrome and pelvic floor tenderness.

PURPOSE: We determined the efficacy and safety of pelvic floor myofascial physical therapy compared to global therapeutic massage in women with newly symptomatic interstitial cystitis/painful bladder syndrome. MATERIALS AND METHODS: A randomized controlled trial of 10 scheduled treatments of myofascial physical therapy vs global therapeutic massage was performed at 11 clinical centers in North America. We recruited women with interstitial cystitis/painful bladder syndrome with demonstrable pelvic floor tenderness on physical examination and a limitation of no more than 3 years' symptom duration. The primary outcome was the proportion of responders defined as moderately improved or markedly improved in overall symptoms compared to baseline on a 7-point global response assessment scale. Secondary outcomes included ratings for pain, urgency and frequency, the O'Leary-Sant IC Symptom and Problem Index, and reports of adverse events. We compared response rates between treatment arms using the exact conditional version of the Mantel-Haenszel test to control for clustering by clinical center. For secondary efficacy outcomes cross-sectional descriptive statistics and changes from baseline were calculated. RESULTS: A total of 81 women randomized to the 2 treatment groups had similar symptoms at baseline. The global response assessment response rate was 26% in the global therapeutic massage group and 59% in the myofascial physical therapy group (p=0.0012). Pain, urgency and frequency ratings, and O'Leary-Sant IC Symptom and Problem Index decreased in both groups during followup, and were not significantly different between the groups. Pain was the most common adverse event, occurring at similar rates in both groups. No serious adverse events were reported. CONCLUSIONS: A significantly higher proportion of women with interstitial cystitis/painful bladder syndrome responded to treatment with myofascial physical therapy than to global therapeutic massage. Myofascial physical therapy may be a beneficial therapy in women with this syndrome.

Variability of creatinine measurements in clinical laboratories: results from the CRIC study.

OBJECTIVES: Estimating equations using serum creatinine (SCr) are often used to assess glomerular filtration rate (GFR). Such creatinine (Cr)-based formulae may produce biased estimates of GFR when using Cr measurements that have not been calibrated to reference laboratories. In this paper, we sought to examine the degree of this variation in Cr assays in several laboratories associated with academic medical centers affiliated with the Chronic Renal Insufficiency Cohort (CRIC) Study; to consider how best to correct for this variation, and to quantify the impact of such corrections on eligibility for participation in CRIC. Variability of Cr is of particular concern in the conduct of CRIC, a large multicenter study of subjects with chronic renal disease, because eligibility for the study depends on Cr-based assessment of GFR. METHODS: A library of 5 large volume plasma specimens from apheresis patients was assembled, representing levels of plasma Cr from 0.8 to 2.4 mg/dl. Samples from this library were used for measurement of Cr at each of the 14 CRIC laboratories repetitively over time. We used graphical displays and linear regression methods to examine the variability in Cr, and used linear regression to develop calibration equations. We also examined the impact of the various calibration equations on the proportion of subjects screened as potential participants who were actually eligible for the study. RESULTS: There was substantial variability in Cr assays across laboratories and over time. We developed calibration equations for each laboratory; these equations varied substantially among laboratories and somewhat over time in some laboratories. The laboratory site contributed the most to variability (51% of the variance unexplained by the specimen) and variation with time accounted for another 15%. In some laboratories, calibration equations resulted in differences in eligibility for CRIC of as much as 20%. CONCLUSIONS: The substantial variability in SCr assays across laboratories necessitates calibration of SCr measures to a common standard. Failing to do so may substantially affect study eligibility and clinical interpretations when they are determined by Cr-based estimates of GFR.

Rescoring the NIH chronic prostatitis symptom index: nothing new.

The National Institutes of Health-chronic prostatitis symptom index (NIH-CPSI) is a commonly used 13-item questionnaire for the assessment of symptom severity in men with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). For each item, score ranges are 0-1 (6 items), 0-3 (2 items), 0-5 (3 items), 0-6 (1 item) and 0-10 (1 item). This scoring system is straightforward, but items with wider score ranges are de facto weighted more, which could adversely affect the performance characteristics of the questionnaire. We rescored the NIH-CPSI so that equal weights were assigned to each item, and compared the performance of the standard and rescored questionnaires using the original validation dataset. Both the original and revised versions of the scoring algorithm discriminated similarly among groups of men with CP (n=151), benign prostatic hyperplasia (n=149) and controls (n=134). The internal consistency of the questionnaire was slightly better with the revised scoring, but values with the standard scoring were sufficiently high (Cronbach's >or=0.80). We conclude that although the rescored NIH-CPSI provides better face validity than the standard scoring algorithm, it requires additional calculation efforts and yields only marginal improvements in performance.

A pilot clinical trial of oral pentosan polysulfate and oral hydroxyzine in patients with interstitial cystitis.

PURPOSE: This pilot study was designed to evaluate the feasibility of a multicenter, randomized, clinical trial in interstitial cystitis (IC). Secondary objectives were to evaluate the safety and efficacy of oral pentosan polysulfate sodium (PPS), hydroxyzine, and the combination to consider their use in a larger randomized clinical trial. MATERIALS AND METHODS: A 2 x 2 factorial study design was used to evaluate PPS and hydroxyzine. Participants met the National Institutes of Health-National Institute for Diabetes and Digestive and Kidney Diseases criteria for IC and reported at least moderate pain and frequency for a minimum of 6 months before study entry. The primary end point was a patient reported global response assessment. Secondary end points included validated symptom indexes and patient reports of pain, urgency and frequency. The target sample size was 136 participants recruited during 10 months. RESULTS: A total of 121 (89% of goal) participants were randomized over 18 months and 79% provided complete followup data. The response rate for hydroxyzine was 31% for those treated and 20% for those not treated (p = 0.26). A nonsignificant trend was seen in the PPS treatment groups (34%) as compared to no PPS (18%, p = 0.064). There were no treatment differences for any of the secondary end points. Adverse events were mostly minor and similar to those in previous reports. CONCLUSIONS: The low global response rates for PPS and hydroxyzine suggest that neither provided benefit for the majority of patients with IC. This trial demonstrated the feasibility of conducting a multicenter randomized clinical trial in IC using uniform procedures and outcomes. However, slow recruitment underscored the difficulties of evaluating commonly available IC drugs.

Quality of life is impaired in men with chronic prostatitis: the Chronic Prostatitis Collaborative Research Network.

OBJECTIVE: Health-related quality of life (HRQOL) impairment may be a central component of chronic prostatitis for men afflicted with this condition. Our objective was to examine HRQOL, and factors associated with HRQOL, using both general and condition-specific instruments. DESIGN: Chronic Prostatitis Cohort (CPC) study. SETTING: Six clinical research centers across the United States and Canada. PARTICIPANTS: Two hundred seventy-eight men with chronic prostatitis. MEASUREMENTS AND MAIN RESULTS: The Short Form 12 (SF-12) Mental Component Summary (MCS) and Physical Component Summary (PCS), and the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) were measures used. CPC subjects' MCS scores (44.0 +/- 9.8) were lower than those observed in the most severe subgroups of patients with congestive heart failure and diabetes mellitus, and PCS scores (46.4+/-9.5) were worse than those among the general U.S. male population. Decreasing scores were seen in both domains with worsening symptom severity (P < .01). History of psychiatric disease and younger age were strongly associated with worse MCS scores, whereas history of rheumatologic disease was associated with worse PCS scores. Predictors of more severe NIH-CPSI scores included lower educational level and lower income; history of rheumatic disease was associated with higher scores. CONCLUSIONS: Men with chronic prostatitis experience impairment in the mental and physical domains of general HRQOL, as well as condition-specific HRQOL. To optimize the care of men with this condition, clinicians should consider administering HRQOL instruments to their patients to better understand the impact of the condition on patients' lives.

Biopsy features are associated with primary symptoms in interstitial cystitis: results from the interstitial cystitis database study.

The purpose of this study was to investigate associations between bladder biopsy features and urinary symptoms for patients enrolled in the Interstitial Cystitis Database (ICDB) Study. Bladder biopsies were obtained during baseline screening in the ICDB Study and were evaluated for histopathologic features. Multivariable models for nighttime voiding frequency, urinary urgency, and pain were developed, incorporating biopsy features from the most diseased area of the bladder as predictors, adjusting for significant clinical factors, and clinical center variation. Among 204 interstitial cystitis (IC) patients providing biopsy specimens, cystoscopic pathology findings were not statistically associated (P >0.1) with primary IC symptoms, although the presence of Hunner's ulcer (n = 12) was suggestive of increased urinary frequency. Within a multivariable predictive model for nighttime voiding frequency, adjusting for age and minimum volume per void, 4 pathology features were noted: (1) mast cell count in lamina propria on tryptase stain; (2) complete loss of urothelium; (3) granulation tissue in lamina propria; and (4) vascular density in lamina propria on factor VIII (F8) stain were statistically significant (P <0.01). Similarly, in a multivariable model for urinary urgency, minimum volume, and percentage of submucosal granulation tissue remained statistically significant (P <0.01). Finally, the percentage of mucosa denuded of urothelium and the percentage of submucosal hemorrhage remained highly associated (P <0.01) with pain in a multivariable predictive model. The fact that the presence or severity of glomerulations was not selected for any of these predictive models suggests that cystoscopic findings of glomerulations are not predictive of IC symptoms. Furthermore, these results suggest an important role for certain pathologic features in the predictive modeling of IC symptoms.

A mixed effects model for the analysis of ordinal longitudinal pain data subject to informative drop-out.

We extend the model of Pulkstenis et al. that models binary longitudinal data, subject to informative drop-out through remedication, to the ordinal response case. We present a selection model shared-parameter approach that specifies mixed models for both ordinal response and discrete survival time to remedication. In this fashion, the random parameter present in both models completely characterizes the relationship between response and time to remedication inducing their conditional independence. With a log-log link function for both response and study 'survival', as well as specification of a log-gamma distribution for the random effect, we obtain a closed-form expression for the marginal log-likelihood of response and time to remedication that does not require approximation or numerical integration techniques. A data analysis is performed and simulation results presented which support the consistency of parameter and standard error estimates.

Evaluation of repeat daily voiding measures in the National Interstitial Cystitis Data Base Study.

PURPOSE: We address the importance of 3 consecutive daily frequency volume charts relative to a single day in research studies for interstitial cystitis. In addition, differences in voiding patterns between weekend days and weekdays were evaluated. MATERIALS AND METHODS: Longitudinal frequency volume chart data for 305 women enrolled in the National Interstitial Cystitis Data Base Study before December 31, 1995 and meeting protocol specifications were summarized for 3 outcome measures. Longitudinal data methods designed to accommodate different within patient correlation patterns for repeat measures within and among patient contacts were implemented in a generalized estimating equation modeling framework, permitting overall testing of day and weekend effects. RESULTS: Day 2 and day 3 measures were not statistically different (1% level) from day 1 for nocturnal voiding frequency and nocturia. Although statistically significant for 24-hour frequency, the mean difference of -0.36 void daily between days 1 and 3 was not likely to be clinically significant. Also, measures on weekdays were not significantly different from those on weekends for each of the 3 outcome measures. CONCLUSIONS: Our results suggest that the current clinical research requirement of 3 consecutive days for frequency volume charts can be reduced to a single day. Furthermore, day selection need not be affected by weekday versus weekend considerations.

Treatments used in women with interstitial cystitis: the interstitial cystitis data base (ICDB) study experience. The Interstitial Cystitis Data Base Study Group.

OBJECTIVES: To evaluate the frequency and types of treatments reported at baseline in women who entered the Interstitial Cystitis Data Base (ICDB) cohort study. METHODS: From 1993 to 1997, 581 women were enrolled and followed in the ICDB. All treatments reported at study entry, including those prescribed for interstitial cystitis (IC) and concomitant medications, were reviewed. The number and types of treatments were evaluated with respect to baseline factors such as prior diagnosis of IC and symptom severity. RESULTS: One hundred five (18%) women were receiving no therapy at baseline. Single-mode therapy was reported by 195 (34%) women, and a combination of two treatments was reported by 119 (21%) women. Three or more treatments were reported in 162 (28%) women. A total of 183 different types of therapies were recorded. The five most commonly used therapies for IC symptoms were cystoscopy and hydrodistention, amitriptyline, phenazopyridine, special diet, and intravesical heparin. Because most patients entered the ICDB before the approval of oral pentosan polysulfate sodium (PPS), only 6% of women reported oral PPS use at baseline. There were statistically significant associations between the number and types of treatments and clinical center, a prior diagnosis of IC, and symptom severity. CONCLUSIONS: The diversity of IC therapies underscores the lack of understanding about the treatment of this syndrome. Further research in IC is essential to develop and to evaluate rational therapies and treatment algorithms. These algorithms should be "evidence based" and should be revised as the underlying etiology and pathophysiology of IC is delineated.

A prospective study of interstitial cystitis: results of longitudinal followup of the interstitial cystitis data base cohort. The Interstitial Cystitis Data Base Study Group.

PURPOSE: We present baseline characteristics and longitudinal profiles of symptoms in the Interstitial Cystitis Data Base study, a prospective cohort study of patients with interstitial cystitis. MATERIALS AND METHODS: A total of 637 eligible patients were entered into the study and followed for symptoms of pain, urgency and urinary frequency. Median followup was 31 months. RESULTS: More than 90% of patients were white women with a median age of 43 years. Using the overall pain-urgency-frequency score 7% of participants presented with mild, 44% with moderate and 49% with severe symptoms. Severe urgency in 41% of cases and severe 24-hour frequency in 41% were more common than severe pain in 29%. Of the patients 51% reported nighttime frequency of 2 or more voids. Median duration of interstitial cystitis symptoms was 8 years and 68% of participants were previously diagnosed with the condition. The 36% of patients who withdrew from study or were lost to followup were more likely to have had more severe symptoms at baseline. Patterns of change with time suggest initial symptom improvement due to regression to the mean, and an intervention effect associated with the increased followup and care of cohort participants. Although all symptoms fluctuated, there was no evidence of significant long-term change in overall disease severity. CONCLUSIONS: Our observations support the clinical observation that interstitial cystitis is a chronic disease and no current treatments have a significant impact on symptoms with time. These results provide a foundation for the design and performance of future clinical trials in interstitial cystitis using these end points in a similar patient population.

Detection of Björk-Shiley convexo-concave heart valve outlet strut single leg separations: consensus image acquisition and interpretation using two different cineradiographic imaging technologies.

BACKGROUND: Conventional cineradiology has been used clinically to detect partially broken outlet struts (single leg separations, SLSs) in normally functioning Björk-Shiley convexo-concave (C/C) heart valves. The value of radiographic screening has, however, been debated in the medical literature. This study uses the same radiographic technique in sheep implanted with known-status C/C valves in combination with a newly developed geometric image magnification radiography system. This study was designed to test whether sensitivity and specificity of radiographic screening of C/C valves in detecting SLSs could be improved through the combination of readers and imaging modalities. METHODS: Twenty-one sheep with mitral C/C valves were studied on both systems. Five were used for extensive scanning training. When operators were expert on both systems, 16 blinded study valves (4 intact and 12 with outlet strut SLSs) were scanned twice on both systems, first on a modified conventional and then a prototype geometric image magnification (Feinfocus(TM)) cineradiographic system by two expert physicians working together. RESULTS: Among the 32 scanned valves, the two combined expert physicians were required to evaluate 40 intact legs and 24 with an SLS. For all SLS valves, the conventional and Feinfocus systems separately detected 50 (12/24) and 54% (13/24), respectively. When the two systems were combined, the final consensus score was correct in 67% (16/24) of all SLS valves. CONCLUSIONS: Combined modality, paired expert physicians detected 67% of all SLSs. The Feinfocus system might be best reserved for those patients in whom the Siemens screening study demonstrates in minimally suspicious (grade 2) or suspicious (grade 3) appearance of a C/C valve outlet strut leg.

The diagnosis of interstitial cystitis revisited: lessons learned from the National Institutes of Health Interstitial Cystitis Database study.

PURPOSE: The lack of a precise working definition of interstitial cystitis may have resulted in the de facto use of the National Institute of Diabetes, Digestive and Kidney Diseases (NIDDK) "research" definition by clinicians. We evaluated these strict criteria in light of the broader inclusion criteria for patients evaluated in the Interstitial Cystitis Database study to determine their utility in clinical practice as a useful basis for the diagnosis of interstitial cystitis. MATERIALS AND METHODS: A total of 379 women who completed screening for the Interstitial Cystitis Database before January 1, 1996 met the basic criteria of urinary frequency, urgency or pain for at least 6 months in duration without a diagnosable etiology. Of these patients 148 underwent cystoscopy and hydrodistention of the bladder as a part of the evaluation. All patients were followed for a minimum of 1 year. Comparisons were made between patients judged to have a clinical diagnosis of interstitial cystitis and those who met the NIDDK research definition of the syndrome. RESULTS: Almost 90% of patients potentially meeting NIDDK criteria are believed by experienced clinicians to have interstitial cystitis, confirming the research value of these criteria in defining a homogeneous population for study. However, strict application of NIDDK criteria would have misdiagnosed more than 60% of patients regarded by researchers as definitely or likely to have interstitial cystitis. CONCLUSIONS: The NIDDK criteria are too restrictive to be used by clinicians as the diagnostic definition of interstitial cystitis.

A prospective study of microvascular free-flap surgery and outcome.

Over a 6-month period, 23 members of the International Microvascular Research Group participated in a prospective survey of their microvascular free-flap practice. Data were recorded with each case for 60 variables covering patient characteristics, surgical technique, pharmacologic treatment, and postoperative outcome. A total of 493 free flaps were reported with a representative demographic distribution for age, sex, indications for surgery, risk factors, flap type, surgical technique, and pharmacologic intervention. Mixed effects logistic regression modeling was used to determine predictors of flap failure and associated complications. The overall incidence of flap failure was 4.1 percent (20 of 493). Reconstruction of an irradiated recipient site and the use of a skin-grafted muscle flap were the only statistically significant predictors of flap failure, with increased odds of failure of 4.2 (p = 0.01) and 11.1 (p = 0.03), respectively. A postoperative thrombosis requiring re-exploration surgery occurred in 9.9 percent of the flaps. The incidence of this complication was significantly higher when the flap was transferred to a chronic wound and when vein grafts were needed, with increased odds of failure of 2.9 (p = 0.02) and 2.5 (p = 0.02), respectively. There was a lower incidence of postoperative thrombosis when rectus/transverse rectus abdominis muscle (TRAM) flaps were used, where odds of failure decreased by 0.36 (p = 0.04), and when subcutaneous heparin was administered in the postoperative period, where odds decreased by 0.27 (p = 0.04). There was an overall 69-percent salvage rate for flaps identified with a postoperative thrombosis. Intraoperative thrombosis occurred in 41 cases (8.3 percent) and was observed more frequently in myocutaneous flaps or when vein grafts were needed (5.5 and 5.0 greater odds, respectively; p < 0.001) but was not associated with higher flap failure (2 of 41 cases; 4.9-percent failure rate). The incidence of a hematoma and/or hemorrhage was increased in obese patients and when vein grafts were needed [2.7 (p = 0.02) and 2.6 (p = 0.03) greater odds, respectively], whereas this complication was significantly decreased in muscle flaps (myocutaneous or skin-grafted muscle), in tobacco users, when a heparinized solution was used for general wound irrigation, and when the attending surgeon performed the arterial anastomosis (in contrast to the resident or fellow on staff) (p < 0.05 for each factor). With the multivariable analysis, many factors were found not to have a significant effect on flap outcome, including the recipient site (e.g., head/neck, breast, lower limb, etc.); indications for surgery (trauma, cancer, etc.); flap transfer in extremes of age, smokers, or diabetics; arterial anastomosis with an end-to-end versus end-to-side technique; irrigation of the vessel without or with heparin added to the irrigation solution; and a wide spectrum of antithrombotic drug therapies. These results present a current baseline for free-flap surgery to which future advances and improvements in technique and practice may be compared.

Systolic blood pressure trends in US adults between 1960 and 1980: influence of antihypertensive drug therapy.

Recent blood pressure trends reflect progress in hypertension control, but prevalent drug therapy precludes direct estimation of the component due to primary prevention. In data gathered on persons aged 35-74 years in three successive US health examination surveys (1960-1980), systolic blood pressure levels assuming no drug therapy were imputed by reassigning blood pressure to the upper end of the distribution for respondents reporting use of antihypertensive medication. Blood pressure was partitioned into four ordinal categories based on weighted percentiles of the 1960-1962 distributions for 35- to 44-year-old males and females who reported no use of antihypertensive medication. Cumulative logit models (alpha = 0.01) were used to estimate age- and sex-specific trends for blacks and whites within two strata (<25 or > or =25) of body mass index (BMI) (weight (kg)/height (m)2). Before imputation, systolic blood pressure decreased between 1960 and 1980; after imputation, significant decreases remained only in 35- to 44-year-olds. Strong associations of black race and BMI > or =25 with higher blood pressures were present in models with and without drug therapy. Thus, according to the models, there has been little progress in decreasing racial or BMI-related blood pressure differentials. Above the age of 44 years, blood pressure trends were largely attributable to medication use. In contrast, data for 35- to 44-year-olds suggest progress in primary prevention.

Mixed effects logistic regression models for longitudinal binary response data with informative drop-out.

A shared parameter model with logistic link is presented for longitudinal binary response data to accommodate informative drop-out. The model consists of observed longitudinal and missing response components that share random effects parameters. To our knowledge, this is the first presentation of such a model for longitudinal binary response data. Comparisons are made to an approximate conditional logit model in terms of a clinical trial dataset and simulations. The naive mixed effects logit model that does not account for informative drop-out is also compared. The simulation-based differences among the models with respect to coverage of confidence intervals, bias, and mean squared error (MSE) depend on at least two factors: whether an effect is a between- or within-subject effect and the amount of between-subject variation as exhibited by variance components of the random effects distributions. When the shared parameter model holds, the approximate conditional model provides confidence intervals with good coverage for within-cluster factors but not for between-cluster factors. The converse is true for the naive model. Under a different drop-out mechanism, when the probability of drop-out is dependent only on the current unobserved observation, all three models behave similarly by providing between-subject confidence intervals with good coverage and comparable MSE and bias but poor within-subject confidence intervals, MSE, and bias. The naive model does more poorly with respect to the within-subject effects than do the shared parameter and approximate conditional models. The data analysis, which entails a comparison of two pain relievers and a placebo with respect to pain relief, conforms to the simulation results based on the shared parameter model but not on the simulation based on the outcome-driven drop-out process. This comparison between the data analysis and simulation results may provide evidence that the shared parameter model holds for the pain data.

In vivo accuracy of two radiographic systems in the detection of Björk-Shiley convexo-concave heart valve outlet strut single leg separations.

OBJECTIVE: Modified cineradiographic systems have been used clinically to detect partially broken outlet struts in normally functioning Björk-Shiley convexo-concave heart valves. Almost all such valves were explanted, presuming that full failure would likely follow. Inasmuch as the clinical setting only rarely permits examination of normally rated valves, the accuracy of radiographic detection cannot be clinically defined. This study uses the clinical radiographic technique in sheep implanted with known-status convexo-concave valves, comparing its accuracy and that of a newly developed, geometric image magnification radiography system. METHODS: Twenty-one sheep with mitral convexo-concave valves were studied on both systems. Five were used for extensive training. When operators were expert with both systems, images of four intact valves and 12 valves with outlet strut single leg separations, along with a seventeenth single leg separation valve used for calibration, were integrated into 112 image sets organized into a balanced incomplete block design for evaluation by eight trained, blinded reviewers. RESULTS: Cineradiography sensitivity was 24% versus 31% for direct image magnification. The odds ratio for detection of single leg separation by direct image magnification versus cineradiography was 2.0 (95% confidence interval, 0.76 to 5.9; p = 0.13). Cineradiography specificity was 93% versus 90% for direct image magnification. Sensitivity and specificity varied markedly by reviewer, with sensitivity ranging from 8% to 55% and specificity from 51% to 100% for the combined technologies. CONCLUSIONS: The data support the need for more intensive training for convexo-concave valve imaging and further investigation of unconventional radiographic technologies. Clinical cineradiography of convexo-concave valves may detect as little as 25% of valves having a single leg separation, underestimating the prevalence of single leg separations and thereby implying more rapid progression to full fracture than is actually the case.

A morphometric analysis of the posed smile.

A fundamental goal of orthodontics is to improve the smile, but no objective criteria exist to assess the lip-teeth relationship, establish objectives of treatment or measure treatment outcome. Here we propose a method to digitally measure the smile characteristics of orthodontic patients. Specifically, the 'posed smile' is measured. By definition the posed smile is voluntary and not elicited by an emotion. It can be a learned greeting or a signal of appeasement and can be sustained. The posed smile is reliably repeatable. The multimedia computer program for smile measurement we developed was based on studies of the utility of the smile photograph and the assessment of the lip-teeth characteristics of the posed smile in treated and untreated patients. On the computer screen a grid, or smile mesh, employs horizontal and vertical lines to measure eleven attributes of a smile. Not all orthodontically 'well-treated' patients with exemplary plaster casts exhibit desirable anterior tooth display while smiling. We suggest that the photographic analysis of an unstrained posed smile might be a standard orthodontic record.

Interaction fallacy.

We define interaction fallacy as the situation in which heterogeneity of odds ratios suggests an interaction that does actually not exist among the corresponding risk ratios. We provide a hypothetical example of interaction fallacy between the presence of the germ-line BRCA1 mutation, age at first live birth, and breast cancer risk based on data from the literature. More generally, we present a set of hypothetical conditions under which interaction fallacy may occur.