Congestive heart failure incidence and prognosis: case identification using central adjudication versus hospital discharge diagnoses.
ABSTRACT We compared hospitalized congestive heart failure (CHF) incidence and prognosis estimates using hospital discharge diagnoses or central adjudication.
We used the Cardiovascular Health Study (CHS), a population-based cohort study of 5888 elderly adults. A physician committee adjudicated potential CHF events, confirmed by signs, symptoms, clinical tests, and/or medical therapy. A CHF discharge diagnosis included any of these ICD-9 codes in any position: 428, 425, 398.91, 402.01, 402.11, 402.91, and 997.1. We constructed an inception cohort of 1209 hospitalized, nonfatal, incident CHF cases, identified by discharge diagnosis, adjudication, or both.
Incidence rates for hospitalized CHF were 24.6 per 1000 person-years using discharge diagnoses and 17.1 per 1000 person-years using central adjudication. Compared to the group identified as having CHF by both methods, the group with only a discharge diagnosis (hazard ratio=0.77, 95% confidence interval=0.65-0.91) and the group with central adjudication only (hazard ratio=0.72, 95% confidence interval=0.55-0.94) had lower mortality rates.
In the elderly, studies using only discharge diagnoses, as compared to central adjudication, may estimate higher rates of incident hospitalized CHF. Mortality following CHF onset may be similar for these methods and higher if both methods are used together.
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ABSTRACT: Many studies have relied on administrative data to identify patients with heart failure (HF). To systematically review studies that assessed the validity of administrative data for recording HF. English peer-reviewed articles (1990 to 2008) validating International Classification of Diseases (ICD)-8, -9 and -10 codes from administrative data were included. An expert panel determined which ICD codes should be included to define HF. Frequencies of ICD codes for HF were calculated using up to the 16 diagnostic coding fields available in the Canadian hospital discharge abstract during fiscal years 2000⁄2001 and 2005⁄2006. Between 1992 and 2008, more than 70 different ICD codes for defining HF were used in 25 published studies. Twenty-one studies validated hospital discharge abstract data; three studies validated physician claims and two studies validated ambulatory care data. Eighteen studies reported sensitivity (range 29% to 89%). Specificity and negative predictive value were greater than 70% across 17 studies. Nineteen studies reported positive predictive values (range 12% to 100%). Ten studies reported kappa values (range 0.39 to 0.84). For Canadian hospital discharge data, ICD-9 and -10 codes 428 and I50 identified HF in 5.50% and 4.80% of discharge records, respectively. Additional HF-related ICD-9 and -10 codes did not impact HF prevalence. The ICD-9 and -10 codes 428 and I50 were the most commonly used to define HF in hospital discharge data. Validity of administrative data in recording HF varied across the studies and data sources that were assessed.The Canadian journal of cardiology 10/2010; 26(8):306-12. DOI:10.1016/S0828-282X(10)70438-4 · 3.94 Impact Factor
Conference Paper: Low-Noise Thin-Film Downconverters for Millimeter Systems Applications[Show abstract] [Hide abstract]
ABSTRACT: Millimeter wave downconverters intended for systems applications have been developed using thin film planar technology. The downconverters, operating with subharmonic-pumping, have achieved a total receiver noise figure as low as 5.7 dB SSB over an RF Bandwidth in excess of 20%. The converters are fixed-tuned, requiring no adjustments, and utilize improved planar Schottky barrier diodes which exhibit up to 3.5 THz zero bias cutoff frequencies. Although subharmonically pumped, the downconverters exhibit performance which in many respects is superior to conventional balanced mixers, and may provide a useful solution to cost effective systems requirements at millimeter wavelengths.Microwave Symposium Digest, 1978 IEEE-MTT-S International; 07/1978
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ABSTRACT: Long baseline (LBL) acoustic navigation techniques have traditionally been used to find the position of vehicles or towed systems in the deep ocean. LBL techniques compute the vehicle position by triangulation, based on measured acoustic ranges to fixed acoustic transponders. There is a considerable motivation to develop an accurate relative navigation system, whereby the subsea vehicle position may be calculated with respect to the surface ship, based on a range and bearing measurement, thus eliminating the need for bottom transponders. The vehicle's position may then be found in world coordinates, by adding the relative position of the vehicle to the GPS position found for the ship. The errors associated with relative navigation are primarily angular in nature, thus making it difficult to achieve sufficient accuracy at long ranges to satisfy the survey requirements. This paper describes RATS (Relative Acoustic Tracking System), which was developed by the Woods Hole Oceanographic Institution specifically for determining the position of the TOSS deep towed imaging vehicle system, operated by the Naval Oceanographic Office. RATS utilizes wide band signaling techniques with DSP (digital signal processor) implementation, combined with six axis motion compensation to obtain high accuracy relative positioning of the towed system with respect to the surface ship. A complete description of the system, as well as field results from deep ocean operations, is presentedOCEANS '97. MTS/IEEE Conference Proceedings; 11/1997