Predictive value of ICD-9-CM codes used in vaccine safety research.

OBJECTIVES: To assess how well selected ICD-9-CM diagnosis codes predict adverse events; to model bias and power loss when vaccine safety analyses rely on unverified codes. METHODS: We extracted chart verification data for ICD-9-CM diagnosis codes from six Vaccine Safety Datalink (VSD) publications and modeled biases and power losses using positive predictive value (PPV) estimates and ranges of code sensitivity. RESULTS: Positive predictive values were high for type 1 diabetes (80%) in children, relative to WHO criteria, and intussusception (81%) in young children, relative to a standard published case definition. PPVs were moderate (65%) for inpatient and emergency department childhood seizures and low (21%) for outpatient childhood seizures, both relative to physician investigator judgment. Codes for incident central nervous system demyelinating disease in adults had high PPV for inpatient codes (80%) and low PPV for outpatient codes (42%) relative to physicians' diagnoses. Modeled biases were modest, but large increases in frequencies of adverse events are required to achieve adequate power if unverified ICD-9-CM codes are used, especially when vaccine associations are weak. CONCLUSIONS: ICD-9-CM codes for type 1 diabetes in children, intussusception in young children, childhood seizures in inpatient and emergency care settings, and inpatient demyelinating disease in adults were sufficiently predictive for vaccine safety analyses to rely on unverified diagnosis codes. Adverse event misclassification should be accounted for in statistical power calculations.

Trivalent inactivated influenza vaccine safety in children: assessing the contribution of telephone encounters.

We assessed the contribution of telephone medical care encounters to surveillance of adverse events (AE) following trivalent influenza vaccination in children age 6 months to 17 years. We used retrospective, self-controlled, case-series analysis to estimate adverse event incidence rate ratios for post-vaccination risk intervals relative to 15-28 days prior to vaccination. We confirmed possible vaccination reactions by medical record abstraction. Detection of 10 of 20 elevated incidence rate ratios required telephone data. We conclude that telephone encounters substantially contribute to the detection of possible influenza vaccination reactions, primarily local injection site and systemic reactions.

Incidence of herpes zoster, 1997-2002.

We estimated age-specific herpes zoster (HZ) incidence rates in the Kaiser Permanente Northwest Health Plan (KPNW) during 1997-2002 and tested for secular trends and differences between residents of two states with different varicella vaccine coverage rates. The cumulative proportions of 2-year-olds vaccinated increased from 35% in 1997 to 85% in 2002 in Oregon, and from 25% in 1997 to 82% in 2002 in Washington. Age-specific HZ incidence rates in KPNW during 1997-2002 were compared with published rates in the Harvard Community Health Plan (HCHP) during 1990-1992. The overall HZ incidence rate in KPNW during 1997-2002 (369/100,000 person-years) was slightly higher than HCHP's 1990-1992 rate when adjusted for age differences. For children 6-14 years old, KPNW's rates (182 for females, 123 for males) were more than three times HCHP's rates (54 for females, 39 for males). This increase appears to be associated with increased exposure of children to oral corticosteroids. The percentage of KPNW children exposed to oral corticosteroids increased from 2.2% in 1991 to 3.6% in 2002. Oregon residents had slightly higher steroid exposure rates during 1997-2002 than Washington residents. There were significant increases in HZ incidence rates in Oregon and Washington during 1997-2002 among children aged 10-17 years, associated with increased exposure to oral steroids.

Drinking patterns, health care utilization, and costs among HMO primary care patients.

A survey of 8,034 primary care patients in a health maintenance organization examined the relationship between alcohol consumption and health care costs and service use. Costs were estimated from service use data for 1 year before and 2 years after study enrollment. No strong, consistent relationships were identified between multiple indicators of drinking patterns and either health care costs or service use. Compared with total costs among very light drinkers, former drinkers were higher, lifetime abstainers were similar, and persons in the higher drinking levels tended to have lower but not significantly different costs. Drinking patterns did not appear to be an important predictor of short-term health care costs or service use in this setting. Further study of former drinkers is warranted to examine the role of alcohol-related illnesses in the decision to quit drinking.

Childhood vaccinations, vaccination timing, and risk of type 1 diabetes mellitus.

OBJECTIVES: To evaluate suggested associations between childhood vaccinations, particularly against hepatitis B and Haemophilus influenzae type b, and risk of developing type 1 diabetes; and to determine whether timing of vaccination influences risk. METHODS: We conducted a case-control study within 4 health maintenance organizations (HMOs) that participate in the Vaccine Safety Datalink project of the Centers for Disease Control and Prevention. Study eligibility was restricted to children who met the following criteria: 1) born during 1988 through 1997; 2) HMO member since birth; 3) continuously enrolled for first 6 months of life; and 4) at least 12 months of HMO membership before diabetes incidence date (or index date for controls) unless incidence date was before 12 months of age. All 4 HMOs maintain registries of their members who have diabetes, and we used the registries to identify potential cases of diabetes. We conducted chart reviews to verify that potential cases met the World Health Organization epidemiologic case definition for type 1 diabetes mellitus (ie, a physician's diagnosis of diabetes plus treatment with daily insulin injections). We defined the incidence date of diabetes as the first date that the child received a diagnosis of diabetes. We attempted to match 3 controls to each case. Controls had the same eligibility criteria as cases and were matched to individual cases on HMO, sex, date of birth (within 7 days), and length of health plan enrollment (up to the incidence or index date). The index date for controls was defined as the incidence date of the case to which the control was matched. Chart abstraction was performed by trained chart abstractors using standardized forms. In addition to complete vaccination histories, the chart abstraction forms for both cases and controls included information on sociodemographic characteristics, selected medical conditions, history of breastfeeding, and family medical history. We used conditional logistic regression to estimate the odds ratio (OR) of diabetes associated with vaccination, with vaccine exposure defined as before the diabetes incidence date (or index date for controls). RESULTS: Two hundred fifty-two confirmed cases of diabetes and 768 matched controls met the study eligibility criteria. The OR (95% confidence interval) for the association with type 1 diabetes was 0.28 (0.07-1.06) for whole cell pertussis vaccine (predominantly in combination as diphtheria, tetanus toxoids and pertussis vaccine), 1.36 (0.70-2.63) for measles-mumps-rubella, 1.14 (0.51-2.57) for Haemophilus influenzae type b, 0.81 (0.52-1.27) for hepatitis B vaccine, 1.16 (0.72-1.89) for varicella vaccine, and 0.92 (0.53-1.57) for acellular pertussis-containing vaccines. Compared with children who had not received hepatitis B vaccine, the OR of diabetes was 0.51 (0.23-1.15) for children vaccinated at birth and 0.86 (0.54-1.35) for those first vaccinated against hepatitis B at 2 months of age or later. Race and ethnicity and family history of diabetes were independently associated with risk of type 1 diabetes, but adjustment for these factors did not materially alter the ORs for any of the vaccines. CONCLUSIONS: In this large, population-based, case-control study, we did not find an increased risk of type 1 diabetes associated with any of the routinely recommended childhood vaccines. Our study adds to previous research by providing data on newer vaccines, including hepatitis B, acellular pertussis, and varicella vaccines. For the older vaccines, our results are generally in agreement with previous studies in not finding any increased risks. Ours is the first epidemiologic study to evaluate the possibility that timing of vaccination is related to risk of clinical diabetes in children. Our results on hepatitis B vaccine do not support the hypothesis; risk of type 1 diabetes was not different between infants vaccinated at birth and those who received their first vaccination later in life. The results of our study and the preponderance of epidemiologic evidence do not support an association between any of the recommended childhood vaccines and an increased risk of type 1 diabetes. Suggestions that diabetes risk in humans may be altered by changes in the timing of vaccinations also are unfounded.

The risk of seizures after receipt of whole-cell pertussis or measles, mumps, and rubella vaccine.

BACKGROUND: The administration of the diphtheria and tetanus toxoids and whole-cell pertussis (DTP) vaccine and measles, mumps, and rubella (MMR) vaccine has been associated with adverse neurologic events, including seizures. We studied the relation between these vaccinations and the risk of a first seizure, subsequent seizures, and neurodevelopmental disability in children. METHODS: This cohort study was conducted at four large health maintenance organizations and included reviews of the medical records of children with seizures. We calculated the relative risks of febrile and nonfebrile seizures among 679,942 children after 340,386 vaccinations with DTP vaccine, 137,457 vaccinations with MMR vaccine, or no recent vaccination. Children who had febrile seizures after vaccination were followed to identify the risk of subsequent seizures and other neurologic disabilities. RESULTS: Receipt of DTP vaccine was associated with an increased risk of febrile seizures only on the day of vaccination (adjusted relative risk, 5.70; 95 percent confidence interval, 1.98 to 16.42). Receipt of MMR vaccine was associated with an increased risk of febrile seizures 8 to 14 days after vaccination (relative risk, 2.83; 95 percent confidence interval, 1.44 to 5.55). Neither vaccination was associated with an increased risk of nonfebrile seizures. Analyses of automated data alone gave results similar to the analyses of the data from medical-record reviews. The number of febrile seizures attributable to the administration of DTP and MMR vaccines was estimated to be 6 to 9 and 25 to 34 per 100,000 children, respectively. As compared with other children with febrile seizures that were not associated with vaccination, the children who had febrile seizures after vaccination were not found to be at higher risk for subsequent seizures or neurodevelopmental disabilities. CONCLUSIONS: There are significantly elevated risks of febrile seizures on the day of receipt of DTP vaccine and 8 to 14 days after the receipt of MMR vaccine, but these risks do not appear to be associated with any long-term, adverse consequences.

Does influenza vaccination prevent asthma exacerbations in children?

OBJECTIVE: Influenza can exacerbate asthma, particularly in children. The effectiveness of influenza vaccine in preventing influenza-related asthma exacerbations, however, is not known. We evaluated influenza vaccine effectiveness in protecting children against influenza-related asthma exacerbations. STUDY DESIGN: We conducted a population-based retrospective cohort study with medical and vaccination records in 4 large health maintenance organizations in the United States during the 1993-1994, 1994-1995, and 1995-1996 influenza seasons. We studied children with asthma who were 1 through 6 years of age and who were identified by search of computerized databases of medical encounters and pharmacy dispensings. Main outcome measures were exacerbations of asthma evaluated in the emergency department or hospital. RESULTS: Unadjusted rates of asthma exacerbations were higher after influenza vaccination than before vaccination. After adjustment was done for asthma severity by means of a self-control method, however, the incidence rate ratios of asthma exacerbations after vaccination were 0.78 (95% CI: 0.55 to 1.10), 0.59 (0.43 to 0.81), and 0.65 (0.52 to 0.80) compared with the period before vaccination during the 3 influenza seasons. CONCLUSIONS: After controlling for asthma severity, we found that influenza vaccination protects against acute asthma exacerbations in children.

Maternal smoking cessation and relapse prevention during health care visits.

BACKGROUND: Although effects of maternal smoking during pregnancy could be alleviated if women quit early in pregnancy, most do not. Relapse rates among quitters are high. OBJECTIVE: To test the effects of a low-intensity, smoking-cessation/relapse-prevention intervention delivered by clinic staff and providers and based on stages-of-change constructs of the transtheoretical model and brief motivational interviewing techniques. METHODS: A quasi-experimental prospective cohort design employed in obstetric, in-patient, and pediatric care delivery settings of a large health maintenance organization in Portland, Oregon. Subjects were pregnant smokers registered for their first prenatal visit. Primary outcome measures were sustained (self-reported) quit rates during pregnancy and smoking abstinence between 6 and 12 months after delivery. RESULTS: Regression analyses found statistically significant improvement for intervention women in sustained pregnancy quit rates (OR=2.7, CI=1. 2-5.7) and on smoking abstinence between 6 and 12 months after delivery (OR=2.4, CI=1.1-5.3). CONCLUSIONS: While these outcomes are based on self-report only, they emerged despite variable delivery of the intervention across clinics and represent clinically meaningful improvements in rates of nonsmoking. The intervention supports women who want to quit smoking during pregnancy and improves the likelihood of their remaining nonsmokers for the long term.

The incidence of Kawasaki syndrome in West Coast health maintenance organizations.

BACKGROUND: Kawasaki syndrome (KS) causes an acute vasculitis of unknown etiology. It is a leading cause of acquired heart disease of children in Japan and the United States. METHODS: We examined the incidence of KS in a well-defined population group of children < or =6 years of age, using data collected through the Vaccine Safety Datalink (VSD) project. The VSD database contains information on >1 million children enrolled in four West Coast health maintenance organizations (HMOs). RESULTS: During 1993 through 1996 a total of 234 physician-diagnosed KS patients were reported in the 4 HMOs; 152 (65.0%) were boys and 195 (83.3%) were <5 years of age. The incidence of KS among children <5 years of age in the HMOs ranged from 9.0 to 19.1 per 100,000 person years. KS incidence was higher among boys in 3 of the sites. In the 2 sites with the highest number of KS patients, a seasonal occurrence of KS in winter and early spring was observed. Overall 226 (96.6%) of the KS patients were reported to have been hospitalized; hospitalization rates for children <5 years of age ranged from 9.0 to 16.8 per 100,000 person years. CONCLUSIONS: The incidence of KS in the HMOs was similar to that reported in other population-based studies in the United States and higher than estimates for Australia and several European countries.

Does influenza vaccination exacerbate asthma? Analysis of a large cohort of children with asthma. Vaccine Safety Datalink Team.

CONTEXT: Although influenza vaccination is recommended for children with asthma, only a minority are vaccinated. One reason for low influenza vaccine coverage among children with asthma may be concern that influenza vaccination may induce an exacerbation of asthma. OBJECTIVE: To evaluate the safety of influenza vaccination in children with asthma, we studied the incidence of hospitalizations and emergency department visits for asthma following influenza vaccination. DESIGN: Retrospective cohort study-analysis of population-based computerized medical and vaccination records. SETTING: : Four large health maintenance organizations on the West Coast of the United States. SUBJECTS: Children with asthma 1 through 6 years of age, identified by search of computerized databases of medical encounters and pharmacy prescriptions. MAIN OUTCOME MEASURES: Exacerbations of asthma. RESULTS: In unadjusted analyses vaccination was associated with high rates of asthma exacerbations. However, after adjusting for asthma severity using a self-control method, the incidence rate ratios of asthma exacerbations after vaccination were 0.58 (95% confidence interval, 0.36-0.95), 0.74 (95% confidence interval, 0.47-1.17), and 0.98 (95% confidence interval, 0.76-1.27) during the 3 influenza seasons. CONCLUSIONS: After controlling for asthma severity, we found that influenza vaccination does not result in acute asthma exacerbations in children. Concern about possible exacerbation of asthma is not a valid reason to not vaccinate children with asthma against influenza.

The Vaccine Safety Datalink: immunization research in health maintenance organizations in the USA.

The Vaccine Safety Datalink is a collaborative project involving the National Immunization Program of the Centers for Disease Control and Prevention and several large health maintenance organizations in the USA. The project began in 1990 with the primary purpose of rigorously evaluating concerns about the safety of vaccines. Computerized data on vaccination, medical outcome (e.g. outpatient visits, emergency room visits, hospitalizations, and deaths) and covariates (e.g. birth certificates, census data) are prospectively collected and linked under joint protocol at multiple health maintenance organizations for analysis. Approximately 6 million persons (2% of the population of the USA) are now members of health maintenance organizations participating in the Vaccine Safety Datalink, which has proved to be a valuable resource providing important information on a number of vaccine safety issues. The databases and infrastructure created for the Vaccine Safety Datalink have also provided opportunities to address vaccination coverage, cost-effectiveness and other matters connected with immunization as well as matters outside this field.

Influenza vaccination in children with asthma in health maintenance organizations. Vaccine Safety Datalink Team.

We assessed vaccination coverage and predictors of influenza vaccination in asthmatic children in four large Health Maintenance Organizations. We studied 68,839 children with asthma at four Health Maintenance Organizations (HMOs) in the 1995-1996 influenza season and 34,032 children at two HMOs in the 1996-1997 influenza season. In both seasons only 9-10% were vaccinated against influenza. Children who were hospitalized, had an emergency department visit for asthma or a prescription for a beta-agonist prior to the influenza season, were more likely to be vaccinated. Overall, 61% of the unvaccinated asthmatic children had made an outpatient clinic visit during months when influenza vaccination would have been appropriate. Vaccination coverage could be increased by taking advantage of all opportunities to vaccinate children with asthma whenever they make clinic visits in the fall and early winter.

The validity of medicaid pharmacy claims for estimating drug use among elderly nursing home residents: The Oregon experience.

This study compared computerized Medicaid pharmacy claims data for nursing home residents with chart data to establish how well the claims data identified those receiving drugs within three different psychoactive drug classes (yes/no for each class) and how well the claims estimated total within-class average daily dose. Percent agreement, positive predictive value (PPV), and negative predictive value (NPV) for drug exposure were over 85% for each class. Kappas were excellent for antipsychotics and antidepressants, and good for anxiolytics. Correspondence was lower for average daily dose. Using an algorithm that credits some but not all doses associated with overlapping claims, correlations ranged from 0.97 to 0.66. Agreement on therapeutic dose was excellent for antipsychotics (kappa = 0.81) and fair to good for antidepressants and anxiolytics (kappa = 0.63, and kappa = 0.52, respectively). The findings suggest that Medicaid pharmacy claims data are reasonably accurate for quality assurance and accreditation purposes.

Controlled trials of CQI and academic detailing to implement a clinical practice guideline for depression.

BACKGROUND: The release of the Agency for Health Care Policy and Research (AHCPR)'s Guideline for the Detection and Treatment of Depression in Primary Care created an opportunity to evaluate under naturalistic conditions the effectiveness of two clinical practice guideline implementation methods: continuous quality improvement (CQI) and academic detailing. A study conducted in 1993-1994 at Kaiser Permanente Northwest Division, a large, not-for-profit prepaid group practice (group-model) HMO, tested the hypotheses that each method would increase the number of members receiving depression treatment and would relieve depressive symptoms. METHODS: Two trials were conducted simultaneously among adult primary care physicians, physician assistants, and nurse practitioners, using the same guideline document, measurement methods, and one-year follow-up period. The academic detailing trial was randomized at the clinician level. CQI was assigned to one of the setting's two geographic areas. To account for intraclinician correlation, both trials were evaluated using generalized equations analysis. RESULTS: Most of the CQI team's recommendations were not implemented. Academic detailing increased treatment rates, but--in a cohort of patients with probable chronic depressive disorder--it failed to improve symptoms and reduced measures of overall functional status. CONCLUSIONS: New organizational structures may be necessary before CQI teams and academic detailing can substantially change complex processes such as the primary care of depression. New research and treatment guidelines are needed to improve the management of persons with chronic or recurring major depressive disorder.

Effect of clinician communication skills training on patient satisfaction. A randomized, controlled trial.

BACKGROUND: Although substantial resources have been invested in communication skills training for clinicians, little research has been done to test the actual effect of such training on patient satisfaction. OBJECTIVE: To determine whether clinicians' exposure to a widely used communication skills training program increased patient satisfaction with ambulatory medical care visits. DESIGN: Randomized, controlled trial. SETTING: A not-for-profit group-model health maintenance organization in Portland, Oregon. PARTICIPANTS: 69 primary care physicians, surgeons, medical subspecialists, physician assistants, and nurse practitioners from the Permanente Medical Group of the Northwest. INTERVENTION: "Thriving in a Busy Practice: Physician-Patient Communication," a communication skills training program consisting of two 4-hour interactive workshops. Between workshops, participants audiotaped office visits and studied the audiotapes. MEASUREMENTS: Change in mean overall score on the Art of Medicine survey (HealthCare Research, Inc., Denver, Colorado), which measures patients' satisfaction with clinicians' communication behaviors, and global visit satisfaction. RESULTS: Although participating clinicians' self-reported ratings of their communication skills moderately improved, communication skills training did not improve patient satisfaction scores. The mean score on the Art of Medicine survey improved more in the control group (0.072 [95% CI, -0.010 to 0.154]) than in the intervention group (0.030 [CI, -0.060 to 0.1201). CONCLUSIONS: "Thriving in a Busy Practice: Physician-Patient Communication," a typical continuing medical education program geared toward developing clinicians' communication skills, is not effective in improving general patient satisfaction. To improve global visit satisfaction, communication skills training programs may need to be longer and more intensive, teach a broader range of skills, and provide ongoing performance feedback.

Immunization levels among premature and low-birth-weight infants and risk factors for delayed up-to-date immunization status. Centers for Disease Control and Prevention Vaccine Safety Datalink Group.

CONTEXT: Studies have noted that health care professionals may not conform to proper immunization schedules for premature and low-birth-weight infants in the United States. Little is known about the success of current efforts to immunize these high-risk infants. OBJECTIVE: To describe current immunization practices for premature and low-birth-weight infants and ascertain risk factors for poor immunization status, using large population-based data sources. DESIGN AND SETTING: Cohort and case-control analyses of immunization data tracked from March 1991 through March 1997 for 3 large health maintenance organizations (HMOs) participating in the Centers for Disease Control and Prevention's Vaccine Safety Datalink project. PARTICIPANTS: A total of 11580 low-birth-weight and premature infants were enrolled from birth to age 2 months; 6832 of these were continuously enrolled from birth to age 24 months. At age 2 months, there were 173373 full-term, normal-birth-weight infants enrolled as controls; at age 24 months, there were 103 324. MAIN OUTCOME MEASURES: Age-specific immunization status by prematurity and birth weight (<1500 g, 1500-2500 g, born at <38 weeks' gestation with birth weight of >2500 g, or full-term with normal birth weight) and patient characteristics associated with up-to-date status. RESULTS: At each age, infants weighing less than 1500 g at birth had lower up-to-date immunization levels than other infants. At age 6 months, 52% to 65% of infants weighing less than 1500 g were up-to-date at each of the 3 HMOs compared with 69% to 73% of those weighing 1500 to 2500 g, 66% to 80% of premature infants weighing more than 2500 g, and 65% to 76% of full-term, normal-birth-weight infants. By age 24 months, 78% to 86% of infants weighing less than 1500 g were up-to-date, significantly less than heavier infants, who had levels of 84% to 89%. Well-child preventive care strongly predicted immunization status, while concomitant pulmonary disease did not. CONCLUSIONS: Our data suggest that infants born prematurely are vaccinated at levels approaching that of the general population, but levels of vaccination for very low-birth-weight infants lag slightly behind.

Epidemiology of diarrheal disease among children enrolled in four West Coast health maintenance organizations. Vaccine Safety Datalink Team.

BACKGROUND: We used information from the Vaccine Safety Datalink (VSD) about approximately 1 million children enrolled in four health maintenance organizations to assess the morbidity from diarrhea and estimate the disease burden of rotavirus. METHODS: We examined trends of diarrhea-associated hospitalizations and emergency room (ER) visits among VSD children ages 1 month through 4 years during October, 1992, through September, 1994 (two rotavirus seasons) and estimated the morbidity from rotavirus on the basis of characteristic patterns of age and seasonality. RESULTS: Overall diarrhea was associated with 6.3% of hospitalizations and 4% of ER visits. During a child's first 5 years of life, we estimated that 1 in 57 was hospitalized and 1 in 21 required an ER visit because of diarrhea. Each year the number of diarrhea-associated hospitalizations and ER visits was greatest in winter among children ages 4 to 23 months and peaked in November in California and during February in Oregon and Washington. The winter seasonality of diarrhea-associated hospitalizations reflected the trends for diarrhea of presumed noninfectious and viral etiologies, which together accounted for most (92.9%) hospitalizations. CONCLUSIONS: Diarrhea is an important cause of morbidity among VSD children. The epidemiologic patterns of diarrhea-associated hospitalizations and ER visits resembled those reported previously for rotavirus diarrhea, suggesting that rotavirus may be a major contributor to the overall morbidity from diarrhea. Enhanced surveillance by screening for rotavirus in a sample of children with diarrhea will permit a more accurate assessment of the disease burden of this pathogen and the cost effectiveness of a rotavirus immunization program.

Trends in hypertension prevalence, treatment, and control: in a well-defined older population.

To assess medical attention focused on hypertension (HBP) in the elderly, this study examines trends in HBP prevalence, treatment, and control status in a defined population of persons > or = 65 years of age enrolled in a large HMO. Random samples of approximately 400 persons were drawn for the years 1967, 1974, 1981, and 1988. First recorded ambulatory pressures, available on over 90% of subjects in each period, were obtained from medical records. Prevalence of HBP (SBP > or = 160 and/or DBP > or = 95, and/or taking anti-HBP drugs) ranged between 44% to 53%. Proportion with HBP on treatment increased from 25% in 1967 to 60% in 1988 (P<.001); proportion on treatment and controlled (SBP < 160, DBP < 95) increased from 8% to 34% (P<.001). Mean population SBP declined from 155.2 in 1967 to 144.0 in 1988 (P<.001); mean DBP declined from 85.2 to 81.2 (P<.001). Proportion with isolated systolic hypertension (ISH) (SBP > or = 160, DBP < 90) remained unchanged at 12% to 14%. Use of diuretics and adrenergic antagonist agents declined while use of beta blockers and newer classes of anti-HBP drugs increased significantly among treated hypertensives in the 1980s. These findings parallel HBP trends in younger adults from National Health Survey data though we find evidence of a substantial gap in addressing the problem in the elderly, who constitute the population at greatest risk of cardiovascular complications of HBP.

Primary care physicians' use of lumbar spine imaging tests: effects of guidelines and practice pattern feedback.

OBJECTIVE: To reduce variability in primary care physicians' use of procedures for imaging the lumbar spine. DESIGN: Controlled intervention using clinical practice guideline and practice pattern feedback. STUDY SAMPLE: Sixty-seven internists and 28 family practitioners in a large, group-model HMO. MEASUREMENTS AND MAIN RESULTS: Intervention group physicians received the clinical practice guideline for low back pain, followed after 4 months by three bimonthly feedback reports on their current use rates for lumber spine x-rays and computed tomography and magnetic resonance imaging scans of the lumbar spine. Control group physicians received neither the guideline nor the feedback reports. Automated radiology utilization data were used to compare intervention and control group physicians' changes in use rates and variability in use rates over the course of the study period. Neither the guideline alone nor the guideline plus feedback was associated with a significant decrease in use rates or in the variability in use rates for the lumbar spine imaging procedures under study. CONCLUSIONS: Clinical practice guidelines and practice pattern feedback fail to achieve their goals when features of the practice setting and patient expectations and behavior are not identified and addressed.