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Biomedical subjects

Richard Platt

Publications and source records attributed to Richard Platt.

At least 37 records · Page 2Linked to original sources
PubMed2006

Potential drug-drug interactions in the outpatient setting.

BACKGROUND: Although medication safety research has tended to focus on inpatients, the safety of drug use among outpatients is also a concern. OBJECTIVE: We estimate the frequency of potentially interacting concomitant medication dispensing among outpatients. RESEARCH DESIGN: We report the number and percent of patients annually dispensed an object drug of interest (ie, warfarin, digoxin, cyclosporine, or lovastatin/simvastatin) with a potentially interacting drug among a random sample of insured adults receiving care from 10 integrated delivery systems. We use 2 definitions of concomitant dispensing: medications dispensed: 1) during the time period for which the patient had the other medication available ('days supply') and 2) on the same day. We also estimate the number of insured U.S. population codispensed these medication pairs. RESULTS: Among patients dispensed a drug of interest, between 17.8% (95% confidence interval [CI]=17.1-18.6%) and 28.0% (95% CI=24.0-32.1%) were concomitantly dispensed a potentially interacting drug using the "days supply" definition, and between 7.1% (95% CI=6.6-7.7%) and 17.7% (95% CI=14.4-21.1%) using the "same day" definition. Extrapolating to the insured U.S. population, between 1.29 (95% CI=1.25-1.33; same day) and 2.67 (95% CI=2.62-2.72; days supply) million insured adults are dispensed 1 of these 4 potentially interacting pairs. CONCLUSIONS: We found evidence of potentially interacting concomitant medication dispensing among outpatients. An opportunity exists to better understand how such dispensing translates into adverse events and ultimately to improved medication safety.

Aged↗
PubMed2006

Computerized prescribing alerts and group academic detailing to reduce the use of potentially inappropriate medications in older people.

OBJECTIVES: To examine the effect of replacing drug-specific computerized prescribing alerts with age-specific alerts on rates of dispensing potentially inappropriate medications in older people and to determine whether group academic detailing enhances the effectiveness of these alerts. DESIGN: Cluster-randomized trial of group academic detailing and interrupted time-series analysis. SETTING: Fifteen clinics of a staff-model health maintenance organization. PARTICIPANTS: Seven practices (113 clinicians, 24,119 patients) were randomly assigned to receive age-specific prescribing alerts plus the academic detailing intervention; eight practices (126 clinicians, 26,805 patients) received alerts alone. Prior implementation of drug-specific alerts established a downward trend in use of target medications that served as the baseline trend for the present study. INTERVENTION: The computerized age-specific alerts occurred at the time of prescribing a targeted potentially inappropriate medication (e.g., tertiary tricyclic amine antidepressants, long-acting benzodiazepines, propoxyphene) and suggested an alternative medication. Clinicians at seven sites were randomized to group academic detailing, an interactive educational program delivering evidence-based information. MEASUREMENTS: Number of target medications dispensed per 10,000 patients per quarter, 2 years before and 1.5 years after the replacement of drug-specific with age-specific alerts. RESULTS: Age-specific alerts resulted in a continuation of the effects of the drug-specific alerts without measurable additional effect (P=.75 for level change), but the age-specific alerts led to fewer false-positive alerts for clinicians. Group academic detailing did not enhance the effect of the alerts. CONCLUSION: Age-specific alerts sustained the effectiveness of drug-specific alerts to reduce potentially inappropriate prescribing in older people and resulted in a considerably decreased burden of the alerts.

Aged↗
PubMed2006

Monitoring of drugs with a narrow therapeutic range in ambulatory care.

OBJECTIVES: To describe the proportion of patients receiving drugs with a narrow therapeutic range who lacked serum drug concentration monitoring during a 1-year period of therapy and to identify patient characteristics associated with lack of monitoring. STUDY DESIGN: Retrospective cohort. METHODS: Ambulatory patients (n = 17,748) at 10 health maintenance organizations who were receiving ongoing continuous drug therapy with digoxin, carbamazepine, divalproex sodium, lithium carbonate, lithium citrate, phenobarbital sodium, phenytoin, phenytoin sodium, primidone, quinidine gluconate, quinidine sulfate, procainamide hydrochloride, theophylline, theophylline sodium glycinate, tacrolimus, or cyclosporine for at least 12 months between January 1, 1999, and June 30, 2001, were identified. Serum drug concentration monitoring was assessed from administrative data and from medical record data. RESULTS: Fifty percent or more of patients receiving digoxin, theophylline, procainamide, quinidine, or primidone were not monitored, and 25% to 50% of patients receiving divalproex, carbamazepine, phenobarbital, phenytoin, or tacrolimus were not monitored. Younger age was associated with lack of monitoring for patients prescribed digoxin (adjusted odds ratio, 1.86; 95% confidence interval, 1.39-2.48) and theophylline (adjusted odds ratio, 1.58; 95% confidence interval, 1.23-2.04), while older age was associated with lack of monitoring for patients prescribed carbamazepine (adjusted odds ratio, 0.59; 95% confidence interval, 0.44-0.80) and divalproex (adjusted odds ratio, 0.50; 95% confidence interval, 0.38-0.66). Patients with fewer outpatient visits were also less likely to be monitored (P < .001). CONCLUSIONS: A substantial proportion of ambulatory patients receiving drugs with narrow intervals between doses resulting in beneficial and adverse effects did not have serum drug concentration monitoring during 1 year of use. Clinical implications of this finding need to be evaluated.

Ambulatory Care↗
PubMed2005

The projected health benefits of maternal group B streptococcal vaccination in the era of chemoprophylaxis.

While maternal antibiotic prophylaxis has greatly reduced early-onset group B streptococcal (GBS) disease in the United States, a GBS vaccine currently under development could potentially prevent additional GBS cases and preterm births. A decision analytic model was created to compare preventive strategies using adolescent, maternal (prenatal), or postpartum vaccination with selective chemoprophylactic strategies. The current practice of culture-based chemoprophylaxis was predicted to prevent 55% of early plus late-onset GBS infections. Maternal vaccination strategies were superior to current practice, preventing 68-69% of all GBS infections and 4% of very preterm births (<32 weeks gestation). The most effective adolescent vaccination strategy combined vaccination with culture-based chemoprophylaxis for all women and prevented 66% of all GBS infections. All other strategies were similar in efficacy to current practice or inferior. Maternal GBS vaccination is predicted to prevent more cases of neonatal GBS disease than current practice and would prevent approximately one in 25 very preterm births.

Adult↗
PubMed2005

Antivirals and antibiotics for influenza in the United States, 1995--2002.

PURPOSE: To measure the rates of antiviral and antibiotic prescribing for patients diagnosed with influenza in the United States. METHODS: We performed a retrospective analysis of visits to ambulatory clinics and emergency departments in the National Ambulatory Medical Care Survey (NAMCS) and the National Hospital Ambulatory Medical Care Survey (NHAMCS) with a diagnosis of influenza that occurred in seven influenza seasons between 1 October 1995 and 31 May 2002 (n=1216). RESULTS: There were an estimated 22 million visits (95%CI, 17--26 million visits) with a diagnosis of influenza to community ambulatory clinics (88% of visits), hospital ambulatory clinics (3%) and emergency departments (9%) in the United States between the 1995--1996 and the 2001--2002 influenza seasons, inclusive. The sample was 63% adults, 44% male and 84% white. Physicians prescribed antivirals in 19% of visits and antibiotics not associated with an antibiotic-appropriate diagnosis in 26% of visits. In multivariable modeling, independent predictors of antiviral prescribing were adult age (OR, 2.1; 95%CI, 1.1--4.0) and Medicare insurance (OR, 0.1 compared to private insurance; 95%CI, 0.0--0.6). Antiviral prescribing was marginally associated with influenza season (OR, 1.2 per influenza season; 95%CI, 1.0--1.4). Independent predictors of antibiotic prescribing were influenza season (OR, 0.8 per influenza season; 95%CI, 0.7--0.9), male sex (OR, 0.6; 95%CI, 0.4--0.9), adult age (OR, 2.3; 95%CI, 1.2--4.2) and emergency department visits (OR, 0.5 compared to community ambulatory visits; 95%CI, 0.3--0.8). CONCLUSIONS: Physicians prescribed antiviral medications to 19% of patients they diagnosed with influenza; the proportion that would have been clinically appropriate is unknown. In contrast, physicians prescribed apparently inappropriate antibiotics to 26% of these same patients, a rate that, encouragingly, decreased over time.

Adolescent↗
PubMed2005

Health plan administrative databases can efficiently identify serious myopathy and rhabdomyolysis.

OBJECTIVE: We evaluated the positive predictive values (PPVs) of specific criteria based upon International Classification of Diseases, 9th revision (ICD-9-CM) codes documented in health plan administrative databases for identification of cases of serious myopathy and rhabdomyolysis. STUDY DESIGN AND SETTING: We conducted a retrospective study among patients enrolled in 11 geographically dispersed managed care organizations. Cohorts of new users of specific statins and fibrates were identified by selecting patients with an initial dispensing of the drug during the period 1 January 1998 to 30 June 2001. Potential cases of serious myopathy or rhabdomyolysis were identified using specific criteria based upon ICD-9-CM codes suggesting a muscle disorder or acute renal failure. RESULTS: A total of 194 hospitalizations meeting the criteria for chart review selection were identified among 206,732 new users of statins and 15,485 new users of fibrates. Overall, 31 cases of serious, clinically important myopathy or rhabdomyolysis (18%) were confirmed through chart review. Of these, 26 (84%) had a claim including codes for myoglobinuria (ICD-9-CM 791.3) or other disorders of muscle, ligament, and fascia (ICD-9-CM 728.89). A PPV of 74% (26 of 35 patients meeting criteria) was found for a composite definition that included (1) a primary or secondary discharge code for myoglobinuria, (2) a primary code for "other disorders of muscle," or (3) a secondary code for "other disorders of muscle" accompanied by a claim for a CK test within 7 days of hospitalization or a discharge code for acute renal failure. CONCLUSION: For rare adverse events such as serious myopathy or rhabdomyolysis, large population-based databases that include diagnosis and laboratory test claims data can facilitate epidemiologic research.

Data Interpretation, Statistical↗
PubMed2005

Infection control practices to reduce airborne bacteria during total knee replacement: a hospital survey in four states.

OBJECTIVE: To describe the use of laminar airflow, body exhaust, and ultraviolet lights during total knee replacement (TKR) in four U.S. states. DESIGN: Survey of healthcare facilities. SETTING: Hospitals in Illinois, North Carolina, Ohio, and Tennessee that performed TKR during 2000 as identified by Medicare claims data. PARTICIPANTS: Hospitals responding to a mailed questionnaire. RESULTS: Two hundred ninety-five (73%) of 405 eligible hospitals that performed 18,374 primary and revision TKR procedures responded to the questionnaire. Among responding hospitals, 30% reported regular use (for > 75% of procedures) of laminar airflow, 42% reported regular use of body exhaust, and 5% reported regular use of ultraviolet lights. Among hospitals providing complete data, 150 (58%) performing 66% of procedures reported regular use of at least one of these techniques. On regression analyses, laminar airflow was used more often by hospitals with a TKR volume greater than 25 procedures per year (odds ratio [OR], 2.0; 95% confidence interval [CI95], 1.1-3.7) and orthopedic residency programs (OR, 2.8; CI95, 1.3-6.3), but its use was not significantly related to hospital setting or ownership status. CONCLUSIONS: Although these clean air practices are not recommended by any U.S. governmental or professional organization, they are used in nearly two-thirds of TKR procedures. Better information about their impact on current practice and more explicit guidelines may aid decisions about the use of these resource-intensive infection control practices.

Air Microbiology↗
PubMed2005

Active surveillance of vaccine safety: a system to detect early signs of adverse events.

BACKGROUND: There currently are no population-based systems in the United States to rapidly detect adverse events after newly introduced vaccines. To evaluate the feasibility of developing such systems, we used 5 years of data from 4 health maintenance organizations within the Centers for Disease Control and Prevention (CDC) Vaccine Safety Datalink. METHODS: Within every year, each week's vaccinated children were followed for 4 weeks, and rates of adverse events were compared with rates among children of similar ages before the introduction of the new vaccine. We assessed risks for intussusception after rotavirus vaccination and risks for fever, seizures, and other neurologic adverse events after the change from whole cell diphtheria-tetanus-pertussis (DTPw) to acellular DTP vaccine (DTPa). We used sequential probability ratio testing, adjusted for age, sex, calendar time, season, and HMO, and with a stopping value based on the probability of an adverse event under the null hypothesis and under a preset alternative hypothesis. RESULTS: We detected an increase in intussusception after 2589 vaccine doses of rotavirus vaccine, about the same time initial reports of intussusception were made to the Vaccine Adverse Events Reporting System. Decreases in risk for fever, seizures, and other abnormal neurologic events became detectable within 12 weeks, 42 weeks, and 18 months, respectively, after the change from DTPw to DTPa. CONCLUSIONS: We conclude that it is feasible to develop systems for rapid and routine population-based assessments of new vaccine safety.

Databases, Factual↗
PubMed2005

Effect of increased cost-sharing on oral hypoglycemic use in five managed care organizations: how much is too much?

BACKGROUND: For patients with a chronic disease, increased cost-sharing for medications may lead to unintended consequences, including reduced use of medications essential for control of their disease. OBJECTIVE: The objective of this study was to estimate the effects of small ($1-6 per 30-day supply), moderate ($7-10), and large (>$10) increases in medication cost-sharing on 12-month trends in oral hypoglycemic (OH) use among adults with type 2 diabetes. METHODS: We conducted a quasiexperimental study using a time series with comparison group design. Data were obtained from computerized membership, benefit, and pharmacy dispensing data of 5 managed care organizations (MCOs). A total of 13,110 12-month episodes of OH use and a medication cost-sharing increase ("intervention") were matched with 13,110 that had no increase. The dependent variable was OH average daily dose (ADD) standardized to each episode's mean OH ADD in the 6-month preintervention period. The principal independent variable was change in cost per 30-day OH supply between the 6-month pre- and postintervention periods. Effects of changes in cost-sharing on OH ADD were estimated using segmented time series regression. RESULTS: Episodes with >$10 increase in cost-sharing had significantly (alpha=0.05) decreased OH ADD in the postintervention period. At 6 months after this increase, OH ADD had decreased by 18.5% from that predicted from the preintervention trend. Episodes with a $1 to $10 increase in cost-sharing and those with no increase in cost-sharing had significant linear increases in OH use over the 12-month period. CONCLUSIONS: Large increases in medication cost-sharing were associated with immediate and persistent reductions in OH use. Small and moderate increases had little effect on OH use in the 6-month period after the increase.

Adolescent↗
PubMed2005

Laboratory monitoring of drugs at initiation of therapy in ambulatory care.

BACKGROUND AND OBJECTIVES: Product labeling and published guidelines reflect the importance of monitoring laboratory parameters for drugs with a risk of organ system toxicity or electrolyte imbalance. Limited information exists about adherence to laboratory monitoring recommendations. The objective of this study was to describe laboratory monitoring among ambulatory patients dispensed medications for which laboratory testing is recommended at therapy initiation. DESIGN AND SUBJECTS: We conducted a retrospective cross-sectional analysis of patients in 10 geographically distributed health maintenance organizations who were newly prescribed medications with recommended laboratory test monitoring. The main outcome measure was the proportion of initial drug dispensing without recommended baseline laboratory monitoring for 35 newly initiated drugs or drug classes. RESULTS: One hundred seven thousand, seven hundred sixty-three of 279,354 (39%) initial drug dispensings occurred without recommended laboratory monitoring. Patients without monitoring were younger than patients who had monitoring (median 57 vs 61 years, P<.001). Thirty-two percent of dispensings where a serum creatinine was indicated did not have it evaluated (range across drugs, 12% to 61%); 39% did not have liver function testing (range 10% to 75%); 32% did not have hematologic monitoring (range 9% to 51%); and 34% did not have electrolyte monitoring (range 20% to 62%) (P<.001). CONCLUSIONS: Substantial opportunity exists to improve laboratory monitoring of drugs for which such monitoring is recommended. This study emphasizes the need for research to identify the clinical implications of not conducting recommended laboratory monitoring, existing barriers to monitoring, and methods to improve practice.

Ambulatory Care↗
PubMed2005

Post-PCV7 changes in colonizing pneumococcal serotypes in 16 Massachusetts communities, 2001 and 2004.

OBJECTIVE: The introduction of heptavalent conjugate pneumococcal vaccine (PCV7) has raised concerns for replacement with nonvaccine serotypes in both invasive disease and asymptomatic carriage. Analysis of colonizing serotypes among healthy children in the community provides critical data on such changes. METHODS: Nasopharyngeal specimens were obtained from children who were younger than 7 years during well-child or sick visits in primary care practices in 16 Massachusetts communities during 2001 and 2004. Susceptibility testing and serotyping were performed on isolated Streptococcus pneumoniae strains. Vaccination history with PCV7 was abstracted from the medical record. RESULTS: Among colonizing pneumococcal isolates, PCV7 serotypes decreased from 36% to 14%, and non-PCV7 serotypes increased from 34% to 55%. Overall carriage did not change (26% to 23%); neither did carriage of potentially cross-reactive serotypes (30% to 31%). The most common non-PCV7 serotypes were serotypes 11, 15, and 29. There was a substantial increase in penicillin nonsusceptibility from 8% to 25% in non-PCV7 serotypes; 35% were highly resistant to penicillin. Penicillin nonsusceptibility increased from 45% to 56% among PCV7 serotypes while remaining stable among PCV7 potentially cross-reactive strains (51% vs 54%). CONCLUSIONS: Pneumococcal colonization has changed after the introduction of PCV7, both in serotype distribution and in patterns of antibiotic resistance. The frequency of nonvaccine strains has increased, and the proportion of nonvaccine isolates that are not susceptible to penicillin has tripled. This shift toward increased carriage of nonvaccine serotypes warrants vigilance for changes in the epidemiology of invasive pneumococcal disease.

Child↗
PubMed2005

Simulated anthrax attacks and syndromic surveillance.

We measured sensitivity and timeliness of a syndromic surveillance system to detect bioterrorism events. A hypothetical anthrax release was modeled by using zip code population data, mall customer surveys, and membership information from HealthPartners Medical Group, which covers 9% of a metropolitan area population in Minnesota. For each infection level, 1,000 releases were simulated. Timing of increases in use of medical care was based on data from the Sverdlovsk, Russia, anthrax release. Cases from the simulated outbreak were added to actual respiratory visits recorded for those dates in HealthPartners Medical Group data. Analysis was done by using the space-time scan statistic. We evaluated the proportion of attacks detected at different attack rates and timeliness to detection. Timeliness and completeness of detection of events varied by rate of infection. First detection of events ranged from days 3 to 6. Similar modeling may be possible with other surveillance systems and should be a part of their evaluation.

Anthrax↗
PubMed2005

Incidence of Churg-Strauss syndrome in asthma drug users: a population-based perspective.

OBJECTIVE: To estimate the incidence of Churg-Strauss syndrome (CSS) among a large population of asthma drug users. METHODS: A retrospective study was conducted among patients who had been dispensed asthma drugs at 3 managed care organizations. Adults who received >or =3 dispensings of an asthma drug during any consecutive 12-month period between January 1, 1995 and June 30, 2000 were identified. Information on patient age, gender, enrollment status, asthma drugs dispensed, and inpatient and outpatient diagnoses and procedures was obtained from automated databases. Chart reviews were performed on persons identified by combinations of diagnostic and billing codes indicative of CSS. A rheumatologist reviewed abstracted information on all subjects; those who met >or =2 American College of Rheumatology criteria for CSS were reviewed by 2 clinical experts. Each clinical expert independently rated the cases; disagreements were resolved by consensus. Cases classified as having "probable/definite" CSS were included in these analyses. The incidence of CSS was estimated overall and according to patient gender, age, and calendar year. RESULTS: From a population of 184,667 asthma drug users contributing 606,184 person-years of exposure, 21 incident cases of CSS were identified (overall incidence of 34.6 per million person-years; 95% confidence interval 21.4 to 53.0). Incidence rates did not differ by gender and age group. The incidence rates for 1995, 1996, 1997, 1998, 1999, and the first 6 months of 2000 were 0, 22, 52, 75, 14, and 14 per million person-years respectively. CONCLUSIONS: Results from this population-based study suggest a somewhat lower incidence of CSS in asthma drug users than previously reported and provides important information as to the risk of developing CSS from a population-based perspective.

Adolescent↗
PubMed2004

Incidence of hospitalized rhabdomyolysis in patients treated with lipid-lowering drugs.

CONTEXT: Lipid-lowering agents are widely prescribed in the United States. Reliable estimates of rhabdomyolysis risk with various lipid-lowering agents are not available. OBJECTIVE: To estimate the incidence of rhabdomyolysis in patients treated with different statins and fibrates, alone and in combination, in the ambulatory setting. DESIGN, SETTING, AND PATIENTS: Drug-specific inception cohorts of statin and fibrate users were established using claims data from 11 managed care health plans across the United States. Patients with at least 180 days of prior health plan enrollment were entered into the cohorts between January 1, 1998, and June 30, 2001. Person-time was classified as monotherapy or combined statin-fibrate therapy. MAIN OUTCOME MEASURE: Incidence rates of rhabdomyolysis per 10,000 person-years of treatment, number needed to treat, and relative risk of rhabdomyolysis. RESULTS: In 252,460 patients treated with lipid-lowering agents, 24 cases of hospitalized rhabdomyolysis occurred during treatment. Average incidence per 10,000 person-years for monotherapy with atorvastatin, pravastatin, or simvastatin was 0.44 (95% confidence interval [CI], 0.20-0.84); for cerivastatin, 5.34 (95% CI, 1.46-13.68); and for fibrate, 2.82 (95% CI, 0.58-8.24). By comparison, the incidence during unexposed person-time was 0 (95% CI, 0-0.48; P = .056). The incidence increased to 5.98 (95% CI, 0.72-216.0) for combined therapy of atorvastatin, pravastatin, or simvastatin with a fibrate, and to 1035 (95% CI, 389-2117) for combined cerivastatin-fibrate use. Per year of therapy, the number needed to treat to observe 1 case of rhabdomyolysis was 22,727 for statin monotherapy, 484 for older patients with diabetes mellitus who were treated with both a statin and fibrate, and ranged from 9.7 to 12.7 for patients who were treated with cerivastatin plus fibrate. CONCLUSIONS: Rhabdomyolysis risk was similar and low for monotherapy with atorvastatin, pravastatin, and simvastatin; combined statin-fibrate use increased risk, especially in older patients with diabetes mellitus. Cerivastatin combined with fibrate conferred a risk of approximately 1 in 10 treated patients per year.

Clofibric Acid↗
PubMed2004

Community-level predictors of pneumococcal carriage and resistance in young children.

Pneumococcal carriage and resistance vary markedly among communities and are not fully explained by individual predictors. Community risk factors may explain this variation. The authors geocoded addresses from a multicommunity sample of 710 Massachusetts children previously swabbed for pneumococcal carriage in 2001. Using regression models, the authors evaluated associations between census tract measures and pneumococcal carriage or resistance. Living in census tracts with an average household size of more than 2.9 predicted carriage (odds ratio = 3.0, 95% confidence interval: 1.7, 5.5), and living in socioeconomically disadvantaged census tracts conferred an additional two- to threefold odds of carriage equal to attending child care. Living in a census tract with a median household income of less than $35,000 predicted carriage among nonattendees (odds ratio = 2.7, 95% confidence interval: 1.7, 4.3). The predictive value of a low-income census tract was interchangeable with any of several socioeconomic measures, including poverty, unemployment, low educational attainment, and low owner occupancy, in addition to high density of children and limited household plumbing facilities. Furthermore, living in census tracts with low educational attainment significantly predicted resistance (odds ratio = 4.0, 95% confidence interval: 1.3, 12.7) and was interchangeable with a high density of children (odds ratio = 3.5, 95% confidence interval: 1.0, 11.7). The two- to threefold odds of pneumococcal carriage conferred by certain community characteristics suggest that these measures may target communities for interventions to decrease transmission.

Carrier State↗