Explaining trends in hospitalizations for pneumonia and influenza in the elderly

Incidence, recurring admissions and mortality of severe bacterial infections and sepsis over a 22-year period in the population-based HUNT study

Purpose

Severe bacterial infections are important causes of hospitalization and loss of health worldwide. In this study we aim to characterize the total burden, recurrence and severity of bacterial infections in the general population during a 22-year period.

Methods

We investigated hospitalizations due to bacterial infection from eight different foci in the prospective population-based Trøndelag Health Study (the HUNT Study), where all inhabitants aged ≥ 20 in a Norwegian county were invited to participate. Enrollment was between 1995 and 1997, and between 2006 and 2008, and follow-up ended in February 2017. All hospitalizations, positive blood cultures, emigrations and deaths in the follow-up period were captured through registry linkage.

Results

A total of 79,393 (69.5% and 54.1% of the invited population) people were included, of which 42,237 (53%) were women and mean age was 48.5 years. There were 37,298 hospitalizations due to infection, affecting 15,496 (22% of all included) individuals. The median time of follow-up was 20 years (25^th percentile 9.5–75^th percentile 20.8). Pneumonia and urinary tract infections were the two dominating foci with incidence rates of 639 and 550 per 100,000 per year, respectively, and with increasing incidence with age. The proportion of recurring admissions ranged from 10.0% (central nervous system) to 30.0% (pneumonia), whilst the proportion with a positive blood culture ranged from 4.7% (skin- and soft tissue infection) to 40.9% (central nervous system). The 30-day mortality varied between 3.2% (skin- and soft tissue infection) and 20.8% (endocarditis).

Conclusions

In this population-based cohort, we observed a great variation in the incidence, positive blood culture rate, recurrence and mortality between common infectious diseases. These results may help guide policy to reduce the infectious disease burden in the population.

Risk factors for pneumonia and influenza hospitalizations in long-term care facility residents: a retrospective cohort study

BACKGROUND

Older adults who reside in long-term care facilities (LTCFs) are at particularly high risk for infection, morbidity and mortality from pneumonia and influenza (P&I) compared to individuals of younger age and those living outside institutional settings. The risk factors for P&I hospitalizations that are specific to LTCFs remain poorly understood. Our objective was to evaluate the incidence of P&I hospitalization and associated person- and facility-level factors among post-acute (short-stay) and long-term (long-stay) care residents residing in LTCFs from 2013 to 2015.

METHODS

In this retrospective cohort study, we used Medicare administrative claims linked to Minimum Data Set and LTCF-level data to identify short-stay (< 100 days, index = admission date) and long-stay (100+ days, index = day 100) residents who were followed from the index date until the first of hospitalization, LTCF discharge, Medicare disenrollment, or death. We measured incidence rates (IRs) for P&I hospitalization per 100,000 person-days, and estimated associations with baseline demographics, geriatric syndromes, clinical characteristics, and medication use using Cox regression models.

RESULTS

We analyzed data from 1,118,054 short-stay and 593,443 long-stay residents. The crude 30-day IRs (95% CI) of hospitalizations with P&I in the principal position were 26.0 (25.4, 26.6) and 34.5 (33.6, 35.4) among short- and long-stay residents, respectively. The variables associated with P&I varied between short and long-stay residents, and common risk factors included: advanced age (85+ years), admission from an acute hospital, select cardiovascular and respiratory conditions, impaired functional status, and receipt of antibiotics or Beers criteria medications. Facility staffing and care quality measures were important risk factors among long-stay residents but not in short-stay residents.

CONCLUSIONS

Short-stay residents had lower crude 30- and 90-day incidence rates of P&I hospitalizations than long-stay LTCF residents. Differences in risk factors for P&I between short- and long-stay populations suggest the importance of considering distinct profiles of post-acute and long-term care residents in infection prevention and control strategies in LTCFs. These findings can help clinicians target interventions to subgroups of LTCF residents at highest P&I risk.

Long-term Care Facility Variation in the Incidence of Pneumonia and Influenza

Background

Pneumonia and influenza (P&I) increase morbidity and mortality among older adults, especially those residing in long-term care facilities (LTCFs). Facility-level characteristics may affect the risk of P&I beyond resident-level risk factors. However, the relationship between facility characteristics and P&I is poorly understood. To address this, we identified potentially modifiable facility-level characteristics that influence the incidence of P&I across LTCFs.

Methods

We conducted a retrospective cohort study using 2013-2015 Medicare claims linked to Minimum Data Set and LTCF-level data. Short-stay (<100 days) and long-stay (100+ days) LTCF residents were followed for the first occurrence of hospitalization, LTCF discharge, Medicare disenrollment, or death. We calculated LTCF risk-standardized incidence rates (RSIRs) per 100 person-years for P&I hospitalizations by adjusting for over 30 resident-level demographic and clinical covariates using hierarchical logistic regression.

Results

We included 1 767 241 short-stay (13 683 LTCFs) and 922 863 long-stay residents (14 495 LTCFs). LTCFs with lower RSIRs had more licensed independent practitioners (nurse practitioners or physician assistants) among short-stay (44.9% vs 41.6%, P < .001) and long-stay residents (47.4% vs 37.9%, P < .001), higher registered nurse hours/resident/day among short-stay and long-stay residents (mean [SD], 0.5 [0.7] vs 0.4 [0.4], P < .001), and fewer residents for whom antipsychotics were prescribed among short-stay (21.4% [11.6%] vs 23.6% [13.2%], P < .001) and long-stay residents (22.2% [14.3%] vs 25.5% [15.0%], P < .001).

Conclusions

LTCF characteristics may play an important role in preventing P&I hospitalizations. Hiring more registered nurses and licensed independent practitioners, increasing staffing hours, and higher-quality care practices may be modifiable means of reducing P&I in LTCFs.

Pneumococcal Conjugated Vaccine Reduces the High Mortality for Community-Acquired Pneumonia in the Elderly: an Italian Regional Experience

Background

Community-acquired pneumonia (CAP) is an important cause of illness and death worldwide, particularly among the elderly. Previous studies on the factors associated with mortality in patients hospitalized for CAP revealed a direct association between the type of microorganism involved, the characteristics of the patient and mortality. Vaccination status against pneumococcal disease was not considered. We conducted a retrospective analysis on the mortality rates after a first hospitalization for CAP in north-east Italy with a view to examining especially the role of anti-pneumococcal vaccination as a factor associated with pneumonia-related mortality at one year.

Method

Between 2012–2013, patients aged 65+ hospitalized with a primary diagnosis of CAP, identified based on International Classification of Diseases, Ninth Revision, Clinical Modification codes 481–486, were enrolled in the study only once. Patients were divided into three groups by pneumococcal vaccination status: 1) 13-valent pneumococcal conjugate vaccine (PCV13) prior to their hospitalization; 2) 23-valent pneumococcal polysaccharide vaccine (PPV23) within 5 years before hospitalization and 3) unvaccinated or PPV23 more than 5 years prior to admission. Gender, age, length of hospital stay and influenza vaccination were considered. Comorbidities were ascertained by means of a properly coded diagnosis. Every patient was followed up for 1 year and the outcome investigated was mortality for any cause and for pneumonia.

Results

A total of 4,030 patient were included in the study; mean age at the time of admission to hospital was 84.3±7.7; 50.9% were female. 74.2% of subjects had at least one comorbidity; 73.7% has been vaccinated against influenza. Regard to pneumococcal vaccine, 80.4% of patients were not vaccinated, 14.5% vaccinated with PPV23 and 5.1% with PCV13. The 1-year survival rates after hospitalization for pneumonia were 83.6%, 85.9% and 89.3% in the unvaccinated, PPV23 and PCV13 groups, respectively. Regression analysis indicated that the risk of death due to pneumonia increased significantly with age (adjusted OR: 1.073; 1.061–1.085), shorter hospital stay (adjusted OR: 0.981; 0.971–0.990), and male gender (adjusted OR: 1.372; 1.165–1.616). The model also confirmed the pneumococcal 13-valent conjugated vaccine as an independent protective factor for mortality-related pneumonia (adjusted OR: 0.599; 0.390–0.921).

Conclusion

The main finding of our observational cohort study is a high mortality rate among elderly patients admitted to hospital for pneumonia. The present study suggests a protective role for PCV13 vaccination.

Do we have enough evidence how seasonal influenza is transmitted and can be prevented in hospitals to implement a comprehensive policy?

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Vaccinated HCW 4.81, unvaccinated 7.54 lab-proven influenza episodes/100 HCWs/ season.

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2 RCTs partly directly-observed HCW mask wearing, 4 not observed underpowered, no effect on influenza transmission.

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There are no RCTs of screening HCWs/patients for influenza before entering hospital to prevent transmission.

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H₂O₂ vapor systems effectively clean patient rooms/medical equipment of influenza

Purpose

To identify if there is enough evidence at low risk-of-bias to prevent influenza transmission by vaccinating health-care workers (HCWs), patients and visitors; screening for laboratory-proven influenza all entering hospitals; screening asymptomatic individuals; identifying influenza supershedders; hand-washing and mask-wearing by HCWs, patients and visitors; and cleaning hospital rooms and equipment.

Principal Results

Vaccination reduces influenza episodes of vaccinated (4.81/100 HCW) compared to unvaccinated (7.54/100) HCWs/influenza season. A Cochrane review found for inactivated vaccines the Number Needed to Vaccinate (NNV) = 71 (95%CI 64%, 80%) for adults 18–60 (same age as HCWs) to prevent laboratory-proven influenza. There are no RCTs of screening HCWs, patients, visitors and influenza supershedders to prevent transmission. None of four RCTs of HCWs mask-wearing (two directly observed, two not) showed an effect because they were underpowered either due to small size or low circulation of influenza. Hospital rooms and equipment can effectively be cleaned of influenza by many chemicals and hydrogen peroxide vapor machines but the cleaning cycle needs shortening to increase the likelihood of adoption.

Major Conclusions

HCW vaccination is a partial solution with current vaccination levels. There are no RCTs of screening HCWs, patients and visitors demonstrating preventing influenza transmission. Only one study costed furloughing HCWs with influenza and no RCTs have identified benefits of isolating influenza supershedders. RCTs of directly- and electronically continuously-observed mask-wearing and hand-hygiene and RCTs of incentives for meticulous hygiene are required. RCTs of engineering solutions (external venting, frequent room air changes) are needed. A wide range of chemicals effectively cleans hospital rooms and equipment from influenza. Hydrogen peroxide vapor is effective against influenza and a wide range of bacterial pathogens with patient room changes, and clean areas cleaners do not clean but its cleaning cycle needs shortening to increase the likelihood of adoption of cleaning rooms vacated by influenza patients.

Evolution over a 15-year period of the clinical characteristics and outcomes of critically ill patients with severe community-acquired pneumonia

OBJECTIVES

To study the characteristics and outcomes of patients in the ICU with severe community-acquired pneumonia (SCAP) over a 15-year surveillance period.

METHODS

We conducted a retrospective cohort study of episodes of SCAP, and assessed the epidemiology, etiology, treatment and outcomes of patients admitted to the ICU, comparing three periods (1999-2003, 2004-2008 and 2009-2013).

RESULTS

A total of 458 patients were diagnosed with SCAP. The overall cumulative incidence was 37.4 episodes/1000 admissions, with a progressive increase over the three periods (P<0.001). Patients fulfilling the two major IDSA/ATS criteria at admission increased from 64.2% in the first period to 82.5% in the last period (P=0.005). Streptococcus pneumoniae was the prevalent pathogen. The incidence of bacteremia was 23.1%, and a progressive significant reduction in overall incidence was observed over the three periods (P=0.02). Globally, 91% of the patients received appropriate empiric antibiotic treatment, increasing from 78.3% in the first period to 97.7% in the last period (P<0.001). Combination antibiotic therapy (betalactam+macrolide or fluoroquinolone) increased significantly from the first period (61%) to the last period (81.3%) (P<0.001). Global ICU mortality was 25.1%, and decreased over the three periods (P=0.001).

CONCLUSIONS

Despite a progressively higher incidence and severity of SCAP in our ICU, crude ICU mortality decreased by 18%. The increased use of combined antibiotic therapy and the decreasing rates of bacteremia were associated to improved patient prognosis.

Diagnoses of early and late readmissions after hospitalization for pneumonia. A systematic review

RATIONALE

Pneumonia is a frequent cause of hospitalization, yet drivers of post-pneumonia morbidity remain poorly characterized. Causes of hospital readmissions may elucidate important sources of morbidity and are of particular interest given the U.S. Hospital Readmission Reductions Program.

OBJECTIVES

To review the primary diagnoses of early (≤30 d) and late (≥31 d) readmissions after pneumonia hospitalization.

METHODS

Systematic review of MEDLINE, Embase, and CINAHL databases. We identified original research studies of adults aged 18 years or older, hospitalized for pneumonia, and for whom cause-specific readmission rates were reported. Two authors abstracted study results and assessed study quality.

MEASUREMENTS AND MAIN RESULTS

Of the 1,243 citations identified, 12 met eligibility criteria. Included studies were conducted in the United States, Spain, Canada, Croatia, and Sweden. All-cause 30-day readmission rates ranged from 16.8 to 20.1% across administrative studies; the weighted average for the studies using chart review was 11.6% (15.6% in United States-based studies). Pneumonia, heart failure/cardiovascular causes, and chronic obstructive pulmonary disease/pulmonary causes are the most common reasons for early readmission after pneumonia hospitalization. Although it was the single most common cause for readmission, pneumonia accounted for only 17.9 to 29.4% of all 30-day readmissions in administrative studies and a weighted average of 23.0% in chart review studies. After accounting for study population, there was no clear difference in findings between claims-based versus chart-review studies. Few studies assessed readmissions beyond 30 days, although the limited available data suggest similar primary diagnoses for early and late readmissions. No studies assessed whether reasons for readmission were similar to patients' reasons for healthcare use before hospitalization.

CONCLUSIONS

Pneumonia, heart failure/cardiovascular disease, and chronic obstructive pulmonary disease/pulmonary disease are the most common readmission diagnoses after pneumonia hospitalization. Although pneumonia was the most common readmission diagnosis, it accounted for only a minority of all readmissions. Late readmission diagnoses are less thoroughly described, and further research is needed to understand how hospitalization for pneumonia fits within the broader context of patients' health trajectory.

Are influenza-associated morbidity and mortality estimates for those ≥ 65 in statistical databases accurate, and an appropriate test of influenza vaccine effectiveness?

PURPOSES

To assess the accuracy of estimates using statistical databases of influenza-associated morbidity and mortality, and precisely measure influenza vaccine effectiveness.

PRINCIPAL RESULTS

Laboratory testing of influenza is incomplete. Death certificates under-report influenza. Statistical database models are used as an alternative to randomised controlled trials (RCTs) to assess influenza vaccine effectiveness. Evidence of the accuracy of influenza morbidity and mortality estimates was sought from: (1) Studies comparing statistical models. For four studies Poisson and ARIMA models produced higher estimates than Serfling, and Serfling higher than GLM. Which model is more accurate is unknown. (2) Studies controlling confounders. Fourteen studies mostly controlled one confounder (one controlled comorbidities), and limited control of confounders limits accuracy.

EVIDENCE FOR VACCINE EFFECTIVENESS WAS SOUGHT FROM

(1) Studies of regions with increasing vaccination rates. Of five studies two controlled for confounders and one found a positive vaccination effect. Three studies did not control confounders and two found no effect of vaccination. (2) Studies controlling multiple confounders. Of thirteen studies only two found a positive vaccine effect and no mortality differences between vaccinees and non-vaccinees in non-influenza seasons, showing confounders were controlled. Key problems are insufficient testing for influenza, using influenza-like illness, heterogeneity of seasonal and pandemic influenza, population aging, and incomplete confounder control (co-morbidities, frailty, vaccination history) and failure to demonstrate control of confounders by proving no mortality differences between vaccinees and non-vaccinees in non-influenza seasons.

MAJOR CONCLUSIONS

Improving model accuracy requires proof of no mortality differences in pre-influenza periods between the vaccinated and non-vaccinated groups, and reduction in influenza morbidity and mortality in seasons with a good vaccine match, more virulent strains, in the younger elderly with less immune senescence, and specific outcomes (laboratory-confirmed outcomes, pneumonia deaths). Proving influenza vaccine effectiveness requires appropriately powered RCTs, testing participants with RT-PCR tests, and comprehensively monitoring morbidity and mortality.

A population-based study on the impact of hospitalization for pneumonia in different age groups

Background

Pneumonia is an important cause of illness and death, particularly in elderly adults. This retrospective study was conducted to estimate the trend of hospitalization for pneumonia in the Veneto from the records of all hospitals in the region (serving a population of 4.81 million) during the years 2004 through 2012.

Methods

The cases of pneumonia identified in the hospital discharge records were all cases in which the first-listed diagnosis was pneumonia, or meningitis, septicemia or empyema associated with pneumonia. The annual total and age-specific hospitalization rates and trends were calculated and correlated with vaccine coverage. Total related costs were also calculated.

Results

There were 110,927 hospitalizations for pneumonia, meaning an annual rate of 256.3/100,000 population, with peaks in children and elderly people. The overall pneumonia-related hospitalization rate did not change significantly during the study period (AAPC: 1.3% [95% CI: −0.5, 3.1]). The rate dropped significantly among the 0- to 4-year-olds, however, from 617.3/100,000 in 2004 to 451.8/100,000 in 2012 (AAPC: −2.5% [95% CI: −4.5; −0.5]), while it increased slightly in adults aged 80+ (AAPC: 1.2% [95% CI: −0.9; 3.4]). The overall pneumonia-related mortality rate was 10.7%. The estimated cost per hospitalized patient was €3,090.

Conclusion

This study shows that hospitalization for pneumonia has a considerable impact on the health services, especially for children and the elderly. No decline in hospitalization rates was seen for the very elderly after the introduction of pneumococcal conjugate vaccination for children.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2334-14-485) contains supplementary material, which is available to authorized users.

Infection hospitalization increases risk of dementia in the elderly

OBJECTIVES

Severe infections, often requiring ICU admission, have been associated with persistent cognitive dysfunction. Less severe infections are more common and whether they are associated with an increased risk of dementia is unclear. We determined the association of pneumonia hospitalization with risk of dementia in well-functioning older adults.

DESIGN

Secondary analysis of a randomized multicenter trial to determine the effect of Gingko biloba on incident dementia.

SETTING

Five academic medical centers in the United States.

SUBJECTS

Healthy community volunteers (n = 3,069) with a median follow-up of 6.1 years.

INTERVENTIONS

None.

MEASUREMENT AND MAIN RESULTS

We identified pneumonia hospitalizations using International Classification of Diseases, 9th Edition-Coding Manual codes and validated them in a subset. Less than 3% of pneumonia cases necessitated ICU admission, mechanical ventilation, or vasopressor support. Dementia was adjudicated based on neuropsychological evaluation, neurological examination, and MRI. Two hundred twenty-one participants (7.2%) incurred at least one hospitalization with pneumonia (mean time to pneumonia = 3.5 yr). Of these, dementia was developed in 38 (17%) after pneumonia, with half of these cases occurring 2 years after the pneumonia hospitalization. Hospitalization with pneumonia was associated with increased risk of time to dementia diagnosis (unadjusted hazard ratio = 2.3; CI, 1.6-3.2; p < 0.0001). The association remained significant when adjusted for age, sex, race, study site, education, and baseline mini-mental status examination (hazard ratio = 1.9; CI, 1.4-2.8; p < 0.0001). Results were unchanged when additionally adjusted for smoking, hypertension, diabetes, heart disease, and preinfection functional status. Results were similar using propensity analysis where participants with pneumonia were matched to those without pneumonia based on age, probability of developing pneumonia, and similar trajectories of cognitive and physical function prior to pneumonia (adjusted prevalence rates, 91.7 vs 65 cases per 1,000 person-years; adjusted prevalence rate ratio = 1.6; CI, 1.06-2.7; p = 0.03). Sensitivity analyses showed that the higher risk also occurred among those hospitalized with other infections.

CONCLUSION

Hospitalization with pneumonia is associated with increased risk of dementia.

Is secondary preventive care improving? Observational study of 10-year trends in emergency admissions for conditions amenable to ambulatory care

OBJECTIVE

To identify trends in emergency admissions for patients with clinical conditions classed as 'ambulatory care sensitive' (ACS) and assess if reductions might be due to improvements in preventive care.

DESIGN

Observational study of routinely collected hospital admission data from March 2001 to April 2011. Admission rates were calculated at the population level using national population estimates for area of residence.

PARTICIPANTS

All emergency admissions to National Health Service (NHS) hospitals in England from April 2001 to March 2011 for people residents in England.

MAIN OUTCOME MEASURES

Age-standardised emergency admissions rates for each of 27 specific ACS conditions (ICD-10 codes recorded as primary or secondary diagnoses).

RESULTS

Between April 2001 and March 2011 the number of admissions for ACS conditions increased by 40%. When ACS conditions were defined solely on primary diagnosis, the increase was less at 35% and similar to the increase in emergency admissions for non-ACS conditions. Age-standardised rates of emergency admission for ACS conditions had increased by 25%, and there were notable variations by age group and by individual condition. Overall, the greatest increases were for urinary tract infection, pyelonephritis, pneumonia, gastroenteritis and chronic obstructive pulmonary disease. There were significant reductions in emergency admission rates for angina, perforated ulcers and pelvic inflammatory diseases but the scale of these successes was relatively small.

CONCLUSIONS

Increases in rates of emergency admissions suggest that efforts to improve the preventive management of certain clinical conditions have failed to reduce the demand for emergency care. Tackling the demand for hospital care needs more radical approaches than those adopted hitherto if reductions in emergency admission rates for ACS conditions overall are to be seen as a positive outcome of for NHS.

Hospital admissions related to influenza in France during the 2006/2007 epidemic

BACKGROUND

The data available on hospital admissions related to influenza mostly concern in-patients admitted via the emergency department. Severe cases have been collated by intensive care practitioners since 2009. For this survey, we searched French hospital admission databases to estimate the prevalence rate of hospital admissions related to influenza and to record qualitative data.

METHOD

All case studies identified between October 2006 and September 2007 were split into two groups: the first displaying symptoms of clinical influenza and the second suffering from influenza as an associated diagnosis.

RESULTS

We collected 6797 hospital admissions, 2126 of which were closely related to clinical influenza. Fifty percent of cases concerned the elderly and young people. Fifty-six hospital deaths were recorded in which influenza was the underlying cause in 21% of the cases (12). When influenza was an associated diagnosis (44/56), cardiovascular or respiratory diseases were the main causes (26/44).

CONCLUSION

During the same period (2006-2007), the French Sentinel Surveillance identified only 105 hospital admissions related to influenza. Our survey was therefore more exhaustive and was able to record qualitative data. Inclusion of hospital admissions with an associated diagnosis of influenza is debatable because this decreases specificity. The relationship between the principal diagnosis and all the associated diagnoses is difficult to study, although exclusion of this type of hospitalization could significantly underestimate these figures. Despite certain limitations, French hospital admissions databases should complement French Sentinel Surveillance data.

Pneumonia and influenza hospitalization in HIV-positive seniors

HIV-positive persons and the elderly have increased risk for influenza-related complications, including pneumonia. Using claims data for pneumonia and influenza (P&I) hospitalization in the USA, we described the temporo-demographic trends and in-patient case-fatality in persons aged ≥ 65 years by HIV status. Our results showed a near doubling in the fraction of P&I admissions representing HIV-positive persons between 1991 and 2004 [relative risk (RR) 1·95, 95% confidence interval (CI) 1·80-2·13]. HIV-positive adults were younger (70·3 vs. 79·9 years, P<0·001), and had higher case-fatality (18·0% vs. 12·6%, P<0·001). Adjusting for other variables, case-fatality decreased by 5·8% in HIV-positive persons with the availability of highly active antiretroviral therapy (P=0·032). However, HIV-positive seniors were still 51% more likely to die during hospitalization than HIV-negative persons in 2004 (OR 1·51, 95% CI 1·23-1·85). HIV-infected persons represent a growing fraction of the elderly population hospitalized with P&I. Additional measures are needed to reduce case-fatality associated with P&I in this population.

Synonyms in Health Services Research Methodology

There are often multiple discipline-specific terms for a given statistical concept, which can sow confusion in multidisciplinary teams or study sections if researchers are not aware of the synonyms from other disciplines. This article incorporates synonyms and a uniform definition of terminology related to study designs, elements of an equation, and types of bias. Greater multidisciplinary collaboration and exploration of new methods can be facilitated by this methods thesaurus.

Does primary language influence the receipt of influenza and pneumococcal immunizations among community-dwelling older adults?

OBJECTIVES

To examine (a) the influence of primary language on the receipt of influenza and pneumococcal immunizations and (b) the feasibility of being immunized in a nontraditional setting.

METHOD

The population was multiethnic, linguistically diverse, community-dwelling, low income, older adults in California. Face-to-face interviews were conducted with 164 participants (response rate 82%). Questions from BRFSS and CHIS were used.The questionnaire was implemented in six languages.

RESULTS

Influenza vaccination within the past 12 months was reported by 75.3%, but only 50.6% reported ever receiving the pneumococcal vaccine. Immunization predictors: Influenza-insurance through MediMedi, rating one's health as excellent/good, living with another person, and English as a primary language; pneumococcal-insurance through MediMedi and English as a primary language. Majority were willing to be immunized in nontraditional setting, especially those with limited English proficiency.

DISCUSSION

Need exists for cultural and linguistically appropriate immunization outreach methods for older adults and practitioners.

Trends for influenza and pneumonia hospitalization in the older population: age, period, and cohort effects

Birth cohort has been shown to be related to morbidity and mortality from other diseases and conditions, yet little is known about the potential for birth cohort in its relation to pneumonia and influenza (P&I) outcomes. This issue is particularly important in older adults, who experience the highest disease burden and most severe complications from these largely preventable diseases. The objective of this analysis is to assess P&I patterns in US seniors with respect to age, time, and birth cohort. All Medicare hospitalizations due to P&I (ICD-9CM codes 480-487) were abstracted and categorized by single-year of age and influenza year. These counts were then divided by intercensal estimates of age-specific population levels extracted from the US Census Bureau to obtain age- and season-specific rates. Rates were log-transformed and linear models were used to assess the relationships in P&I rates and age, influenza year, and cohort. The increase in disease rates with age accounted for most of the variability by age and influenza season. Consistent relationships between disease rates and birth cohorts remained, even after controlling for age. Seasonal associations were stronger for influenza than for pneumonia. These findings suggest that there may be a set of unmeasured characteristics or events people of certain ages experienced contemporaneously that may account for the observed differences in P&I rates in birth cohorts. Further understanding of these circumstances and those resulting age and cohort groups most vulnerable to P&I may help to target health services towards those most at risk of disease.

Increasing hospital admissions for pneumonia, England

This rise in recorded incidence from 2001 to 2005 was particularly marked among the elderly.

Pneumonia is an important cause of illness and death in England. To describe trends in pneumonia hospitalizations, we extracted information on all episodes of pneumonia that occurred from April 1997 through March 2005 recorded in the Hospital Episode Statistics (HES) database by searching for International Classification of Diseases 10th revision codes J12–J18 in any diagnostic field. The age-standardized incidence of hospitalization with a primary diagnosis of pneumonia increased by 34% from 1.48 to 1.98 per 1,000 population between 1997–98 and 2004–05. The increase was more marked in older adults, in whom the mortality rate was also highest. The proportion of patients with recorded coexisting conditions (defined by using the Charlson Comorbidity Index score) increased over the study period. The rise in pneumonia hospital admissions was not fully explained by demographic change or increasing coexisting conditions. It may be attributable to other population factors, changes in HES coding, changes to health service organization, other biologic phenomenon, or a combination of these effects.

Duration of influenza A virus shedding in hospitalized patients and implications for infection control

OBJECTIVE

To assess the duration of shedding of influenza A virus detected by polymerase chain reaction (PCR) and cell culture among patients hospitalized with influenza A virus infection.

SETTING

Mayo Clinic (Rochester, Minnesota) hospitals that cater to both the community and referral populations.

METHODS

Patients 18 years old and older who were hospitalized between December 1, 2004, and March 15, 2005, with a laboratory-confirmed (ie, PCR-based) diagnosis of influenza A virus infection were consecutively enrolled. Additional throat swab specimens were collected at 2, 3, 5, and 7 days after the initial specimen (if the patient was still hospitalized). All specimens were tested by PCR and culture (both conventional tube culture and shell vial assay). Information on demographic characteristics, date of symptom onset, comorbidities, immunosuppression, influenza vaccination status, and receipt of antiviral treatment was obtained by interview and medical record review. Patients were excluded if informed consent could not be obtained or if the date of symptom onset could not be ascertained.

RESULTS

Of 149 patients hospitalized with influenza A virus infection, 50 patients were enrolled in the study. Most patients were older (median age, 76 years), and almost all (96%) had underlying chronic medical conditions. Of 41 patients included in the final analysis, influenza A virus was detected in 22 (54%) by PCR and in 12 (29%) by culture methods at or beyond 7 days after symptom onset. All 12 patients identified by culture also had PCR results positive for influenza A virus.

CONCLUSION

Hospitalized patients with influenza A virus infection can shed detectable virus beyond the 5- to 7-day period traditionally considered the duration of infectivity. Additional research is needed to assess whether prolonging the duration of patient isolation is warranted to prevent nosocomial outbreaks during the influenza season.

Decline in pneumonia admissions after routine childhood immunisation with pneumococcal conjugate vaccine in the USA: a time-series analysis

BACKGROUND

Routine infant immunisation with seven-valent pneumococcal conjugate vaccine (PCV7) began in the USA in 2000. Although invasive pneumococcal disease has declined substantially, the programme's effect on hospital admissions for pneumonia is unknown. We therefore assessed the effect of the programme on rates of all-cause and pneumococcal pneumonia admissions.

METHODS

Data from the Nationwide Inpatient Sample, the largest inpatient database available in the USA, were analysed with an interrupted time-series analysis that used pneumonia (all-cause and pneumococcal) admission rates as the main outcomes. Monthly admission rates estimated for years after the introduction of PCV7 vaccination (2001-2004) were compared with expected rates calculated from pre-PCV7 years (1997-1999). The year of vaccine introduction (2000) was excluded, and rates of admission for dehydration were assessed for comparison.

FINDINGS

At the end of 2004, all-cause pneumonia admission rates had declined by 39% (95% CI 22-52) for children younger than 2 years, who were the target population of the vaccination programme. This annual decline in all-cause pneumonia admissions of 506 (291-675) per 100,000 children younger than 2 years represented about 41,000 pneumonia admissions prevented in 2004. During the 8 study years, 10,659 (2%) children younger than 2 years admitted with pneumonia were coded as having pneumococcal disease; these rates declined by 65% (47-77). This decline represented about 17 fewer admissions per 100,000 children in 2004. Admission rates for dehydration for children younger than 2 years remained stable over the study period.

INTERPRETATION

The reduction in all-cause pneumonia admissions in children younger than 2 years provides an estimate of the proportion of childhood pneumonias attributable to Streptococcus pneumoniae in the USA that are vaccine preventable. Our results contribute to the growing body of evidence supporting the beneficial effects of the pneumococcal conjugate vaccines in children.