2012/13 influenza vaccine effectiveness against hospitalised influenza A(H1N1)pdm09, A(H3N2) and B: estimates from a European network of hospitals

While influenza vaccines aim to decrease the incidence of severe influenza among high-risk groups, evidence of influenza vaccine effectiveness (IVE) among the influenza vaccine target population is sparse. We conducted a multicentre test-negative case-control study to estimate IVE against hospitalised laboratory-confirmed influenza in the target population in 18 hospitals in France, Italy, Lithuania and the Navarre and Valencia regions in Spain. All hospitalised patients aged ≥18 years, belonging to the target population presenting with influenza-like illness symptom onset within seven days were swabbed. Patients positive by reverse transcription polymerase chain reaction for influenza virus were cases and those negative were controls. Using logistic regression, we calculated IVE for each influenza virus subtype and adjusted it for month of symptom onset, study site, age and chronic conditions. Of the 1,972 patients included, 116 were positive for influenza A(H1N1)pdm09, 58 for A(H3N2) and 232 for influenza B. Adjusted IVE was 21.3% (95% confidence interval (CI): -25.2 to 50.6; n=1,628), 61.8% (95% CI: 26.8 to 80.0; n=557) and 43.1% (95% CI: 21.2 to 58.9; n=1,526) against influenza A(H1N1) pdm09, A(H3N2) and B respectively. Our results suggest that the 2012/13 IVE was moderate against influenza A(H3N2) and B and low against influenza A(H1N1) pdm09.

Effectiveness of a co-ordinated nation-wide programme to improve influenza immunisation rates in The Netherlands

OBJECTIVE

To assess t he effectiveness of a nation-widemultifaceted intervention programme involving general practitioners (GPs) on influenza immunisation practice.

DESIGN

Pragmatic before-after trial using pre- and post-measurement questionnaires.

SETTING AND SUBJECTS

Random sample of Dutch general practices.

INTERVENTION

During a 2.5-year period (1995-1997) a variety of methods was implemented to enhance physician adoption of the immunisation guideline, including employment of facilitators, information-based methods, small-group consensus meetings, individual instructions and introduction of supportive computer software.

MAIN OUTCOME MEASURES

Influenza immunisation practice and influenza vaccine uptake.

RESULTS

In 988 practices all influenza vaccination characteristics markedly improved from 1995 to 1997. The most significant changes were found in computerised marking of high-risk patients (from 54% to 82% of practices), computerised selection (41% to 77%) and sending personal reminders (40% to 77%). Vaccine uptake increased from 9% to 16% of the practice population (78% increase, p < 0.001). Uptake was most prominent in urban and single-handed practices and in those with more patients insured through the National Health Service, low GP workload and low baseline uptake.

CONCLUSION

Our data suggest that a co-ordinated approach involving primary care physicians can succeed in enlarging the public health impact of a population-based preventive measure.

Time for first antibiotic dose is not predictive for the early clinical failure of moderate-severe community-acquired pneumonia

The time to first antibiotic dose (TFAD) has been mentioned as an important performance indicator in community-acquired pneumonia (CAP). However, the advice to minimise TFAD to 4 hours (4 h) is only based on database studies. We prospectively studied the effect of minimising the TFAD on the early clinical outcome of moderate–severe CAP. On admission, patients’ medical data and TFAD were recorded. Early clinical failure was expressed as the proportion of patients with clinical instability, admission to the intensive care unit (ICU) or mortality on day three. Of 166 patients included in the study, 27 patients (29.7%) with TFAD <4 h had early clinical failure compared to 23 patients (37.7%) with TFAD >4 h (odds ratio [OR] 0.69; 95% confidence interval [CI] 0.35–1.35). In multivariate analysis, the pneumonia severity index (OR 1.03; 95%CI 1.01–1.04), confusion (OR 2.63; 95%CI 1.14–6.06), Staphylococcus aureus infection (OR 7.26; 95%CI 1.33–39.69) and multilobar pneumonia (OR 2.40; 95%CI 1.11–5.22) but not TFAD were independently associated with early clinical failure. Clinical parameters on admission other than the TFAD predict early clinical outcome in moderate–severe CAP. In contrast to severe CAP necessitating treatment in the ICU directly, in the case of suspected moderate–severe CAP, there is time to establish a reliable diagnosis of CAP before antibiotics are administered. Therefore, the implementation of the TFAD as a performance indicator is not desirable.

Improving influenza vaccination coverage among high-risk patients: a role for computer-supported prevention strategy?

BACKGROUND

Worldwide, population-based influenza vaccination strategies are being developed to trace, immunize and monitor high-risk persons efficiently. Computerized prevention modules may facilitate such a strategy in general practice.

OBJECTIVES

We established the applicability of a computerized influenza prevention module and specifically addressed improvement of immunization coverage in high-risk patients during two consecutive influenza vaccination rounds after introduction of the module.

METHODS

In this descriptive study, four computerized practices of the Utrecht General Practices Network, covering about 36000 patients, participated. In 1995, all patients with high-risk diseases were traced by relevant tags, ICPC- and ATC-codes, using the module. According to changed Dutch immunization guidelines in 1996, healthy elderly people over 65 years were also traced. Demographical and medical data included age, high-risk disease and vaccine uptake.

RESULTS

In October 1995, 3871 high-risk patients were identified (11% of population); overall vaccination coverage was 68%. Over one-third of these patients had not been indicated before. In between the two vaccination rounds, 1104 previously unknown patients with high-risk disease <65 years were found by means of the module's on-line status. In October 1996, 6889 persons, including 2308 healthy elderly, were indicated (19%), and vaccination coverage was 62%. Of 3477 patients whose high-risk diseases were documented in both vaccination rounds, an overall improvement of vaccination coverage from 71 % in 1995 to 76% in 1996 was observed (P < 0.05). Main improvements were found in elderly patients. Immunization rates were highest in those with more than one risk factor, lung or cardiac disease, and lowest in healthy elderly and patients under 65 years with lung, renal or other diseases.

CONCLUSION

Computerized prevention modules and CMRs may facilitate population-based prevention of influenza and the use should be further encouraged.

Prenatal exposure to acid-suppressive drugs and the risk of allergic diseases in the offspring: a cohort study

BACKGROUND

Recent studies reported increased risks for the development of asthma in children after prenatal exposure to acid-suppressive drugs. As a result of common pathogenesis, associations could also be present for other allergic diseases.

METHODS

Using the prescription database IADB.nl, we conducted a cohort study amongst 33 536 children in the Netherlands, with a maximum follow-up of 8 years. Maternal exposure was defined as ≥1 dispensed prescription for proton pump inhibitors (PPIs) and/or Histamine 2-antagonists (H2As) during pregnancy. Children were considered to have a drug-treated allergic disease if they received either ≥2 prescriptions for dermal (atopic dermatitis), inhaled (asthma) or nasal (allergic rhinitis) steroids within a 12-month period. Clustered Cox proportional hazard regression was used to estimate crude and adjusted hazard ratios (aHR) with 95% confidence intervals (95% CI).

RESULTS

The aHR for the development of any allergic disease was 1.37 (95% CI: 1.14-1.66) for children exposed to PPIs or H2As. Prenatal exposure to PPIs and/or H2As was associated with atopic dermatitis, asthma and allergic rhinitis with aHRs of 1.32 (95% CI 1.06-1.64), 1.57 (95% CI 1.20-2.05) and 2.40 (95% CI 1.42-4.04), respectively. The aHR for the development of two or more (aHR 2.13 95% CI: 1.43-3.19) and three allergic diseases (aHR 5.18 95% CI: 2.16-12.42) were even more elevated after prenatal exposure to PPIs or H2As.

CONCLUSION

Prenatal exposure to PPIs and H2As appeared associated with an increased risk for the development of atopic dermatitis, asthma and allergic rhinitis in the offspring, especially with the development of multiple allergic diseases. Because our study has limitations inherent to observational studies, prospective studies are now warranted to confirm our findings.

Clinical and economic impact of medication non-adherence in drug-susceptible tuberculosis: a systematic review

BACKGROUND: Despite considerable efforts to globally eradicate TB, and the availability of effective antibiotics, TB elimination goals are falling behind. While non-adherence to TB drug regimens may compromise effective treatment, its full impact is still unknown.OBJECTIVE: To determine the clinical and economic impact of non-adherence to TB medication on treatment outcomes in drug-susceptible TB patients (DS-TB).METHODS: A systematic review was performed using PubMed and Embase for studies published between 2009 and 2019 reporting associations between adherence and WHO-defined TB treatment outcomes and economic outcomes in DS-TB patients.RESULTS: A total of 14 studies were included. Eight focused on the association between non-adherence and death, 2 on treatment failure, 1 study on successful treatment outcome, 1 study on both successful and unsuccessful treatment outcomes and 2 on cost outcomes. Most studies (71.4%) were retrospective cohort or case-control studies. The results showed that non-adherence to TB drug regimens was associated with death, treatment failure and lower cure rates.CONCLUSION: Non-adherence to TB drugs has a profound impact on both clinical and economic TB outcomes. To reach WHO TB elimination goals, preventing non-adherence and the implementation of cost-effective intervention programmes should receive the highest priority.

A prediction rule for elderly primary-care patients with lower respiratory tract infections

Prognostic scores for lower respiratory tract infections (LRTI) have been mainly derived in a hospital setting. The current authors have developed and validated a prediction rule for the prognosis of acute LRTI in elderly primary-care patients. Data including demographics, medication use, healthcare use and comorbid conditions from 3,166 episodes of patients aged > or =65 yrs visiting the general practitioner (GP) with LRTI were collected. Multiple logistic regression analysis was used to construct a predictive model. The main outcome measure was 30-day hospitalisation or death. The Second Dutch Survey of GPs was used for validation. The following were independent predictors of 30-day hospitalisation or death: increasing age; previous hospitalisation; heart failure; diabetes; use of oral glucocorticoids; previous use of antibiotics; a diagnosis of pneumonia; and exacerbation of chronic obstructive pulmonary disease. A prediction rule based on these variables showed that the outcome increased directly with increasing scores: 3, 10 and 31% for scores of <2 points, 3-6 and > or =7 points, respectively. Corresponding figures for the validation cohort were 3, 11 and 26%, respectively. This simple prediction rule can help the primary-care physician to differentiate between high- and low-risk patients. As a possible consequence, low-risk patients may be suitable for home treatment, whereas high-risk patients might be monitored more closely in a homecare or hospital setting. Future studies should assess whether information on signs and symptoms can further improve this prediction rule.

Prognostic factors for early clinical failure in patients with severe community-acquired pneumonia

For patients with community-acquired pneumonia (CAP), clinical response during the first days of treatment is predictive of clinical outcome. As risk assessments can improve the efficiency of pneumonia management, a prospective cohort study to assess clinical, biochemical and microbiological predictors of early clinical failure was conducted in patients with severe CAP (pneumonia severity index score of >90 or according to the American Thoracic Society definition). Failure was assessed at day 3 and was defined as death, a need for mechanical ventilation, respiratory rate >25/min, PaO2 <55 mm Hg, oxygen saturation <90%, haemodynamic instability, temperature >38 degrees C or confusion. Of 260 patients, 80 (31%) had early clinical failure, associated mainly with a respiratory rate >25/minute (n = 34), oxygen saturation <90% (n = 28) and confusion (n = 20). In multivariate logistic regression analysis, failure was associated independently with altered mental state (OR 3.19, 95% CI 1.75-5.80), arterial PaH <7.35 mm Hg (OR 4.29, 95% CI 1.53-12.05) and PaO2 <60 mm Hg (OR 1.75, 95% CI 0.97-3.15). A history of heart failure was associated inversely with clinical failure (OR 0.30, 95% CI 0.10-0.96). Patients who failed to respond had a higher 28-day mortality rate and a longer hospital stay. It was concluded that routine clinical and biochemical information can be used to predict early clinical failure in patients with severe CAP.

Quantifying the potential role of unmeasured confounders: the example of influenza vaccination

BACKGROUND

The validity of non-randomized studies using healthcare databases is often challenged because they lack information on potentially important confounders, such as functional health status and socioeconomic status. In a study quantifying the effects of influenza vaccination among community-dwelling elderly we assessed whether additional information on not routinely available covariates was indeed associated with exposure to influenza vaccination and could, therefore, have led to residual confounding in healthcare databases.

METHODS

We randomly selected 500 persons aged 65 years and older from the computerized Utrecht General Practitioner database. Information on exposure status and on demographics, co-morbidity status, prior healthcare use and medication use was extracted from the database. A questionnaire was used to obtain additional information on not routinely available risk factors [e.g. functional health status (SF-20), smoking status and alcohol consumption]. Missing data from the questionnaire was imputed and multivariable logistic regression analysis was applied to quantify the influence of covariates on the prediction of exposure to influenza vaccination. Within an existing dataset the potential impact of functional health status on the relation between influenza vaccination and mortality was simulated.

RESULTS

We obtained questionnaire data from 365 of 500 (73%) subjects. The model including routinely available data from the database appeared accurate in predicting exposure to influenza vaccination (c-statistic 0.86, 95% CI: 0.82-0.89). Functional health status was the only additional characteristic measured with the questionnaire that was not similar in vaccinated and unvaccinated subjects. However, extending the multivariable regression model with functional health status did not significantly improve the prediction of exposure to influenza vaccination, nor did it affect the relation between influenza vaccination and mortality.

CONCLUSION

The potential for unmeasured confounding on the association between influenza vaccination and health outcomes as quantified in healthcare databases seems small for non-randomized intervention studies within extensive and reliable databases.

Rates, determinants and success of implementing deprescribing in people with type 2 diabetes: A scoping review

BACKGROUND

Individualizing goals for people with type 2 diabetes may result in deintensification of medication, but a comprehensive picture of deprescribing practices is lacking.

AIMS

To conduct a scoping review in order to assess the rates, determinants and success of implementing deprescribing of glucose-, blood pressure- or lipid-lowering medications in people with diabetes.

METHODS

A systematic search on MEDLINE and Embase between January 2007 and January 2019 was carried out for deprescribing studies among people with diabetes. Outcomes were rates of deprescribing related to participant characteristics, the determinants and success of deprescribing, and its implementation. Critical appraisal was conducted using predefined tools.

RESULTS

Fourteen studies were included; eight reported on rates, nine on determinants and six on success and implementation. Bias was high for studies on success of deprescribing. Deprescribing rates ranged from 14% to 27% in older people with low HbA1c levels, and from 16% to 19% in older people with low systolic blood pressure. Rates were not much affected by age, gender, frailty or life expectancy. Rates were higher when a reminder system was used to identify people with hypoglycaemia, which led to less overtreatment and fewer hypoglycaemic events. Most healthcare professionals accepted the concept of deprescribing but differed on when to conduct it. Deprescribing glucose-lowering medications could be successfully conducted in 62% to 75% of participants with small rises in HbA1c .

CONCLUSIONS

Deprescribing of glucose-lowering medications seems feasible and acceptable, but was not widely implemented in the covered period. Support systems may enhance deprescribing. More studies on deprescribing blood pressure- and lipid-lowering medications in people with diabetes are needed.

Cost-effectiveness of potential infant vaccination against respiratory syncytial virus infection in The Netherlands

INTRODUCTION

Respiratory syncytial virus (RSV) infection is one of the major causes of respiratory illness in infants, infecting virtually every child before the age of 2 years. Currently, several Phase 1 trials with RSV vaccines in infants are ongoing or have been completed. As yet, no efficacy estimates are available for these vaccine candidates. Nevertheless, cost-effectiveness estimates might be informative to enable preliminary positioning of an RSV vaccine.

METHODS

A decision analysis model was developed in which a Dutch birth cohort was followed for 12 months. A number of potential vaccination strategies were reviewed such as vaccination at specific ages, a two- or three-dosing scheme and seasonal vaccination versus year-round vaccination. The impact of the assumptions made was explored in various sensitivity analyses, including probabilistic analysis. Outcome measures included the number of GP visits, hospitalizations and deaths, costs, quality-adjusted life years and incremental cost-effectiveness ratios (ICERs).

RESULTS

Currently, without vaccination, an annual number of 28,738 of RSV-related GP visits, 1623 hospitalizations, and 4.5 deaths are estimated in children in the age of 0-1 year. The total annual cost to society of RSV in the non-vaccination scenario is €7.7 million (95%CI: 1.7-16.7) and the annual disease burden is estimated at 597 QALYs (95%CI: 133-1319). In case all infants would be offered a potentially safe and effective 3-dose RSV vaccination scheme at the age of 0, 1 and 3 months, the total annual net costs were estimated to increase to €21.2 million, but 544 hospitalizations and 1.5 deaths would be averted. The ICER was estimated at €34,142 (95%CI: € 21,652-€ 87,766) per QALY gained. A reduced dose schedule, seasonal vaccination, and consideration of out-of-pocket expenses all resulted in more favorable ICER values, whereas a reduced vaccine efficacy or a delay in the timing of vaccination resulted in less favorable ICERs.

DISCUSSION

Our model used recently updated estimates on the burden of RSV disease in children and it included plausible utilities. However, due to the absence of clinical trial data, a number of crucial assumptions had to be made related to the characteristics of potential RSV vaccine. The outcomes of our modeling exercise show that vaccination of infants against RSV might be cost-effective. However, clinical trial data are warranted.

Predictors of response in initial users of metformin and sulphonylurea derivatives: a systematic review

AIM

To provide an overview of factors predicting metformin and sulphonylurea treatment response.

BACKGROUND

A large variability between individuals in treatment response to metformin and sulphonylurea derivatives exists. Understanding which factors determine response to these drugs may pave the way for more individualized therapy.

METHODS

We conducted a systematic search in the MEDLINE, Cochrane and EMBASE databases, between 2003 and 2012 for articles assessing demographic and clinical prediction factors of treatment response in initial users of metformin or sulphonylurea. A literature search of articles referenced within the studies identified was also performed. Treatment response was defined as change in HbA1c level, reaching target HbA1c levels or time to treatment change. Studies were assessed on quality, sample size and type of analysis. Results were summarized by tabulating positive, null and negative associations observed for included predictors.

RESULTS

A total of 10 articles (six trial reports and four cohort studies) were obtained, including three of sufficient quality. For metformin, baseline HbA1c , older age, lower BMI and shorter disease duration were found to be predictors of better treatment response in at least three studies of sufficient quality. For sulphonylurea derivatives, baseline HbA1c and shorter duration were identified as predictors of better treatment response in at least two studies of sufficient quality. Race, smoking status, lipid levels, blood pressure, kidney function and comorbidities were not significantly associated with treatment response.

CONCLUSIONS

Several demographic and clinical factors were identified as possible predictors of response to metformin and sulphonylurea, but the number of studies with sufficient quality was small. Generally, early treatment seems important for achieving better glycaemic outcomes.

Increased risk of early virological failure in non-European HIV-1-infected patients in a Dutch cohort on highly active antiretroviral therapy

OBJECTIVE

To compare early and late responses to highly active antiretroviral therapy (HAART) in European and non-European HIV-1 infected patients in a Dutch cohort.

METHODS

We retrospectively analysed the response to HAART of 216 previously treatment-naive HIV-1-infected patients using the University Medical Centre Utrecht HIV database. African (n=51), Asian (n=7), and Central/South American (n=6) patients were classified as non-European, and others as European (n=152). Early failure was defined as a viral load that remained above 400 HIV-1 RNA copies/mL after 6 months of treatment with HAART. Late-phase failure was determined in patients who were successfully treated in the early phase and was defined as two consecutive viral load measurements above 400 copies/mL, a new AIDS-defining event or death.

RESULTS

In the early phase, four of 152 (2.6%) European and eight of 64 (12.5%) non-European patients failed HAART. A significant increased risk of virological failure in the early phase of treatment was observed for non-Europeans as compared to Europeans (odds ratio 4.6; 95% confidence interval 1.1-20.2). Low serum drug levels in the absence of resistant virus were often seen at the time of early failure. No difference in late-phase failure was observed between the two groups (adjusted hazard ratio 0.6; 95% confidence interval 0.3-1.2).

CONCLUSIONS

Non-European patients had a 4.6 times higher risk of virological failure than their European counterparts in the first 6 months of treatment with HAART. This failure seemed to be associated with low serum drug levels at the time of failure. However, if HAART was successful in the early phase, response rates in the late phase were similar for Europeans and non-Europeans.

Results of aortic screening in the brothers of patients who had elective aortic aneurysm repair

BACKGROUND

Brothers of patients with an abdominal aortic aneurysm (AAA) are at high risk. In the present study brothers of patients who underwent elective AAA surgery were invited for aneurysm screening and the psychological consequences studied.

METHODS

All brothers over the age of 50 years were invited for abdominal ultrasonography. They were asked to complete a standard psychological well-being questionnaire both before, and 3 months after screening.

RESULTS

Some 571 brothers were identified: 251 were dead, 35 lived abroad, 16 could not be contacted for other reasons, 46 refused to participate and 13 were already known to have an AAA. Some 210 subjects (37.8 per cent) accepted the offer of screening. A new AAA was detected in 26 (12.3 per cent, 95 per cent confidence interval 8-18 per cent) of the men screened resulting in an overall prevalence of 18 per cent (95 per cent confidence interval 13-26 per cent). Eight (3.8 per cent) aneurysms were 5 cm or more in diameter and elective surgery was performed in five patients (2.4 per cent). The psychological dimensions of well-being (depression, anxiety, energy, and positive well-being) had not changed significantly 3 months after screening.

CONCLUSION

The prevalence of AAA in brothers of patients with AAA is far higher than in the overall male population of the same age. Screening does not seem to have a negative influence on psychological well-being.

Resistance of uropathogens in symptomatic urinary tract infections in León, Nicaragua

Management of urinary tract infections (UTI) in Central America and especially Nicaragua, is complicated by the lack of knowledge about the antibiotic resistance of uropathogens. We conducted a prevalence study to gain more insight into the aetiology, bacterial resistance and risk factors for symptomatic UTI in the region of León, Nicaragua. In 2002, all consecutive patients with UTI symptoms and pyuria >/=10 WBC/hpf were admitted to the study. Positive cultures from midstream urine specimens were defined as >/=10(5) cfu/ml of a single uropathogen. Susceptibility tests were performed with disc diffusion tests using the Kirby-Bauer method and broth microdilution using National Committee for Clinical Laboratory Standards criteria both in León and a reference laboratory in Utrecht. A positive culture was present in 62 of 208 study subjects (30%). Escherichia coli (56%), Klebsiella spp. (18%) and Enterobacter spp. (11%) were the most frequent pathogens isolated. Presence of cystocele, incontinence and increasing age were risk factors for bacterial UTI. E. coli was least resistant to ceftriaxone, amikacin and nitrofurantoin (>90% susceptible). We observed high resistance rates in E. coli to amoxicillin (82%, MIC(90) 128 mg/l), trimethoprim-sulphamethoxazole (TMP-SMX) (64%, MIC(90) 32 mg/l), cephalothin (58%, MIC(90), 32 mg/l), ciprofloxacin (30%; MIC(90), 32 mg/l), amoxicillin/clavulanate (21%, MIC(90) 8 mg/l) and gentamicin (12%, MIC(90) 2 mg/l). Our results suggests that community acquired uropathogens in Nicaragua are highly resistant to many antimicrobial agents. The use of amoxicillin, trimethoprim-sulphamethoxazole and cephalothin against uropathogens needs to be reconsidered. High quinolone resistance rates among E. coli in Nicaragua gives cause for great concern.

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

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.

Conventional influenza vaccination is not associated with complications in working-age patients with asthma or chronic obstructive pulmonary disease

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.

The significance of rhinovirus detection in hospitalized children: clinical, epidemiological and virological features

Recent developments in molecular diagnostic tools have led to the easy and rapid detection of a large number of rhinovirus (HRV) strains. However, the lack of clinical and epidemiological data hampers the interpretation of these diagnostic findings. From October 2009 to January 2011, we conducted a prospective study in hospitalized children from whom samples were taken for the detection of respiratory viruses. Clinical, epidemiological and microbiological data from 644 patients with 904 disease episodes were collected. When HRV tested positive, strains were further characterized by sequencing the VP4/VP2 region of the HRV genome. HRV was the single respiratory virus detected in 254 disease episodes (28%). Overall, 99 different serotypes were detected (47% HRV‐A, 12% HRV‐B, 39% HRV‐C). Patients with HRV had more underlying pulmonary illness compared with patients with no virus (p 0.01), or patients with another respiratory virus besides HRV (p 0.007). Furthermore, cough, shortness of breath and a need for oxygen were significantly more present in patients with HRV infection. Particularly, patients with HRV‐B required extra oxygen. No respiratory symptom, except for oxygen need, was predictive of the presence of HRV. In 22% of HRV‐positive disease episodes, HRV infection was hospital acquired. Phylogenetic analysis revealed several clusters of HRV; in more than 25% of these clusters epidemiological information was suggestive of transmission within specific wards. In conclusion, the detection of HRV may help in explaining respiratory illness, particular in patients with pulmonary co‐morbidities. Identifying HRV provides opportunities for timely implementation of infection control measures to prevent intra‐hospital transmission.

Relation between CYP2D6 Genotype, Phenotype and Therapeutic Drug Concentrations among Nortriptyline and Venlafaxine Users in Old Age Psychiatry

Objectives: To determine relations between drug concentrations and the cytochrome P450-CYP2D6 genotype or phenotype among elderly patients treated with nortriptyline or venlafaxine. Methods: A post-hoc analysis of a clinical trial was performed. Patients were grouped into phenotypes according to the metabolite/mother compound ratio. Genotypes were assessed by the CYP2D6 *3 and *4 alleles. Results: Data was available from 81 patients (41 nortriptyline, 40 venlafaxine) with a mean age of 72 years. No phenoconversion from poor metabolizers (PM) to extensive metabolizers (EM), or vice versa, was found. However, we did find phenoconversion from PM to intermediate metabolizers (IM), IM to EM, or vice versa in 36% of observations. Among nortriptyline users, patients with a PM or IM genotype had more supra-therapeutic blood levels, although this did not reach statistical significance. In exploratory analyses we found men were more likely (RR: 2.4; 95% CI: 1.14-5.07) to display phenoconversion from an IM genotype to EM phenotype. In addition, compared to non-PMs, PMs were found to have higher risk (RR: 1.56; 95% CI: 1.03-2.37) on non-response, although this was only significant when response was measured on the Hamilton Rating Scale for Depression and not on the Montgomery Åsberg Depression Rating Scale. Conclusion: Patients phenoconversed, but we did not observe phenoconversion from PM to EM or vice versa. Genotype information could be used as a valuable tool, in addition to therapeutic drug monitoring, to prevent supratherapeutic drug levels of nortriptyline or venlafaxine in elderly patients with a PM genotype.

A nested case-control study of influenza vaccination was a cost-effective alternative to a full cohort analysis

OBJECTIVE

In the absence of trial results that are applicable to the target population, nested case-control studies might be an alternative to full-cohort analysis. We compared relative and absolute estimates of associations in an influenza vaccine study using both designs.

STUDY DESIGN AND SETTING

Data from elderly persons enrolled during six consecutive influenza seasons were used (147,551 person-periods). The endpoints "hospitalization for pneumonia or influenza" (P&I) or "death" were used combined and separately to define three types of cases. Controls for the case-control samples were randomly selected from the remainder of the total cohort at different ratios (1:1 to 1:4). Logistic regression analysis was used to assess adjusted vaccine effectiveness (VE). Sampling fractions were used to determine the number needed to treat to prevent one outcome. Receiver-operator-curve analysis was conducted to estimate the area under the curve (AUC) as a measure of discriminative capacity of the prognostic model.

RESULTS

In all, 978 P and I hospitalizations and 1,339 deaths were observed. The adjusted estimates of relative estimates (VE, AUC) and their corresponding 95% confidence intervals were virtually the same using both study designs, notably when the case-control ratio was high (1:4).

CONCLUSION

A nested case-control design can provide valid and precise estimates of associations and is a cost-effective alternative for full-cohort analysis.

No intention to comply with influenza and pneumococcal vaccination: behavioural determinants among smokers and non-smokers

OBJECTIVE

Smoking increases the risk for influenza and pneumococcal disease, but vaccination uptake is lower among smokers than non-smokers. We therefore aimed to determine reasons for not complying with vaccination among smokers and non-smokers.

METHOD

In 2005 a self-administered questionnaire was sent to a random sample of Dutch patients (n=4,000) assessing medical, social and behavioural determinants. Independent factors associated with not complying with influenza and pneumococcal vaccination among smokers and non-smokers were assessed by multivariate logistic regression analysis.

RESULTS

In all, 1,725 of 4,000 patients returned the questionnaire (response rate: 43%), 426 (25%) were smokers. Among smokers self-reported flu vaccine uptake was 42% and among non-smokers 52% among both only 0,2% received both vaccines. Most important predictors of not complying in smokers and non-smokers were patient's beliefs not to be susceptible to disease (odds ratio (OR) 4.0, 95% confidence interval (CI): 2.0, 8.0 and OR 2.8, CI: 2.0, 3.9), finding it difficult to go to the GP for vaccination (OR 2.5, CI: 1.3, 4.8 and OR 1.8, CI: 1.3, 2.6) and being against vaccination (OR 2.4 CI: 1.3, 4.4 and OR 1.8, CI: 1.3, 2.6), respectively.

CONCLUSION

There are no substantial differences in determinants associated with not complying with influenza and pneumococcal vaccination between smokers and non-smokers but there is a trend towards stronger associations in smokers.

Modelling the health-economic impact of the next influenza pandemic in The Netherlands

To optimally develop or adjust national contingency plans to respond to the next influenza pandemic, we developed a decision type model and estimated the total health burden and direct medical costs during the next possible influenza pandemic in the Netherlands on the basis of health care burden during a regular epidemic. Using an arithmetic decision tree-type model we took into account population characteristics, varying influenza attack rates, health care consumption according to the Dutch health care model and all-cause mortality. Actual direct medical cost estimates were based on the Dutch guidelines for pharmaco-economic evaluation. In the base-case scenario with no preventive measure available and an average influenza attack rate of 30%, 4,958,188 influenza infections, 1,552,687 GP consultations, 83,515 hospitalizations and 173,396 deaths will take place in The Netherlands. The burden is highest in adults aged 20 to 64 years. If minimizing the total mortality and sustaining highest net economic returns is the objective, this group needs to be targeted in interventions.