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Featured researches published by G A van Essen.


Journal of Epidemiology and Community Health | 1998

Is immunising all patients with chronic lung disease in the community against influenza cost effective? Evidence from a general practice based clinical prospective cohort study in Utrecht, the Netherlands

Eelko Hak; G A van Essen; Erik Buskens; W.A.B. Stalman; R A de Melker

STUDY OBJECTIVE: There is little information on the potential benefit of immunising all patients with chronic lung disease in the community against influenza. The clinical effectiveness and economic benefit was established of the influenza vaccination programme in a general practice based cohort of adult patients with chronic lung disease followed up during the 1995/96 influenza A epidemic. DESIGN: A prospective cohort study from October 1995 to March 1996. SETTING: The study was undertaken in the Utrecht General Practices Network with six large group practices, covering a total population of approximately 50,000 patients in the Netherlands. PATIENTS: Computerised medical records of 1696 patients with chronic lung disease aged over 18 years with an indication for vaccination according to the Dutch GP guidelines were reviewed. MAIN RESULTS: The overall attack rate of any complication, including all cause death, low respiratory tract infection, and acute cardiac disease was 15%. Exacerbations of lung disease were most frequent (13%). Death, pneumonia, and acute cardiac disease were mainly limited to patients > or = 65 years. No effectiveness of the immunisation programme could be established in patients 18-64 years (n = 1066), after controlling for baseline prognosis in multivariable logistic regression analysis. In vaccinees > or = 65 years (n = 630), the occurrence of any complication was reduced by 50% (95% CI 17, 70%). The economic benefit was estimated at 50 Pounds per elderly vaccinee. CONCLUSIONS: This study suggests that in the Netherlands immunisation of elderly patients with chronic lung disease against influenza is effective and cost-saving, hence these patients should be given high priority. More, preferably experimental, studies are needed to establish whether adult lung patients under 65 years in the community will also benefit from vaccination.


Vaccine | 2009

Which determinants should be targeted to increase influenza vaccination uptake among health care workers in nursing homes

I Looijmans-van den Akker; J.J.M. van Delden; Th J M Verheij; G A van Essen; M.A.B. van der Sande; M.E.J.L. Hulscher; Eelko Hak

Although health care workers (HCWs) have been recommended to be immunized against influenza, vaccine uptake remains low. So far, research on determinants of influenza vaccination among HCWs has been limited by design, population or theoretical framework. Therefore we conducted a questionnaire study in Dutch nursing homes to assess which demographical, behavioural and organisational determinants were associated with influenza vaccine uptake among HCWs. We were able to accurately predict vaccine uptake based on a 13-item prediction model including two demographical, nine behavioural and two organisational determinants developed with data from 1,125 respondents (response rate 60%). To further increase influenza vaccine uptake, implementation programs should target these determinants.


Epidemiology and Infection | 2002

Clinical effectiveness of conventional influenza vaccination in asthmatic children.

A J Smits; Eelko Hak; W A B Stalman; G A van Essen; Arno W. Hoes; Th J M Verheij

Influenza immunization rates among young asthmatics remain unsatisfactory due to persistent concern about the impact of influenza and the benefits of the vaccine. We assessed the effectiveness of the conventional inactivated trivalent sub-unit influenza vaccine in reducing acute respiratory disease in asthmatic children. We conducted a two-season retrospective cohort study covering the 1995-6 and 1996-7 influenza outbreaks in 22 computerized primary care practices in The Netherlands. In total, 349 patients aged between 0 and 12 years meeting clinical asthma-criteria were included; 14 children were lost to follow-up in the second season. The occurrence of physician-diagnosed acute respiratory disease episodes including influenza-like illness, pneumonia. bronchitis, bronchiolitis, asthma exacerbation and acute otitis media in vaccinated and unvaccinated children were compared after adjustments for age, prior health care and medication use. The occurrence of acute respiratory disease in unvaccinated children was 28% and 24% in the 1995-6 and 1996-7 season, respectively, and was highest in children under 6 years of age (43%). The overall pooled clinical vaccine effectiveness was 27% (95% confidence interval -7 to 51%, P = 0.11) after adjustments. A statistically higher vaccine protectiveness of 55% (95% CI 20-75%, P = 0.01) was observed among asthmatics under 6 years of age compared with -5% in older children (95% CI -81 to 39%). The occurrence of acute respiratory disease among asthmatic children during influenza epidemics is very high, notably in the youngest. Influenza vaccination may reduce morbidity in asthmatic infants and pre-school children. However, larger, preferably experimental, studies are needed to establish the benefits of vaccination, notably in older asthmatic children.


Vaccine | 2010

Effects of a multi-faceted program to increase influenza vaccine uptake among health care workers in nursing homes: A cluster randomised controlled trial

I Looijmans-van den Akker; J.J.M. van Delden; Theo Verheij; M.A.B. van der Sande; G A van Essen; J. Riphagen-Dalhuisen; M.E.J.L. Hulscher; Eelko Hak

Despite the recommendation of the Dutch association of nursing home physicians (NVVA) to be immunized against influenza, vaccine uptake among HCWs in nursing homes remains unacceptably low. Therefore we conducted a cluster randomised controlled trial among 33 Dutch nursing homes to assess the effects of a systematically developed multi-faceted intervention program on influenza vaccine uptake among HCWs. The intervention program resulted in a significantly higher, though moderate, influenza vaccine uptake among HCWs in nursing homes. To take full advantage of this measure, either the program should be adjusted and implemented over a longer time period or mandatory influenza vaccination should be considered.


American Journal of Epidemiology | 2003

Conventional Influenza Vaccination Is Not Associated with Complications in Working-Age Patients with Asthma or Chronic Obstructive Pulmonary Disease

Eelko Hak; Arno W. Hoes; D. E. Grobbee; Jan Willem J. Lammers; G A van Essen; A. M. van Loon; Theo Verheij

Abstract By using a nested case-control design, the authors studied the effectiveness of the influenza vaccine in reducing severe and fatal complications in 4,241 and 5,966 primary care, working-age patients aged 18–64 years who had asthma or chronic obstructive pulmonary disease during the 1998–1999 and 1999–2000 influenza epidemics in the Netherlands. Patients developing fatal or nonfatal exacerbations of lung disease, pneumonia, congestive heart failure, or myocardial infarction during either epidemic were considered cases. For each case, four age- and sex-matched controls were randomly sampled, and patient records were reviewed. Conditional logistic regression and propensity scores were used to assess vaccine effectiveness after adjustment for confounding factors. In seasons one and two, respectively, 87% (47/54) and 85% (171/202) of the cases and 74% (155/210) and 75% (575/766) of the controls had been vaccinated. After adjustments, vaccination was not associated with reductions in complications (season one: odds ratio = 0.95, 95% confidence interval (CI): 0.26, 3.48; season two: odds ratio = 1.07, 95% CI: 0.59, 1.96; pooled odds ratio = 1.07, 95% CI: 0.63, 1.80). Because influenza vaccination appeared not to be associated with a clinically relevant reduction in severe morbidity, other measures need to be explored.


Epidemiology and Infection | 2001

Prognostic factors for influenza-associated hospitalization and death during an epidemic

Eelko Hak; Theo Verheij; G A van Essen; A B Lafeber; Diederick E. Grobbee; Arno W. Hoes

To predict which patients with current high-risk disease in the community may benefit most from additional preventive or therapeutic measures for influenza, we determined prognostic factors for influenza-associated hospitalization and death in a general practice-based case-control study among this segment of the vaccine target population with high influenza vaccination rates. In 103 general practices followed during the 1996/7 influenza epidemic, cases were either hospitalized, or died due to influenza, bronchitis, pneumonia, diabetes, heart failure or myocardial infarction. Age- and gender-matched controls were randomly sampled from the remaining cohort. Information was collected by review of patient records. In total, 119 cases and 196 matched controls were included. Of the cases, 34, 25 and 4% were hospitalized for acute pulmonary and cardiac disease and diabetes, respectively, and 37% died. Multivariate conditional logistic regression analysis revealed that presence of chronic obstructive pulmonary disease, heart failure, previous hospitalization, high GP visiting rate and polypharmacy were independent prognostic factors. Several non-modifiable determinants can be used to ensure targeting additional preventive or therapeutic measures at the most vulnerable segment of the vaccine target group.


Family Practice | 2009

Intervention with educational outreach at large scale to reduce antibiotics for respiratory tract infections: a controlled before and after study

H. M. Smeets; Marijke M. Kuyvenhoven; A. E. Akkerman; Ineke Welschen; G. P. Schouten; G A van Essen; Theo Verheij

BACKGROUNDnA multiple intervention targeted to reduce antibiotic prescribing with an educational outreach programme had proven to be effective in a randomized controlled trial in 12 peer review groups, demonstrating 12% less prescriptions for respiratory tract infections.nnnOBJECTIVEnTo assess the effectiveness of a multiple intervention in primary care at a large scale.nnnMETHODSnA controlled before and after study in 2006 and 2007 was designed. Participants were from general practices within a geographically defined area in the middle region of The Netherlands. Participants were GPs in 141 practices in 25 peer review groups. A control group of GP practices from the same region, matched for type of practice and mean volume of antibiotic prescribing. The multiple intervention consisted of the following elements: (i) group education meeting and communication training; (ii) monitoring and feedback on prescribing behaviour; (iii) group education for GPs and pharmacists assistants and (iv) patient education material. The main outcome measures are as follows: (i) number of antibiotic prescriptions per 1000 patients per GP and (ii) number of second-choice antibiotics, obtained from claims data from the regional health insurance company. The associations between predictors and outcome measurements were assessed by means of a multiple regression analyses.nnnRESULTSnAt baseline, the number of antibiotic prescriptions per 1000 patients was slightly higher in the intervention group than in the control group (184 versus 176). In 2007, the number of prescriptions had increased to 232 and 227, respectively, and not differed between intervention and control group.nnnCONCLUSIONSnThe implementation of an already proven effective multiple intervention strategy at a larger scale showed no reduction of antibiotic prescription rates. The failure might be attributed to a less tight monitoring of intervention and audit. Inserting practical tools in the intervention might be more successful and should be studied.


Vaccine | 2003

Design of the Dutch prevention of influenza, surveillance and management (PRISMA) study

Eelko Hak; S. van Loon; Erik Buskens; G A van Essen; D.H. de Bakker; M.A.J.B. Tacken; B.A. van Hout; D. E. Grobbee; Th J M Verheij

Rationale and design of a study on the cost-effectiveness of the Dutch influenza vaccination campaign are described. During two influenza epidemics, about 75,000 primary care patients recommended for influenza vaccination are included. Cases have fatal or non-fatal influenza, pneumonia, otitis media, acute respiratory disease (ARD), heart failure, myocardial infarction, depression or diabetes dysregulation. Per case four controls are sampled, frequency matched on age and high-risk co-morbidity (<18 years, 18-64, >/=65 healthy, >/=65 with co-morbidity). Baseline and outcome data are retrieved from patient records. During the 1999-2000 influenza A epidemic 5891 (7.9%) high-risk children, 24,848 (33.2%) high-risk adults aged 18-64 years, 18,484 (24.7%) elderly with co-morbidity and 25,527 (34.1%) healthy elderly had been included. The mortality rate was 5.2 per 1000 and 2035 non-fatal outcome events were recorded (incidence rate 27.2/1000).


Epidemiology and Infection | 2012

Cost-effectiveness of targeted screening for hepatitis C in The Netherlands.

Charles W Helsper; B. A. Borkent-Raven; N.J. de Wit; G A van Essen; Marc J. M. Bonten; Andy I. M. Hoepelman; Mart P. Janssen; G.A. de Wit

On account of the serious complications of hepatitis C virus (HCV) infection and the improved treatment possibilities, the need to improve HCV awareness and case-finding is increasingly recognized. To optimize a future national campaign with this objective, three pilot campaigns were executed in three regions in The Netherlands. One campaign was aimed at the general population, a second (similar) campaign was extended with a support programme for primary care and a third campaign was specifically aimed at hard-drug users. Data from the pilot campaigns were used to build a mathematical model to estimate the incremental cost-effectiveness ratio of the different campaigns. The campaign aimed at the general public without support for primary care did not improve case-finding and was therefore not cost-effective. The similar campaign accompanied by additional support for primary care and the campaign aimed at hard-drug users emerged as cost-effective interventions for identification of HCV carriers.


Postgraduate Medical Journal | 2001

Determinants for the course of acute sinusitis in adult general practice patients

W A B Stalman; G A van Essen; Y. van der Graaf

BACKGROUND Although the prognosis of acute sinusitis is important, little is known about it and the factors predicting its course in a general practice population. OBJECTIVE To determine the course of acute sinusitis and factors predicting it in adults in general practice. METHODS The prognostic value of demographic and clinical factors and the patients emotional state, for example anxious or depressed, were determined prospectively by means of multivariate analysis. MAIN OUTCOME MEASUREMENTS Resolution of facial pain, resumption of daily activities, and the patients reported improvement. Factors with a significant predictive value were used to classify the patients into three different groups: quick, moderate, and slow recovery. RESULTS The median time from enrolment to recovery was six (range percentile 25–75: 4–10) days in a population of 177 patients. Factors predictive of a prolonged clinical course were: female sex (hazard ratio (HR) 0.60; 95% confidence interval (CI) 0.42 to 0.83), history longer than 14 days before inclusion (HR 0.62; 95% CI 0.41 to 0.94), headache, cold, or cough as a reason for the encounter (HR 0.65; 95% CI 0.44 to 0.96), and absence of cervical adenopathy (HR 0.71; 95% CI 0.51 to 0.96). Antibiotic treatment did not influence the course of disease. The median time to recovery was three days for patients with a quick, five days for those with a moderate, and seven days for those with a slow recovery. CONCLUSION In general practice acute sinusitis is mostly a self limiting disease. A limited number of characteristics are predictive of a (slightly) prolonged clinical course of acute sinusitis in general practice.

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Eelko Hak

University of Groningen

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W.A.B. Stalman

VU University Medical Center

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