Biomedical subjects

R Platt

Publications and source records attributed to R Platt.

At least 19 recordsLinked to original sources

PubMed2006

Sex differences in gout epidemiology: evaluation and treatment.

BACKGROUND: Little is known about the characteristics, evaluation and treatment of women with gout. OBJECTIVE: To examine the epidemiological differences and differences in treatment between men and women in a large patient population. METHODS: The data from approximately 1.4 million people who were members of seven managed care plans in the USA for at least 1 year between 1 January 1999 and 31 December 2003 were examined. Adult members who had pharmacy benefits and at least two ambulatory claims specifying a diagnosis of gout were identified. In addition, men and women who were new users of urate-lowering drugs (ULDs) were identified to assess adherence with recommended surveillance of serum urate levels within 6 months of initiating urate-lowering treatment. RESULTS: A total of 6133 people (4975 men and 1158 women) with two or more International Classification of Disease-9 codes for gout were identified. As compared with men with gout, women were older (mean age 70 (SD 13) v 58 (SD 14), p<0.001) and had comorbidities and received diuretics more often (77% v 40%; p<0.001). Only 37% of new users of urate-lowering treatment had appropriate surveillance of serum urate levels post-initiation of urate-lowering treatment. After controlling for age, comorbidities, gout treatments, number of ULD dispensings and health plan, women were more likely (odds ratio 1.36, 95% confidence interval 1.11 to 1.67) to receive the recommended serum urate level testing. CONCLUSIONS: Women with gout were older, had greater comorbidities and more often used diuretics and received appropriate surveillance of serum urate levels, suggesting that the factors leading to gout as well as monitoring of treatment are very different in women and men.

Adult↗

PubMed2005

Simulation for assessing statistical methods of biologic terrorism surveillance.

INTRODUCTION: Multiple systems have been developed that use surveillance of health-care encounters to provide early warning of a terrorist attack. Limited practical experience and the absence of adequate theoretical assessments have precluded determining which alarm-generating algorithms should be preferred. In the absence of practical and theoretical results, choosing a particular statistical algorithm can be difficult. One way to evaluate algorithms is through simulation. OBJECTIVES: This report describes conceptual features of an example simulation based on the dispersal of anthrax spores and presents results based on the example simulation. METHODS: A simulation was implemented based on the dispersal of anthrax spores from a crop-dusting plane. Simulated cases were then included into an observed data stream. Detection approaches included SaTScan trade mark and small area regression and testing (SMART) scores. An evaluation metric was developed for comparison of results. In addition, a simulation of a separate data stream was added; and then separate and combined surveillance data were compared. RESULTS: In the simulation in which a single data stream was used, the two statistical approaches were substantially similar in performance. The combined surveillance based on two data streams is superior to surveillance based on either stream separately. CONCLUSION: The other potential uses of such a system are considered. These uses include the comparison of different data sources (e.g., outpatient versus emergency department and evaluating the impact of potential changes to the surveillance system, and increasing the population under surveillance). Simulation is a valuable technique for evaluating and planning for syndromic surveillance.

Algorithms↗

PubMed2005

Connecting health departments and providers: syndromic surveillance's last mile.

INTRODUCTION: A critical need exists for mechanisms to identify and report acute illness clusters to health departments. The Massachusetts Department of Public Health (MDPH) works with partner organizations to conduct syndromic surveillance. This effort is based on CDC's Health Alert Network program and includes automated generation and notification of signals and a mechanism to obtain detailed clinical information when needed. METHODS: Syndromic surveillance partners collect emergency department and ambulatory care data. The principal communications platform between syndromic surveillance partners and MDPH is the Massachusetts Homeland and Health Alert Network (HHAN). This Internet-based application serves as a portal for communication and collaboration and alerts predefined groups of users involved in emergency response. Syndromic surveillance partners' systems report to HHAN by using Public Health Information Network Messaging System events that meet thresholds selected by MDPH. Cluster summaries are automatically posted into a document library. HHAN notifies users by electronic mail, alphanumeric pager, facsimile, or voice communications; users decide how they want to be notified for each level of alert. Discussion threads permit real-time communication among all parties. RESULTS: This automated alert system became operational in July 2004. During July-December 2004, HHAN facilitated communication and streamlined investigation of 15 alerts. CONCLUSION: The system allows rapid, efficient alerting and bidirectional communication among public health and private-sector partners and might be applicable to other public health agencies.

Disaster Planning↗

PubMed2005

Comparison of syndromic surveillance and a sentinel provider system in detecting an influenza outbreak--Denver, Colorado, 2003.

INTRODUCTION: Syndromic surveillance systems can be useful in detecting naturally occurring illness. OBJECTIVES: Syndromic surveillance performance was assessed to identify an early and severe influenza A outbreak in Denver in 2003. METHODS: During October 1, 2003-January 31, 2004, syndromic surveillance signals generated for detecting clusters of influenza-like illness (ILI) were compared with ILI activity identified through a sentinel provider system and with reports of laboratory-confirmed influenza. The syndromic surveillance and sentinel provider systems identified ILI activity based on ambulatory-care visits to Kaiser Permanente Colorado. The syndromic surveillance system counted a visit as ILI if the provider recorded any in a list of 30 respiratory diagnoses plus fever. The sentinel provider system required the provider to select "influenza" or "ILI." RESULTS: Laboratory-confirmed influenza cases, syndromic surveillance ILI episodes, and sentinel provider reports of patient visits for ILI all increased substantially during the week ending November 8, 2003. A greater absolute increase in syndromic surveillance episodes was observed than in sentinel provider reports, suggesting that sentinel clinicians failed to code certain cases of influenza. During the week ending December 6, when reports of laboratory-confirmed cases peaked, the number of sentinel provider reports exceeded the number of syndromic surveillance episodes, possibly because clinicians diagnosed influenza without documenting fever. CONCLUSION: Syndromic surveillance performed as well as the sentinel provider system, particularly when clinicians were advised to be alert to influenza, suggesting that syndromic surveillance can be useful for detecting clusters of respiratory illness in various settings.

Algorithms↗

PubMed2005

Ambulatory-care diagnoses as potential indicators of outbreaks of gastrointestinal illness--Minnesota.

INTRODUCTION: Syndromic surveillance's capability to augment existing surveillance for community-acquired gastrointestinal disease is unknown. OBJECTIVE: The objective of this study was to evaluate the capability of a syndromic surveillance system to detect outbreaks of gastrointestinal disease. METHODS: A retrospective analysis was conducted comparing ambulatory care data from a health plan with a set of 110 gastrointestinal-disease outbreaks identified by the Minnesota Department of Health during 2001-02. Unusual clusters of illness (i.e., signals) in the health-plan data were identified by analyzing daily counts of gastrointestinal illness using an adjusted space-time scan statistic. Concordance was defined as < or =5 km between outbreak and signal and the signal occurring within 1 week of the outbreak. RESULTS: During 104 weeks, the number of signals was roughly what would have been expected by chance, suggesting that the modeling did a good job of estimating the expected counts of illness and that false alarms would not have occurred much more often than the number predicted at the various thresholds. During the same period, the health department identified 110 eligible gastrointestinal outbreaks. Apparent associations of the three statistically most unusual concordant signals with outbreaks of viral or bacterial gastrointestinal illness were ruled out by the health department on the basis of detailed knowledge of the circumstances and low numbers of affected persons seeking medical care. CONCLUSION: No previously known gastrointestinal outbreaks were identified by this surveillance system. However, relatively few recognized outbreaks resulted in patients seeking medical care, and the sensitivity of this system to detect outbreaks of real significance to public health remains to be determined. Prospective evaluation probably will be required to understand the usefulness of syndromic surveillance systems to enhance existing disease surveillance.

Ambulatory Care↗

PubMed2005

A model-adjusted space-time scan statistic with an application to syndromic surveillance.

The space-time scan statistic is often used to identify incident disease clusters. We introduce a method to adjust for naturally occurring temporal trends or geographical patterns in illness. The space-time scan statistic was applied to reports of lower respiratory complaints in a large group practice. We compared its performance with unadjusted populations from: (1) the census, (2) group-practice membership counts, and on adjustments incorporating (3) day of week, month, and holidays; and (4) additionally, local history of illness. Using a nominal false detection rate of 5%, incident clusters during 1 year were identified on 26, 22, 4 and 2% of days for the four populations respectively. We show that it is important to account for naturally occurring temporal and geographic trends when using the space-time scan statistic for surveillance. The large number of days with clusters renders the census and membership approaches impractical for public health surveillance. The proposed adjustment allows practical surveillance.

Censuses↗

PubMed2004

National Bioterrorism Syndromic Surveillance Demonstration Program.

The National Bioterrorism Syndromic Surveillance Demonstration Program identifies new cases of illness from electronic ambulatory patient records. Its goals are to use data from health plans and practice groups to detect localized outbreaks and to facilitate rapid public health follow-up. Data are extracted nightly on patient encounters occurring during the previous 24 hours. Visits or calls with diagnostic codes corresponding to syndromes of interest are counted; repeat encounters are excluded. Daily counts of syndromes by zip code are sent to a central data repository, where they are statistically analyzed for unusual clustering by using a model-adjusted SaTScan approach. The results and raw data are displayed on a restricted website. Patient-level information stays at the originating health-care organization unless required by public health authorities. If a cluster surpasses a threshold of statistical aberration chosen by the corresponding public health department, an electronic alert can be sent to that department. The health department might then call a clinical responder, who has electronic access to records of cases contributing to clusters. The system is flexible, allowing for changes in participating organizations, syndrome definitions, and alert thresholds. It is transparent to clinicians and has been accepted by the health-care organizations that provide the data. The system's data are usable by local and national health agencies. Its software is compatible with commonly used systems and software and is mostly open-source. Ongoing activities include evaluating the system's ability to detect naturally occurring outbreaks and simulated terrorism events, automating and testing alerts and response capability, and evaluating alternative data sources.

Ambulatory Care↗

PubMed2004

Glucocorticoids for acute viral bronchiolitis in infants and young children.

BACKGROUND: Systemic glucocorticoids have been widely prescribed for use in infants and young children with acute viral bronchiolitis but the actual benefit of this intervention requires clarification. OBJECTIVES: To systematically review the evidence on the effectiveness of systemic glucocorticoids for the treatment of infants and young children with acute viral bronchiolitis. SEARCH STRATEGY: Multiple strategies were incorporated to maximize identification of suitable studies. The following databases were searched: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 3, 2003); MEDLINE (January 1966 to September 2003); Current Contents (1998 to 2000); EMBASE (January 1990 to September 2003); and Sci Search. Handsearches through cited references and contacts with experts were also used. SELECTION CRITERIA: Only randomised controlled trials (RCT) were eligible for inclusion. Studies were included if participants were diagnosed with acute viral bronchiolitis and treated with systemic (oral, intramuscular or intravenous) corticosteroids. Three reviewers independently selected potentially relevant articles. Four reviewers evaluated these studies, determined eligibility and assessed the methodological quality of each RCT. DATA COLLECTION AND ANALYSIS: The primary outcome of interest was length of hospital stay (LOS). Secondary outcomes were: respiratory rate, haemoglobin oxygen saturation, and hospital admission and revisit rates. Data were extracted independently by the four reviewers and the results compiled and compared. Two reviewers reassessed studies to clarify points of discrepancy in the data extraction and database entry processes. Missing data were requested from the authors or calculated from other data presented in the study report. MAIN RESULTS: There was complete agreement on the inclusion of 13 trials and the exclusion of five studies. Two main study recruitment groups were identified: a) infants and young children within the first 48 hours of hospitalisation (10 trials), and b) outpatient infants and young children who were randomised from the emergency department and who may nor may not have required hospital admission (three trials).A total of 1,198 children aged 0 to 30 months were treated with the equivalent of 0.5 to 10 mg/kg of systemic prednisone for two to seven days. Outcomes of interest were not measured in each RCT. In the pooled analysis of seven trials, there was a decrease in LOS in treated children of 0.38 days (95% confidence interval (CI) -0.81 to 0.05), indicating no significant difference between treatment groups. In the pooled analysis of eight trials, the day three clinical score measured: a standard mean difference (SMD) of -0.20 (95% CI -0.73 to 0.32), indicating no difference between treatment groups. Subgroup analyses for base LOS and clinical score outcomes were performed on infants who were a) less than 12 months of age, b) all respiratory syncytial virus (RSV) positive, c) treated with less than 6 mg/kg of prednisone equivalent throughout the illness and d) first-time wheezers. These were limited by the small number of studies in each subgroup. Hospital admission rates were examined in three trials and no difference was seen between treatment groups (odds ratio (OR) 1.05 (95% CI 0.23 to 4.87). Readmission rates were reported in six studies; with no significant differences between treatment groups. Hospital revisit rates were reported in three studies, with a significant difference between treatment groups reported in one study only. The respiratory rate and haemoglobin oxygen saturation were reported descriptively in six RCTs; no differences were found between groups. Co-interventions (oxygen, supportive fluids and bronchodilators) were used similarly between treatment groups in all RCTs. REVIEWERS' CONCLUSIONS: No benefits were found in either LOS or clinical score in infants and young children treated with systemic glucocorticoids as compared to placebo. There were no differences in these outcomes between treatment groups; either in the pooled groups; either in the pooled analysis or in any of the sub analyses. Among the three studies evaluating hospital admission rates following the initial hospital visit there was no difference between treatment groups. There were no differences found in respiratory rate, haemoglobin oxygen saturation, hospital revisit or readmission rates. Subgroup analyses were significantly limited by the low number of studies in each comparison. Marked study heterogeneity and occasionally conflicting direction of benefit between trials suggests that these results should be interpreted with caution. Specific data on the harm of corticosteroid therapy in this patient population are lacking. Available evidence suggests that corticosteroid therapy is not of benefit in this patient group.

Acute Disease↗

PubMed2004

Seasonal congestive heart failure mortality and hospitalisation trends, Quebec 1990-1998.

STUDY OBJECTIVE: To describe seasonal congestive heart failure (CHF) mortality and hospitalisations in Quebec, Canada between 1990-1998 and compare trends in CHF mortality and morbidity with those in France. DESIGN: Population cohort study. SETTING: Province of Quebec, Canada. PATIENTS: Mortality data were obtained from the Quebec Death Certificate Registry and hospitalisation from the Quebec Med-Echo hospital discharge database. Cases with primary ICD-9 code 428 were considered cases of CHF. RESULTS: Monthly CHF mortality was higher in January, declined until September and then rose steadily (p<0.05). Hospital admissions for CHF declined from May until September (moving averages analysis p<0.0001). Seasonal mortality patterns observed in Quebec were similar to those observed in France. CONCLUSION: CHF mortality in Quebec is highest during the winter and declines in the summer, similar to observations in France and Scotland. This suggests that absolute temperatures may not necessarily be that important but increased CHF mortality is observed once environmental temperatures fall below a certain "threshold" temperature. Alternatively better internal heating and warmer clothing required for survival in Quebec may ameliorate mortality patterns despite colder external environments.

Climate↗

PubMed2004

Heart defects and other malformations in the Inuit in Canada: a baseline study.

OBJECTIVES: Birth defects occur in all ethnic groups, remaining an important world-wide cause of perinatal and infant morbidity. This contributes greatly to an excess of health care dollars allocated to the care and repair of those affected. This is especially true when those affected live in remote geographical locations. STUDY DESIGN: A chart review of 2567 live births of children of Inuit parents residing in Arctic Quebec (Nunavik) and on Baffin Island (Nunavut) between 1989 and 1994 (five years) was carried out compared to rates of anomalies of the Alberta Congenital Anomalies Surveillance System (ACASS). RESULTS: Birth defects were higher in the Inuit sample in nearly every major ICD-9 category with the exception of neural tube defects, eye anomalies and chromosome abnormalities. (Total: 99.7/1000 Vs 51.5/1000; OR 1.93 95% CI 1.7-2.3). Congenital heart defects were significantly increased 22.9/1000 Vs 5.6/1000, with an OR of 4.18 (95% CI 3.2-5.4) in the ICD-9 category 745. In particular, ventricular septal defects (VSDs) and atrial septal defects (ASDs) (OR 4.9 CI 3.5-6.9 and 4.6 CI 2.9-7.2) were frequent. CONCLUSIONS: A high rate of heart defects was an important contributor to the nearly two times rate of total birth defects in the Inuit compared to the ACASS. Further study should be carried out to determine the contributing factors. Genetic predisposition to specific heart defects, and a diet low in folate and vitamin A are considerations. The use of alcohol may exacerbate vitamin status in pregnancy. Optimizing vitamin status in the periconceptional period may reduce the rate of birth defects.

Canada↗

PubMed2002

Automated analysis of paradoxical ribcage motion during sleep in infants.

Identification of thoracoabdominal asynchrony (TAS) during breathing is currently detected by visual coding of records of ribcage (RC) and abdominal (AB) movements. There is thus a need to automate this process in order to save time and improve TAS detection accuracy. We studied 15 infants of 39-49 weeks postconceptional age. RC and AB signals were recorded continuously by inductance plethysmography for 4-24 hr immediately after herniorraphy. In our novel analysis approach, the records were divided into 10 sec epochs, and the equation RC = alphaAB + beta was fit to each epoch, using recursive linear regression with an exponential memory time constant of 1 and 2 sec. This yielded 10 sec signals for alpha corresponding to each epoch. The fraction of time that each alpha signal was positive was taken as a measure of synchrony between RC and AB for that epoch, while asynchrony was indicated by the fraction of time the signal was negative. We also assessed synchrony and asynchrony using a conventional measure known as thoracic delay (TD), which is based on the degree to which the peaks in RC and AB are coincident in time. Using TD as the basis of comparison, we found that our new recursive least squares method gave a positive predictive value of 99%. We conclude that our recursive least squares method is able to accurately identify portions of the RC and AB records that correspond to TAS, and we speculate that it may be useful in automating detection of TAS.

Abdominal Muscles↗

PubMed2001

A cohort study of possible risk factors for over-reporting of antihypertensive adherence.

BACKGROUND: The identification of poor medicinal adherence is difficult because direct observation of medication use is usually impractical. Up to 50% of individuals on chronic therapies may not be taking their medication as prescribed. This study is one of the first to explore possible risk factors for over-reporting of antihypertensive adherence using electronic medication monitoring. METHODS: The adherence of 286 individuals on single-drug antihypertensive therapy in a large managed care organization was electronically monitored for approximately three months. Questionnaires on socioeconomic background, adherence to therapy, health beliefs, and social support before and after adherence monitoring were completed. Over-reporting of antihypertensive adherence was assessed by comparing the self-reported frequency of noncompliance with that determined from electronic dosing records. Risk factors for over-reporting were identified by contingency table analysis and step-wise logistic regression. RESULTS: Although only 21% of participants acknowledged missing doses on one or more days per week, electronic monitoring documented nonadherence at this or a higher level in 42% of participants. The following variables were associated with over-reporting: >1 versus 1 daily dose (OR = 2.58; 95% CI = 1.50-4.41; p =.0006), lower perceived health risk from nonadherence (OR = 1.35; 95% CI = 1.10-1.64; p =.0035), and annual household income of <15,000 dollars versus >30,000 dollars (OR = 2.64; 95% CI = 1.13-6.18; p =.025). CONCLUSIONS: Over-reporting of adherence may be affected by factors related to dosing frequency, health beliefs and socioeconomic status. This topic deserves further investigation in other patient populations to elucidate possible underlying behavioral explanations.

Adolescent↗

PubMed2001

Chromosomal integration and expression of the Escherichia coli K88 gene cluster in Salmonella enterica ser. Choleraesuis strain 54 (SC54).

Attempts to develop live vaccines to protect against enterotoxigenic Escherichia coli (ETEC) infection by induction of both cell-mediated and mucosal immunity, and serum antibody responses have included use of recombinant Salmonella strains that produce K88 fimbrial antigens (Hone et al., 1988; Attridge et al., 1988; Morona et al., 1994). However, none of the recombinant Salmonella vectors has been licensed by the United States Department of Agriculture (USDA) for use as a live vaccine in pigs in the United States. A variant of Salmonella enterica ser. Choleraesuis strain 54 (SC54) is currently used as a safe and effective intranasal attenuated live vaccine in pigs. In order to expand the efficacy of this live vaccine strain, we sought to modify strain SC54 to express the K88 antigens of ETEC. To accomplish this, a plasmid-based system was used to integrate the K88 gene cluster into the chromosome of strain SC54 by site-specific recombination. The K88 antigens were expressed by strain SC54, and the gene cluster was stably maintained in the host.

Administration, Intranasal↗

PubMed2001

Using automated medical records for rapid identification of illness syndromes (syndromic surveillance): the example of lower respiratory infection.

BACKGROUND: Gaps in disease surveillance capacity, particularly for emerging infections and bioterrorist attack, highlight a need for efficient, real time identification of diseases. METHODS: We studied automated records from 1996 through 1999 of approximately 250,000 health plan members in greater Boston. RESULTS: We identified 152,435 lower respiratory infection illness visits, comprising 106,670 episodes during 1,143,208 person-years. Three diagnoses, cough (ICD9CM 786.2), pneumonia not otherwise specified (ICD9CM 486) and acute bronchitis (ICD9CM 466.0) accounted for 91% of these visits, with expected age and sex distributions. Variation of weekly occurrences corresponded closely to national pneumonia and influenza mortality data. There was substantial variation in geographic location of the cases. CONCLUSION: This information complements existing surveillance programs by assessing the large majority of episodes of illness for which no etiologic agents are identified. Additional advantages include: a) sensitivity, uniformity and efficiency, since detection of events does not depend on clinicians' to actively report diagnoses, b) timeliness, the data are available within a day of the clinical event; and c) ease of integration into automated surveillance systems. These features facilitate early detection of conditions of public health importance, including regularly occurring events like seasonal respiratory illness, as well as unusual occurrences, such as a bioterrorist attack that first manifests as respiratory symptoms. These methods should also be applicable to other infectious and non-infectious conditions. Knowledge of disease patterns in real time may also help clinicians to manage patients, and assist health plan administrators in allocating resources efficiently.

Acute Disease↗

PubMed2001

Mortality and costs of acute renal failure associated with amphotericin B therapy.

To assess the mortality and resource utilization that results from acute renal failure associated with amphotericin B therapy, 707 adult admissions in which parenteral amphotericin B therapy was given were studied at a tertiary-care hospital. Main outcome measures were mortality, length of stay, and costs; we controlled for potential confounders, including age, sex, insurance status, baseline creatinine level, length of stay before beginning amphotericin B therapy, and severity of illness. Among 707 admissions, there were 212 episodes (30%) of acute renal failure. When renal failure developed, the mortality rate was much higher: 54% versus 16% (adjusted odds of death, 6.6). When acute renal failure occurred, the mean adjusted increase in length of stay was 8.2 days, and the adjusted total cost was $29,823. Although residual confounding exists despite adjustment, the increases in resource utilization that we found are large and the associated mortality is high when acute renal failure occurs following amphotericin B therapy.

Acute Kidney Injury↗

PubMed2001

Reforming the core clerkship in internal medicine: the SGIM/CDIM Project. Society of General Internal Medicine/Clerkship Directors in Internal Medicine.

Dramatic changes in health care have stimulated reform of undergraduate medical education. In an effort to improve the teaching of generalist competencies and encourage learning in the outpatient setting, the Society of General Internal Medicine joined with the Clerkship Directors in Internal Medicine in a federally sponsored initiative to develop a new curriculum for the internal medicine core clerkship. Using a broad-based advisory committee and working closely with key stakeholders (especially clerkship directors), the project collaborators helped forge a new national consensus on the learning agenda for the clerkship (a prioritized set of basic generalist competencies) and on the proportion of time that should be devoted to outpatient care (at least one third of the clerkship). From this consensus emerged a new curricular model that served as the basis for production of a curriculum guide and faculty resource package. The guide features the prioritized set of basic generalist competencies and specifies the requisite knowledge, skills, and attitudes/values needed to master them, as well as a list of suggested training problems. It also includes recommended training experiences, schedules, and approaches to faculty development, precepting, and student evaluation. Demand for the guide has been strong and led to production of a second edition, which includes additional materials, an electronic version, and a pocket guide for students and faculty. A follow-up survey of clerkship directors administered soon after completion of the first edition revealed widespread use of the curricular guide but also important barriers to full implementation of the new curriculum. Although this collaborative effort appears to have initiated clerkship reform, long-term success will require an enhanced educational infrastructure to support teaching in the outpatient setting.

Clinical Clerkship↗

PubMed2001

Derivation of adherence metrics from electronic dosing records.

Numerous adherence variables have been created from electronic dosing records hindering synthesis of the vast body of adherence research. To elucidate the mathematical foundation for electronic adherence monitoring and to understand how diverse electronic adherence metrics are related to each other and the underlying construct of adherence behavior. Several representative adherence metrics are derived mathematically and their relationship to the underlying consumption (or dosing event) rate analyzed. Data from a 3-month study of 286 individuals on single-drug antihypertensive therapy are then used to empirically study the statistical properties of several of these electronic adherence metrics. As suggested by their common link to the consumption (or dosing event) rate, the analyzed electronic adherence metrics were generally strongly correlated (r <- .6 and > .4). The lowest correlation (r = .15) involved the ratio of the observed number of doses to the recommended number (called average adherence), which tended to emphasize quantity consumed, and the ratio of the observed to maximum mean squared rate deviation (MSRD ratio), which focused more on dose timing. Despite their different formulations, electronic adherence variables are generally closely correlated. Adherence metrics that average the consumption rate over multiple doses (by summing up the number of doses and dividing by the monitored time) may be less sensitive to short-term fluctuations in medication intake. Metrics that are more sensitive to timing variability may thus be preferable when timing as well as quantity of dosing are of interest.

Adult↗

PubMed2001

Single ventricle with systemic obstruction in early life: comparison of initial pulmonary artery banding versus the Norwood operation.

OBJECTIVES: The outcomes of initial pulmonary artery banding (PAB)+/-coarctation repair are compared with the Norwood operation in newborns with single ventricle (SV) and systemic obstruction (SO). METHODS: Between January 1987 and July 2000, 22 patients (median age, 12 days) with SV and aortic arch obstruction (AAO), subaortic stenosis (SAS), or both underwent surgery. Two initial surgical approaches were used: PAB+/-coarctation repair (group I, seven patients); Norwood type operation (group II, 15 patients). RESULTS: The overall mortality was 32% (seven of 22 patients). There was no late mortality. The mortality in group I was 43% versus 27% in group II. Recently, there has been no mortality following the Norwood operation in the last eight patients operated since 1995. Of the survivors, nine patients have undergone the Fontan operation and four patients have had the bidirectional Glenn (BDG) with no deaths. There was one repair of supravalvar aortic stenosis at the time of BDG in group II as opposed to eight reinterventions for SAS and/or AAO in four patients in group I (P=0.01). CONCLUSIONS: PAB+/-coarctation repair for SV and SO is associated with a high mortality and a high reoperation rate for SAS or recurrent AAO. Although the Norwood operation was also associated with a high mortality early on, it can now be performed with excellent outcome. This improvement, combined with a low reintervention rate for SAS or AAO, suggests that the Norwood operation is likely to emerge as the procedure of choice for SV and SO.

Aortic Coarctation↗