Challenges of decision making regarding futility in a randomized trial: the Interventional Management of Stroke III experience.

BACKGROUND AND PURPOSE: Interventional Management of Stroke (IMS) III is a randomized, parallel arm trial comparing the approach of intravenous tissue-type plasminogen activator followed by endovascular treatment with intravenous tissue-type plasminogen activator alone in patients with acute ischemic stroke presenting <3 hours of symptom onset. The trial intended to enroll 900 subjects to ensure adequate statistical power to detect an absolute 10% difference in the percentage of subjects with good outcome, defined as modified Rankin Scale score of 0 to 2 at 3 months. In April 2012, after 656 subjects were randomized, further enrollment was terminated by the National Institute of Neurological Disorders and Stroke based on the prespecified criterion for futility using conditional power<20%. METHODS: Conditional power was defined as the likelihood of finding statistical significance at the end of the study, given the accumulated data to date and with the assumption that a minimum hypothesized difference of 10% truly exists between the 2 groups. The evolution of study data leading to futility determination is described, including the interaction between the unblinded study statisticians and the Data and Safety Monitoring Board in the complex deliberation of analysis results. RESULTS: The futility boundary was crossed at the trial's fourth interim analysis. At this point, based on the conditional power criteria, the Data and Safety Monitoring Board recommended termination of the trial. CONCLUSIONS: Even in spite of prespecified interim analysis boundaries, interim looks at data pose challenges in interpretation and decision making, underscoring the importance of objective stopping criteria. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00359424.

Measuring blood pressure for decision making and quality reporting: where and how many measures?

BACKGROUND: The optimal setting and number of blood pressure (BP) measurements that should be used for clinical decision making and quality reporting are uncertain. OBJECTIVE: To compare strategies for home or clinic BP measurement and their effect on classifying patients as having BP that was in or out of control. DESIGN: Secondary analysis of a randomized, controlled trial of strategies to improve hypertension management. (ClinicalTrials.gov registration number: NCT00237692) SETTING: Primary care clinics affiliated with the Durham Veterans Affairs Medical Center. PATIENTS: 444 veterans with hypertension followed for 18 months. MEASUREMENTS: Blood pressure was measured repeatedly by using 3 methods: standardized research BP measurements at 6-month intervals; clinic BP measurements obtained during outpatient visits; and home BP measurements using a monitor that transmitted measurements electronically. RESULTS: Patients provided 111,181 systolic BP (SBP) measurements (3218 research, 7121 clinic, and 100,842 home measurements) over 18 months. Systolic BP control rates at baseline (mean SBP<140 mm Hg for clinic or research measurement; <135 mm Hg for home measurement) varied substantially, with 28% classified as in control by clinic measurement, 47% by home measurement, and 68% by research measurement. Short-term variability was large and similar across all 3 methods of measurement, with a mean within-patient coefficient of variation of 10% (range, 1% to 24%). Patients could not be classified as having BP that was in or out of control with 80% certainty on the basis of a single clinic SBP measurement from 120 mm Hg to 157 mm Hg. The effect of within-patient variability could be greatly reduced by averaging several measurements, with most benefit accrued at 5 to 6 measurements. LIMITATION: The sample was mostly men with a long-standing history of hypertension and was selected on the basis of previous poor BP control. CONCLUSION: Physicians who want to have 80% or more certainty that they are correctly classifying patients' BP control should use the average of several measurements. Hypertension quality metrics based on a single clinic measurement potentially misclassify a large proportion of patients. PRIMARY FUNDING SOURCE: U.S. Department of Veterans Affairs Health Services Research and Development Service.

Application of beta regression to analyze ischemic stroke volume in NINDS rt-PA clinical trials.

BACKGROUND AND PURPOSE: Ischemic stroke lesion volumes have proven difficult to analyze due to the extremely skewed shape of their underlying distribution. We introduce an extension of generalized linear models, beta regression, as a possible method of modeling extremely skewed distributions as evidenced in ischemic stroke lesion volumes. METHODS: The NINDS rt-PA clinical trials measured ischemic stroke lesion volume as a secondary trial outcome. Three-month lesion volumes from these trials were analyzed using beta regression. A multi-variable regression model associating explanatory variables with ischemic stroke lesion volumes was constructed using accepted model building strategies and compared with the previously published volumetric analysis. RESULTS: Beta regression produced a similar model when compared to the previous analysis published by the study group. All previously identified variables of importance were detected in the model building process. The age by treatment interaction described in previous studies was also found in this analysis, confirming the strong effect age has on stroke outcomes. Further, a treatment effect was elicited in terms of odds ratios, yielding a previously unknown quantification of the effect of rt-PA on lesion volumes. CONCLUSIONS: Beta regression proved adept in modeling ischemic stroke lesions and offered the interpretation of covariates in terms of odds ratios. Beta regression is seen as a legitimate alternative to analyze ischemic stroke volumes.

Analyses of renal outcome following transplantation adjusting for informative right censoring and demographic factors: A longitudinal study.

Demographic factors such as race, vital status, gender, and age could affect the final renal outcome of patients who undergo renal transplantation. These demographic factors could be assessed at the recipient and donor levels. Repeated measures for blood urea nitrogen (BUN) are typically recorded for each patient following renal transplantation, as a biomarker to assess renal progress. However, once a patient develops renal failure due to graft rejection, no measurement of BUN can be registered and the patient goes back to dialysis. This causes loss of follow-up and incomplete data on BUN measurements, a problem referred to as informative right censoring. If this problem is ignored, inaccurate, and biased estimates will be generated. In this study, unbiased estimates for the rate of change of BUN levels over time adjusted for informative right censoring and demographic factors were acquired using a sophisticated model of analysis. Our results demonstrated that BUN levels for Caucasians were decreasing at a greater rate than African Americans (p < 0.0001). When donors are deceased, African American recipients showed an increase instead of a decrease in their BUN levels following transplantation. Moreover, African Americans showed a decrease in their BUN levels when the donors were African Americans compared with when donors were Caucasians (p = 0.03). Our results also showed that BUN levels were decreasing at a greater rate when donors and recipients were of different gender than when they were of the same gender (p = 0.009). These results suggest that the success of renal transplantation is impacted by the donor/recipient demographic factors.

Using global statistical tests in long-term Parkinson's disease clinical trials.

Parkinson's disease (PD) impairments are multidimensional, making it difficult to choose a single primary outcome when evaluating treatments to stop or lessen the long-term decline in PD. We review commonly used multivariate statistical methods for assessing a treatment's global impact, and we highlight the novel Global Statistical Test (GST) methodology. We compare the GST to other multivariate approaches using data from two PD trials. In one trial where the treatment showed consistent improvement on all primary and secondary outcomes, the GST was more powerful than other methods in demonstrating significant improvement. In the trial where treatment induced both improvement and deterioration in key outcomes, the GST failed to demonstrate statistical evidence even though other techniques showed significant improvement. Based on the statistical properties of the GST and its relevance to overall treatment benefit, the GST appears particularly well suited for a disease like PD where disability and impairment reflect dysfunction of diverse brain systems and where both disease and treatment side effects impact quality of life. In future long term trials, use of GST for primary statistical analysis would allow the assessment of clinically relevant outcomes rather than the artificial selection of a single primary outcome.

Differences in cardiovascular disease mortality associated with body mass between Black and White persons.

We analyzed cardiovascular disease mortality risks associated with obesity using participant-level meta-analysis of data from the Black Pooling Project for Black and White individuals. The adjusted relative risks (ARRs) were stronger among White participants than among Black participants for coronary heart disease AAR=1.21 (95% confidence interval [CI]=1.07, 1.36) versus 0.87 (95% CI=0.69, 1.09), respectively, and cardiovascular disease ARR=1.18 (95% CI=1.07, 1.29) versus 0.91 (95% CI=0.77, 1.05), respectively. The results suggest that obesity is an independent risk factor in White people, and additional study of body size and disease progression is necessary in the assessment of racial disparities.

Effect of psyllium fiber supplementation on C-reactive protein: the trial to reduce inflammatory markers (TRIM).

PURPOSE: Recent evidence supports a significant association between the intake of dietary fiber and levels of inflammatory markers. The objective of this study was to determine whether daily fiber supplementation would reduce levels of inflammatory markers. METHODS: This study was a prospective randomized controlled trial at a single university medical center. Participants were overweight or obese adults with no history of heart disease. The intervention was psyllium supplementation at either 7 or 14 g/d for 3 months compared with no supplements in a control group. The main outcome measure was change in level of high-sensitivity C-reactive protein (hsCRP) concentration; secondary outcomes included changes in interleukin-6 (IL-6) levels, fibrinogen levels, and white blood cell (WBC) count. Protocol completers attended at least 2 visits and took more than 75% of the prescribed fiber dose. RESULTS: In this intent-to-treat analysis (n = 158), there were no significant differences between either of the 2 treatment groups and the control group in the amount of change in CRP, fibrinogen, or IL-6 levels or in WBC count (P>.05). In the analysis of protocol completers (n = 132), there also were no significant differences between the groups except for a small decrease in fibrinogen level in the high-fiber group (-6 mg/dL [-0.18 micromol/L] compared with 13 mg/dL [0.38 micromol/L] in the control group, P<.05). CONCLUSION: Psyllium fiber supplementation did not significantly reduce CRP levels in overweight or obese individuals in this trial, and changes in other markers were not consistent. Further research is needed to determine whether other fibers or nutrients can reduce inflammatory markers.

Effect of a high-fiber diet vs a fiber-supplemented diet on C-reactive protein level.

BACKGROUND: Diets high in fiber are associated with lower levels of inflammatory markers. This study examined the reduction in inflammation from a diet supplemented with fiber compared with a diet naturally high in fiber. METHODS: Randomized crossover intervention trial of 2 diets, a high-fiber (30-g/d) Dietary Approaches to Stop Hypertension (DASH) diet or fiber-supplemented diet (30 g/d), after a baseline (regular) diet period of 3 weeks. There were 35 participants (18 lean normotensive and 17 obese hypertensive individuals) aged 18 to 49 years. RESULTS: The study included 28 women and 7 men; 16 (46%) were black, the remainder white. The mean (SD) fiber intake on baseline diets was 11.9 (0.3) g/d; on the high-fiber DASH diet, 27.7 (0.6) g/d; and on the supplemented diet, 26.3 (0.4) g/d. Overall, the mean C-reactive protein (CRP) level changed from 4.4 to 3.8 mg/L (-13.7%; P = .046) in the high-fiber DASH diet group and to 3.6 mg/L (-18.1%) in the fiber-supplemented diet group (P = .03). However, CRP levels decreased in the 18 lean normotensive participants in either intervention diet group (2.0 mg/L [baseline] vs 1.4 mg/L [high-fiber DASH] vs 1.2 mg/L [supplemented]); P<.05) but did not change significantly (7.1 mg/L [baseline] vs 6.2 mg/L [high-fiber DASH] vs 6.5 mg/L [supplemented]; P>.05) in obese hypertensive participants. Neither age nor race influenced the response of CRP levels to the diets. No evidence of a crossover effect was detected. CONCLUSIONS: The results demonstrate that fiber intake of about 30 g/d) from a diet naturally rich in fiber or from a supplement can reduce levels of CRP. Further research is needed to more clearly elucidate the differential effect seen in lean vs obese individuals and whether modification of dietary fiber may be helpful in modulating inflammation and its consequent cardiovascular consequences.

Health services use among Gulf War veterans and Gulf War era nondeployed veterans: a large population-based survey.

We sought to analyze the self-reported hospitalization, emergency department visits, and outpatient visits of Persian Gulf War (deployed; n=1896) and Persian Gulf War-era (nondeployed; n=1799) military personnel 5 years postconflict to determine whether these groups had different rates of health care use. Compared with personnel who had not been deployed, personnel who had been deployed were more likely to have visited an emergency department (25% vs 21%; odds ratio [OR]=1.24; 95% confidence interval [CI] = 1.06, 1.51]). Among these groups, the National Guard and Reserve personnel were more likely to have been hospitalized than were the regular military personnel (OR= 1.65; 95% CI=1.21, 2.26).

Chronic widespread pain in veterans of the first Gulf War: impact of deployment status and associated health effects.

UNLABELLED: Our study sought to 1) determine if deployment status is associated with chronic widespread pain (CWP), and 2) evaluate whether veterans with CWP have greater psychiatric comorbidity, higher health care utilization, and poorer health status than veterans without CWP. Five years after the conclusion of the first Gulf War (August 1990 to June 1991), we conducted a cross-sectional study of veterans who listed Iowa as the home of record using a stratified sampling design to determine their health status. We compared the prevalence of CWP between deployed and nondeployed veterans. Logistic and multiple linear regression models were constructed to test whether CWP was associated with comorbidities and health-related outcomes of interest. Five hundred ninety of 3695 veterans interviewed (16%) had CWP. Gulf deployment was associated with higher prevalence of CWP than deployment elsewhere (OR = 2.03, 95%CI = 1.60-2.58), after adjustment. Both deployed and nondeployed veterans with CWP reported more health care utilization and comorbidities and lower health-related quality of life scores than veterans without CWP. Deployed veterans were more likely to have CWP than nondeployed veterans, and CWP was associated with poor health outcomes. Military and medical personnel should be aware that efforts to prevent, identify, and treat CWP in veterans returning from the current war may be needed. PERSPECTIVE: This article indicates that deployed veterans may have an increased risk for development of CWP, which is associated with greater healthcare utilization and comorbidity and lower quality of life. The risk of poor health outcomes suggests that veterans returning from the present conflict should be screened for CWP on their return.

Age and race impact the association between BMI and CVD mortality in women.

OBJECTIVES: In previous studies, we have shown that obesity is associated with increased cardiovascular disease (CVD) mortality in white women but not in black women. Earlier research suggests that body mass index (BMI) has a greater effect on CVD mortality in younger white females than older white females, whereas this relationship in black women is not as clear. This study examines the effect of age on the association of BMI to CVD in black and white women. METHODS: The Black Pooling Project includes data on 2,843 black women with 50,464 person-years of follow-up, and 12,739 white women with 214,606 person-years of follow-up. A Cox proportional hazards model was used to examine the association between BMI and CVD mortality for specific age/race groups. The younger group was < 60 years of age and the older group was > 60 years of age. RESULTS: In younger white women, the relative risk (95% confidence interval [CI]) for CVD mortality was significant in obese women (BMI > 30 kg/m2) vs. women of normal weight (BMI 18.5-24.9 kg/m2) (1.59 [CI 1.20, 2.09]). Similarly, in older white women, the relative risk for CVD mortality in obese women vs. women of normal weight was significant (1.21 [CI 1.04, 1.41]). There were no such associations for black women. Overweight (BMI 25-29.9 kg/m2) was not associated with increased risk in black or white women. CONCLUSION: These findings indicate that obesity is associated with a significantly greater risk of CVD mortality among white women, with the strongest association among white women < 60 years of age.

Credibility of neuropsychological performances of Persian Gulf War veterans and military control subjects participating in clinical epidemiological research.

We investigated whether Persian Gulf War veterans (GWVs) were more likely than Persian Gulf War-era veterans deployed elsewhere (GEVs) to have noncredible neuropsychological examinations. A total of 301 GWVs and 99 GEVs underwent neuropsychological testing. The credibility of 173 examinations showing impairment was evaluated based on test performances, clinical background, psychometric measures, and other self-report data. All 11 examinations judged less than fully credible by one neuropsychologist, plus 19 examinations judged impaired but credible, were then evaluated independently by two more neuropsychologists. Noncredibility was judged with excellent reliability (93% agreement). Seven examinations were judged noncredible. Rates of noncredibility did not differ between GWVs (1%) and GEVs (4%). The pattern of associations of noncredible examinations with cognitive, psychological, and clinical variables generally indicated defective neuropsychological scores, with no coherent pattern, and personality disorder. Findings supported the validity of noncredibility judgments and suggested that noncredible examinations are not a significant problem in neuropsychological investigations of GWVs.

Use of the OSCE to evaluate brief communication skills training for dental students.

Although communications competency is recommended by the American Dental Education Association, only a few (n=5) dental schools report evaluating students' skills using a competency examination for communication. This study used an objective structured clinical examination (OSCE) to evaluate dental students' competency in interpersonal and tobacco cessation communication skills. All students were evaluated on their interpersonal communication skills at baseline and at six months post-OSCE by standardized patients and on their tobacco cessation communication skills by two independent raters. First- and second-year dental students (n=104) were randomized to a control or intervention group. One month after the baseline OSCE, students in the intervention group participated in a two-hour training session in which faculty members communicated with a standardized patient during a head and neck examination and counseled the patient about tobacco cessation. There were no statistically significant differences from baseline to post-test between the intervention and control group students as measured by the OSCE. However, among first-year students, both the intervention (n=23) and control (n=21) groups significantly increased in tobacco cessation communication scores. Second-year students in both intervention (n=24) and control (n=28) groups declined in interpersonal communication skills from baseline to post-test. Overall, this one-shot intervention was not successful, and results suggest that a comprehensive communication skills training course may be more beneficial than a single, brief training session for improving dental students' communication skills.

Medical comorbidity in women and men with schizophrenia: a population-based controlled study.

BACKGROUND: Persons with persistent mental illness are at risk for failure to receive medical services. In order to deliver appropriate preventive and primary care for this population, it is important to determine which chronic medical conditions are most common. OBJECTIVE: We examined chronic medical comorbidity in persons with schizophrenia using validated methodologies. DESIGN: Retrospective analysis of longitudinal administrative claims data from Wellmark Blue Cross/Blue Shield of Iowa. PARTICIPANTS: Subjects with schizophrenia or schizoaffective disorder (N=1,074), and controls (N=726,262) who filed at least 1 claim for medical services, 1996 to 2001. MEASUREMENTS: Case subjects had schizophrenia as the most clinically predominant psychotic disorder, based on psychiatric hospitalization, psychiatrist diagnoses, and outpatient care. Controls had no claims for any psychiatric comorbidity. Using a modified version of the Elixhauser Comorbidity Index, inpatient and outpatient claims were used to determine the prevalence of 46 common medical conditions. Odds ratios (ORs) were adjusted for age, gender, residence, and nonmental health care utilization using logistic regression. RESULTS: Subjects with schizophrenia were significantly more likely to have 1 or more chronic conditions compared with controls. Adjusted OR (95% confidence interval [CI]) were 2.62 (2.09 to 3.28) for hypothyroidism, 1.88 (1.51 to 2.32) for chronic obstructive pulmonary disease, 2.11 (1.36 to 3.28) for diabetes with complications, 7.54 (3.55 to 15.99) for hepatitis C, 4.21 (3.25 to 5.44) for fluid/electrolyte disorders, and 2.77 (2.23 to 3.44) for nicotine abuse/dependence. CONCLUSIONS: Schizophrenia is associated with substantial chronic medical burden. Familiarity with conditions affecting persons with schizophrenia may assist programs aimed at providing medical care for the mentally ill.

Predictors of incident chronic widespread pain among veterans following the first Gulf War.

OBJECTIVE: We sought to determine the predictors of incident chronic widespread pain (CWP), specifically, the effect of preexisting symptoms, stress, and psychosocial factors in the subsequent development of CWP among veterans from the first Gulf War (GW). METHODS: We conducted a structured telephone survey (baseline) of military personnel originally from Iowa who were either eligible for or deployed to Operation Desert Shield/Desert Storm, approximately 5 years postconflict. We conducted a follow-up, clinical, in-person study of those who met a priori-defined outcomes of symptoms of cognitive dysfunction, depression, or CWP, and also a sample of those who did not meet any of the outcomes of interest. RESULTS: A total of 370 of 602 evaluated GW veterans were free of CWP 5 years postconflict. At follow-up, 69 (19%) of these had developed CWP. A positive family history of medically unexplained persistent symptoms [odds ratio (OR)=4.8 (2.3, 13.2)] was strongly associated with CWP. At baseline, individuals who reported preexisting symptoms of bronchitis [OR=4.9 (1.9, 12.3)] and cognitive dysfunction [OR=2.1 (1.1, 4.2)] were more likely to develop CWP. Alcohol use [OR=0.2 (0.1, 0.7)] was protective against CWP. Rather than combat-related exposure per se, the perception of stress at the time of the GW [OR=1.6 (1.1, 2.3)] correlated with CWP. DISCUSSION: Among the GW veterans evaluated longitudinally in this study, family history, predeployment symptoms, and the level of perceived stress during the GW were associated with subsequent development of CWP.

Clinical hypertension research tools: the randomized controlled clinical trial.

The randomized clinical trial is used in hypertension research as a primary mode for evaluating new, promising therapies. Herein, the authors provide an overview of design features of clinical trials, particularly those useful for designing a hypertension therapeutic clinical trial.

To condition or not condition? Analysing 'change' in longitudinal randomised controlled trials.

OBJECTIVE: The statistical analysis for a 2-arm randomised controlled trial (RCT) with a baseline outcome followed by a few assessments at fixed follow-up times typically invokes traditional analytic methods (eg, analysis of covariance (ANCOVA), longitudinal data analysis (LDA)). 'Constrained' longitudinal data analysis (cLDA) is a well-established unconditional technique that constrains means of baseline to be equal between arms. We use an analysis of fasting lipid profiles from the Group Medical Clinics (GMC) longitudinal RCT on patients with diabetes to illustrate applications of ANCOVA, LDA and cLDA to demonstrate theoretical concepts of these methods including the impact of missing data. METHODS: For the analysis of the illustrated example, all models were fit using linear mixed models to participants with only complete data and to participants using all available data. RESULTS: With complete data (n=195), 95% CI coverage are equivalent for ANCOVA and cLDA with an estimated 11.2 mg/dL (95% CI -19.2 to -3.3; p=0.006) lower mean low-density lipoprotein (LDL) cholesterol in GMC compared with usual care. With all available data (n=233), applying the cLDA model yielded an LDL improvement of 8.9 mg/dL (95% CI -16.7 to -1.0; p=0.03) for GMC compared with usual care. The less efficient, LDA analysis yielded an LDL improvement of 7.2 mg/dL (95% CI -17.2 to 2.8; p=0.15) for GMC compared with usual care. CONCLUSIONS: Under reasonable missing data assumptions, cLDA will yield efficient treatment effect estimates and robust inferential statistics. It may be regarded as the method of choice over ANCOVA and LDA.

Incarceration and veterans of the first Gulf War.

OBJECTIVE: This study investigated the prevalence of incarceration and the association with deployment among veterans of the first Persian Gulf War (GW). METHODS: A structured telephone interview of military personnel from Iowa deployed to the Persian Gulf and a comparison sample of nondeployed military personnel was conducted. The interview consisted of validated questions, validated instruments, and investigator-derived questions to assess relevant medical and psychiatric conditions. A total of 4,886 subjects were randomly drawn from one of four study domains, i.e., GW regular military, GW National Guard/Reserve, non-GW regular military, or non-GW National Guard/Reserve. Symptoms of medical conditions, psychiatric disorders, and health care utilization were the main outcome measures. RESULTS: Nearly one-quarter (845 of 3,695 subjects, 22.9%) had been incarcerated at some point before the interview ("ever incarcerated"). Ever incarcerated veterans had a higher frequency of psychiatric and medical comorbidity and higher rates of health care utilization. Ever incarcerated status was associated with male gender, enlisted rank, lower educational levels, low levels of military preparedness, discharge from service, cigarette smoking, antisocial traits, court martial and/or other military discipline, having seen a mental health professional, and having used illegal drugs. GW veterans who participated in combat had a modestly higher risk for incarceration after the GW than did noncombatants (odds ratio, 1.6; 95% confidence interval, 1.0-2.5). CONCLUSIONS: Military recruits with a history of incarceration more often displayed problematic behaviors, more often developed psychiatric/medical conditions, and had high rates of health care utilization. A history of incarceration may be a behavioral marker for substance abuse, antisocial behavior, and mental illness. Importantly, GW deployment carried no increased risk of subsequent incarceration overall.

Slope estimation for informatively right censored longitudinal data modelling the number of observations using geometric and Poisson distributions: application to renal transplant cohort.

Analysis of longitudinal data is often complicated by the presence of informative right censoring. This type of censoring should be accounted for in the analysis so that valid slope estimates are attained. In this study, we developed a new likelihood-based approach wherein the likelihood function is integrated over random effects to obtain a marginal likelihood function. Maximum likelihood estimates for the population slope were acquired by direct maximisation of the marginal likelihood function and empirical Bayes estimates for the individual slopes were generated using Gaussian quadrature. The performance of the model was assessed using the geometric and Poisson distributions to model the number of observations for every individual subject. Our model generated valid estimates for the slopes under both distributions with minimal bias and mean squared errors. Our sensitivity analysis confirmed the robustness of the model to assumptions pertaining to the underlying distribution and demonstrated its insensitivity to normality assumptions. Moreover, superiority of the model in terms of accuracy of slope estimates was consistently shown across the different levels of censoring in comparison to the naïve and bootstrap approaches. This model was illustrated using the cohort of renal transplant patients and estimates of the slopes that are adjusted for informative right censoring were acquired.

Percutaneous injury, blood exposure, and adherence to standard precautions: are hospital-based health care providers still at risk?

To examine factors associated with blood exposure and percutaneous injury among health care workers, we assessed occupational risk factors, compliance with standard precautions, frequency of exposure, and reporting in a stratified random sample of 5123 physicians, nurses, and medical technologists working in Iowa community hospitals. Of these, 3223 (63%) participated. Mean rates of hand washing (32%-54%), avoiding needle recapping (29%-70%), and underreporting sharps injuries (22%-62%; overall, 32%) varied by occupation (P<.01). Logistic regression was used to estimate the adjusted odds of percutaneous injury (aOR(injury)), which increased 2%-3% for each sharp handled in a typical week. The overall aOR(injury) for never recapping needles was 0.74 (95% CI, 0.60-0.91). Any recent blood contact, a measure of consistent use of barrier precautions, had an overall aOR(injury) of 1.57 (95% CI, 1.32-1.86); among physicians, the aOR(injury) was 2.18 (95% CI, 1.34-3.54). Adherence to standard precautions was found to be suboptimal. Underreporting was found to be common. Percutaneous injury and mucocutaneous blood exposure are related to frequency of sharps handling and inversely related to routine standard-precaution compliance. New strategies for preventing exposures, training, and monitoring adherence are needed.