Hypoglycemic events and glycosylated hemoglobin values in patients with type 2 diabetes mellitus newly initiated on insulin glargine or premixed insulin combination products.

PURPOSE: Rates of hypoglycemic events and their associated costs were compared among patients with type 2 diabetes mellitus newly initiated on insulin glargine or a premixed insulin fixed-combination product. METHODS: Patients newly initiated on insulin glargine or premixed insulin fixed-combination products (including pen delivery systems) between June 1, 2001, and February 29, 2004, were identified using an administrative claims database. Hypoglycemic events were identified from International Classification of Diseases, 9th Revision, Clinical Modification codes. Multivariate analyses were performed. RESULTS: A total of 2315 patients met the inclusion criteria. Of those, 1212 received insulin glargine and 1103 received a premixed fixed-combination insulin product. The mean +/- S.D. treatment duration was 13.7 +/- 8.1 months. Patients treated with premixed insulin had a higher hypoglycemic event rate than glargine patients (13.8 versus 7.0/100 patients/year; p = 0.027), which yielded a number needed to treat of 15 patients. The mean cost per hypoglycemic event was $1049 (95% confidence interval, $426-1672). The mean annual cost of all insulin use was $46 more for the insulin glargine cohort than for those who received premixed insulin ($534 versus $488, respectively) (p < 0.05). Mean postindex insulin use was higher in patients receiving premixed insulin than in those treated with insulin glargine (48.1 versus 43.8 units per day) (p < 0.05). CONCLUSION: Patients with type 2 diabetes mellitus who were newly initiated on insulin glargine had a lower rate of hypoglycemic events compared with patients newly initiated on a premixed fixed-combination insulin product. Treatment of 15 patients with insulin glargine instead of premixed insulin for one year would avoid one hypoglycemic event per year.

Health care resources and costs for treating peripheral artery disease in a managed care population: results from analysis of administrative claims data.

OBJECTIVE: Peripheral arterial disease (PAD) is associated with high rates of morbidity and mortality and serves as an important marker for advanced systemic atherosclerosis accompanied by symptomatic or asymptomatic ischemia of the coronary, cerebral, and visceral vasculature. There are little published data on the use of health care resources and costs attributable to PAD. The objectives of this study were to evaluate, from a societal perspective, PAD-related health care resource utilization and to determine the total annualized costs and cost components for patients with PAD, with particular attention to the key outcomes of myocardial infarction (MI), transient ischemic attacks (TIA), stroke, and amputations. METHODS: This study examined medical, hospital and outpatient, and pharmacy claims from a large managed care database with dates of service from January 1, 1999, through August 31, 2003. Patients with PAD were identified from claims using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis codes (primary or secondary codes), ICD-9-CM procedure codes, current procedural terminology (CPT) codes, or by a pharmacy claim for cilostazol or pentoxifylline. The index date for each patient was the first occurrence of either a medical claim for PAD or a pharmacy claim for 1 of the 2 drugs. Patients were required to be a minimum of 18 years old with continuous plan eligibility. The prevalence of PAD in adults in a managed care setting was also determined, as were annual rates for the key outcomes of MI, TIA, stroke, and amputations. Health care resource utilization and costs were calculated for PAD patients after the index date for a period of at least 12 months per patient for medications, outpatient/physician office visits, laboratory/diagnostic procedures, emergency department visits, and hospitalization. Cost was defined as the allowed charge on each administrative claim, including the amount paid by the insurer plus the amount paid by the health plan members (copay, deductible, and coinsurance). RESULTS: Prior to application of exclusion criteria for patients aged 18 years or older and the minimum period of continuous eligibility, the overall prevalence of PAD was 1.18% of the total managed care organization population.s 6.67 million members. The PAD study cohort consisted of 30,561 patients with a mean age of 70.7 years at index. The most common comorbidities identified in the preindex period for these PAD patients included hypertension (67% of patients); metabolic disorders/hypercholesterolemia (57%); heart disease including cardiomyopathy, dysrhythmias, and heart failure (55%); and ischemic heart disease (47%). Over a mean postindex period of 25.2 months (median 23.4 months), the total mean annualized PAD-related cost was $5,955 per patient per year (PPPY). Hospitalizations accounted for the largest component cost category, averaging $4,442 PPPY or 75% of the total annualized PAD-related cost per PAD patient. PAD-related noncoronary procedures averaged $729 PPPY (12.2% of total annual PAD-related costs), and PAD-related medications (including antihypertensives and lipid-lowering therapy) totaled $610 (10.2% of total annual costs), including $313 PPPY for antihypertensives and $207 for lipid-lowering therapy. For the subgroup of 24,075 newly identified PAD patients, 8,479 (35.2%) were hospitalized during an average 25.2 months of follow-up, with the mean time to first hospitalization of 8.9 months. CONCLUSIONS: Approximately 75% of the total PAD-related patient cost in an average of 25 months of follow-up is contributed by hospital costs, and 35% of patients newly diagnosed with PAD experienced a hospitalization in a mean of 8.9 months after the index diagnosis. Based upon mean annual health and member costs of only $313 PPPY for antihypertensives and $207 for lipid-lowering therapy, drug therapy in PAD patients may be underutilized.

Use of radial density plots to calibrate image magnification for frozen-hydrated specimens.

Accurate magnification calibration for transmission electron microscopy is best achieved with the use of appropriate standards and an objective calibration technique. We have developed a reliable method for calibrating the magnification of images from frozen-hydrated specimens. Invariant features in radial density plots of a standard are compared with the corresponding features in a "defocused" X-ray model of the same standard. Defocused X-ray models were generated to mimic the conditions of cryo-electron microscopy. The technique is demonstrated with polyoma virus, which was used as an internal standard to calibrate micrographs of bovine papilloma virus type 1 and bacteriophage phi X174. Calibrations of the micrographs were estimated to be accurate to 0.35%-0.5%. Accurate scaling of a three-dimensional structure allows additional calibrations to be made with radial density plots computed from two- or three-dimensional data.

Analysis of the multi-channel epileptiform EEG using the Markov chains formalism.

A multi-level scheme of syntactic reduction of the epileptiform EEG data is briefly discussed and the possibilities it opens up in describing the dynamic behaviour of a multi-channel system are indicated. A new algorithm for the inference of a Markov network from finite sets of sample symbol strings is introduced. Formulae for the time-dependent state occupation probabilities, as well as joint probability functions for pairs of channels, are given. An exemplary case of analysis in these terms, taken from an investigation of anticonvulsant drug effects on EEG seizure patterns, is presented.

The use of a multi-channel Kalman filter algorithm in structural analysis of the epileptic EEG.

An extension of the Kalman filter algorithm to the multi-channel case is presented and its application as a segmenting procedure in the analysis of the epileptic EEG is discussed. An analytical example of structural analysis, using the segments extracted by the proposed filter, is presented for a particular set of 4-channel EEG recordings. This analysis is shown to be especially fruitful if the autoregressive coefficients - a byproduct of the filtering procedure - are used to estimate the information flow between the channels by the calculation of partial as well as directed coherences for the representative segments.

Computer-aided analysis of the epileptic EEG.

An introductory review of a comprehensive approach to the problem of automatic evaluation of the epileptic EEG in the frame of syntactic analysis is presented. The aims and merits of the syntactic approach are discussed and the viability of the method is demonstrated on a few chosen examples. Working procedures for automatic segmentation and classification of patterns in single- as well as in multi-channel case of the epileptic EEG are briefly described. These include algorithms for segmentation by a finite-state automaton technique (single channel) and, in multi-channel case, a sparsely updated Kalman filter algorithm. Inherent possibilities of the approach presented are shown to open the way for a global description of a seizure in terms of the Markov chains theory.

Syntactic analysis of the epileptic electroencephalogram.

A full-scale scheme of the multi-level syntactic analysis of the epileptic EEG is presented and discussed in detail. An exhaustive description of basic procedures necessary to obtain a meaningful description of any set of epileptic EEG recordings is given; these procedures include algorithms for extraction of various elementary peaks from the EEG signal, for segmentation of the recording, for classification of the segments found into distinct groups of characteristic patterns and, finally, for calculation of the Levenshtein distance between the individual recordings, each recording regarded as a string of symbols taken to represent different classes of patterns. An example of global analysis in terms of such a distance, performed on a typical set of epileptic EEG recordings, is supplied to prove the feasibility of the scheme proposed.

Segmentation of the epileptic EEG by means of a finite state automaton.

The aims and merits of the syntactical decomposition of the epileptic EEG are discussed in some detail. General assumptions in the design of segmenting algorithm--an essential part of the reduction of data program--are considered and a working example of segmenting routine is presented. This routine is designed as a finite state automaton, equivalent to a formal regular grammar. The performance of the routine on two sets of experimental data is presented and its intrinsic stability is shown in terms of cluster analysis of the segments produced. Means of extension of the proposed scheme to other cases of potential interest as well as possible applications in the higher level syntactical analysis are pointed out.

Application of combined median-averaging filters to scintigraphic image processing.

Statistical and deterministic properties of median filters are briefly discussed and their inherent advantages as a prospective tool in scintigraphic data processing are pointed out. The ability of median filters of suppressing impulse noise while the edge-like features of an image are preserved, is demonstrated on phantom data. The residual high-frequency noise remaining after median filtering can be subsequently reduced by standard smoothing procedures. A simple algorithm, made up of the superposition of a median and an averaging filter, is presented and shown to be a promising candidate in the quest for fast and easy-to-implement processing routine.