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ABSTRACT: PURPOSE: This study aimed to develop Natural Language Processing (NLP) approaches to supplement manual outcome validation, specifically to validate pneumonia cases from chest radiograph reports. METHODS: We trained one NLP system, ONYX, using radiograph reports from children and adults that were previously manually reviewed. We then assessed its validity on a test set of 5000 reports. We aimed to substantially decrease manual review, not replace it entirely, and so, we classified reports as follows: (1) consistent with pneumonia; (2) inconsistent with pneumonia; or (3) requiring manual review because of complex features. We developed processes tailored either to optimize accuracy or to minimize manual review. Using logistic regression, we jointly modeled sensitivity and specificity of ONYX in relation to patient age, comorbidity, and care setting. We estimated positive and negative predictive value (PPV and NPV) assuming pneumonia prevalence in the source data. RESULTS: Tailored for accuracy, ONYX identified 25% of reports as requiring manual review (34% of true pneumonias and 18% of non-pneumonias). For the remainder, ONYX's sensitivity was 92% (95% CI 90-93%), specificity 87% (86-88%), PPV 74% (72-76%), and NPV 96% (96-97%). Tailored to minimize manual review, ONYX classified 12% as needing manual review. For the remainder, ONYX had sensitivity 75% (72-77%), specificity 95% (94-96%), PPV 86% (83-88%), and NPV 91% (90-91%). CONCLUSIONS: For pneumonia validation, ONYX can replace almost 90% of manual review while maintaining low to moderate misclassification rates. It can be tailored for different outcomes and study needs and thus warrants exploration in other settings. Copyright © 2013 John Wiley & Sons, Ltd.
Pharmacoepidemiology and Drug Safety 04/2013; · 2.53 Impact Factor
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ABSTRACT: OBJECTIVE: The test-negative design has emerged in recent years as the preferred method for estimating influenza vaccine effectiveness (VE) in observational studies. However, the methodologic basis of this design has not been formally developed. METHODS: In this paper we develop the rationale and underlying assumptions of the test-negative study. Under the test-negative design for influenza VE, study subjects are all persons who seek care for an acute respiratory illness (ARI). All subjects are tested for influenza infection. Influenza VE is estimated from the ratio of the odds of vaccination among subjects testing positive for influenza to the odds of vaccination among subjects testing negative. RESULTS: With the assumptions that (a) the distribution of non-influenza causes of ARI does not vary by influenza vaccination status, and (b) VE does not vary by health care-seeking behavior, the VE estimate from the sample can generalized to the full source population that gave rise to the study sample. Based on our derivation of this design, we show that test-negative studies of influenza VE can produce biased VE estimates if they include persons seeking care for ARI when influenza is not circulating or do not adjust for calendar time. CONCLUSIONS: The test-negative design is less susceptible to bias due to misclassification of infection and to confounding by health care-seeking behavior, relative to traditional case-control or cohort studies. The cost of the test-negative design is the additional, difficult-to-test assumptions that incidence of non-influenza respiratory infections is similar between vaccinated and unvaccinated groups within any stratum of care-seeking behavior, and that influenza VE does not vary across care-seeking strata.
Vaccine 03/2013; · 3.77 Impact Factor
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Jason M Glanz,
Sophia R Newcomer,
Komal J Narwaney,
Simon J Hambidge,
Matthew F Daley,
Nicole M Wagner,
David L McClure,
Stan Xu,
Ali Rowhani-Rahbar,
Grace M Lee, Jennifer C Nelson,
James G Donahue,
Allison L Naleway,
James D Nordin,
Marlene M Lugg,
Eric S Weintraub
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ABSTRACT: OBJECTIVES To examine patterns and trends of undervaccination in children aged 2 to 24 months and to compare health care utilization rates between undervaccinated and age-appropriately vaccinated children. DESIGN Retrospective matched cohort study. SETTING Eight managed care organizations of the Vaccine Safety Datalink. PARTICIPANTS Children born between 2004 and 2008. MAIN EXPOSURE Immunization records were used to calculate the average number of days undervaccinated. Two matched cohorts were created: 1 with children who were undervaccinated for any reason and 1 with children who were undervaccinated because of parental choice. For both cohorts, undervaccinated children were matched to age-appropriately vaccinated children by birth date, managed care organization, and sex. MAIN OUTCOME MEASURES Rates of undervaccination, specific patterns of undervaccination, and health care utilization rates. RESULTS Of 323 247 children born between 2004 and 2008, 48.7% were undervaccinated for at least 1 day before age 24 months. The prevalence of undervaccination and specific patterns of undervaccination increased over time (P < .001). In a matched cohort analysis, undervaccinated children had lower outpatient visit rates compared with children who were age-appropriately vaccinated (incidence rate ratio [IRR], 0.89; 95% CI, 0.89- 0.90). In contrast, undervaccinated children had increased inpatient admission rates compared with age-appropriately vaccinated children (IRR, 1.21; 95% CI, 1.18-1.23). In a second matched cohort analysis, children who were undervaccinated because of parental choice had lower rates of outpatient visits (IRR, 0.94; 95% CI, 0.93-0.95) and emergency department encounters (IRR, 0.91; 95% CI, 0.88-0.94) than age-appropriately vaccinated children. CONCLUSIONS Undervaccination appears to be an increasing trend. Undervaccinated children appear to have different health care utilization patterns compared with age-appropriately vaccinated children.
JAMA pediatrics. 01/2013;
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Lisa A Jackson,
Do Peterson, Jennifer C Nelson,
S Michael Marcy,
Allison L Naleway,
James D Nordin,
James G Donahue,
Simon J Hambidge,
Carolyn Balsbaugh,
Roger Baxter,
Tracey Marsh,
Lawrence Madziwa,
Eric Weintraub
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ABSTRACT: OBJECTIVE:Our objective was to assess whether the occurrence of medically attended local reactions to intramuscularly administered vaccines varies by injection site (arm versus thigh) in children 1 to 6 years of age.METHODS:This is a retrospective cohort study of children in the Vaccine Safety Datalink population from 2002 to 2009. Site of injection and the outcome of medically attended local reactions were identified from administrative data.RESULTS:The study cohort of 1.4 million children received 6.0 million intramuscular (IM) vaccines during the study period. The primary analyses evaluated the IM vaccines most commonly administered alone, which included inactivated influenza, hepatitis A, and diphtheria-tetanus-acellular pertussis (DTaP) vaccines. For inactivated influenza and hepatitis A vaccines, local reactions were relatively uncommon, and there was no difference in risk of these events with arm versus thigh injections. The rate of local reactions after DTaP vaccines was higher, and vaccination in the arm was associated with a significantly greater risk of this outcome compared with vaccination in the thigh, both for children 12 to 35 months (relative risk: 1.88 [95% confidence interval: 1.34-2.65]) and 3 to 6 years of age (relative risk: 1.41 [95% confidence interval: 0.84-2.34]), although this difference was not statistically significant in the older age group.CONCLUSIONS:Injection in the thigh is associated with a significantly lower risk of a medically attended local reaction to a DTaP vaccination among children 12 to 35 months of age, supporting current recommendations to administer IM vaccinations in the thigh for children younger than 3 years of age.
PEDIATRICS 01/2013; · 4.47 Impact Factor
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Jennifer C Nelson,
Onchee Yu,
Clara P Dominguez-Islas,
Andrea J Cook,
Do Peterson,
Sharon K Greene,
W Katherine Yih,
Matthew F Daley,
Steven J Jacobsen,
Nicola P Klein,
Eric S Weintraub,
Karen R Broder,
Lisa A Jackson
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ABSTRACT: To address gaps in traditional postlicensure vaccine safety surveillance and to promote rapid signal identification, new prospective monitoring systems using large health-care database cohorts have been developed. We newly adapted clinical trial group sequential methods to this observational setting in an original safety study of a combination diphtheria and tetanus toxoids and acellular pertussis adsorbed (DTaP), inactivated poliovirus (IPV), and Haemophilus influenzae type b (Hib) conjugate vaccine (DTaP-IPV-Hib) among children within the Vaccine Safety Datalink population. For each prespecified outcome, we conducted 11 sequential Poisson-based likelihood ratio tests during September 2008-January 2011 to compare DTaP-IPV-Hib vaccinees with historical recipients of other DTaP-containing vaccines. No increased risk was detected among 149,337 DTaP-IPV-Hib vaccinees versus historical comparators for any outcome, including medically attended fever, seizure, meningitis/encephalitis/myelitis, nonanaphylactic serious allergic reaction, anaphylaxis, Guillain-Barré syndrome, or invasive Hib disease. In end-of-study prespecified subgroup analyses, risk of medically attended fever was elevated among 1- to 2-year-olds who received DTaP-IPV-Hib vaccine versus historical comparators (relative risk = 1.83, 95% confidence interval: 1.34, 2.50) but not among infants under 1 year old (relative risk = 0.83, 95% confidence interval: 0.73, 0.94). Findings were similar in analyses with concurrent comparators who received other DTaP-containing vaccines during the study period. Although lack of a controlled experiment presents numerous challenges, implementation of group sequential monitoring methods in observational safety surveillance studies is promising and warrants further investigation.
American journal of epidemiology 01/2013; · 5.59 Impact Factor
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ABSTRACT: PURPOSE: To test whether angiotensin-converting enzyme (ACE) inhibitor use is associated with decreased risk of community-acquired pneumonia in older adults. METHODS: We analyzed data from a nested case-control study of community-dwelling, immunocompetent adults aged 65-94 within an integrated healthcare delivery system. Cases of ambulatory and hospitalized pneumonia from 2000 to 2003 were identified from International Classification of Disease, version 9, codes and validated using medical record review. Controls were matched to cases by age, sex, and calendar year. Using health plan pharmacy data, we defined current use as filling ≥2 prescriptions during the 180 days prior to the case's diagnosis date. We calculated standardized doses per day using World Health Organization defined daily doses. Multivariable conditional logistic regression estimated adjusted odds ratios (ORs) for pneumonia in relation to ACE inhibitor use, adjusting for comorbidity, functional and cognitive status, and other covariates from medical record review and pharmacy data. RESULTS: Current use of ACE inhibitors was seen in 23% (242/1039) of cases and 21% (433/2022) of controls. Lisinopril accounted for 95% of prescriptions. The OR for pneumonia comparing current use to no current use was 0.99 (95% confidence interval [CI] 0.83-1.19). The OR for use of more than two standardized daily doses per day was 1.39 (95% CI 0.93-2.06) compared to no current use. CONCLUSIONS: ACE inhibitor use is not associated with reduced pneumonia risk in community-dwelling older adults. Copyright © 2012 John Wiley & Sons, Ltd.
Pharmacoepidemiology and Drug Safety 09/2012; · 2.53 Impact Factor
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The Journal of Infectious Diseases 05/2012; 206(2):303-4; author reply 304-5. · 6.41 Impact Factor
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ABSTRACT: We introduce a new sequential monitoring approach to facilitate the use of observational electronic healthcare utilization
databases in comparative drug safety surveillance studies comparing the safety between two approved medical products. The
new approach enhances the confounder adjustment capabilities of the conditional sequential sampling procedure (CSSP), an existing
group sequential method for sequentially monitoring excess risks of adverse events following the introduction of a new medical
product. It applies to a prospective cohort setting where information for both treatment and comparison groups accumulates
concurrently over time. CSSP adjusts for covariates through stratification and thus it may have limited capacity to control
for confounding as it can only accommodate a few categorical covariates. To address this issue, we propose the propensity
score (PS)-stratified CSSP, in which we construct strata based on selected percentiles of the estimated PSs. The PS is defined
as the conditional probability of being treated given measured baseline covariates and is commonly used in epidemiological
studies to adjust for confounding bias. The PS-stratified CSSP approach integrates this more flexible confounding adjustment,
PS-stratification, with the sequential analytic approach, CSSP, thus inheriting CSSP’s attractive features: (i)it accommodates
varying amounts of person follow-up time, (ii)it uses exact conditional inference, which can be important when studying rare
safety outcomes, and (iii)it allows for a large number of interim tests. Further, it overcomes CSSP’s difficulty with adjusting
for multiple categorical and continuous confounders.
KeywordsCSSP–Propensity score–Drug safety surveillance–Comparative effectiveness–Electronic healthcare databases–Group sequential analysis
Statistics in Biosciences 04/2012; 3(1):45-62.
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ABSTRACT: Many challenges arise when conducting a sequentially monitored medical product safety surveillance evaluation using observational electronic data captured during routine care. We review existing sequential approaches for potential use in this setting, including a continuous sequential testing method that has been utilized within the Vaccine Safety Datalink (VSD) and group sequential methods, which are used widely in randomized clinical trials.
Using both simulated data and preliminary data from an ongoing VSD evaluation, we discuss key sequential design considerations, including sample size and duration of surveillance, shape of the signaling threshold, and frequency of interim testing.
All designs control the overall Type 1 error rate across all tests performed, but each yields different tradeoffs between the probability and timing of true and false positive signals. Designs tailored to monitor efficacy outcomes in clinical trials have been well studied, but less consideration has been given to optimizing design choices for observational safety settings, where the hypotheses, population, prevalence and severity of the outcomes, implications of signaling, and costs of false positive and negative findings are very different. Analytic challenges include confounding, missing and partially accrued data, high misclassification rates for outcomes presumptively defined using diagnostic codes, and unpredictable changes in dynamically accessed data over time (e.g., differential product uptake). Many of these factors influence the variability of the adverse events under evaluation and, in turn, the probability of committing a Type 1 error. Thus, to ensure proper Type 1 error control, planned sequential thresholds should be adjusted over time to account for these issues.
Pharmacoepidemiology and Drug Safety 01/2012; 21 Suppl 1:62-71. · 2.53 Impact Factor
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ABSTRACT: This manuscript describes the current statistical methodology available for active postmarket surveillance of pre-specified safety outcomes using a prospective incident user concurrent control cohort design with existing electronic healthcare data.
Motivation of the active postmarket surveillance setting is provided using the Food and Drug Administration's Mini-Sentinel Pilot as an example. Four sequential monitoring statistical methods are presented including the Lan-Demets error spending approach, a matched likelihood ratio test statistic approach with the binomial MaxSPRT as a special case, the conditional sequential sampling procedure with stratification, and a generalized estimating equation regression approach using permutation. Information on the assumptions, limitations, and advantages of each approach is provided, including how each method defines sequential monitoring boundaries, what test statistic is used, and how robust it is to settings of rare events or frequent testing.
A hypothetical example of how the approaches could be applied to data comparing a medical product of interest, drug A, to a concurrent control drug, drug B, is presented including providing the type of information one would have available for monitoring such drugs.
Pharmacoepidemiology and Drug Safety 01/2012; 21 Suppl 1:72-81. · 2.53 Impact Factor
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ABSTRACT: Post-licensure medical product safety surveillance is important for detecting adverse events potentially not identified pre-licensure. Historically, post-licensure safety monitoring has been accomplished using passive reporting systems and by conducting formal Phase IV randomized trials or large epidemiological studies, also known as safety surveillance or pharmacovigilance studies. However, crucial gaps in the safety evidence base provided by these approaches have led to high profile product withdrawals and growing public concern about unknown health risks associated with licensed products. To address the limitations of existing surveillance systems and to facilitate more accurate and rapid detection of safety problems, new systems involving active surveillance of large, population-based cohorts using observational health care utilization databases are being developed. In this article, we review common statistical methods that have been employed previously for post-licensure safety monitoring, including data mining and sequential hypothesis testing, and assess which methods may be promising for potential use within this newly proposed prospective observational cohort monitoring framework. We discuss gaps in existing approaches and identify areas where methodological development is needed to improve the success of safety surveillance efforts in this setting.
Statistical Methods in Medical Research 12/2011; · 2.44 Impact Factor
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ABSTRACT: To examine whether use of opioids or benzodiazepines is associated with risk of community-acquired pneumonia in older adults.
Population-based case-control study.
An integrated healthcare delivery system.
Community-dwelling, immunocompetent adults aged 65 to 94 from 2000 to 2003. Presumptive pneumonia cases were identified from health plan automated data and validated through medical record review. Two controls were selected for each case with pneumonia, matched on age, sex, and calendar year.
Information about opioid and benzodiazepine use came from computerized pharmacy data. Information on covariates including comorbid illnesses and functional and cognitive status came from medical record review and electronic health data.
One thousand thirty-nine validated cases of pneumonia and 2,022 matched controls were identified. One hundred forty-four (13.9%) cases and 161 (8.0%) controls used prescription opioids (adjusted odds ratio (OR) = 1.38, 95% confidence interval (CI) = 1.08-1.76 vs nonuse). Risk was highest for opioids categorized as immunosuppressive based on immunological studies (OR = 1.88, 95% CI = 1.26-1.79 vs nonuse), whereas for nonimmunosuppressive opioids the OR was 1.23 (95% CI = 0.89-1.69). Risk was highest in the first 14 days of use (OR = 3.24, 95% CI = 1.64-6.39 vs nonuse). For long-acting opioids, the OR was 3.43 (95% CI = 1.44-8.21) versus nonuse, whereas for short-acting opioids, it was 1.27 (95% CI = 0.98-1.64). No greater risk was seen for current benzodiazepine use compared to nonuse (OR = 1.08, 95% CI = 0.80-1.47).
Use of opioids but not benzodiazepines was associated with pneumonia risk. The differences in risk seen for different opioid regimens warrant further study.
Journal of the American Geriatrics Society 10/2011; 59(10):1899-907. · 3.74 Impact Factor
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ABSTRACT: The common practice of using administrative diagnosis codes as the sole source of data on potential confounders in pharmacoepidemiologic studies has been shown to leave substantial residual confounding. We explored reasons why adjustment for comorbid illness defined from International Classification of Diseases (ICD) codes fails to remove confounding.
We used data from a case-control study among immunocompetent seniors enrolled in Group Health to estimate bias in the estimated association between receipt of influenza vaccine and the risk of community-acquired pneumonia during non-influenza control periods and to estimate the effects of adjusting for comorbid illnesses defined from either ICD codes or the medical record. We also estimated the accuracy of ICD codes for identifying comorbid illnesses compared with the gold standard of medical record review.
Sensitivity of ICD codes for illnesses recorded in the medical record ranged from 59 to 97% (median, 76%). Strong confounding was present in the vaccine/pneumonia association, as evidenced by the non-null odds ratio of 0.60 (95% confidence interval, 0.38-0.95) during this control period. Adjusting for the presence/absence of comorbid illnesses defined from either medical record review (odds ratio, 0.73) or from ICD codes (odds ratio, 0.68) left considerable residual confounding.
ICD codes may fail to control for confounding because they often lack sensitivity for detecting comorbid illnesses and because measures of the presence/absence of comorbid illnesses may be insufficient to remove confounding. These findings call for caution in the use of ICD codes to control for confounding.
Pharmacoepidemiology and Drug Safety 06/2011; 20(8):858-65. · 2.53 Impact Factor
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ABSTRACT: In vaccine safety studies, subjects are considered at increased risk for adverse events for a period of time after vaccination known as risk window. To our knowledge, risk windows for vaccine safety studies have tended to be pre-defined and not to use information from the current study. Inaccurate specification of the risk window can result in either including the true control period in the risk window or including some of the risk window in the control period, which can introduce bias. We propose a data-based approach for identifying the optimal risk windows for self-controlled case series studies of vaccine safety. The approach involves fitting conditional Poisson regression models to obtain incidence rate ratio estimates for different risk window lengths. For a specified risk window length (L), the average time at risk, T(L), is calculated. When the specified risk window is shorter than the true, the incidence rate ratio decreases with 1/T(L) increasing but there is no explicit relationship. When the specified risk window is longer than the true, the incidence rate ratio increases linearly with 1/T(L) increasing. Theoretically, the risk window with the maximum incidence ratio is the optimal risk window. Because of sparse data problem, we recommend using both the maximum incidence rate ratio and the linear relationship when the specified risk window is longer than the true to identify the optimal risk windows. Both simulation studies and vaccine safety data applications show that our proposed approach is effective in identifying medium and long-risk windows.
Statistics in Medicine 03/2011; 30(7):742-52. · 1.88 Impact Factor
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Lisa A Jackson,
Onchee Yu, Jennifer C Nelson,
Clara Dominguez,
Do Peterson,
Roger Baxter,
Simon J Hambidge,
Allison L Naleway,
Edward A Belongia,
James D Nordin,
James Baggs
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ABSTRACT: To assess whether the risk of medically attended local reactions to the fifth dose of the diphtheria and tetanus toxoids and acellular pertussis (DTaP) vaccine varies according to injection site (arm versus thigh).
We conducted a retrospective cohort study of children aged 4 through 6 years in the Vaccine Safety Datalink population who received a DTaP vaccination during the period from 2002 through 2006. Medically attended local reactions to the DTaP vaccine were presumptively identified from administrative data and were confirmed by medical record review.
Among the 233,616 children in the study population, 1017 (0.4%) had a confirmed medically attended local reaction to the fifth dose of the DTaP vaccine. The rate of those reactions was significantly higher with vaccinations given in the arm (47.4 per 10,000 vaccinations) compared with vaccinations given in the thigh (32.1 per 10,000 vaccinations) (P < .001). In a multivariable analysis adjusted for age, gender, and study site, children vaccinated in the arm had a 78% higher risk of a local reaction (relative risk: 1.78 [95% confidence interval: 1.43-2.21]).
Local reactions to the fifth dose of the DTaP vaccine that require medical evaluation are uncommon, but the risk of those reactions is significantly higher when the vaccine is injected in the arm. These findings suggest that the thigh should be considered as an acceptable site of injection for this vaccination.
PEDIATRICS 02/2011; 127(3):e581-7. · 4.47 Impact Factor
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Lisa A Jackson,
Do Peterson,
John Dunn,
Simon J Hambidge,
Maya Dunstan,
Patty Starkovich,
Onchee Yu,
Joyce Benoit,
Clara P Dominguez-Islas,
Barbara Carste,
Patti Benson, Jennifer C Nelson
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ABSTRACT: Fever is common following infant vaccinations. Two randomized controlled trials demonstrated the efficacy of acetaminophen prophylaxis in preventing fever after whole cell pertussis vaccination, but acetaminophen prophylaxis has not been evaluated for prevention of fever following contemporary vaccines recommended for infants in the United States.
Children six weeks through nine months of age were randomized 1:1 to receive up to five doses of acetaminophen (10-15 mg per kg) or placebo following routine vaccinations. The primary outcome was a rectal temperature ≥38°C within 32 hours following the vaccinations. Secondary outcomes included medical utilization, infant fussiness, and parents' time lost from work. Parents could request unblinding of the treatment assignment if the child developed fever or symptoms that would warrant supplementary acetaminophen treatment for children who had been receiving placebo.
A temperature ≥38°C was recorded for 14% (25/176) of children randomized to acetaminophen compared with 22% (37/176) of those randomized to placebo but that difference was not statistically significant (relative risk [RR], 0.63; 95% CI, 0.40-1.01). Children randomized to acetaminophen were less likely to be reported as being much more fussy than usual (10% vs 24%) (RR, 0.42; 95% CI, 0.25-0.70) or to have the treatment assignment unblinded (3% vs 9%) (RR, 0.31; 95% CI, 0.11-0.83) than those randomized to placebo. In age-stratified analyses, among children ≥24 weeks of age, there was a significantly lower risk of temperature ≥38°C in the acetaminophen group (13% vs. 25%; p = 0.03).
The results of this relatively small trial suggest that acetaminophen may reduce the risk of post-vaccination fever and fussiness.
Clinicaltrials.gov NCT00325819.
PLoS ONE 01/2011; 6(6):e20102. · 4.09 Impact Factor
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ABSTRACT: To examine whether use of proton pump inhibitors (PPIs) and H2 blockers is associated with increased pneumonia risk.
We conducted a population-based, nested case-control study within Group Health, an integrated healthcare delivery system. Among community-dwelling, immunocompetent adults aged 65-94, we identified presumptive cases of ambulatory and hospitalized community-acquired pneumonia in 2000-2003 from ICD-9 codes and validated them by medical record review (N = 1125). Controls were selected, matched to cases on age, sex, and calendar year (N = 2235). Current PPI or H2 blocker use was ascertained from computerized pharmacy records. Comorbid illnesses and other characteristics were ascertained by medical record review. Multivariable conditional logistic regression was used to examine the association between medication use and pneumonia risk. We conducted sensitivity analyses using only administrative and pharmacy data to assess how these results differed from our primary results.
The prevalence of PPI or H2 blocker use was 21% (241/1125) for pneumonia cases and 16% (350/2235) for controls (adjusted odds ratio [OR] 1.03, 95% CI 0.86-1.24, compared to nonuse). No increased risk was seen for recent initiation. The prevalence of PPI use was 12% (132/1125) for cases and 7% (160/2235) for controls (adjusted OR 1.13, 95% CI 0.88-1.44). Analyses using only administrative and pharmacy data yielded risk estimates farther from the null (adjusted OR 1.32, 95% CI 1.17-1.49, for current PPI use versus nonuse).
Use of PPIs and H2 blockers is not associated with increased pneumonia risk in older adults. The increased risk observed in some prior studies may reflect confounding.
Pharmacoepidemiology and Drug Safety 08/2010; 19(8):792-802. · 2.53 Impact Factor
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Jennifer C Nelson,
Rachel C L Bittner,
Lora Bounds,
Shanshan Zhao,
James Baggs,
James G Donahue,
Simon J Hambidge,
Steven J Jacobsen,
Nicola P Klein,
Allison L Naleway,
Kenneth M Zangwill,
Lisa A Jackson
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ABSTRACT: We studied compliance with multiple-dose vaccine schedules, assessed factors associated with noncompliance, and examined timeliness of series completion among older children, adolescents, and adults.
We conducted a large, multisite, retrospective cohort study of older children, adolescents, and adults in the Vaccine Safety Datalink population from 1996 through 2004. We quantified the rates of completion of all required doses for varicella, hepatitis A, and hepatitis B vaccines according to their recommended schedules.
Among those who received a first dose of varicella (n = 16 075), hepatitis A (n = 594 917), and hepatitis B (n = 590 445) vaccine, relatively few completed the series (55%-65% for hepatitis B vaccine and 40%-50% for hepatitis A and varicella vaccines in most age groups). Compliance was lowest among adolescents (35.9%) and Medicaid recipients (29.7%) who received varicella vaccine and among younger adult age groups who received hepatitis A vaccine (25%-35% across those age groups). Even among series completers, there was a relatively long interval of undervaccination between the first and last doses.
Compliance with multiple-dose vaccine series among older children, adolescents, and adults is suboptimal. Further evaluations of strategies to improve compliance in these populations are needed.
American Journal of Public Health 10/2009; 99 Suppl 2:S389-97. · 3.93 Impact Factor
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ABSTRACT: To identify risk factors for developing community-acquired pneumonia (CAP) in seniors.
Nested case-control study.
Group Health, a health maintenance organization in Washington state.
One thousand one hundred seventy-three immunocompetent seniors with CAP and 2,346 age- and sex-matched controls, sampled during influenza seasons and pre-influenza periods of 2000/01 and 2002/03. CAP cases were presumptively identified according to diagnosis codes assigned to outpatient and inpatient encounters and validated according to review of chest radiograph reports or medical records.
Medical records were used to assess body mass, the presence and severity of cardiopulmonary and other chronic diseases, and the presence of functional or cognitive impairments. Use of prescription medications and inpatient, outpatient, and home medical services were identified from administrative databases.
Independent predictors of CAP include the presence and severity of cardiopulmonary disease, low weight and recent weight loss, and poor functional status; 42.0% of pneumonia cases can be attributed to underlying cardiopulmonary disease.
Seniors with cardiopulmonary disease, poor functional status, low weight, or recent weight loss have a greater risk of developing CAP. Preventative efforts should be targeted toward these individuals.
Journal of the American Geriatrics Society 05/2009; 57(5):882-8. · 3.74 Impact Factor
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ABSTRACT: To test the hypothesis that hydroxymethyl glutaryl coenzyme A reductase inhibitors (statins) may decrease the risk of community acquired pneumonia.
Population based case-control study.
Group Health, a large integrated healthcare delivery system. Population Immunocompetent, community dwelling Group Health members aged 65 to 94; two matched controls for each case with pneumonia. Information on comorbid illnesses and functional and cognitive status, potential confounders of the association between statin use and risk of pneumonia, came from medical record review and computerised pharmacy data.
Adjusted estimates of risk of pneumonia in relation to current statin use.
1125 validated cases of pneumonia and 2235 matched controls were identified. Compared with controls, cases were more likely to have chronic lung and heart disease, especially severe disease, and functional or cognitive impairment. Current statin use was present in 16.1% (181/1125) of cases and 14.6% (327/2235) of controls (adjusted odds ratio 1.26, 95% confidence interval 1.01 to 1.56). Among cases admitted to hospital and matched controls, current statin use was present in 17.2% (68/395) of cases and 14.2% (112/788) of controls (adjusted odds ratio 1.61, 1.08 to 2.39, compared with non-use). In people in whom statins were indicated for secondary prevention, the adjusted odds ratio for risk of pneumonia in relation to current statin use was 1.25 (0.94 to 1.67); in those with no such indication, it was 0.81 (0.46 to 1.42).
Statin use was not associated with decreased risk of pneumonia among immunocompetent, community dwelling older people. Findings of previous studies may reflect "healthy user" bias.
BMJ (Clinical research ed.). 02/2009; 338:b2137.
