Association between morbidity among term newborns and low-risk caesarean delivery rates

OBJECTIVE

To examine the association between county-level caesarean delivery (CD) rates among women at low risk and morbidity among term newborns.

DESIGN

Cross-sectional study.

SETTING

Population-based study of US county-level birth data from 2015 to 2017.

POPULATION

Nulliparous women with term, singleton, vertex-presenting infants (NTSV) at low risk for morbidity.

METHODS

The primary exposure was county-level CD rates.

MAIN OUTCOME MEASURES

The outcome was morbidity among the low-risk NTSV cohort, categorised as severe (5-minute Apgar score of ≤3, assisted ventilation for ≥6 hours, severe neurologic injury or seizure, transfer or death) or moderate (5-minute Apgar score of <7 but >3, administration of antibiotics or assisted ventilation at delivery). We used linear regression models to determine the association between county NTSV CD and neonatal morbidity rates with cluster robust standard errors.

RESULTS

The analysis included data from 2 753 522 births in 952 counties from all 48 states. The mean NTSV CD rate was 23.6% (standard deviation 4.8%). The median severe and moderate neonatal morbidity rates were 15.2 (interquartile range, IQR 9.4-23.6) and 52.5 (IQR 33.4-75.7) per 1000 births, respectively. In the unadjusted analysis using the risk-adjusted exposure and outcome, every percentage point increase in the CD rate of a county was associated with 0.6 (95% CI -0.9, -0.3) and 2.3 fewer (95% CI -3.4, -1.1) cases of severe and moderate neonatal morbidity per 1000 live births. After adjustment for other county factors, the relationships remained significant. These findings were tested in multiple sensitivity analyses.

CONCLUSIONS

Lower county-level NTSV CD rates were associated with a small increase in morbidity among term newborns in the USA.

TWEETABLE ABSTRACT

Lower county-level caesarean delivery rates were associated with an increase in morbidity among term newborns in the USA.

Hospital volume and cesarean delivery among low-risk women in a nationwide sample

OBJECTIVE

We sought to determine if hospital delivery volume was associated with a patient's risk for cesarean delivery in low-risk women.

STUDY DESIGN

This study retrospectively examines a cohort of 1 657 495 deliveries identified in the 2013 Nationwide Readmissions Database. Hospitals were stratified by delivery volume quartiles. Low-risk patients were identified using the Society for Maternal-Fetal Medicine definition (n=845 056). A multivariable logistic regression accounting for hospital-level clustering was constructed to assess the factors affecting a patient's odds for cesarean delivery.

RESULTS

The range of cesarean delivery rates was 2.4-51.2% among low-risk patients, and the median was 16.5% (IQR 12.8-20.5%). The cesarean delivery rate was higher in the top two-volume-quartile hospitals (17.4 and 18.2%) compared to the bottom quartiles (16.4 and 16.3%) (P<0.001). Hospital volume was not associated with a patient's odds for cesarean delivery after adjusting for patient and other hospital characteristics (P=0.188).

CONCLUSION

Hospital delivery volume is not an independent predictor of cesarean delivery in this population.

Auditory test result characteristics of subjects with and without tinnitus

Tinnitus is the perception of sound that does not have an acoustic source in the environment. Ascertaining the presence of tinnitus in individuals who claim tinnitus for compensation purposes is very difficult and increasingly becoming a problem. This study examined the potential to observe differences in loudness and pitch matches between individuals who experience tinnitus versus those who do not. This study follows a previous pilot study we completed that included 12 subjects with and 12 subjects without tinnitus. The current study included 36 subjects with and 36 without tinnitus. Results of this study revealed no significant differences between groups with regard to decibel sensation level (SL) loudness matches and within-session loudness-match reliability. Between-group differences revealed that the tinnitus subjects had (1) greater decibel sound pressure level loudness matches, (2) better between-session loudness-match reliability, (3) better pitch-match reliability, and (4) higher frequency pitch matches. These findings support the data from our pilot study with the exception that decibel SL loudness matches were greater for the tinnitus subjects in the pilot study. Tinnitus loudness and pitch matching may have some value in an overall battery of tests for evaluating tinnitus claims.

Evaluation of audiometric threshold shift criteria for ototoxicity monitoring

BACKGROUND

There is disagreement about ototoxicity monitoring methods. Controversy exists about what audiometric threshold shift criteria should be used, which frequencies should be tested, and with what step size. An evaluation of the test performance achieved using various criteria and methods for ototoxicity monitoring may help resolve these issues.

PURPOSE

(1) Evaluate test performance achieved using various significant threshold shift (STS) definitions for ototoxicity monitoring in a predominately veteran population; and (2) determine whether testing in (1/6)- or (1/3)-octave steps improves test performance compared to (1/2)-octave steps.

RESEARCH DESIGN

A prospective, observational study design was used in which STSs were evaluated at frequencies within an octave of each subject's high-frequency hearing limit at two time points, an early monitoring test and the final monitoring test.

STUDY SAMPLE

Data were analyzed from 78 ears of 41 patients receiving cisplatin and from 53 ears of 28 hospitalized patients receiving nonototoxic antibiotics. Cisplatin-treated subjects received a cumulative dosage > or =350 mg by the final monitoring test. Testing schedule, age, and pre-exposure hearing characteristics were similar between the subject groups.

DATA COLLECTION AND ANALYSIS

Threshold shifts relative to baseline were examined to determine whether they met criteria based on magnitudes of positive STS (shifts of > or =5, 10, 15, or 20 dB) and numbers of frequencies affected (shifts at > or =1, 2, or 3 adjacent frequencies) for data collected using approximately (1/6)-, (1/3)-, or (1/2)-octave steps. Thresholds were confirmed during monitoring sessions in which shifts were identified. Test performance was evaluated with receiver operating characteristic (ROC) curves developed using a surrogate "gold standard"; true positive (TP) rates were derived from the cisplatin-exposed group and false positive (FP) rates from the nonexposed, control group. Best STS definitions were identified that achieved the greatest areas under ROC curves or resulted in the highest TP rates for a fixed FP rate near 5%, chosen to minimize the number of patients incorrectly diagnosed with ototoxic hearing loss.

RESULTS

At the early monitoring test, average threshold shifts differed only slightly across groups. Test-frequency step size did not affect performance, and changes at one or more frequencies yielded the best test performance. At the final monitoring test, average threshold shifts were +10.5 dB for the cisplatin group, compared with -0.2 dB for the control group. Compared with the (1/2)-octave step size used clinically, use of smaller frequency steps improved test performance for threshold shifts at > or =2 or > or =3 adjacent frequencies. Best overall test performance was achieved using a criterion cutoff of > or =10 dB threshold shift at > or =2 adjacent frequencies tested in (1/6)-octave steps. Best test performance for the (1/2)-octave step size was achieved for shifts > or =15 dB at one or more frequencies.

CONCLUSIONS

An ototoxicity monitoring protocol that uses an individualized, one-octave range of frequencies tested in (1/6)-octave steps is quick to administer and has an acceptable FP rate. Similar test performance can be achieved using (1/3)-octave test frequencies, which further reduces monitoring test time.

Determinants of outcomes of sinus surgery: a multi-institutional prospective cohort study

OBJECTIVES

1) To measure the proportion of patients with chronic rhinosinusitis (CRS) who experience clinically significant improvement after endoscopic sinus surgery (ESS) in a prospective, multi-institutional fashion. 2) To identify preoperative characteristics that predict clinically significant improvement in quality of life (QOL) after ESS.

STUDY DESIGN

Prospective, multi-institutional cohort study.

SETTING

Academic tertiary care centers.

SUBJECTS AND METHODS

A total of 302 patients with CRS from three centers were enrolled between July 2004 and December 2008 and followed for an average of 17.4 months postoperatively. Preoperative patient characteristics, CT scan, endoscopy score, and pre- and postoperative quality of life (QOL) data were collected. Univariate and multivariate analyses were performed.

RESULTS

Patients improved an average of 15.8 percent (18.9 points) on the Rhinosinusitis Disability Index and 21.2 percent (21.2 points) on the Chronic Sinusitis Survey (both P < 0.001). Patients significantly improved on all eight Medical Outcomes Study Short Form-36 (SF-36) subscales (all P < 0.001). Among patients with poor baseline QOL, 71.7 percent of patients experienced clinically significant improvement on the RSDI and 76.1 percent on the CSS. Patients undergoing primary surgery were 2.1 times more likely to improve on the RSDI (95% confidence interval [CI], 1.2, 3.4; P = 0.006) and 1.8 times more likely to improve on the CSS (95% CI, 1.1, 3.1; P = 0.020) compared with patients undergoing revision surgery.

CONCLUSION

In this prospective, multi-institutional study, most patients experienced clinically significant improvement across multiple QOL outcomes after ESS. Specific patient characteristics provided prognostic value with regard to outcomes.

Long-term survival after colon cancer surgery: a variation associated with choice of anesthesia

BACKGROUND

A previously published clinical trial of epidural-supplemented versus general anesthesia, Veterans Affairs Cooperative Study No. 345, showed no difference in 30-day mortality and morbidity rates between the two treatments. We hypothesized that long-term postoperative survival would be increased by epidural anesthesia/analgesia supplementation during colon cancer resection.

METHODS

We studied long-term survival after resection of colon cancer in a trial of general anesthesia with and without epidural anesthesia and analgesia supplementation for resection of colon cancer in Veterans Affairs Cooperative Study No. 345. Cox and log-normal survival models were used to test the effects of pathological stage, type of anesthesia and other covariates on survival in 177 patients.

RESULTS

The presence of distant metastases had the greatest effect on survival. Thus, analyses were performed separately for patients with and without metastases. For those without metastasis, the hazard ratio for the treatment effects changed at 1.46 years. Before 1.46 years, epidural supplementation was associated with improved survival (P = 0.012), while later, the type of anesthesia did not appear to affect survival (P = 0.27). Hypertension was associated with poorer survival (P = 0.029), as was alcoholism in patients who received epidural anesthesia (P = 0.014). Survival of patients with metastases was unaffected by type of anesthesia. There was a significant age by hypertension interaction (P = 0.002). Patients survived longer if they were hypertensive, but had reduced survival if they were older than 66 years and hypertensive.

CONCLUSION

Epidural supplementation was associated with enhanced survival among patients without metastases before 1.46 years. Epidural anesthesia had no effect on survival of patients with metastases. Additional studies to confirm or refute these findings are warranted.

Endoscopic and Quality-of-Life Outcomes After Revision Endoscopic Sinus Surgery

OBJECTIVES

First, to examine the impact of endoscopic sinus surgery (ESS) on endoscopic and quality-of-life (QOL) outcomes after revision ESS as compared to primary ESS. Second, to evaluate whether or not other risk factors and/or co-morbidities influence the relationship between revision surgery status and outcomes of ESS.

STUDY DESIGN

Prospective observational study with an internal comparison group.

METHODS

Preoperative computed tomography scores, pre and postoperative endoscopy scores, and two validated disease-specific QOL instruments, the Rhinosinusitis Disability Index (RSDI) and Chronic Sinusitis Survey (CSS), were collected on a prospective cohort of patients undergoing ESS for chronic rhinosinusitis. Data were analyzed using Pearson's chi and multiple logistic regression models.

RESULTS

Mean preoperative Lund-Mackay computed tomography scan scores were similar in primary and revision surgery patients. In patients without polyps, revision ESS patients were 3.88 times more likely to improve on endoscopy scores than primary ESS patients (95% confidence interval 1.70, 8.83; P = .001). In nasal polyp patients, there was no difference by revision status (odds ratio 0.48; 95% confidence interval 0.15, 1.59; P = .23). The odds of improving on the RSDI (odds ratio 0.51, 95% confidence interval 0.25, 1.04, P = .065) and CSS (odds ratio 0.98, 95% confidence interval 0.51, 1.89, P = .950) were not significantly different by revision status.

CONCLUSIONS

Both revision and primary ESS patients improved after ESS with regard to endoscopy, RSDI, and CSS scores. In non-polyp patients, revision ESS patients were more likely to improve on endoscopy scores than primary ESS patients; there was no difference in polyp patients by revision status. Revision ESS patients and primary ESS patients were equally as likely to improve on two QOL instruments.

Impact of aspirin intolerance on outcomes of sinus surgery

OBJECTIVES

To compare objective and quality of life (QOL) outcomes after endoscopic sinus surgery (ESS) in aspirin (ASA)-tolerant patients and ASA-intolerant patients over intermediate and long-term follow-up.

STUDY DESIGN

Prospective analysis of a cohort of patients with chronic rhinosinusitis.

METHODS

Preoperative computed tomography (CT), pre- and postoperative endoscopy, and two validated disease specific QOL instruments, the Rhinosinusitis Disability Index (RSDI) and Chronic Sinusitis Survey (CSS), were collected. Differences in the proportions of patients who improved were analyzed using Pearson's chi-square and Fisher's exact test.

RESULTS

Nineteen ASA-intolerant patients and 104 ASA-tolerant patients were followed for a mean of 17.7 months. Patients with ASA intolerance had significantly worse preoperative CT (P < .0001) and endoscopy scores (P < .0001). After ESS, 57% to 74% of patients improved on endoscopy scores, 63% to 71% improved on the RSDI, and 58% to 73% improved on the CSS; improvement did not significantly differ by ASA status.

CONCLUSIONS

Similar proportions of ASA-tolerant and ASA-intolerant patients showed improvement on endoscopy and QOL measures after ESS.

Randomized clinical trial: Group counseling based on tinnitus retraining therapy

The main component of tinnitus retraining therapy (TRT) is structured counseling. We conducted a randomized clinical trial to test the hypothesis that group educational counseling based on TRT principles would effectively treat veterans who have clinically significant tinnitus. Veterans with clinically significant tinnitus were randomized into one of three groups: educational counseling, traditional support, and no treatment. Subjects in the first two groups attended four 1.5 h group sessions each week. All subjects completed outcome questionnaires at baseline and at 1, 6, and 12 mo. A total of 269 subjects participated: 94 in the educational counseling group, 84 in the traditional support group, and 91 in the no-treatment group. Statistical analyses showed that educational counseling provided significantly more benefit than either traditional support or no treatment, as measured by the Tinnitus Severity Index. Results suggest that group educational counseling can significantly benefit many tinnitus patients and could be integral to a "progressive intervention" approach to tinnitus clinical management.

The influence of physician gender on practice satisfaction among obstetrician gynecologists

OBJECTIVE

A survey was conducted to investigate the hypothesis that female gender would positively affect job satisfaction among obstetrician gynecologists.

STUDY DESIGN

A survey was sent to 500 randomized, age matched American College of Obstetrics and Gynecology members, 50% each men and women: 49.8% responded. Data were analyzed with the chi2 contingency test, Cochran's test for linear trends, Student t tests, and multiple regression.

RESULTS

Women considered their gender an asset in deciding on a career in obstetrics and gynecology, in obtaining jobs, and in maintaining their practices. Men considered that their gender limited their practice options and were more likely to report that they would not choose a career in obstetrics and gynecology if they could choose again. The only significant difference between men and women in measures of obtaining and maintaining a practice was that men were more likely to practice in small urban or rural settings. Men reported higher incomes. Both genders were equally satisfied with their jobs.

CONCLUSION

Although both genders considered female gender to be an asset in obstetrics and gynecology, this survey showed no difference in their ratings of overall career satisfaction.

Issues in the design of multisite clinical trials of psychotherapy: VA Cooperative Study No. 494 as an example

This article describes issues in the design of an ongoing multisite randomized clinical trial of psychotherapy for treating posttraumatic stress disorder (PTSD) in female veterans and active duty personnel. Research aimed at testing treatments for PTSD in women who have served in the military is especially important due to the high prevalence of PTSD in this population. VA Cooperative Study 494 was designed to enroll 384 participants across 12 sites. Participants are randomly assigned to receive 10 weekly sessions of individual psychotherapy: Prolonged Exposure, a specific cognitive-behavioral therapy protocol for PTSD, or present-centered therapy, a comparison treatment that addresses current interpersonal problems but avoids a trauma focus. PTSD is the primary outcome. Additional outcomes are comorbid problems such as depression and anxiety; psychosocial function and quality of life; physical health status; satisfaction with treatment; and service utilization. Follow-up assessments are conducted at the end of treatment and then 3 and 6 months after treatment. Both treatments are delivered according to a manual. Videotapes of therapy sessions are viewed by experts who provide feedback to therapists throughout the trial to ensure adherence to the treatment manual. Discussion includes issues encountered in multisite psychotherapy trials along with the rationale for our decisions about how we addressed these issues in CSP #494.

Repeated split sample validation to assess logistic regression and recursive partitioning: an application to the prediction of cognitive impairment

Screening strategies play an important part in the identification and diagnosis of illness. Testing of such strategies in a clinical trial can have important implications for the treatment of such illnesses. Before the clinical trial, however, it is important to develop a practical screening/classification procedure that accurately predicts the presence of the illness in question. Recent published studies have shown a growing preference for classification tree/recursive partitioning procedures.This paper compares the application of logistic regression and recursive partitioning to a neuropsychological data set of 252 patients recruited from four Veterans Affairs Medical Centers. Logistic regression and recursive partitioning was used to predict cognitive impairment in 12 randomly selected exploratory/validation samples. We assessed the effect of sampling on variable selection and predictive accuracy.Predictive accuracy of the logistic regression and recursive partitioning procedures was comparable across the exploratory data samples but varied across the validation samples. Based on shrinkage, both classification procedures performed equally well for the prediction of cognitive impairment across the twelve samples. While logistic regression provided an estimated probability of outcome for each patient, it required several mathematical calculations to do so. However, logistic regression selected one or two less predictors than recursive partitioning with comparable predictive accuracy. Recursive partitioning, on the other hand, readily identified patient characteristics and variable interactions, was easy to interpret clinically and required no mathematical calculations. There was a high degree of overlap of the predictor variables between the two procedures.In the context of neuropsychological screening, logistic regression and recursive partitioning performed equally well and were quite stable in the selection of predictors for the identification of patients with cognitive impairment, although recursive partitioning may be easier to use in a clinical setting because it is based on a simple decision tree.

Neuropsychological screening for cognitive impairment using computer-assisted tasks

The aim of this study was to validate a computer-assisted screening battery for classifying patients into two groups, those with and without cognitive impairment. Participants were all patients referred to the neuropsychology clinics at four VA medical centers during a 1-year period. Patients meeting the study inclusionary criteria (N = 252) were administered the Neurobehavioral Evaluation System-3 (NES3) computer-assisted battery. A detailed neuropsychological examination was carried out by an experienced neuropsychologist, who diagnosed the patient as cognitively impaired or not impaired. The neuropsychologist's diagnosis was the gold standard. Recursive partitioning analyses yielded several classification procedures using the NES3 data to predict the gold standard These procedures produced a set of six NES3 tasks that provide good sensitivity and specificity in predicting di- agnosis. Sensitivity and specificity for the least random classification procedure were 0.87 and 0.67, respectively. The results suggest that computer-assisted screening methods are a promising means of triaging patients.

Interrater reliability of neuropsychological diagnoses: a Department of Veterans Affairs cooperative study

This study examined the interrater reliability of neuropsychological diagnoses produced by clinical neuropsychologists across 4 medical centers. These diagnoses were based on evaluations using a comprehensive battery of commonly used neuropsychological test instruments, interview, history and medical chart review. The diagnoses of individual neuropsychologists were compared to those made by members of an external review panel for each patient evaluated. Patients were first diagnosed as showing cognitive impairment versus no cognitive impairment. If a patient was diagnosed as impaired, a specific neuropsychological diagnosis was assigned. The diagnostic classification for cognitive impairment was moderately reliable [kappa = .48 +/- s.e.(kappa) = .062]. The interrater reliability for specific diagnoses was in the fair to good range [kappa = .44 +/- s.e.(kappa) = .029]. These levels of reliability are comparable to those found for other psychiatric and neurologic specialties and for medical diagnoses made by other health care disciplines.

The role of patients and providers in the timing of follow-up visits. Telephone Care Study Group

OBJECTIVE

Although the decision about how frequently to see outpatients has a direct impact on a provider's workload and may impact health care costs, revisit intervals have rarely been a topic of investigation. To begin to understand what factors are correlated with this decision, we examined baseline data from a Department of Veterans Affairs (VA) Cooperative Study designed to evaluate telephone care.

DESIGN

Observational study based on extensive patient data collected during enrollment into the randomized trial. Providers were required to recommend a revisit interval (e.g., "return visit in 3 months") for each patient before randomization, under the assumption that the patient would be receiving clinic visits as usual. POPULATION/SETTING: Five hundred seventy-one patients over age 55 cared for by one of the 30 providers working in three VA general medical clinics. Patients for whom immediate follow-up (</=2 weeks) was recommended were excluded.

MEASUREMENTS

Mean revisit interval was adjusted for patient factors using a regression model that accounted for patients being nested within providers and providers being nested within sites. Four patient-level variable blocks (illness burden-patient, travel time, illness burden-physician, and prior utilization) were sequentially entered into a linear model to determine their role in explaining the variance in revisit intervals. Physician identity was also entered after four blocks.

MAIN RESULTS

Recommended revisit intervals ranged from 1 month to over 1 year with the most common recommended intervals being 2, 3, or 6 months. About 10% of the variance in revisit interval was explained by illness measures independent of provider (e.g., general health perception) and travel time. Adding other illness measures (e.g., diagnoses, medications) and prior utilization (e.g., clinic visits) doubled the variance explained (R2 =.21). Finally, the identification of individual provider doubled the explained variance again (R2 =.45). After adjusting for patient factors, the average revisit interval for individual providers ranged from 8 to 26 weeks (8 to 19 weeks when restricted to the 16 staff physicians). There were also substantial differences across the three sites (adjusted means: 14, 17, and 11 weeks).

CONCLUSIONS

Even after adjusting for a detailed array of patient-level data, primary care providers have different practice styles regarding the timing of return visits. These may, in turn, reflect the local "culture" in which they practice. How many patients providers are able to care for may be determined by the providers' inclinations toward the timing of follow-up visits.

Initiating and Maintaining Patients on Warfarin Anticoagulation: The Importance of Monitoring

BACKGROUND: The VA Stroke Prevention in Nonrheumatic Atrial Fibrillation study was a prospective, randomized, double-blind study comparing low-dose warfarin with placebo in patients with nonrheumatic atrial fibrillation. The trial showed a 79% reduction in stroke rate in warfarin randomized patients without an increase in bleeding complications. We examined the need for frequent prothrombin time monitoring (international normalized ratios [INR] were not measured directly) in patients receiving warfarin.</P METHODS AND RESULTS: Patients were initiated on 4.0 mg/d warfarin with a goal of maintaining the prothrombin time ratio (PTR) within the range of 1.2-1.5 (estimated INR: 1.4-2.8). PTR monitoring was performed weekly during a 12-week induction period and monthly thereafter for a total follow-up of 3 years. Two hundred sixty patients were randomized to receive warfarin. During the induction period, the proportion of patients whose PTRs were in the desired range increased from 28% at 1 week postrandomization to 65% at 12 weeks postrandomization; the proportion of patients requiring a dose adjustment decreased from 52% to 16% during the same period. During the maintenance period, the mean proportion of patients whose PTRs were within 1.2-1.5 was 60.5% +/- 6.2%. CONCLUSIONS: Low-dose anticoagulation with warfarin in outpatients should be initiated at the anticipated maintainance dose. This approach reduces the chance of being out of range on the high side. Weekly INR estimation during this phase seems optimal. Considerable dose adjusting was required during the maintenance phase to keep patients within range; monthly INRs are required. Because of the need for dose adjustments, fixed-dose warfarin regimens are unlikely to keep patients in the desired narrow therapeutic range.

Impact of gowning on visit length and physical examinations

We evaluated the effect of a randomized trial of gowning on length of visit and number of physical examinations performed in an outpatient clinic. Nineteen senior internal medicine trainees saw 110 patients without gowns and 113 patients with gowns. Patients without gowns were with the trainees 25.2 +/- 11.9 (mean +/- SD) minutes versus 24.2 +/- 10.3 minutes for gowned patients (p = .51). Ungowned patients were in the examination room a total of 38.5 +/- 15.9 minutes versus 42.9 +/- 17.6 minutes for gowned patients (p = .06). The number of patients that underwent physical examinations was the same (89) for gowned and ungowned groups, and the distribution of the number of examinations by patient group differed only slightly (p = .88). Gowning did not significantly decrease the length of visit or increase the number of physical examinations performed.

Health services clinical trials: design, conduct, and cost methodology

Randomized clinical trials and their developing methodology have had substantial impact on the advancement of medical practice. With the emergence of managed care and increased emphasis on the reduction of medical care expenditures, cost evaluation is now becoming a part of clinical trial research. The papers by Henderson et al. and Manheim that follow address the evolution of health services research, its application to multicenter clinical trials in a major U.S. health-care system, and methods of assessing costs in health services clinical trials.

An index for assessing blindness in a multi-centre clinical trial: disulfiram for alcohol cessation--a VA cooperative study

This paper considers an index to assess the success of blinding with application to a clinical trial of disulfiram. The index increases as the success of blinding increases, accounts for uncertain responses, and is scaled to an interval of 0.0 to 1.0, 0.0 being complete lack of blinding and 1.0 being complete blinding.

Bladder washing cytology. Comparison of two analytic methods and two proposed quantitative criteria for carcinoma in situ

OBJECTIVE

To compare bladder washing cytology preparations created by the Nucleopore filter and slide centrifuge techniques and to evaluate a marker for carcinoma in situ (CIS).

STUDY DESIGN

Nucleopore filter and slide centrifuge preparations from 27 patients with urothelial carcinoma were compared and used to create two criteria for CIS. To study reproducibility, three observers evaluated 25 filter preparations for these CIS criteria.

RESULTS

The filter technique displayed more better-preserved single cancer cells (P = .02) and a higher percent group count (the number of cancer cell groups divided by the sum of the number of single cancer cells plus the number of cancer cell groups) (P = .005) than did the cytocentrifuge technique. The initial study showed that patients with many single tumor cells and lower percent group counts were more likely to have CIS than patients without this combined condition (P = .001). This CIS marker had moderate reproducibility (kappa = 0.47 +/- 0.12).

CONCLUSION

The filter technique had better cellular recovery and preservation of tumor cells than did the centrifuge technique. Quantitative cytologic criteria proposed in this study may be an indication that CIS may be present; improved sensitivity and specificity may be obtained if they are combined with other criteria.

An index for assessing blindness in a multi-centre clinical trial: disulfiram for alcohol cessation--a VA cooperative study

This paper considers an index to assess the success of blinding with application to a clinical trial of disulfiram. The index increases as the success of blinding increases, accounts for uncertain responses, and is scaled to an interval of 0.0 to 1.0, 0.0 being complete lack of blinding and 1.0 being complete blinding.

Silent cerebral infarction in patients with nonrheumatic atrial fibrillation. The Veterans Affairs Stroke Prevention in Nonrheumatic Atrial Fibrillation Investigators

BACKGROUND

Cerebral infarction in patients with atrial fibrillation may vary from being clinically silent to catastrophic. The prevalence of silent cerebral infarction and its effect as a risk factor for symptomatic stroke are important considerations for the evaluation of patients with atrial fibrillation.

METHODS AND RESULTS

This Veterans Affairs cooperative study was a double-blind controlled trial designed primarily to determine the efficacy of warfarin for the prevention of stroke in neurologically normal patients with nonrheumatic atrial fibrillation. It also was designed to evaluate patients with silent cerebral infarction. Computed tomography scans of the head were performed at entry, at the time of any subsequent stroke, and at termination of follow-up on all patients who completed the study without a neurological event. Of 516 evaluable scans performed at entry, 76 (14.7%) had evidence of one or more silent cerebral infarcts. Age (P = .011), a history of hypertension (P = .003), active angina (P = .012), and elevated mean systolic blood pressure (P < .001) were associated with the presence of this finding. Silent cerebral infarction occurred during the study at rates of 1.01% and 1.57% per year for the placebo and warfarin treatment groups, respectively (NS). Silent cerebral infarction at entry was not an independent predictor of later symptomatic stroke, but active angina was a significant predictor; 15% of the placebo-assigned patients with angina developed a stroke compared with 5% of the placebo-assigned patients without angina.

CONCLUSIONS

Silent cerebral infarction is frequently seen in asymptomatic patients with atrial fibrillation. Age, history of hypertension, active angina, and elevated mean systolic blood pressure were associated with silent infarction at entry. The sample size was too small to determine whether warfarin had an effect on the incidence of silent infarction during the trial. Active angina at baseline was the only significant independent predictor for the later development of symptomatic stroke.

Role of transesophageal echocardiography in the detection of left atrial thrombus in patients with chronic nonrheumatic atrial fibrillation

Transesophageal echocardiography was used to assess cardiac abnormalities associated with embolization in patients who had completed the Department of Veterans Affairs Cooperative Study of Stroke Prevention in Nonrheumatic Atrial Fibrillation at the Minneapolis and West Haven Department of Veterans Affairs Medical Centers without an embolic event. Patients were men, 71 +/- 7 years old, with atrial fibrillation of 6.2 +/- 4.3 years' duration who had received warfarin (n = 32) or placebo (n = 23) for 2 years. Thrombi were found in 5 of 55 patients (warfarin 4 and placebo 1; p = 0.39); spontaneous echo contrast was seen in 4 of 5 patients. Other abnormalities identified included spontaneous echo contrast (47%), patent foramen ovale (54%), atrial septal aneurysm (7.3%), and left ventricular thrombus (3.6%). During 34 months of posttreatment follow-up, 5 patients had a stroke (1 fatal), and 10 died. Potential sources of emboli did not predict subsequent outcome. Thus warfarin therapy did not preclude the presence of thrombi. Stroke reduction likely involves the prevention of emboli from sources in addition to the atrial appendage.

Warfarin in the prevention of stroke associated with nonrheumatic atrial fibrillation. Veterans Affairs Stroke Prevention in Nonrheumatic Atrial Fibrillation Investigators

BACKGROUND

Nonrheumatic atrial fibrillation is common among the elderly and is associated with an increased risk of stroke. We investigated whether anticoagulation with warfarin would reduce this risk.

METHODS

We conducted a randomized, double-blind, placebo-controlled study to evaluate low-intensity anticoagulation with warfarin (prothrombin-time ratio, 1.2 to 1.5) in 571 men with chronic nonrheumatic atrial fibrillation; 525 patients had not previously had a cerebral infarction, whereas 46 patients had previously had such an event. The primary end point was cerebral infarction; secondary end points were cerebral hemorrhage and death.

RESULTS

Among the patients with no history of stroke, cerebral infarction occurred in 19 of the 265 patients in the placebo group during an average follow-up of 1.7 years (4.3 percent per year) and in 4 of the 260 patients in the warfarin group during an average follow-up of 1.8 years (0.9 percent per year). The reduction in risk with warfarin therapy was 0.79 (95 percent confidence interval, 0.52 to 0.90; P = 0.001). The annual event rate among the 228 patients over 70 years of age was 4.8 percent in the placebo group and 0.9 percent in the warfarin group (risk reduction, 0.79; P = 0.02). The only cerebral hemorrhage occurred in a 73-year-old patient in the warfarin group. Other major hemorrhages, all gastrointestinal, occurred in 10 patients: 4 in the placebo group, for a rate of 0.9 percent per year, and 6 in the warfarin group, for a rate of 1.3 percent per year. There were 37 deaths that were not preceded by a cerebral end point--22 in the placebo group and 15 in the warfarin group (risk reduction, 0.31; P = 0.19). Cerebral infarction was more common among patients with a history of cerebral infarction (9.3 percent per year in the placebo group and 6.1 percent per year in the warfarin group) than among those without such a history.

CONCLUSIONS

Low-intensity anticoagulation with warfarin prevented cerebral infarction in patients with nonrheumatic atrial fibrillation without producing an excess risk of major hemorrhage. This benefit extended to patients over 70 years of age.

Residual analgesic effects of morphine in 55 four-period crossover analgesic studies

Subjective response data from 55 postoperative pain studies were examined for the residual analgesic effects of morphine. The studies were planned as four-period crossover designs for four treatments. Each patient received 5 and 10 mg of morphine and two doses of a test preparation. Two measures of analgesia were used: Sum of the Pain Intensity Difference (SPID) and Total Pain Relief (TOTPAR). To facilitate analysis, two two-period groups were defined. Morphine data for periods 1 and 2 were designated as group A, and morphine data for periods 3 and 4 were designated as group B. Residual analgesic effects were 0.12 for both SPID and TOTPAR in group A and were 0.65 and 0.17 for SPID and TOTPAR, respectively, in group B. In these 55 studies, there was no evidence of significant residual analgesic effects. Thus the crossover design is an appropriate method for the evaluation of selected parenteral analgesics in the postoperative pain model.

A randomized trial of acetohydroxamic acid for the treatment and prevention of infection-induced urinary stones in spinal cord injury patients

Acetohydroxamic acid is known to inhibit bacterial urease activity, thus, reducing urinary ammonia levels. A double-blind placebo-controlled clinical trial of acetohydroxamic acid was conducted at 12 Veterans Administration spinal cord injury units. A total of 210 male spinal cord injury patients with chronic urea-splitting urinary infection was enrolled for a scheduled followup of 2 years. The study data support the usefulness of acetohydroxamic acid in reducing urinary ammonia. At every followup visit the acetohydroxamic acid patients with stones had decreases in ammonia of 30 to 48 mg. per dh., while the placebo patients had increases in ammonia. Acetohydroxamic acid also retarded stone growth. Patients with stones treated with acetohydroxamic acid exhibited significantly longer intervals from randomization to first stone growth than patients treated with placebo (p less than 0.005, medians 15 versus 9 months). Acetohydroxamic acid reduced significantly the proportion of patients with stone growth at 12 months (33 versus 60 per cent, p equals 0.017). This decrease was diminished at 24 months (42 versus 60 per cent, p equals 0.260). Patient attrition was 31 per cent in the placebo group and 62 per cent in the acetohydroxamic acid group, the latter attrition being primarily owing to patient request because of mild symptoms. Of the acetohydroxamic acid and placebo patients 62 and 29 per cent, respectively, reported drug side effects but all were reversible and no unanticipated or life-threatening reactions occurred.

Disulfiram treatment of alcoholism. A Veterans Administration cooperative study

We conducted a controlled, blinded, multicenter study of disulfiram treatment of alcoholism in 605 men randomly assigned to 250 mg of disulfiram (202 men); 1 mg of disulfiram (204 men), a control for the threat of the disulfiram-ethanol reaction; or no disulfiram (199 men), a control for the counseling that all received. Bimonthly treatment assessments were done for one year. Relative/friend interviews and blood and urine ethanol analyses were used to corroborate patients' reports. There were no significant differences among the groups in total abstinence, time to first drink, employment, or social stability. Among the patients who drank and had a complete set of assessment interviews, those in the 250-mg disulfiram group reported significantly fewer drinking days (49.0 +/- 8.4) than those in the 1-mg (75.4 +/- 11.9) or the no-disulfiram (86.5 +/- 13.6) groups. There was a significant relationship between adherence to drug regimen and complete abstinence in all groups. We conclude that disulfiram may help reduce drinking frequency after relapse, but does not enhance counseling in aiding alcoholic patients to sustain continuous abstinence or delay the resumption of drinking.

Crossover and noncrossover designs in four-point parallel line analgesic assays

Fifty-nine analgesic investigations designed as four-point parallel line crossover assays were examined. Sum of pain intensity differences (SPID) and total pain relief (TOTPAR) were the subjective response measures. Separate analyses with four-point crossover data and first-dose data (noncrossover) allowed comparison within each study of these two approaches. The crossover analysis allows for removal of the subject component of variance, which in these studies was a substantial fraction of the error variance (0.49 for SPID; 0.56 for TOTPAR). For this type of study, 2.4 times as many subjects would have to be recruited in a noncrossover design to obtain precision equivalent to that of the crossover design. Thus efficiency considerations argue for the crossover design in cases in which a treatment carryover effect may be assumed to be negligible.

A model for the development, conduct, and monitoring of multicenter clinical trials in the Veterans Administration

In the past 20-30 years, increased interest on the part of biostatisticians and medical investigators has been exhibited in clinical trial research. In the mid-1940's, the Veterans Administration Hospital system was recognized as an ideal environment for the conduct of multicenter clinical trials, with the initiation of a study to determine the effectiveness of chemotherapy in the treatment of tuberculosis, in a joint effort with the United States Armed Forces. This research effort later evolved into what is presently known as the Cooperative Studies Program of the Medical Research Service. Within the past seven years, this program has undergone considerable growth and reorganization. This paper describes a system for the review, operation, and conduct of multicenter clinical research in a wide variety of medical specialty areas. In particular, it stresses the importance of core biostatistical coordinating centres where biostatisticians and other key support personnel constitute an integral part of the planning and development, implementation, conduct, and reporting of many cooperative studies in diverse disciplines. The paper also describes the interaction of various review bodies and a check and balance system to promote sound management and opportunity for the exchange of clinical and biostatistical methodology in the cooperative study setting.

Dextroamphetamine with morphine for the treatment of postoperative pain

In a double-blind, single-dose study, dextroamphetamine combined with morphine was compared with morphine alone to determine the relative efficacy of the combination given intramuscularly for postoperative pain. Each of 450 patients received one treatment of morphine sulfate (3, 6 or 12 mg) with dextroamphetamine (0, 5 or 10 mg). Analgesia, as measured by the patients' subjective responses to questions about relief of pain, was augmented when dextroamphetamine was given with morphine; the combination of dextroamphetamine, 10 mg, with morphine was twice as potent as morphine alone, and the combination with 5 mg was 1 1/2 times as potent as morphine. In simple performance tests, and in measures of side effects, dextroamphetamine generally offset undesirable effects of morphine (sedation and loss of alertness) while increasing analgesia. Effects on blood pressure, pulse and respiratory rate were minimal.

Combined routes of administration to assay oral analgesia in postoperative pain

To increase the sensitivity of the method for evaluating oral analgesics in postoperative patients, we designed a combined oral/parenteral bioassay. Drugs studied were parenteral morphine, parenteral propiram, and oral codeine at two dose levels each and oral propiram at four dose levels. Results from data on 308 patients suggest that future studies designed to establish the relative potencies of oral analgesics should use parenteral morphine as the standard in a combined oral/parenteral study because this approach provides a very sensitive measure of analgesia. Further, with one drug as the reference compound, results from many sources would be more readily compared.

Assay of aspirin and naproxen analgesia

To establish the relative potency of naproxen and aspirin for oral analgesia, a 4-point, noncrossover bioassay with placebo control was undertaken with 197 patients. Subjective-response methods were used to determine two measures of postoperative analgesia over a period of 6 hr. With reasonable confidence for an oral analgesic assay, we found 220 mg of naproxen to be equivalent to 600 mg of aspirin for pain relief and 330 mg of naproxen to be equivalent to 600 mg of aspirin for decreased pain intensity.

Hypnotic efficacy of diphenhydramine, methapyrilene, and pentobarbital

The antihistamines diphenhydramine and methapyrilene were compared with pentobarbital for hypnotic effect in two Veterans Administration Hospital populations using subjective-response methods. In the first part of the study, 60 mg and 180 mg of pentobarbital were compared with 50 mg and 150 mg of diphenhydramine. A positive dose-response relationship was obtained only for pentobarbital; neither dose of diphenhydramine was significantly different from 60 mg of pentobarbital for any response variable. In the second part of the study, 100 mg of pentobarbital, 50 mg of diphenhydramine, and 50 mg of diphenhydramine, and 50 mg of methapyrilene were compared with placebo. One hundred mg of pentobarbital and 50 mg of diphenhydramine were significantly different from placebo, but 50 mg of methapyrilene was not.