Noninferiority of functional outcome in ambulatory management of obstructive sleep apnea.

RATIONALE: Home portable monitor testing is increasingly being used to diagnose patients with obstructive sleep apnea (OSA) and to initiate them on continuous positive airway pressure (CPAP) treatment. OBJECTIVES: To compare functional outcome and treatment adherence in patients who receive ambulatory versus in-laboratory testing for OSA. METHODS: Veterans with suspected OSA were randomized to either home testing or standard in-laboratory testing. Home testing consisted of a type 3 portable monitor recording followed by at least three nights using an automatically adjusting positive airway pressure apparatus. Participants diagnosed with OSA were treated with CPAP for 3 months. MEASUREMENTS AND MAIN RESULTS: We measured the change in Functional Outcomes of Sleep Questionnaire score, with an a priori noninferiority delta of -1, and the mean daily hours of objectively measured CPAP adherence, with an a priori noninferiority delta of -0.75 hour/day. Of the 296 subjects enrolled, 260 (88%) were diagnosed with OSA, and 213 (75%) were initiated on CPAP. Mean ± SD functional outcome score improved 1.74 ± 2.81 in the home group (P < 0.001) and 1.85 ± 2.46 in the in-laboratory group (P < 0.0001). The lower bound of the one-sided 95% noninferiority confidence interval was -0.54. Mean ± SD hours of daily CPAP adherence were 3.5 ± 2.5 hours/day in the home group and 2.9 ± 2.3 hours/day in the in-laboratory group (P = 0.08). The lower bound of the one-sided 95% noninferiority confidence interval was 0.03. CONCLUSIONS: Functional outcome and treatment adherence in patients evaluated according to a home testing algorithm is not clinically inferior to that in patients receiving standard in-laboratory polysomnography.

Factors associated with the use of preventive care for contrast-induced acute kidney injury.

BACKGROUND: The factors that affect the implementation of preventive care for contrast-induced acute kidney injury (CIAKI) are unknown. OBJECTIVE: To assess patient and provider factors associated with the use of preventive care for CIAKI. DESIGN: Prospective cohort study. PARTICIPANTS: Patients with kidney disease undergoing procedures with intravascular iodinated radiocontrast. MEASUREMENTS: We recorded the use of preventive care defined as the administration of: (1) pre- and post-procedure isotonic intravenous (IV) fluid, (2) N-acetylcysteine, and (3) iso-osmolal radiocontrast. We surveyed patients' providers to assess their knowledge, experience, and training on CIAKI and used multiple logistic regression to assess the independent associations of patient and provider factors with the use of these preventive interventions. RESULTS: We enrolled 660 patients and 87 providers. Patient factors associated with use of IV fluid and N-acetylcysteine were higher baseline serum creatinine (OR 1.5 and 5.0, p < 0.05) and inpatient status (OR 3.0 and 6.3, p < 0.05), while higher baseline serum creatinine was associated with the use of iso-osmolal contrast (OR = 13.4, p < 0.01). The primary provider characteristics associated with the use of IV fluid and N-acetylcysteine were a greater degree of prior training on CIAKI (OR 1.9 and 2.8, p < 0.05) and higher number of prior patients with CIAKI (OR 2.7 and 2.6, p < 0.05). CONCLUSIONS: Patient baseline kidney function and provider training and experience with CIAKI are independently associated with the use of preventive care. Efforts to increase and intensify the training providers receive on CIAKI may help decrease the incidence of this costly iatrogenic condition.

The incidence of clinically significant contrast-induced nephropathy following non-emergent coronary angiography.

OBJECTIVES: The primary aim of this study was to assess the incidence of clinically significant contrast-induced nephropathy (CIN) among patients undergoing non-emergent coronary angiography. BACKGROUND: Although retrospective analyses have emphasized the association of CIN with adverse patient outcomes, the actual incidence of clinically significant CIN following non-emergent coronary angiography is not clear. METHODS: We prospectively identified patients with baseline estimated glomerular filtration rates (eGFR) < 60 ml/min/1.73 m(2) undergoing non-emergent coronary angiography. We measured serum creatinine 48-96 hr following angiography and assessed the incidence of CIN using two definitions, a rise in Scr > or = 25% and > or = 0.5 mg/dl. We tracked the need for dialysis, hospitalization related to kidney injury, and 30-day mortality to examine the association of CIN with these outcomes. RESULTS: We enrolled 181 patients with a median eGFR of 52 ml/min/1.73 m(2). Of the 165 patients (91%) with post-procedure Scr data, the incidence of CIN was 6.1-8.5%. One patient required dialysis (0.55%) and one (0.55%) died within 30 days. Although 38 patients required hospital admission, CIN was not associated with the need for hospitalization. Patients with an increase in Scr > or = 25% demonstrated a trend toward increased risk for 30-day mortality (P = 0.09), whereas those with increments in Scr > or = 0.5 mg/dl had a marginally higher risk for dialysis (P = 0.06) and 30-day mortality (P = 0.06), although these associations failed to meet the level of statistical significance. CONCLUSIONS: Biochemically defined CIN occurs in a small, but notable proportion of patients undergoing non-emergent coronary angiography. However, clinically significant CIN is very uncommon.

The effect of coronary angiography on residual renal function in patients on peritoneal dialysis.

BACKGROUND: The risk of intravascular radiocontrast to residual renal function (RRF) in patients on peritoneal dialysis (PD) remains largely unknown. HYPOTHESIS: This study sought to estimate the effect of coronary angiography on RRF in patients on PD. METHODS: All patients at the VA Pittsburgh Healthcare System and University of Pittsburgh who underwent coronary angiography between 1993 and 2005 while on PD and who had RRF measured prior to angiography were identified retrospectively. For patients without a postprocedure RRF recorded, medical records were reviewed to determine whether anuria had developed. The longer-term rate of loss of RRF among cases was compared with a composite rate of decline in RRF among cases before angiography and matched controls. RESULTS: Twenty-nine patients with a mean preprocedure RRF of 4.4+/-3.2 ml/min/1.73m(2) were evaluated. Of these patients, 23 (79%) had postangiography RRF assessments (mean clearance 3.4+/-3.0 ml/min/1.73m(2)). One of the remaining six patients definitely became permanently anuric following angiography, one was lost to follow-up, and there was no postprocedure RRF assessment in four others. The rate of decline in RRF in the cases was similar to the composite rate (0.07 ml/min/1.73m(2)/month vs. 0.09 ml/min/1.73m(2)/month, p=0.53) CONCLUSION: The risk for permanent anuria in patients on PD undergoing coronary angiography appears to be quite small. Patients who do not develop anuria following coronary angiography have the same gradual rate of loss of RRF as other patients on PD. Providers should be vigilant in protecting RRF in patients on PD undergoing coronary angiography.

Authors' reports about research integrity problems in clinical trials.

BACKGROUND: There is little information about the prevalence of research integrity problems in the scientific literature. We sought to determine how frequently authors of published pharmaceutical clinical trials reported fabrication of data or misrepresentation of research. METHODS: We conducted a mail survey of 549 authors who had published reports of pharmaceutical clinical trials from 1998 to 2001 that appeared in the Cochrane Database of Systematic Reviews. We asked authors about fabricated data or misrepresentations of research in three contexts: the target study (the report from which their name was obtained), another study they had participated in, or a study that they personally knew about. RESULTS: We received replies from 64% of authors with valid addresses. Two authors (1%) reported that the target article misrepresented the research. Almost 5% reported fabrication or misrepresentation in a study they had participated in the last 10 years, and 17% of authors personally know about a case of fabrication or misrepresentation in the last 10 years from a source other than published accounts of research misconduct. CONCLUSIONS: Fraud and misrepresentation in clinical trials appear to be rare on a per-published report basis. However, they occur sufficiently frequently that scientists have a significant chance of participating in a project affected by fraud or misrepresentation during their research careers. These rates of exposure justify vigorous efforts to prevent research misconduct.

Provider knowledge of contrast-induced acute kidney injury.

BACKGROUND: Although past research has elucidated the principal risk factors and efficacy of preventive interventions for contrast-induced acute kidney injury (CIAKI), provider awareness of this empiric evidence base is largely unknown. We sought to assess provider knowledge of the risk factors and preventive interventions for CIAKI. METHODS: We asked medical providers caring for patients undergoing procedures with intravascular iodinated contrast to complete a survey designed to assess their knowledge of the risk factors and preventive interventions for CIAKI. RESULTS: Of the 87 participating providers, nearly all (n = 85; 98%) recognized chronic kidney disease and intravascular volume depletion as risk factors. However, 35 (41%) incorrectly identified allergy to contrast media as a risk factor and 8 (10%) incorrectly identified intravenous (IV) water as an effective preventive intervention. Compared with those with little or no prior training on CIAKI, those with substantial prior training correctly reported that peripheral vascular disease and atrial fibrillation are not risk factors and that fenoldopam and IV water are ineffective preventive interventions (P < 0.05). Trainees were more likely than those who had completed their postgraduate medical training to correctly report that IV saline and sodium bicarbonate are effective preventive interventions and that fenoldopam, dopamine, mannitol, and IV water are ineffective measures (P < 0.05). CONCLUSIONS: There is wide variability in providers' knowledge of CIAKI. Providers with more training on CIAKI and trainees had greater knowledge of the risk factors and preventive interventions for CIAKI. These findings underscore the need to standardize and intensify provider education of this costly and preventable iatrogenic condition.

Incidence and outcomes of contrast-induced AKI following computed tomography.

BACKGROUND AND OBJECTIVES: Most studies of contrast-induced acute kidney injury (CIAKI) have focused on patients undergoing angiographic procedures. The incidence and outcomes of CIAKI in patients undergoing nonemergent, contrast-enhanced computed tomography in the inpatient and outpatient setting were assessed. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Patients with estimated glomerular filtration rates (GFRs) <60 ml/min per 1.73 m(2) undergoing nonemergent computed tomography with intravenous iodinated radiocontrast at an academic VA Medical Center were prospectively identified. Serum creatinine was assessed 48 to 96 h postprocedure to quantify the incidence of CIAKI, and the need for postprocedure dialysis, hospital admission, and 30-d mortality was tracked to examine the associations of CIAKI with these medical outcomes. RESULTS: A total of 421 patients with a median estimated GFR of 53 ml/min per 1.73 m(2) were enrolled. Overall, 6.5% of patients developed an increase in serum creatinine >or=25%, and 3.5% demonstrated a rise in serum creatinine >or=0.5 mg/dl. Although only 6% of outpatients received preprocedure and postprocedure intravenous fluid, <1% of outpatients with estimated GFRs >45 ml/min per 1.73 m(2) manifested an increase in serum creatinine >or=0.5 mg/dl. None of the study participants required postprocedure dialysis. Forty-six patients (10.9%) were hospitalized and 10 (2.4%) died by 30-d follow-up; however, CIAKI was not associated with these outcomes. CONCLUSIONS: Clinically significant CIAKI following nonemergent computed tomography is uncommon among outpatients with mild baseline kidney disease. These findings have important implications for providers ordering and performing computed tomography and for future clinical trials of CIAKI.

Prevention, incidence, and outcomes of contrast-induced acute kidney injury.

BACKGROUND: Little is known about whether health care providers (physicians) implement preventive care for contrast-induced acute kidney injury (CIAKI). The objectives of our prospective cohort study were (1) to assess provider use of preventive strategies for CIAKI, (2) to determine the incidence of CIAKI, and (3) to examine the association of CIAKI with adverse outcomes at 30 days, including death, need for dialysis, and hospital admission. METHODS: We prospectively identified patients with estimated glomerular filtration rates less than 60 mL/min/1.73 m(2) undergoing procedures with intravascular radiocontrast agents and recorded the use of intravenous fluids and N-acetylcysteine and the discontinuation of nonsteroidal anti-inflammatory medications. We measured postprocedure serum creatinine levels to quantify the incidence of CIAKI and tracked 30-day mortality and need for dialysis or hospitalization to evaluate the association of CIAKI with these outcomes. RESULTS: Preprocedure and postprocedure intravenous fluids were administered to 264 of 660 study patients (40.0%), more commonly with coronary angiography than with computed tomography (91.2% vs 16.6%, P < .001). N-acetylcysteine was administered to 39.2% of patients, while only 6.8% of patients using nonsteroidal anti-inflammatory drugs were instructed to discontinue the medication. In a propensity analysis, the use of intravenous fluids was associated with a reduced rate of CIAKI. The incidence of CIAKI was lowest following computed tomography (range, 0.0%-10.9%) and was highest following noncoronary angiography (range, 1.9%-34.0%). Eleven patients (1.7%) died, 1 patient (0.2%) required dialysis, and 83 patients (12.6%) were hospitalized; however, CIAKI was not independently associated with hospital admission or death. CONCLUSIONS: Strategies to prevent CIAKI are implemented nonuniformly. Although biochemical evidence of CIAKI is relatively common, clinically significant CIAKI is rare. These findings should help health care providers focus the use of preventive care on the highest-risk patients and have important implications for future clinical trials.